WSU: Nature’s Constituents with Maria Spiropulu

it's a pleasure to be giving this lecture and telling you something about mainly what i do in the implications and also to do it being dressed up which is completely unusual for an experimentalist um i'm going to be talking about the constituents um going elementary in in that sense but i want to give you the warning that what we consider elementary and what we consider as primary constituents may change in the future and so we're going to discuss with the approximations we're using to describe nature and are going to always scrutinize on what is beyond that um so i will start with the standard model um and i will call it the standard theory because it's really truly a remarkable theory that um deserves the applause of the measurement of quantum mechanic measurement that brian showed you together with the prediction the standard theory or the standard model of particle physics or the standard model of particles and their interactions namely the forces has been has been verified across many length scales um 24 in particular to with two to one per meal with more than a hundred measurements this does not happen in any other field of science there's no such a theory uh in any other field of science that covers so many phenomena over so many energy and length scales so we need to keep this in mind and this is why um i like it to call it the standard theory it's a it's very much a very very beautiful theory and standard it is it means that it works it doesn't mean that it is in any way form or shape trivial so the the quantum field theory is the standard framework that we're talking about particles and all the interactions and whatever we are going to be talking about in terms of collider physics we're talking in graphs the easiest way is we're talking in graphs we have also other frameworks that that have a lot of algebra and matrices and so on but the easiest way was in graphs and the because it was the easiest and the most intuitive way of describing the interactions of the particles we made it a stamp so that everybody can can feel comfortable looking at these graphs the graphs have little on the on the right side you see a graph that has lines wiggles squiggles arrows and usually a convention means that such a graph is describing an interaction from the particles in the left as initial states to the particles on the right as final stage states through an exchange of a particle in the middle which in this case is the photon is the particle of the the mediates electromagnetism and so you've got there e plus minus um annihilation it goes to a photon and the photon gives you quark an antiquark pair two pairs of uh of particles um in the meantime on the outside line you've got the squiggly thing which is a gluon so gluon uh the mediator of the strong force is being is being emitted if i want to take this diagram and one graduate student that has learned how to write down the mathematical expression for how this diagram can be can be mathematically calculated calculate the the strength of this reaction then i can actually assign for every vertex for every line and for every squiggle i can assign a term and then i'm talking about i can talk about this reaction in terms in math and and figure out rates for for this reaction to be happening so this is the language that we are talking about and you will hear more on this throughout the day so now it gets hairy with this language when you try to make it math the standard model or the standard theory is giving you the blueprint of the universe and in here um the thing that i want you to notice is that it looks it looks to a greek it looks like chinese somebody who knows the math and the physics can actually read this and you can read in this light you can read interactions you can see the higgs field but all of you can see that there is not a single mass term in there there is nothing that says mash of electron mass of higgs mass of anything all right so this is the theory that we have for particles before they acquire mass in its normal state the standard theory um did not have particles did not have natural mass which is in in violent disagreement with all our um when we weigh ourselves with all our weights so um we're going to come back to this representation a little bit because this is uh this is before the dynamics of the theory is giving me the mass through the higgs that you all have heard um you're going to hear also this about this representation of the particles throughout the day we've got on the top block quarks and on the bottom block leptons and we've got one column there the photon the gluon the z boson and the w plus and minus two of them bosons and all of these are mediators of the forces of nature um well what is is there anything impressive here this looks like categorization it looks like we're taking specimen and we're making categorization and indeed it is we have uh the categorization is made according to the symmetries that these particles are um are interacting according with and all their quantum mechanical properties including also the mass okay of each one of these there is some patterns there on the mass but we cannot say much about these patterns where they come from it's an open-ended question now the one thing that will be recurring in what we're talking about is spin and for the um for the leptons on the bottom and the quarks on the top the two blocks up up and down there um the spin is um is a half and for the column on the right the spins are um the spin of the w and the and the the z and the gluon and the and the photon is uh one and um i'm not including in this picture anything about gravity unlike brian i'm very scared of gravity so when i mention it you will know that it will bring all dark problems so um but let me let me show you in in the pure feynman way what is the difference