A Decade of Discoveries at the Large Hadron Collider

i think it's time to introduce four absolutely fantastic physicists who are going to be telling you all about the four experiments that have been going on deep underground in switzerland over the last 10 years so to start with um i'd like to introduce uh sudan palmer vasarin he's a lecturer at the university of bristol he's worked on the cms experiment at lhc for 10 years having achieved his phd at royal holloway university of london working on the bar bar experiment at slack in 2010 if you just google barbara and slack you can find out what those are but i think he'll also tell you later um so secondly we have barbara i hope i pronounced that correctly she's a researcher at the laboratory nationale di frascati of the national institute of nuclear physics in italy uh scientific activities in the field of high energy experimental physics mainly studying flavor physics through participation in the chloe experiment at lnf and the lhcb experiment at large hadron collider from 2011. thirdly we have another italian moniker donofrio she's the team leader of the liverpool group at the atlas experiment at the lhc previously she started her undergraduate at the university of pisa and then did a phd at the university of geneva in switzerland since 2010 she's worked at the university of liverpool she but she also did a postdoc at ifae in barcelona she's been working on the atlas experiment since 2002 working on searches for new physics in particular super symmetry and i'll cut off the end there it just says and dark i think that would be dark matter but if it's dark energy i do apologize and finally uh our fourth speaker is jan fitter glossaring house he's section leader of the cern alice particle physics and performance group and the alice analysis coordinator he achieved his phd at the university of munster in germany in 2009 he's worked at cern since 2006 and has been a staff member since 2012 so please welcome all of our panel so firstly i'd like to start with jan really and that's just the real basic question what is the large hadron collider where is it and what does it do yeah thank you very much martin so the lhc the large hadron collider is the largest particle accelerator and collider in the world and let me explain you a bit what that means so the name contains the words large hadron and collider so let's dissect this a bit so large is easiest explained the lhc has a circumference of 27 kilometers and is located about 100 meters below the ground of switzerland and france and in this photograph you see the geneva area with cern on the right the lake of geneva and the alps in the background and then you see this yellow circle which is the lhc and you also see it's four large experiments indicated cern is directly on the border between switzerland and france and it is partially in both countries and so is the lhc the name lhc also contains hadron not only large so this is a category of particles made of quarks and in practice up to now out of all the many hadrons that they exist the lhc has accelerated mostly protons but also the ions xenon and lead for short periods so lastly what is a collider so a collider is a very complex machine which accelerates particles to a very high speed which is actually close to the speed of light when you accelerate an object faster and faster and its speed becomes closer to the speed of light its weight or sp physicists say its mass increases the reason is that no object can fly faster or be faster than the speed of light so when we indicate the speed of something we don't give actually the speed but we use its energy and the lhc which is the most powerful collider ever built accelerate protons up to 6.5 tv and this means 6.5 terra electron volt so for comparison if you remember these old non-flat tvs so this with a which were a bit heavy and and uh seem to have some big bulb inside these accelerated electrics higher than that and that's actually very challenging to achieve so the the journey of the protons in the lhc starts from a hydrogen bottle hydrogen consists of a proton and an electron the electron is removed and then the proton travels to a number of accelerators first we have straight ones called linear accelerators and then circular ones the lhc is the last circular accelerator through which the protons travel why are those actually circular well it takes time to accelerate protons to such an energy so they do travel about 11 000 times per second around the ring you you see on the image and accelerating them takes about 15 minutes so you can imagine how often they have to go around until they have the speed we want and we have to keep them exactly in the same spot all the time for that we need large magnets and otherwise if you would have not a magnet the particle would just travel straight so one of the main elements of the lhc are so-called dipole magnets it is uh one about 1 200 of them and you see here a picture where this blue element on the left is a dipole magnet and you see here the lhc tunnel and how it is at the end of the picture you see this slide bending around the ring so on the right side there's some space left what's this for well this is actually to go to the place where you may have to work or repair something or bring something and this can be a few kilometers sometimes as there are only x eight access points to the lhc ring so in order to operate these dipole magnets have to be cooled so that they can be superconducting and they have to be cooled to minus 271.3 degrees centigrade which is very close actually to the lowest temperature that can be reached at all which we call absolute zero and um just as a fact it's also colder one degree colder than the universe so if you imagine we would be alone in the universe if there is no alien species somewhere which has built a similar device than the lhc at cern and in the lhc we have created the coldest place in the universe which i find kind of quite amazing the lhc itself consists of two rings so one for particles traveling clockwise the other four particles traveling anti-clockwise and once they have reached their final energy these two two particle beams are still together into collision in four collision points where the four large experiments are located so we have alice cms lhcb and atlas and you will hear more about that later a collision is then twice the energy of the single beam so if you have 6.5 db protons you reach 13 tv collisions and once they collide we produce millions of collisions per second which then the experiments inspect and eventually record for later analysis we provide them continuous collisions for about 10 hours before we have to fill new protons and typically the lhc runs 24 7 throughout the year you have a number of trained operators and engineers work on that and you can imagine they really have to do do a tremendous job because the machine is so sensitive that it has been adjusted even to the face of the moon depending where the moon is due to its gravitational force the length of the this 27 kilometer long ring actually changes by about 200 micrometers so why do we need such a device to produce such large energy collisions so this large collision energy enables particles to be produced which have not been seen before and can then answer some of the open puzzles which you have in particle physics so that's i mean i'm absolutely fascinated by by that change just use the moon that's amazing so we can understand the questions that you're trying to answer at the lhc but um barbara would you be able to give us a brief summary into particle physics and how we sort of think the world is made and why why that model isn't actually you know we don't think that model's correct uh yes yes we maybe we should start from very ancient time maybe the greeks the idea that the reality among us is made of small bricks and so you need just a few bricks to describe all around us and this idea okay went eden for many centuries and jump up again in the 19th century when the idea of atoms was uh brought to the uh up the scientists and the the idea of very few elementary particles uh was in some sense destroyed by the number of atoms that they were they were finding so if we look sorry uh to this uh plot of it's not a plot but the notes uh of sorry why okay this on the on the left is uh the notes taken by mandela jf was trying to trying to organize the about 60 elements known at that time about 150 years ago to find some regularities because he had the idea that there would be something more deeper more profound and now we know how and up this is the periodic tables of the elements and this is a fantastic but having about 120 elementary particles is and was too much and at some point the idea uh arrived that all the these varieties of atoms comes from just a few particles so it seems like a dream you can just have one proton one neutron one electron so three kind of particles and this could apparently explain the variety of this table and this was around the the third in the 30s or the 20 20th century and apparently it was a dream but at some point uh there was a new particle discovered by chance there was a physicist isaac rabin saying ordered that because was a just an electron just 200 times more heavy than the electron this was being found in the in the cosmic rays it's called muon and this was really strange because uh uh this one was not needed for understanding the the the word uh and the periodic table and all the experiments but this was not the the first new particle in fact with the passing of the years many many were discovered in particular in between the 1953 for six years and until 1963 uh about 60 new particles your new address were discovered in the cosmic rays and in the accelerators and they were similar to the protons so so-called address and no no way of uh considering them elementary and likely the new idea to build a new table this arrives many many steps in fact now we have this fantastic table with really few elements at least compared with a periodic table and i could speak for hours describing the discovery of each of these each time has been an adventure but let's contin concentrates in the first column so we have uh two kind of quarks the up and down an electron and a neutrino and this is enough to explain all the universe around us