between spin because spin is associated with spinning you know you all know ballet and spinning spinning so if i if i spin and i do a full spin i will see the world the way i left it i will see the same world that i left the the fermion however that has a half spin it has it looks like a system that it is my hand together with a bottle so if i turn it in space a full 360 i got a problem it acquired the phase i have to turn in another 360 in order to be where i started from that's the difference of the fermions with the with the with the bosons um although another thing to remember is that if we had a theory if we if we needed to build theory of the world and the world was only bosons it would be a very easy world fermions are the difficult really difficult part of the of understanding the universe um okay so there they are fermion spin a half bozon spin one and all of these bosons were force carriers and now i'm putting them in a little different way so i'm categorizing them according to their masses the on the top the leptons we've got neutrinos um and we've got the leptons electron neon and tau and on the bottom quarks i've got up down charm strange top bottom and the top i had to take it out a little bit because it's huge um in fact when we when i went to school the top had um the top had less mass than the w version and so the w was decaying to a top and the bottom and then during the time that i was at school the top was uh discovered to be 170 gv and decayed to a w and a b now um and here are the bosons um there is uh the w the z the photon which would we which mediate electro weak force all together or the photon alone electromagnetism the w and the z the weak nuclear force and then the gluons um are are mediating the strong the strong nuclear force and we're going to see them a little bit in a moment right now what how exactly which are the phenomena for the photons you know the phenomena um there is uh electromagnetism and you know physic physical phenomena that occur in the everyday life that involve of these reactions um in the in the description that we have in the blueprint that i show you which didn't have masses when we put the masses by whichever mechanism we will see it's the higgs the the terms that are showing up there is electromagnetism are shown up there there are there is a there is electrons and you quarks and d quarks and the aim knew there this is the mathematical way of describing this phenomena for the for the weak um for the weak interactions the phenomena that we see from the thermonuclear reactions in the sun all the neutrinos that we get for example are based on the reactions of the w changing the flavor of one quark to another quark when i when i'm speaking in those terms i want you to remember when i'm talking about decays of a particle to two particles or a particle to three particles it does not mean that a particle contains those particles it means this is a quantum mechanical process and so there is a transmutation if you want of one quantum mechanical state into other quantum mechanical states um now the gluons mediate the strong force responsible for holding the quarks together into the protons for example and in fact we know that the lifetime of the proton is as big as the lifetime of the universe so this is one of the constrained experimental constraints when we build theories now the full standard model was written in 1967 before the higgs mechanism or the higgs particle or the higgs field was discovered but the higgs field was theorized the higgs field is very difficult to discover you have to excite it and make particles and this is why it took so long time in order to create particles and this is the now the blueprint became from the top which we saw on the previous page into the bottom okay so a lot of people say that the standard model is very beautiful and simple so this is the amount of simplicity we're talking about here now but now i want you to look here and start identifying terms with masses a mass another mass the mass of the higgs it's a massive square so what happened between in the way we went from the top uh equation to the bottom equation is that um we call it symmetry breaking um as fact we call it spontaneous symmetry breaking so some dynamics happened and the particles acquired mass and the dynamics is is happening via the higgs field again if i take all these lines i can find now again light um the electromagnetism i can find the weak force and then this balance there is where i pointed out we have all the mass terms so the the simple picture is the the quarks the leptons and the forces through the gauge path through the gauge mediators there um the w the z the photon and the gluon and behind it behind all that is actually the higgs which we have been looking for 40 years and uh is there anyone in this class who doesn't know that the higgs was discovered recently no so the higgs became a superstar the higgs the particle the people who found it etc it became a part of our everyday life because it is extremely important and because without it we were not this beautiful standard model with all this confirmation that we had was sitting in a in a place in a very peculiar place without understanding the the source of mass so now we got it um in so it was it was uh in 1967 it was put into the theory into the theory of leptons and quarks and into the theory of leptons first and we had the electro wick standard model and then the theory of quarks chromodynamics came along and we have the full theory of quarks and leptons and forces which is called the standard theory now in order to arrive to this point experimentally uh the program of the past century included the cosmic rays because a century ago uh yes a century ago we were not we didn't have accelerators yet however the accelerators big accelerators exist in the universe supernova we have protons arriving in our atmosphere they interact with with the molecules and the atoms in the atmosphere and they create subatomic particles like ions and neurons all the subatomic particles that went then we discovered in colliders um it was it is the accelerators there is a great number of accelerators that are shown here um usually um the accelerators are based exactly on the fact that you can give exactly the fact like as a battery you can give impetus to a subatomic particle usually electrons or protons protons are taken if you strip the electron of a hydrogen atom and then you circulate them you put magnets around their path and you pump a lot of energy in them and bringing it into collisions either head-on collisions between two colliding beams this was the the big advance of the 20th century that gave us the the that gave us many discoveries like the top quark for example or in fixed target experiments which was previously um the case um you you see that the the accelerator started in the middle with an 11 inch cyclotron so in berkeley and now as you know the lhc is 27 kilometers in the in the circumference so we have gone from very small table top accelerators into the godzilla accelerators and of course when you [Music] when you go through through this process you realize at some point that materials are your issues and you have to start again shrinking your accelerators so you have to find new techniques to accelerate particles and this is on the forefront right now of accelerator technologies to figure out a way to make an lhc on my table at least not your table but my table my lab and then we are going to have some more progress with regards to how we're going to high energy higher and higher energies okay so let me tell you my trajectory through this um through this accelerators i went first i started as an undergraduate i did some work in a synchrotron lab in in germany and then doing material science using the photons from using the light from a signature source it was again a synchrotron machine an accelerator and then i went to cern again as an undergraduate and i was completely fascinated with the fact that i could build an experiment it was a prototype but i could build it on my own i could calibrate it i could do the elect to the data acquisition so i can hands-on put together an experiment myself which was then used for uh purposes of the which was of a bigger experiment at that time it was delphi uh which was a large uh electron uh positron collider in geneva on the same tunnel that the lhc is so i went from the devaturn and there are some pictures there from the tevatron um with the shorter hair and younger face all the way to the lhc uh 20 years so 10 years at the table run and 11 years at the lhc it's a long path for for these type of experiments to yield results and as an experimentalist the the work that we do is to build the detectors to test the detectors um to take data analyze data and make sure we produce results of course like the higgs now from the full standard model uh the the thing to remember is that naturally the particles do not have mass they can acquire mass through dynamics and for gauge bosons the higgs mechanism is exactly how it works so the little uh sombrero that we saw uh which represents the symmetry breaking mechanism is how the the w and the z acquire mass the other particles the quarks and the leptons they also get they also acquire mass through interactions with the higgs and on these we have a lot of work to do in order to measure the higgs decaying directly to the fermions for the bosons what we have found is enough to tell us that these higgs that we found is indeed the symmetry breaking mechanism that gives mass to the w and the z for the for the mass generation for all these different flavors why for example the strength of the coupling of the higgs to the electron is smaller than that to the moon is smaller than that to the tau which gives you the higher error give the masses of the particles and the patterns that we had there previously we have really no clue it's a big mystery all right so now um i want to wrap our minds one moment again on on quantum on the quantum when we talk about particles we talk about particles as states that are interacting through a particular through a particular kind of asymmetry and force and in addition we have the what we call the mass eigenstates in other words the physical realization and in nature it is allowed and specifically for the quarks and for the leptons we will see that they mix so there is a little bit of each of the flavor in one mass realization and it's they are not pure um in in that sense and how much they mix is important because behind the mixing of the of of the of the particles um one might explore a big question about the universe namely why the universe is mostly matter and not antimatter the universe we live in all of us we are considering we are matter and everything on the universe the universe is dominated by matter and not antimatter so in this representation here there is a matrix that you see all the all the the elements are talking about the strength by which a quark goes to another quark um and they're called the co it's called kabibo kobayashi maskawa metrics and i'm not going to repeat it throughout what we are talking today but in every slide there is a usually a nobel prize or two of what we are of what i'm showing and on the on the on the bottom here i've got again all the quarks that we talked before in the same sense ud cs tb and then strong weak the way each one is uh the way each one decays can trans trans transist transition to another one and so um the the we have we have a program of 50 years of understanding the quarks sector of the standard model understanding how they mix and measuring the mixing angles and and what we call the cp violating phase cp stands for charge