essentially what although that we can see is made by this uh these uh elements in particular uh the proton is made of two quarks of up type and three one quark of uh down type so it's just uh three quarks um together the other particles so we have other four quarks and other electrons behavior electrons are not needed for to explain the the world around us we just discovered them on the right instead you have not the bricks but the the connection the media we call mediator so the particles that allow the one on the left to interact among among them uh we start we have the photon which is say responsible of the charge interaction the well-known electromagnetic force then the column on the on the on the middle which are the mediator of the weak force is the thing that uh if you want to keep the stars and the sun burning and giving us the energy to to to live and on the right the glooms that just keep the cork together and in particular keep the protons that we need to exist there was a missing part uh because all this fantastic uh uh list of particles that is called the standard model uh in theory uh doesn't foresee any mass so all this party also been massless while in the experiments we we they were finding a different value of masses and at some point in 64 two different group of people so peter x and angular brew to people from france at the idea of how to give mass also in the theory and this is important because at the end the theory must describe the reality and this was the idea of the exposure and it is very interesting to see this chart prepared by the economist when the x has been discovered and this is really interesting to see the time taken between the theoretical explanation uh so the blue line the vertical blue line for each particle and the red one then the the time when each particle has been discovered and so what we learned from this table is that it takes it takes some time between the idea of something and finding and be sure that this exists we have some surprise the third line is the moon where first it has been discovered and then we say ah okay we have to put in the theory and then all the others and the the last one uh the last two that have been discovered has been the top quark and the town neutrino so the aviar particle of the this uh this uh this table and the very last was the famous expo boson and it uh took something like 40 years between our idea of how to give mass of all the these particles and i will be sure that this mechanism could uh could work and even if the standard model is really fantastic and is working perfectly we know we know that is not enough really and so we have to go on that's fantastic barbara so now moving on um so we know that the lhc is really helping us to get to not just it's not it's not just like a science experiment where you know you're sort of mixing things but you can't understand how the world works this is really digging into the fundamental sort of fabric of how of how the laws of nature work and how the universe is constructed so so what what do we hope to find by by doing all this and and what do we hope that we can add to the standard model well hi so yeah that's uh well that's really true i mean um we can really do a lot of things and with with the lac and um and we want to know more because i think it's fair to say the more we uh we dig into things and the more questions arise and the more things we want to learn and and certainly yes as barbara was there was inferring yes this thunder model is is clearly very successful to to explain our daily life but we want to know more because we want to really understand uh how we got here and the the how the universe has has become what we see around us and perhaps i mean i i have um i i wanted to kind of use this beautiful picture that i mean it's very colorful um and and very instructive actually they managed to concentrate like something like 13 billion years in one plot which is astonishing so uh so if you if you if you look at the in the in the right hand side that's that is basically our today i mean today and our daily life and on the other side is at the moment of the big bang so in the middle there is this this nice evolution in time and why this is relevant for the lac is because when we look at the stars we can definitely are from today we can we can go and understand the history of the universe up to a certain point which is indicated by that that vertical line but then if we want to understand what happened before so really really what how we got from the explosion to to to deny today to the stars and galaxy um we do want to study and we want we do want to go back in time and now if you if you look attentively at the at the slides you see that that on the top uh on the top part there is an lhc protons and lac heavy iron and you see at the energy at which it corresponds i mean that's that's the key point so the universe at the beginning of time was really hot so really a lot of energy and this energy can be recreated and reproduced at the lac of course we cannot go to the moment zero but we are very very close and so so so with that i mean we can actually produce particles that in our daily life eventually are not we don't see because i mean the building blocks are much simpler but but they can be reproduced at a higher energy and eventually also new particles of which we don't have for which we don't we don't know much um and you were you were mentioning about the the new physics beyond the standard model i mean what we want to understand why we need to go there it's it's actually another an an important chapter of the high energy physics the the standard model is definitely um it's definitely not enough to to explain the history of the of the universe um so even starting just from from from the first moments matter and anti-matter for example should have been produced with the exact same quantity so there should have been a complete symmetry between the two but we are done of matter so somehow the antimatter is is gone and of this matter that that the reality of the matter that compose the universe so we we do not know everything and in fact i mean when you look at the nice galaxies and stars that there is something in the middle we know from from from from gravitational measurements so that cosmological measurements that there is some kind of matter in the middle that it's dark that we don't see and that's the dark matter that you were mentioning before about the thing that i that i have uh worked on and and it's and this dark matter it's actually could actually be something like five ma five times more than the matter um of the normal matter of the standard model so um there are i mean in addition to that there is there is really many more many more open questions that that we have in the standard model like why gravity is so different with respect to the other forces or why there are only three families i mean nobody knows and in principle that's not written anywhere why the neutrinos are have such a small mass in fact that sunder modern doesn't even predict the mass of the neutrinos so so i think in in the last decades i think it's fair to say generations of theorists have really tried to think about very hard about theories beyond the standard model and this theories usually they theorize the presence of other particles usually heavier that eventually were present at the beginning of of in this in this kind of a big primordial soup but they go with the very nice funny names sometimes like super symmetry the sector extra dimension and we'll touch on a few of them but uh but the key point is then that that we as experimentalists we try to uh to really find eventually if there is new physics and if there is um if there is there is any of these theories is in fact to true and so with proton proton collision and also heavy ion collision at the possible highest energy with the lac we can really try to shed some light on the the the the open questions of the of the standard model so that's uh perhaps it's like the beginning of a fascinating journey that we we have started 10 years ago and that is still continuing that's absolutely fascinating monica thank you so much for that so so you've people watching might have heard me say at the start we've got four scientists i introduced four scientists and i said there were four experiments as well um but also many of you might be thinking well why do we need four experiments i mean it's just one big thing surely we could just have one so so sudan if you tell us why do we need four experiments and what do they all do yeah thank you yes so it's uh actually a really interesting question about why we have four experiments and what they will do um so they all provide a unique picture basically of what's going on um in the uh in the in the collisions after they collide at the experiments and the way i say the way that uh the word i use is picture because actually we like to think of architectures as cameras uh a bit like cameras they're taking photos of the collisions after they happen and then we try and study them in detail and try and figure out exactly what happened in the collision and after the collision and you know one of the things we like to we like to think about is to try and get the most out of those collisions the most out of the data and one of the you know if you think about it having four independent collaborations or four independent experiments with all with different teams of scientists and engineers and i.t people and technicians you know they've all got different ideas and so we're kind of coming at the data from different angles and that gives us a much bigger kind of range of ideas to test when we're looking at the data so that's kind of one reason about why we have different experiments another one actually going back to the um camera analogy i'm sure keen photographers out there know that you use different cameras different lenses uh for different types of picture that you want to take um there's some suited better things and some than some others that's also something that we really kind of use with our different experiments because they're not all identical and they're optimized and they're kind of uh suited to different things and that's something that um you know i can talk about now and try and show you as i go through them so the