and parity charge is the symmetry between mata and antimatter if you change charge you go from matar antimatter parity is looking at the phenomenon in the mirror and so together if you combine these two symmetries you get the charge parity symmetry which when you violate you can start understanding for example the matter antimatter asymmetry and we see that it happens in the in the quarks these are the measurements the measurements of the elements that i showed you before so you can start observing and doing a little bit of of numerology here the the elements on the diagonal are the strongest they are one the elements of diagonal they have some sort of a symmetry one is smaller than the other is very very small the very diagonal ones the 0.03 and 0.008 and this is giving us insights on on the structure again of the of the mass eigenstates and the and and the gauge eigenstates as we call them the program has taken us for 50 years with experiments in japan on the top it's called bell experiments at slack which have now finished in the past five years they they stopped in the past five years which is called babar the bar stands for b b bar b bar is the anti-particle of the b quark and uh what we were trying to find is this type of oscillations and mixing in b measurements which are comprised of big quarks also and right now the lhc be at cern now when we go to leptons the situation becomes hairier in the in the sense that we've got uh we um well whatever we predicted in theory for the for the part of the leptons that are neutrinos was wrong and uh we found we thought that the neutrinos would be massless but then neutrinos we measured them to have mass because they oscillate because the same quantum phenomenon happens and everything that we expected about the about the strength of the oscillation and and the way they mix was pretty much uh off to give you an example this theta 1 3 which is one of the mixing angles we see there that it's 9.6 degrees and before the experiment measured that it was thought to be 10 to the minus 10 or so so it was thought to be very very small now we have not measured this phase that is related to shipping violation and this is part of a program that is being initiated so that with uh an international program but based in the united states i can ask i can answer questions about that so now if we write the same the same kind of mixing matrix for the leptons we see that the numbers are all over the place and they have not and very different from the quark one so and we have we don't understand this yet um and i want to say that indeed for for 50 years this is another program of 50 years that started with ray davies at homestake mine and everybody thought he was crazy he measured that the solar flux the neutrino flux from the sun had much had a deficit compared to the solar model and then supercamiocanda in japan and snow in canada they verified in fact that we do have oscillations of neutrinos and the neutrinos have tiny masses now so close so far away this is what i i think to take home here is that there is an analogy the quantum world between leptons and quarks is working in some analogy in that those uh new new new tau are the three neutrinos these are the gauge eigen states and one two three is the physical um manifestation of them and you see that they are comprised each one one two three a little bit of each this is again the quantum mechanical um the quantum mixing of the gauge eigenstates and the same thing is happening as we said in the quark sector but you see it's the the magnitude of it is very very different of the mixing of the states all right so now the the the the question the flavor questions um are what are the the the dynamical origins of the fermion masses their mixings and cp violation what are the energy scales that are associated with the dynamics and also which uh which are the symmetries and symmetry breakings associated with that as i speak like that since i explained to you something about the higgs being the the symmetry breaking mechanism that gives masses to the w's disease you might already suspect that we might have more higgs is an extended higgs sector that will start giving us answer for these type of problems um in addition uh we're going to see that in order to patch some issues that we have with the theory and the higgs at the master we found it we might need supersymmetry and supersymmetry is giving us also additional additional particles that have to do with dark matter so we have to establish the connections among um among all of these at when when we are doing the analysis of the data um it is it is always we we are not just trying to verify the theory we are always trying to see the data for what they are okay we're not always including the theory before we analyze the data of course when we have many theories we can analyze the data into many ways and this is where the standard model won in all these cases okay so the let's move to the lhc and the higgs now the higgs is the boson that was missing in the table that we had before but it is not the same kind of boson like the other bosons we talked about it we talked about bosons with spin one this one has a spin zero we have not discovered the particle with spin 0 elementary ever this is the first one and we think it's elementary but we're still working to figure out whether it's yes or no now in in these words that i have up there i call the higgs also a new force of nature and the nomenclature is a little bit mixed up because the forces we um we note as the ones that are carried by gauge bosons which are the w's disease and the photons and not by and and the gluon and not by a spin zero poison but for all practical purposes you can change a little bit the nomenclature and call the higgs a force a new fundamental force um let me show you a little bit how an area of going down to the lhc 27 kilometers around in between switzerland and france my office is somewhere there at cern close to the airport and now we're going to go underground about 100 meters on the ground both experiments this is the atlas experiment which is cl which is in switzerland and this experiment was built in situ there and what we're looking is a time lapse of uh four years where the experiment was built part of the detector was built where we're looking inside is the calorimeter and this arachnoid structure around is nothing but the toroidal magnet the magnet is used in order to bend the particles because when you bend the particles you can figure out their momenta and this is why you have the magnets and this is the the tunnel there's about 1300 of these dipoles 14 meters each the dipole technology is pretty amazing within the same magnet you have beams of protons and protons going the other way in order to collide within the same magnetic field this is highly non-trivial this was discovered in this was discovered by john blewett at brookhaven laboratory in 1970 and it was not picked as a technology for the ssc um the ssc was two tunnels with two different beam pipes this one is one beam pipe which is only splitting at the experiments um and and it's it's an amazing technology to actually build this type of magnets that will do this now what we saw in the movie was also another kind of pipe you saw there and this is the pipe of the liquid helium i said that the magnets are superconducting magnets and they produce the field needed for the protons to remain around the ring and be and be brought to the very high energies and the the superconducting magnets they need about nine nine tons of helium in order to be operating this is most this is the biggest density of helium in the entire universe and and also why helium got so expensive all right so here is something about particle interactions in this little graphic we see uh first we saw a new one going through the detector on the middle is a silicon camera and in the intermediate layers there there are layers of detectors that um that detect electromagnetic radiation um hydronic the hydronic particles as well as the muons that went through the steel and go through the chambers that we saw outside each particle when it interacts with each detector leaves a different signature there are about 100 million channels in this detector the collector the signals from each detector where particle went through and when you reconstruct all of these heats of all of these particles that went through in a collision you reconstruct what we call an event the detectors are very giant this is the other detector i showed you atlas before this is the cms detector and the the cms detector unlike the atlas one was built um on the surface and then it was brought down and it was built in uh 12 different pieces like a lego the the the heaviest of of these were was a 5000 piece which had the magnet and in our case cms means compact neon solenoid the magnet was a solenoidal magnet all right so this is the day after the first uh collisions in in september uh 2008 um the first collisions were september 12 and september 18 there was the we blew it up as you remember and the lynn evans is on the right and and um and i am on the left and my hair isn't washed and his hair is uncalmed and we are talking with about the success of the of the machine also being worried about when we are going to have collisions in the detector then the then we blew it we fixed it and there we are in december of the next year i was running the first shift where um we took data at the highest energy we beat the the energy of the tevatron this was a 2.6 tv and now um the difference is that i and despite the fact that i was on night shift you see i'm dressed well i have my hairs washed so you can imagine what happened my mom and dad were there and uh and in the middle of the night uh we we woke up the spokesperson jim verdi in order to make in order to make a record of the fact that we were the first to take the highest energy collision so we were very excited now the particle discovery is within the time of the lhc i want to show you that in nine months of the lhc we have rediscovered all the particles of the standard model from a century so the machine the first thing that you do when you bring a new machine up is you try to verify everything that you know so far and that it is correct and so we have done that in a very fast period of time from nine nine months running and a few months of cosmic ray data and we had a visit of course from peter higgs because the lhc was built to discover the higgs that was the main mission of the experiments both atlas and cms were designed each of the elements of the detector was designed such that we are able to identify a higgs in in a mass range that it is very huge from 100 gv all the way to a tv and more it it is important to keep in mind that the higgs is um um the hunt for the higgs is not just at the lhc that we had decades in fact the largest time for the hunt of the higgs was at the experiments before at the tevatron at fermilab in batavia illinois and before that back in geneva at the at lab and experiment by experiment and data period by data period we narrowed the window all these stripes that you see uh the colored stripes the vertical color stripes are exclusion regions where the higgs is not and there was this little slither that was left here there was that was allowed for the higgs and look where it is it is between 122 and 120 and this came in 2011 when we had the first lhc run so um i want to put a few a little bit of emphasis on the data because we are the the lhc this is in fact a slide a picture from the department of defense um the internet before the lhc around 2008 is one little dot one pixel in this super highway of data according to the doe and it's true in terms