first ones i want to talk about are actually what we refer to as gpds or general purpose detectors um there's two of them atlas and cms these are the largest detectors um at the lhc um when i say large i mean large atlas is 46 meters in length and 25 meters high 25 meters wide uh weighs 7 000 tons so you can uh well i'm not sure if you can imagine but it is a really big piece of equipment um and then the other one we have uh is cms as the second gpd um it's actually a bit smaller so it's 21 meters long 15 meters high 50 meters wide but it actually weighs twice as much as atlas it weighs 14 000 tons and so that's where the c comes from in cms because it's kind of compact and dense um the gpds are there to study a wide range of physics you know from things like the higgs boson which you may have heard of to dark matter and kind of even more exotic things than that as well as kind of more standard model type particles things that we already know exist but we want to find out um more about them um so those are the gpds if we move on to the other experiments so we have two that actually are not so general but they're a lot more focused on specific physics um so we have one here which is called lhcb and i think it was uh monica or his name was barbara that was talking about the difference between mata and antimatter and this is really what this experiment is designed to look at those small differences that we have between um mata and antimatter and it does this by looking at a a particle called a b quark or a beauty quark that's where the b comes from in lacb so it looks at these types of particle in a lot of detail and then the last experiment uh is uh called alice and that's the last one we'll talk about now this is also a kind of specialized experiment and um as jan was saying some part of the year we don't actually collide protons we collide heavy ions or lead ions which are essentially the nuclei from elements and the reason we do this is to try and recreate some of the conditions after the big bang where a really interesting state of matter um existed called a quark gluon plasma now yan will actually talk a bit more about that later and it's really interesting but um this is what this experiment alice's is really designed to study now they although i've said they're um quite unique they're also quite similar in some ways as they work on similar principles you know there's there's things like um trackers they have trackers these detectors um so all of the experiments i mentioned have trackers these kind of map the trajectory of particles they also have calorimeters which are designed to measure the energy of particles they all have really powerful magnets the reason they have magnets is that by by having a magnet and charged particles that are in the detector will actually bend as a result of the magnetic field and this tells us quite a lot about the particles it tells us for example whether they're charged or not um charged particles will bend and particles with no charge won't but it also tells us a bit more than that um if we look at for example one of the um particles and as it goes through a detector let me just share that this might give you a better idea of how how the different bits of the detector kind of work together to try and help us identify them and find out what's going on in the collision so this is a just like a transverse slice through the detector and the collision will be happening on the left-hand side and if you look if you can see on the kind of uh bottom of the bottom of the um left-hand side there's a red curved line so that's actually the path that an electron would take uh through the detector so you you can see that it's actually curved and that's because of the magnetic field that's applied um and it stops in the electromagnetic calorimeter where we measure its energy now whether you can see at the top there's like a faint blue dash line so that actually represents the path of a photon and um a photon is not charged and so that's why it's not uh not bending in the magnetic field so we use these types of we use the detectors all together and we come up with our picture of what actually happens um in a collision now one thing that is quite interesting i don't have here on this slide um is that some people might not know that all these collisions that are going on we can't actually um store them all we can't store all the data from all of them and there's a couple of reasons um one is just a huge amount of data we can't physically get it off the detectors and analyze it and the second reason is not all of this data is actually interesting for us and there's a lot of data that we kind of won't learn that much from and so we want to try and get all the interesting data um in our kind of you know analysis basically when we look at it so what we do is all of the detectors that i mentioned all the experiments they implement what we call a trigger system which is like a filter system and so what it does is it decides whether or not an event is interesting or not and then if it is interesting it kind of saves it for us so we can look at it um later and analyze it um in detail now one of the fascinating things about these trigger systems is they only have about three millionths of a second to make the decision to store the event or not so you can imagine to kind of make a decision on that kind of time scale you need to use quite um robust and reliable electronics and that's what we do at the lhc so i hope i've managed to give a picture of all the experiments and also try to kind of give you an understanding that there's such huge endeavors um that we need really large collaborations to kind of make everything work and we have thousands of people from hundreds of institutes working on them and all working together really to try and get this endeavor to be as successful as possible that's fantastic thank you so much sudan we've actually now got a short video so obviously we've been hearing a lot about these detectors and we've seen a few slides as well but we've actually got a short video from the alice detector which is not launching and works on um but uh that should give you a bit of a better idea of uh of what it looks like down there hello i'm dr pipperwells and i'm standing in the huge cavern that houses the atlas experiment the floor of the cavern is 100 meters under the swiss countryside near geneva and the detector completely fills it it's it's 44 meters long from this end where i'm standing to the other end at the far side of the cavern and the detector is 25 meters tall the particles from the lhc meet at the exact center of the detector and the high energy from some of the protons can get converted into new particles that fly out through the detector layers the innermost layers of the detector are very thin and very high granularity they are to measure the tracks of charged particles and find the points of origin as they merge from the collision area then outside this inner tracking detector is a set of detectors called calorimeters that means energy measuring detector they are much denser they have things like layers of lead or iron between the sensor elements now most of the particles actually get stopped in the calorimeters but a few actually managed to escape in particular muon particles that are charged particles that interact weakly in the calorimeters and can fly all the way through so the outermost part of the detector is to measure the tracks of these muon particles the sensors are arranged in cylinders around the interaction point and then the ends of the cylinders are capped to make sure that we catch all of the particles so the thing you can see behind me is the big wheel that caps the end of the muon detection system so that's giving you a little bit of an idea of what it's like down there and what one of those big detectors actually looks like in real life so uh as we've sort of been doing this event we've been saying it's been 10 years uh since this large hadron collider has been opened and i'm sure many of you watching if you say you know what's the large hadron collider what's it for two words will definitely spring to mind and those two words are higgs boson so uh sudan i wonder if you could uh tell us a little bit about what the higgs boson is and why it's important yeah absolutely um so as uh i think barbara was saying um when she was describing the kind of standard model we had this kind of really great model um and the only the problem or one of the problems with it or one of the major problems was that the uh it wasn't able to give mass to the particles and we we knew that the particles did have mass so this was like a pretty big problem for us luckily in the mid 60s um we we had this team of scientists so um robert um browsed um francois francois anglair and peter higgs who came up with this theory to to solve this problem and as a result of their theory they predicted the mechanism predicted something called a higgs field and an excitation or a manifestation of this higgs field would be a higgs boson the way i like to think about it is the higgs field is kind of like the ocean and uh a higgs boson is like a wave on that ocean so it's just a little kind of blip a little excitation so of course uh since then since then we've been trying to find this particle because obviously it would solve a lot of questions that we have um and will prove this theory and so on the fourth of july 2012 the atlas and cms experiments announced the discovery of a particle which very much uh resembled higgs boson and uh i can tell you that was a really kind of momentous day for science um here's a picture of the auditorium and you can see it's completely packed um higgs himself is there somewhere as well as uh angler um and yeah it was you know it's one of those kind of crazy days where it was uh there was a real buzz around the place you couldn't really walk uh you had to queue up to get into the auditorium out colleagues who queued up for several hours just to get in and hear the announcement of discovery and so yeah it was a really kind of great moment um just to maybe talk a little bit about how the discovery kind of occurred well i've got a couple of graphs here that i'll explain um firstly though the higgs can decay in in in numerous ways it can be produced in numerous ways and decay in