of data transfers of networking of distribution of data the grid and between 2008 and now we have learned from building the computing system of the lhc we have learned a lot the thing to remember here is that we are susceptible to between 100 terabytes per second to one petabyte per second of data this is a lot of data um um there's it's not comparison to the data that google is handle is handling and and so of course with the advent of all the the social media there is now data everywhere uh of of that sort of magnitude on the right is a little graphic that shows you the data of the lhc compared with the tweets per year in 2011 the human memory the world of warcraft servers the us library of cons of congress and wikipedia where wikipedia is a dot and the large hadron collider is over there with 25 petabytes per year this is how the network is looking right now due to the lhc um it's becoming a live organism of hardware and software in communications it's extremely important i just want to note on the on the bottom right there for those who can see it that we actually saw by monitoring all the networks because we have to since we cannot keep our data on site and we have to distribute it and we monitor our networks we saw the when when syria for example lost their internet a couple of years ago um in in the future for the for the for the lhc what we are targeting is uh in principle real time a live adapting network that are intelligent and self-organizing in order to deal with an increase of a thousand and another thousand and another thousand of data so we're going we're talking about from petabytes going to zettabytes and yactobytes this is huge increase in data that we have to deal with and we have to deal with not only talking about big data but in fact talking about smart data as well so here's the eureka moment um in at the at the lhc uh well the eureka moment was we we described we we made the announcement on july four uh we described all the analysis in a publication that it is available to everyone one publication from atlas one publication from cms we had the the the the three channels that gave us the discovery described in there and the channels or the final states or the the the higgs decays that we detected that gave us the higgs was in two photons two z bosons two w versions all bosons this is why on the first slide i said the issue of the electroweak symmetry breaking is settled for what has to do with w with the with the bosons you see on the left there is the congratulatory note from peter higgs who said thank you for my nobel prize and on the right side we see the note that we got all the experiments this is the note for the for the uscms um we you see the note that we got uh from holdren from the office of science who acknowledged that the the us has played an invaluable role in the discovery of the lhc in terms of not only funding and people but in terms of all the know-how technology that was built in this country in the past 50 years okay so now we're going to see how the signal looks like and we're going to see it in what is called the golden mode first i want you to i want everybody to be noting as we accumulate data i want you to be looking at the data and i want you to be looking at the blue histogram the blue histogram is what i would expect from the standard model without the higgs don't look at the don't look at the red histogram at the moment look only the blue and the data if you look at this by eye this is why it's called golden mode you see an excess of events at around 125 gv this is the higgs this is the higgs decaying into two z bosons each of the z bosons decays into two muons so you've got four muons in the final state or four electrons in the final state or two muns and two two electrons you analyze these and you get um and you get the mass of the higgs the the histogram there is if you do the theory the simulation of the theory for a higgs of 125 gv so that you have to you can compare your discovery with some theory and the theory you compared it there the red is the higgs in the other channel which is not so golden and you will see why uh it's a little more difficult it's the channel with the two photons and notes there as we accumulate data there is a little there is a little blip which in the data minus the fit it appears also like a little blip this is the discovery of the higgs in the two photon case much more difficult because the background you see but if you the the background is the blue is very huge noise compared to the signal so um let's look at the some event displays the event display from the two photons this is real events um the the the little dots and the little tracks that you see around is from reconstructing all the particles of the event in the tracker or in the calorimeter and the two towers on the the two orange towers that we have to on the on the one side and on the other side is representing the photons the photons are dotted because they don't leave they're not charged particles so they don't leave any signals in the tracker if we look at the ones how they look uh with four electrons or four muons okay we're going to go a little uh a little now weird here but you see four tracks on the left these are the new ones now on the right four tracks and electromagnetic energy these are the electrons so the electrons look like little tau they have little towers like the photons and also they have tracks and this is the in words this is how we actually do the reconstruction of particles we go through all the detectors and we figure out which particle leaves which characteristic signature and which detector and we construct everything together okay so now we're going now i want you to take a breath because where i'm going to say maybe you have never heard but the higgs the higgs it doesn't come really from particle physics notions on the contrary