numerous ways one of the ways that we were first trying to detect it was through its decay to two photons so it's something that we something that we refer to as gamma gamma gamma being a photon so what we did was look at um events where we had two photons and then try and see if there was anything there that didn't agree with our kind of current expectations and that's what you can kind of see on these two plots the left one is from atlas and the right one is from cms now the kind of smooth lines which are kind of going down smooth distributions which are dotted actually um that's the kind of background line so that's what we know to exist at this time and anything that deviates from it we can kind of you know infer that is is something new and the black points on these plots represent the actual data that we took um at the lhc and you can see at two points on the left and the right remarkably at very similar places um you can see these black points start to go up a bit and you can see we've drawn a red line through it to show the little bump and this is actually the higgs boson decaying to two photons so this is um a common method that we use to search for new particles is is something we call bump hunting so we kind of look at the background that we have the things we know are there and then we look for deviations from that to see if there's enough deviations from it for us to kind of really claim that we can that we can see something now this was um you know a really exciting time as i've said and you know this work result resulted in the nobel prize in 2013 uh going to peter higgs and francois anglair unfortunately the third member of the um of the team had died at that point and and kind of contrary to this being the the kind of culmination or end of a of an endeavor it was it was it was more like the start actually it was like the start of a new area of physics where we could look at the higgs in detail really study its properties and try and understand as much as we as much as we could about it and we've been doing that ever since um in fact only last month um we we saw evidence of a of a new way that it decays which is higgs to two muons um barbara talked about muons and cosmic rays earlier earlier in the panel and so we saw evidence of the decaying to that so we're learning things about it all the time and there's still a lot more that we can learn about it i mean it's still a new particle um and i like to end this really by saying that you know we've got to continue studying the higgs in as much detail as we can because after all you know if you think back to the electron which was discovered in 1897 where would we be if we stopped uh to stop to stop studying that when it was discovered so uh thanks for that uh sudan but it it's not just the higgs boson is it i mean there's there's been plenty of other science that's been going on uh since that time monica i believe you're gonna tell us a bit about that yeah definitely yes i mean actually there has been uh i mean many many uh papers i mean i think that it's it's really thousands of people that are cms but also lscb and alice have published so it's it's definitely really a lot of things and i mean of course in like a few minutes it's it's very hard to say uh to list all the achievements that that we have we got at the uh at the lhc experiments and in particular i mean i'll i'll probably try to illustrate a few things from from from athletes and cms and maybe i can um i can attempt now uh the uh to show uh um something that perhaps is going to be difficult to um i mean let's see if i manage to explain this so i think that it's fair to say that um i mean there are many many measurements and many many searches for new physics so that we have been doing these the experiments that we are still doing now and um even at the beginning from since the beginning 2010 when we started taking data uh it was it was really a lot of work from a dedicated physicist to understand the characteristics and to to calibrate the detector and which worked really really well the detectors and um and then we started to to to take with the data taken and we started to try to rediscover and measure the standard model and the standard model in in really the best precision possible so what this plot is is that so on the horizontal line you can probably not see it but it's like many kind of processes that you can have in the standard model and so the the on on one side on the left hand side is is the uh all the processes with the w of z boson so the carrier of the weak force and on the right hand side are all processes characterized by the presence of one or two top quarks and why the dinosaurs well because i mean at the beginning i think it was already from 2011 to 2012 when we started to put together all these cloths and all these measurements is that they they look like a dinosaur a little brontosaurus so we called it the dino plot but how does it work so so as i said in the horizontal line you have all the possible events and kind of processes that where these particles appear and then on the uh on on the vertical line well you can think that all the dots that are close to the head of the dinosaur are events and process that are very frequent and on the tails are all processes that are extremely rare and so with them we can do a lot of things with the one that very frequent we can take the data from this and reconstruct very precisely the characteristics of the sander model particles i mean take the top quark the top cork was is the heaviest of the quark was discovered in 1995 at the fermi lab but it was quite a rare event at that time at the lac we can produce 10 top quark pairs every second so it's really a lot of them and we can really study that with with very high precision and we we have measured its mass at the permeable level and same thing with the with the w boson i mean despite the fact that it was discovered in 84 we are still really trying to dig into the characteristics of this of this and just in in and we we just measured very precisely it's its mass um now i mean if you go to the tails instead there are all very rare process and in fact if you take again the top the top pairs can be produced together with the hicks and i mean and understanding the higgs it's not just only identifying and find it the beautiful plot that that sudan was mentioning but it's also studying all the the the couplings so how the hex behaves with all the other standard modal particles and in the case of the top pair i mean that's a very rare um coupling that you have but it's quite important and in fact i think it was only in 2018 that others and cms have announced the observation of this phenomenon now i mean this is actually a real event that shows you the the green towers are the two photons from the hicks and the little bones in the middle represents the the products of the top so it's it's quite a fascinating um events um but but actually i think that it's also important to say that i mean you you would say okay but what about you you measure the standard model processes so something that you know that is there but of course if you measure it precisely then you can also see if there are deviations from the prediction you can understand if there is a new physics and and i think that um the the searches for new physics is certainly one important part of the physics program of the the gdp experiment um personally i mean so so we have been looking and we are looking for all um possible theories the one that i mentioned at the beginning and personally i have been really involved in the searches for super symmetry and now in a nutshell in this supersymmetry there are new particles that are so-called superpartners of the standard model particle and and some of them they go with funny names so for instance the partner of the top quark is called stop or top squawk and it's very important because this this is supposedly playing an important role in the defining the higgs the higgs the mass for example so we really looked for it from from from the start even where we didn't think that we could we could achieve the results and and uh yes we haven't found that but uh but clearly i mean it's i mean the the the search is still still ongoing and then another thing that uh if you allow me one second the the to go back to this slide say is i mean we talked about dark matter and and clearly i mean dark matter is it can be can be anywhere i mean we we we don't know how it is and we don't know which mass it is so now and in this this figure i think that it's nice because you see dark matter in the middle and all the rest is all the possible explanations of dark matter so each is is a possible explanation of that matter and behind each there is a team of physicists and others in cms that are looking for uh for this this hypothesis and they are trying to to to understand whether this hypothesis is true or or not and and this is not only at the lsc but there is also some collaborative and synergy synergistic efforts also with the astrophysics and cosmological experiment so so it's in a nutshell i think i mean yeah in 10 years we have achieved many things and and on on different aspects so so that's that's certainly uh very uh very exciting i think so so that's and that's only the proton proton part so that's uh that's fascinating thank you so much monica so we've had um we've known we've discovered the higgs we've been learning so much more about these other particles as well and how they decay but you might remember at the start barbara was talking about using the lhc to sort of probe what was going on in the very hot very energetic early universe so yang can you tell us a bit more about uh what what the lhc has told us about uh the birth of uh yeah indeed we also study uh a part of the evolution of the early universe for one month per year we inject lead ions into the lhc accelerate them and bring them into collision now compared to the proton which we discussed earlier a lead ion is much larger and in a collision would therefore create a larger volume with an incredible amount of energy compressed in it its temperature is a about hundred thousand times the temperature of the core of the sun so don't mention this and uh that what happens is that inside this hot and dance matter even protons and neutrons melt into its constituents and um then we have three quarks and gluons which we can study in what we call the quad gluon plasma this is a state of matter that we had already in about 10 microseconds after the big bang so 0.0001 second after the big bang and that's why also at the lhc we sometimes say the collisions are mini banks now this hot and dense volume exists only for a small fraction of a second but during this time lots of interactions between the corks and gluons happen and then shortly after particles are formed from the quadro and plasma which fly in all directions and then they're measured by the detectors so in such a lead-on-led collision about 10 000 particles are produced which require particular care when such collision are studied in the detector so i'd like to show you this image which is the event display of a single collision and each of the lines you see here is a is a trajectory of a particle that has been produced so um this is an image from alice which was built to study the quaglun plasma but you'll see experiments study these collisions and learn from them and by looking at how these particles are produced in which directions they go what type is produced we learn about the evolution of the early universe and about the fundamental theory of physics which is called quantum chromodynamics since lhc started colliding the lead ions a number of important discoveries have been made and i can just pick out two of them and one interesting one is in the area of so-called jet quenching so with the research we did we could show how dense this quad blue and plasma is it is so dense that it actually can absorb the energy of very energetic objects called jets so i have a cartoon here on the left side which shows two energetic objects they're always produced in pairs and fly in opposite directions and depending where they come from in the quaglun plasma only one of them may be absorbed and this is illustrated in the left but that's theoret theory illustration while on the right you see what you actually see in the experiment so here you see in the bottom left corner of this image you see a um see the remnant of one of this object it's still there you see a large blue and red bar well on the other side they're just small ones and it has disappeared also i like this comparison because on the left you see something which actually is only 12 centimeter large so 0.00012 meters while on the right it's the size of the detectors we have at uh at lhc and the size you see there is about 10 meters a second very interesting discovery which we made at lhc concerns concerns an interesting particle called the jape sci this particle is built out of a charm and an anti-charm cork and was discovered in 1974 and it's an interesting object because when it goes through the coagulan plasma it doesn't survive it melts the plasma is too hot so the charm and the antique charm don't stay together so typically in the lead-on-led collision you find very few of them however at lhc there are so many charm quarks in a collision that when the plasmas cool down it can happen that they find themselves again and form a new jape sci so i tried to show you a cartoon here on the left where in the in the in the top left you see you just have one charm in anti-charm quark they're shown here in blue and they once they melt they don't find each other anymore but the situation at lhc is that we have many of them here they are shown with the green blue black and orange circles and then you may just randomly have that some find each other again so the right side shows how we physicists look at this so this is a histogram um which shows you some red points which are higher than the blue points and that tells us there are more types of psi have been found at lhc than at earlier experiments so and this was actually the initial discovery of this so-called regeneration of the gpsi which had before been predicted by theories but not unseen so these were just two examples of the many insights into fundamental physics which we have discovered wow absolutely fascinating thank you so much jan so uh assuming now that we've we've got this information we know how this you know how super sorry we know how the standard model works we know about the higgs boson and we've been probing this the early universe so so now assuming is it enough to say that we now have all the ingredients to build the universe using the knowledge that we have barbara yes or no because many of us mentioned the matter and the matter so one of the big things that happened at the beginning of the universe is that the matter antimatter formed in the same amount and if they form under the same amount then they can in some sense annihilate and transform again in energy and this would leave an universe without matter and without us so we need some difference between matter antimatter and this uh is related to uh something that we physicists like a lot that are the study of the symmetries i will not go into details but let's uh let's start thinking to left and right uh we want to assume that the physics the basic laws of physics do not know anything about left and right so they should be the same if we turn just our experiment in the other direction and so and the same is for for the charge uh if we reverse all the charges so the positive and negative is something that uh uh we invented just to call different charges and this was uh in some sense uh true for uh for many many uh years many centuries voila but at some point uh this fact that uh left to right and are equal for basic low physics and the plus and minus charge are equal was not more true for a kind of uh interaction so it was true for a strong interaction the one thing taking all the quarks all together in the in the particles but no no it was not true for the weak interaction that the one responsible for for the sun was eating this before and so this is called parity uh violation uh this means that the weak interaction uh changes if we change the orientation and the charge of the system this is a bit strange but this has been confirmed first and found first in a kind of particles called cam in the 64. then again in a particle containing uh a big work that is it's called beauty particles and this was a the major success of the babar and bell experiments one us and one in japan and these two were related only to quarks of down type while recently in elizabeth has been found the sap violation so this is the way in which we call the difference between matter antimatter also in charm decays so in particles containing a cork of archetype and this difference can be an hint for the existence of our universe because tell us that the matter antimatter are different but it's not enough we are out of something like eight nine order orders of magnitude so we have to continue to search and what we are doing uh now they seem the real the fact of the different the existence of antimatter is not uh appeared while studying the beginning of the universe was a kind of out of the blue when one of the founder fathers of the quantum mechanics dirac was trying to understand the electron the basic normal electron and he was able to find a theoretical way to describe the electrons only introducing a a partner with the opposite charge this was really a kind of mathematical artifact and it was in doubt if public or not this is result but the end he decided to go with the publication and so he assumed he he put eyes that existed an anti-electron and this was found a few year years later in the cosmic rays again so this is fantastic idea of find inventing something to solve a theoretical problem the description of the electron and then finding this invention in in real life and this is not only this is fantastic because it is an idea of us and then become becomes real but while us scientists continue to study mater antimatter difference until nowadays uh this in the 60s uh became a way to uh diagnosis and cure cancer so the idea of injecting i try to be really basic trying to inject some antimatter this is possible using some nuclide in some glucose enriched by a special kind of isotopes so we can inject antimatter in the body of a person and then use this to agnostic or cure a cancer obviously this was not the idea of dirac or none of us is studying physics or is trying to understand physics just because then we can use this but this is something that happened many many times in many areas of the science and we hope that this will continue with the future development and detectors well thank you so so much barbara and that's a really important point i think that so much technology and other things has spun out of of what's been created at the large hadron collider yeah it's it actually does end up benefiting us all even despite the uh the increased knowledge of the standard model and so forth as well um so we've talked a lot now about what's happened and what's been going on and what's happened in the last 10 years so now i'd really like to move on to the future so um you might have heard that the large hadron cloud is going to get upgraded so i think we've got a short video that will show you a bit of the upgrade process [Music] [Music] so uh just incidentally i think uh there is there probably are pantone colors for cern blue and cern yellow because they kind of crop up in a lot of these videos um can you tell us a bit about what we were watching though yeah sure i can't tell you about the colors but um yeah you were just seeing some um upgrade work being done on the lhcb detector uh which is one of the ones um we mentioned um earlier so one of the questions that comes out from this is you know why upgrade what what do we mean by upgrade and that's kind of some of the things i want to talk about now um to really understand that we do need to understand a little bit the way that the lhc operates and in particular the fact that we run in cycles so we kind of run and we take proton data and heavy iron data for about three years four years and then we have maybe a two year shutdown and we do this kind of repetitively and the reason that we have these shutdowns is because we're really dealing with such a harsh environment in terms of you know the the equipment is uh under very very severe radiation there's a very strong magnetic field 100 meters underground i mean it's not easy to get in and