it comes from notions it's not on the contrary i would say in parallel it came from notions about materials so when people are studying materials ferromagnets and when ferromagnets become magnets and when they are not magnetized and why this is happening with changing the temperature people started understanding that there are phenomena of symmetry breaking in materials and materials are easier to study because they are materials you have them you study them you can put pressure on them you can put the temperature in them you can measure thermoelectrics you might you study them so this um this was emphasized specifically for the for for what has to do with symmetry breaking by nambu um our professor from um the university of chicago who got the nobel prize um for spontaneous immediate breaking and he talked in his nobel lecture not about he talked about cross-fertilization a case of cross-fertilization meaning cross-fertilization between condensed matter and particle physics i should say when i showed you the stamp that the language that i talked about quantum field theory um with the diagrams and all that refers to particle physics and condensed matter quasiparticles etc so the language already is shared but also the phenomena and the description of the phenomena despite the fact that they are at different scales which is mind-boggling okay and then the analogy is not exactly is not exact we have to keep in mind so for physical systems like ferromagnet a broken a broken symmetry is giving rise to what we call spin waves which is the symmetry the symmetry is rotational in variance it has to do with the spin and how they are aligned in the ferromagnet in crystals if you break the symmetry which is transl translational symmetry how the you put in crystals and you put all the atoms and they have a lattice if you break the symmetry the translational rotational asymmetry you get something which is called phonons and in superconductors you break some more esoteric symmetry which is the gauge symmetry of the particle number symmetry and you get copper pairs um and so the the these kind of notions of super sim of symmetry breakings that give you states they were not particles spin waves or spin waves but brian explained to you waves and particles and states are all in the in are all states in the end in the bigger language and so um you apply these notions to from condensed matter ideas to particle physics and the difference is that you don't have a material you have the quantum vacuum so now in the analogy is that the quantum vacuum is not uh is is uh is a is all is almost a representation of many quantum states it's not a representation of something pure and one and this is also the the magic of quantum mechanics now phil anderson this is again the chambra the mexican hut potential where um the the states that they are on the trough which are the red are the higgs modes and the states that are around the circle are the w's and the z's and they're called phase modes um phil anderson pointed out that the the quantum vacuum is like a many body system in the same sense as in as in the um as in the quantum as in the condensed matter systems um and he wrote this paper which was called morris different in 1972 talking about symmetry breaking as a property of large systems so while we're talking about elementary and going deep to elementary we have to keep in mind that there is interactions and the universe is not made by one particle not interacting with anything and in all of what we are talking about there is also complexity in fact after symmetry breaking all the particles get mass and you've got some sort of complexity there and in fact in condensed matter physics for the past many years people are tweezing out higgs states from condensed matter systems um the from bose-einstein condensates from in superconductors and the energy scales are much different they're little tiny higgs in terms of vvs you see there there are 13 orders of magnitude in the case of bose einstein condenses compared to the let's say the cosmic higgs which is the elementary higgs the the spontaneous symmetry breaking in the vacuum higgs and in fact i met somebody very recently from the lab in uh from a lab in uh in max planck um where with uh with a set of rubidium atoms they make a lattice and they start bombarding it with three lasers until they go into a phase transition between super fluid and insulator of this material and in the exactly where the phase transition is they get a higgs and the higgs is there in the data now the higgs is not measured in mevs or vs because it's practically zero it's 400 hertz which is very small if you consider one tera heads is about one ev so hicks there are there are there are tons of higgs is in condensed matter physics there are different but the symmetry breaking the considerations are very very similar so um let me turn now from the from the history let me turn to the susie partners but i want to say that why i'm going now from the higgs to sushi there is a there is a big anathema with the with the higgs that in quantum field theory the higgs corrections can be quantum corrections can be bigger than the higgs and this is like your lunch being bigger than you so this is not very normal so susie came in for other reasons to explain fermions in fact um but sushi comes in and it fixes that problem so um you can say that the electron in super space and again robert will explain to you what is this new quantum coordinate where you don't have just space time but a new angle a new quantum coordinate you can write it as the super electron which is a partner with spin zero and the electron the normal electron so a linear combination of these is the bigger field now um this supersymmetry with the assumption that the particles that supersymmetric particles will be at the tv scale this is a necessary assumption