replace things and so we kind of try and accumulate uh some of the problems and then we kind of go in uh in a long period and where we can really get to the heart of the detectors and really make changes that we need to and of course technologically things will obviously improve and we want to try and get the best stuff in there so that we can get the best physics out um we're actually in the middle of a shutdown at the moment we're in what's what we call long shutdown 2 or ls2 um and then that will run until um the start of 2022 and then we'll start taking data again for three years so in fact the next 10 years is going to be really exciting so we're going to have a data taking period 2022 to 2024 where we're going to try and uh we're going to add to our data set and hopefully discover some interesting stuff and then we're going to have another long shutdown imaginatively called long shutdown 3. so this is actually quite an important shutdown because in long shutdown 3 we're going to really um change a lot of things so the lhc itself is going to replace and upgrade huge numbers of its magnets and its core components and atlas and cms in particular are going to essentially rebuild their detectors the reason that they're going to do this is because of the lhc upgrade we're going to get a lot more data than we get now and therefore the environment is beginning is going to become even more difficult for us to actually um to deal with so if i show you uh one of these pictures so this was actually one of the the higgs event displays which just basically shows a visualization of the detector and and as you can see there's a lot in the middle you can see a lot of lines there's a lot of overlapping stuff going on now if i showed you what that looks like when we have say 80 overlapping collisions this is what it looks like and you can see to try and sift through all those things and actually figure out what's interesting and find what we actually want is not uh not an easy endeavor and this is actually going to almost double when we go to our our next big upgrade after long shutdown three what what we call a high luminosity lac so you can imagine that the detectors really have to be upgraded to deal with this type of environment and that's something that where you know really drives us forward the fact that we're going to get all this extra data there could be loads of interesting things hiding in it and we want the best the best detector that we can actually have at the time to get the most out of it one interesting thing uh that i should mention is the amount of data we're going to get after long shutdown 3 is actually so much bigger than what we're getting now that right now if we talk about the whole data state that we expect to have in the next say 15 to 20 years we've only got five percent of it now so actually a very small amount of it that we have to find new physics or to to do all the studies that we want to so the fact that still 95 left to come uh really drives us on and really makes us excited about about the next 10 15 years to make sure that we can actually address it the best we can that's absolutely fascinating sudan and what's interesting actually what you were talking about there is a lot of people at home will be familiar with doing upgrades on their own technological setup usually that would be their kind of pc or you know gaming laptop or whatever it is they use and probably the thing a lot of people will upgrade would be their graphics card um so i think barbara you're going to tell us a bit about how the lhc scientists are effectively doing the same thing uh in fact sudan mentioned a couple of very important things for for all the four experiments that is we have to trigger so we have to select the events and we are going to have more and more data more complicated and for selecting this data and analyzing we use both electronics and then so a kind of fast selection it's typically called the trigger system and hardware trigger system and uh also uh then we analyze the data using the software the the cpu and uh already in this uh long shot down to uh all the four experiments are starting to think how to improve these uh these uh this capability of of uh analyzing a lot of data and the one of the idea okay for imperfectory for an acb is a uh is a major change because the experiment removed completely the artwork trigger and the trigger become only software so we are going to analyze something like 30 megahertz of events just using cpus or gpus so the collaboration and together with the other all the four trusts start to understand if it was better to continue to use cpus like we did in the past or start to use the gpus and gpus as a different approach in calculating uh thing things for us are the pro the characteristics of the event that we we collect and at the end we decided to start to go with gpus and it's fun that we had to uh obviously to buy this and to find the the right gpus and we so we go to the commercial one and at the end we have a lot of gpus and one of the problems were to try to test this uh 24 hours seven days and some point we had the idea of inviting some teenagers to to work just to play maybe fortnite or something like this on our system but then we decide to test in a more reliable way and so each of the four experiments start to use gpus this is an important step because gpus are developed for other goals outside physics and this is true for for many many aspects of the computing the energy physics uh on the one end is driving the advances in computing on the other end is start to use advances made outside science just to have better performance and so we are going to to use gpu and once the events will be analyzed and so we will know how uh which event we had to write on disk then we had to manage and sudan was mentioning the amount of data that the four experiments collect is only a tiny fraction of what we are going to collect in the next years and so another big problem is how to store where to store this data and how to analyze them and for this uh has been created many many years ago the grid which is a kind of network of uh storing storage and the computer all around the world and so we can just use this enormous facility that is hosted in many places in many institutions around the world and so each of us can analyze the the data just sitting on on his or her laptop using this enormous facility which is maintained by a large community of experts and so is again a good exam example of collaboration to make the science uh advance fascinating but of course as sudan was saying uh earlier it's not just the sort of uh technology and the sort of processing power that's being upgraded it's the actual sort of hardware and the luminosity as well so yeah and i believe you're going to tell us a little bit about the sort of hardware upgrades that we can expect absolutely so all experiments are undergoing major hardware upgrades uh for instance uh alice and lhcd currently work on improving yeah and can just try to turn your camera on i think it's gone off hold on yeah i'm sorry i think there's a problem with the with the bandwidth oh it's okay to turn it on as soon as it works again so yeah we see here even our technology doesn't always work so um i was saying um as mentioned before all the experiments undergo major hardware upgrades so for example allison is we currently upgrade uh such that we will be able to take 100 times more data once that is series starts in 2022 and atlas and cms are preparing for large upgrades in about five years and they will build almost their whole detectors with cutting-edge technology so these uh detector upgrades are based on a significant detector r d so research and development which actually happens at cern and the collaborating institute so institute so one example of this r d which i would like to to speak about is the one on so-called monolithic active pixel sensors so what uh is hiding behind this uh complicated world a complicated device well an active pixel sensor most of you actually have most likely even several so the camera in your mobile phone um actually contains a pixel sensor and this is used to capture images and we use the same technology to trace particles just we use lots of them and very advanced self-developed sensors for example for the alice pixel detector 24 000 of those sensors are used so this you can imagine this is like a huge digital camera which would have 12 gigapixel or 12 000 megapixels so i like to show you here on the left top side which is shining in golden part of this detector which will be actually installed in the next few months so this is still in the clean room and will then be lowered into the cabin and the sensors that are used in such technologies you can just buy them in industry they're customly designed for the luc experiments by engineers electricians etc etc who work with us and such designs often push the technology limits so this monolithic active pixel sensors are new kind of pixel sensor which is produced in a in a ship factory as a single chip while all the present technology always needs two different chips which have been glued together so doing this in one ship allows us to produce extremely thin and light chips for example the ones which are in the detector on the image are 50 microns thick so 0.0005 meters and that's thinner than a human hair and we don't stop there so the currently ongoing research and development plans to reduce this to 20 microns and to curve them and if you imagine you could have them curved then you can actually bend them around the collision region and um when you do that you you have a much better coverage and detection of the particles that are produced and there is a message i would like to give you because i was personally involved in this exciting research and that is not everything happens uh with lots of technology in a lab with a white white coat so these three images which you see in the bottom here was an idea of a colleague who said okay let's try to bend this sensor and this was done with a with a double-sided tape roll which you see here so from the left to right you see how this is rolled over the the actual pixel sensor and it glues on it and it's curved after that so um this was an exciting moment i took these pictures myself and of course you can imagine that that is not something that then we can connect electrically electrically and used but it was the first demonstration of this bending and in the top right picture you actually see now how this is connected electrically and put in a test beam and actually used for detection so the aim here is to make these much larger up to 20 centimeter large and then bend them around the interaction region and this allows to make extremely thin detectors we actually call them massless detectors with a smile and we hope to install such a device for the first time in the next shutdown of the lhc so in about five years from now and who knows maybe such sensors will also in the future be used in my mobile phones or other devices wow that's absolutely fascinating thank you ann so we've been doing the stream for about an hour so we are slightly over running so sorry about that but i think we've now reached the point that probably everyone's been waiting for right so we've talked about the history of the lhc we've talked about the standard model we've talked about the upgrades we've talked about the pricing power the hardware so i think now this is i was going to say this is the 64 000 question but uh i think the lhc's already cost 4.75 billion dollars so this is the 4.75 billion dollar question what are we actually going to hope to find in the next 10 years what particles or other things or do we hope are out there monica okay so i'll try to answer this this mommy i don't know how many billion questions um i mean many things let's see this is the short answer i mean there is there is an enormous physics program from from the experiments it's it's really and this is involving really thousands of physicists i mean and and it's it's it's quite a big uh program and it's very very exciting i mean starting from now jan already showed that just now the the alice upgrades and analysis actually hoping to to do more studies and more detailed studies on the port blue and plasma and to understand it's it's a how it really acts and and it's inner components but perhaps i mean very long program of future things is that the gt gdps so atlas and cms and also lscb um i think one key point that maybe i mean taking up from what sudan was saying i mean that that yes we are planning to increase a lot of the data sets so so the the part of events from which we are looking for things i mean that is a very important concept people usually think about the energy the very high energy but even the statistics i mean how much data we have it's very important because if we have to to tackle very rare events i mean exotic very exotic events we have to have a lot of data and and this is true for in order to improve the precision but also in order to find new physics and new physics that could lie even in the newly understood the higgs sector so so for the higgs i think perhaps the the key example is is the fact that um at the high luminosity lac we would be athletes in cms would be able i mean to uh to to observe i mean or at least to declare evidence of the so-called di-higgs production so if it's harder to find a higgs i mean you can imagine when you have the pear production this is an even rarer process and and this might seems uninteresting but it's actually a very very this is the ultimate test of the standard model and if we find the deviation there that's definitely a sign of the of new physics and it could even tell us where new physics is lying and of course i mean with with more data and higher energy and we have the possibility to explore uh i mean eight to ten tera electron volt mass of new particles for instance and we can explore many many new models for dark matter this is something that for which we have just some some hint now but but we'll have more and last but not least i think it seems it's important to say that in all the data i mean in all the events and the studies that we are making uh we we do see that that there are things that that are interesting that we want to follow up because there are little fluctuations and and and kind of uh i mean interesting hints that might turn out to be nothing or might turn out to be something interesting and perhaps i mean maybe barbara you want to say something about the lsb and all and so something like that yes they are not really uh lesbian anomalies because this has been found also by other experiments so uh again is the game comparing theory versus experiments uh results and in the standard model the theory uh says that electrons and muons behave in the same way and also muon and thousands so all the electrons should behave in the same way it's called the lepton flavor universality and it has been i mean found that some difference between the behavior and electron and muon we in the dragon we call the rk class measurement and some difference between the muon and the tongue leptons these have been found by babar embell experiments and then confirmed by lacp this even though many experiments find some evidence and so uh it can still be that the this a normal is this difference between theory and and experiment disappear with uh studying new data lsb and has already a lot of data collected in run two and we hope to publish the results in the next months or years depending on the on the channel but more will come hopefully in in the next in the next rounds and any car in any case both if either if either if confirmed or uh not the information that we will have up with from these anomalies will be important to build which is the uh possible new phases that you was uh hinting and now thanks i mean if i have one more minute maybe i mean i know we are in later but just just one more thing i mean this is this is actually where we are supposed to to look for things i mean you see this is the environment expected at the high luminosity lac for athletics and and cms um but i think i think perhaps also to to kind of ramp up sometimes so we we we yeah it looks like that we are we are um doing things that perhaps we were already doing before uh but the reality is that that i mean it's it's it's very interesting how the more time we pass and the more time we we we get to work with these detectors and the more ideas experimentalists as experimentalists we get to to use and to exploit them at best and perhaps a good example of that if you if you if you can follow me for one second this is a sort of transversal view of uh the typical gdp detector so atlas or cms and now i mean if you remember at the beginning i was thinking about the new particles that might come from dark sectors or other exotics standard beyond standard model theories and it turned out that many of these models might come might might lead to uh to particles that are really weakly interacting with any standard modal particle and might be very slow and they might decay or behave in a in a slightly unconventional way so this is what this this this graph shows that these these particles produce in the center of the collision might give a very very peculiar signature and the fact that we have really spent time to understand our detectors now and that we are planning for for new brand new detectors for the future that we really know a lot and that they are really cutting edge technology as jan was saying i think that it will open even more roots of what what we were thinking at the beginning when starting this this journey so i think that that i would i would leave it there and but just to say that there are many many ideas that are coming up and this is just one of them wow that's incredibly exciting monica thank you so much for that so that uh brings us to the end of the presentations bit but just before we uh throw over to some questions and i've noticed there's been loads of great questions in the chat i've got about about 10 minutes or so i think we can try and put as many as we can to our fantastic panel and haven't they just been brilliant um so i think this is a good question from steve dunn uh i might put it to you sudan because i think you were talking about triggers the most but but anyone else feel free to chip in uh steve asks does the fact that you have to use triggers in the detectors lead to an unavoidable selection bias because obviously you're kind of triggering things that you think are going to be interesting but we base basing what we think is interesting on our standard model um and what about all that data we're chucking away do we randomly take bits of it to make sure we're not throwing away anything important yeah that's in fact a very good question um and question that we ask ourselves uh people that work in the in the community and on triggers uh quite a lot actually and you you're absolutely right we have to be very careful about uh biasing ourselves and we do have certain things that we try and do to make sure that we don't do that we try and collect samples of what we call actually unbiased events uh to try and make you know really using the terminology of the question to try and to try and compare to to make sure that we are we have kind of control samples um to to study basically um another part of that question i think was to do with that yeah yeah are we throwing away things that we don't that we don't know about uh because we're kind of basing our triggers on the standard model again that's really interesting and so you know one of the things that we do to try and combat that is in our kind of triggers we try and have kind of quite loose criteria like quite general criteria and we try and capture as much as we can of that so we're not trying to focus too much on things that we just know um one example of this if i if i have 30 seconds is you know when we there are certain particles that might escape the detector and if they escape the detector um and we don't know about them it creates a momentum what we call a momentum imbalance this is something that we can try and trigger on because it's a signature of lots of new physics not just one particular model of new physics so if we develop a trigger based on say that type of variable which we call missing energy so it's like momentum imbalance then we should um then we should capture lots of things that we don't understand basically so uh we can have a large sample of that um so yeah i mean it's a very good question i hope i've uh answered most of it that was great if anyone else wants to contribute anything or if you're happy for me to move on um so a a word has been coming up a lot in the chat and i uh actually i've just noticed that uh faith and and naka uh in the chat has said it's 2 23 am here so thanks caleb for staying up and i will therefore ask you a question um but a lot of other people have mentioned this uh they mentioned the word graviton um now does anyone want to talk about what a graviton is why are we looking for it what have those theorists come up with um monica would you you've reacted to that one yeah yes i can go with that so so okay the graviton i only mentioned uh the word extra dimension but i didn't mention the gravity yeah of course um yeah the graviton is let's say it's the equivalent of the photon for the electromagnetic force in the case of gravity and but it's it's very different from from that because gravity is very different so um now the graviton can have depending on the hypothesis i mean it's not it's not really part of the standard model so you have to go beyond the standard model to to to to try to to to implement the graviton in the big picture and so depending on the model actually might have different characteristics and you might actually find it or look for that search for it um picking on different characteristics usually the graviton turns out quite it's it's quite a big important part of the extra dimension uh theories so basically instead of thinking that there are many new particles or new symmetries you think that what we see of our universe is only like the manifestation of the three plus the three dimension plus time and that there are a small other smaller dimension that we don't see in our daily life but the graviton sees them and and then and then it escapes also somehow it's produced it can be produced at the lhc and then it escapes detection so one of the character the possibility to catch the graviton is to study event as that are triggered by this unbalanced energy that sudan was saying or the other on the other end you can find them as a resonance and this is one of the things for which the high luminous dlac is gonna be great because we can get up to eight to ten tv for these resonances so i mean maybe if the graviton is there we might see it well exciting exciting times so uh you might have expected this but we've had a few people talking about coronavirus um because even the uh you know the pure laws of nature world particle physics is not immune from uh current events so ken stowers or star wars uh don't know how to pronounce that name uh he said if in 1964 antimatter could fix cancer can events in lhe future fix covert and also some other people have been asking in a sort of more present way i mean obviously if there's a global pandemic going on is this not going to affect the plans of the lhc or can you all work remotely or how does it how does it all work uh barbara i don't know if you want to answer that one yes i can comment okay the mechanism by which the antimatter can be used to cure cancer is exactly destroying the the the cancer so the is to put some glucose in the in the blood and this go uh to the cancer because cancer likes very much the glucose a very basic and not an expert but and then uh the release of the antimatter can destroy because antimatter when meets matter electron and positron really produce energy and this can be used to see this uh annihilation from outside this for diagnostic or just to destroy cells with the bad ones so to cure the coronavirus we should understand how to put our antimatter on coronavirus and i think that is not easy but okay we think i can think about that uh for what concern how we manage this obviously cern went in lockdown like many other places around the world and the activity almost stopped we were able to keep essentially the computing center alive so we could continue to work on data uh remotely and in there so we tried our best and then starting from may as long as the activity the activity is resumed this is still difficult because obviously since we are large collaborations with people coming from all around the world even the the the things that we need the electronics uh all the experts come all around the world is really tough to put all together now so maybe now we have the expert from uk available but now the other expert from german germany are not more available or the some pieces arriving from china is late so we are really learning how to uh to manage this this is more for the uh construction part that is the more important part during ls2 while for the analysis data probably we were able to to go on almost normally like like without a pandemic on yeah it's uh well obviously it's an incredibly strange and bizarre time for lots of people sorry jan did you want to jump in yeah maybe maybe just to add that because i think the question was also if we had a delay which occurred to this so of course by what barbara described you can easily imagine there's a delay so initially uh lhc was was hoped in a restart next year so now we always say 22 so we we think that there's probably a delay of about three months which happens this and that we're quite happy about that it's not more and then of course one one has to see yeah well i've got you on the screen i noticed that your job title is about analysis of the data uh and tanish was was asking does the data from the lhc experiments does it get like put online anywhere does it get uh you know posted to the web can any can i just as a random member of the public go and look at the data that you're receiving and come up with my own theories yeah that's that's a good very good question so um indeed there is an initiative on going which is called open data so um the idea is to make the data of the hc experiments public so that anyone can analyze them for that you can imagine it's not enough to just give the data out we have because we have very complex software to analyze that you need training to know what is in the data to actually understand you need to calibrate things so this is actually a complex process and it will not happen right away so let's say head start is giving to the physicist working on the actual experiment but the plan is actually with the delay of of a few years of a small amount of data and a longer delay uh for for the full data to make this data sample public and available for anyone who wants to analyze it which is also one of the missions we i mean uh cern is funded publicly so the data the research is all the research that is published is already public and the idea is that also the data should be public for future research maybe i think maybe i cannot yeah sorry go ahead probably i think maybe jan said it but there is already some data which is public which we take which we took maybe in 2011 or 2012 um and so if people are you know interested to already there is some which is available but like yeah i said there is a delay so this is not data we took you know last year but if you google um uh certain open data i'm sure the first link will be the the one that tells you the information that you need to know on that yeah i just wanted to say this and in fact i mean even with with some of the students undergraduate students so we we also do like uh i mean for for a university and educational purpose we we use this open data to find the higgs or or i like to small proto so it's it's quite interesting so they can be used already so i think we're probably coming uh just about to the end of the session this evening but i thought i didn't even prepare this with you so sorry everyone for dropping this question on you um but uh i guess i was going to leave you with the question if there was one thing that you hoped that would be discovered or found or worked out uh at the large hadron collider in the next 10 years what would that be uh barbara should i go with you first yes okay probably uh something related to the dark uh the dark world because uh we are so many compelling evidence or any red evidence from gravitational and also our model for the birth of the universe the big banger needs dark matter so probably uh in all the retroduct matter or ins about dark matter would be something fantastic that will really bridge two fields that are astrophysics cosmology and particle physics so go with this fantastic uh moniker would you like to uh contribute oh wow i mean okay okay i would have said the dark matter as well but then i should i want to switch because i hold to myself into the many years looking for this to suzy particles so i would like to find the stop so fantastic so so recent years have uh have shown us actually that um heavy iron physics and uh high energy physics with pp collisions is not that far as people thought actually this is growing together because we have seen that the effects we see are also happening in high multiplicity pp and the other way around and that's a very interesting avenue on the theoretical side and i would really like to see that we understand that actually there's only one explanation and there's not two for both these systems thank you finally sudan yes so first uh barbara took my one and then then i'm gonna say i'm gonna say something maybe more likely that we might see uh yeah like what one of us is talking about i think if we get to high lumi nhc and we actually observe the digs it will make a big difference to the uh to the field and really you know be interesting because we can use it in all the models that that we have and we really need to to observe things like that so yeah well thank you thank you all so much for an absolutely uh fascinating evening i've been uh absolutely riveted by everything you've had to say also can i just say a big shout out to some of the people in the chat i know lauren's been in the chat answering some questions and clara as well who's actually been working with us on some of the videos here as well she's been in the chat to answering questions so uh thanks to everyone that's been uh been taking part thank you all so much for joining us sudan yeah and monica and barbara it's been an absolutely fascinating evening and thank you so thank you much thank you bye

Channel: The Royal Institution

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Keywords: Ri, Royal Institution

Id: fsnDZ4zCQ8g

Length: 91min 1sec (5461 seconds)

Published: Thu Oct 22 2020