can is is the most complete and beautiful uh framework in order to complete the standard model um now the attractive property is the is the property that i told you is that uh it it it helps us with the higgs pathology but also as a matter of principle it's not just an ad hoc inclusion of new particles there is a symmetry being involved this is how the um the sushi partners would look if we had the standard model particles the higgs is added there and now we have all the super particles so we just doubled the particle spectrum that we have and again somebody might ask why why this sounds very complicated why do you double all the particles that you have and there is an added value to that however the supersymmetry gives you out as a theory more than assumptions you put in and this is why we have been fascinated with this theory for the past 40 years 40 something years and this is why we're not giving it up and also possibly in the next two years we are going to actually discover um a kind of super symmetry not the vanilla kind but a kind of super symmetry um i'm not gonna go through that because robert is going to explain it to you this is the language in diagrams of how the the the pathological diagram with the big quantum corrections is being fixed by adding these twiddle particles the super particles with opposite spin mathematically if you add all these diagrams there is a cancellation what we call a cancellation of the divergences so the sushi models have also many many other features i'm not going to go through the features but i'm going to tell you one of them which is spectacular and it was not put in in the theory the sushi models are giving you a particle that could be the entire mass dark matter of the of the universe so the big big question that we have for what is dark matter could come to be solved by the supersymmetric particles um and this is why in a visual term if we look at this event over here you can see yourselves that there is the the there is a there is a transverse view of a detector it's pretty it's pretty symmetrical in terms of the detector itself and it is completely asymmetrical with where the energy deposits are so we've got one half one half of the circle filled with energy and the other half there is nothing this type of events within balance in the event could be at the story behind a a what we call a neutral lino it's not a neutrino it's a neutral linear that has escaped detection from the detector and that could be the dark matter particle i have to go fast now but i this my prediction is that if the supersymmetry is the solution to the problem with the higgs the so-called naturalness problem um that we talk about then we we are going to see it in in two years from now and it's going to be a 1.4 1.5 tv partner of the gluon gluino and we have had cases like that where we missed we were just around the corner with lap and we missed the higgs like that so now i'm going to go um five five or ten minutes over time no more um because i want to tell you the big beyond beyond the higgs first of all within the higgs that we found we have not clarified completely that it is the standard model higgs we have not measured completely its characteristics we we're doing this now with the full data set and we will do it as we go in the higher energy run which is going to be the almost 14 tv run that will start in a year from now we have to clarify if there is more than one higgs and how many more and the reason for that i alluded when i was talking about all these flavor problems that we might have to to have an extended heat sector to understand all these different patterns in the masses of all the particles and this is in fact one of the biggest part of the of the of the lhc challenge and program in the in the next round um supersymmetry in fact predicts when i talk about the extended higgs um the richer higgs supersymmetry predicts five he exists that they are different in masses and other properties okay now we you might you might have read that eureka the higgs let's celebrate champagne and go home no not the way it is we are scratching our heads completely with the with the mass of the higgs we measured because in fact the mass of the higgs it has the mass of the higgs it's it's sitting it's giving us a borderline disorder the 126 higgs mass is at the edge of the stability of the vacuum and i will explain that in a minute it has to do with the calculation for the vacuum of the universe based on the mass of the higgs and the mass of the top and the the 126 is giving us a big headache if there is no other new physics i will explain in a minute if we start thinking about supersymmetry the way we have been thinking about it for 40 years the 126 is giving us a very big headache it is it is at the border of being acceptable for for normal sushi which is the minimal supersymmetric standard model mssm and it you see the border there and in order to accommodate it mostly we have to make extensions of supersymmetry so super symmetry the vanilla supersymmetry is not good enough for this 126 higgs and if we consider other stronger dynamics and composite higgs it is rather too low so it's too fat to be an ssm it's too low to be composite if there's no other physics it bri it makes a disaster for the vacuum of the universe so this is kind of a situation where um after the champagne you have uh you have a hangover and you wake up to this problem and you need to and you need now to go and analyze the data now the question is for the connections of the higgs to the beyond is is it indeed true that um is it indeed the case that the higgs destabilizes the vacuum how does the the scale in other words why the higgs has the 126 gv mass and then the connection of the higgs to the dark matter now um i think that that i alluded again in the flavor problem is that we need to understand how the higgs talks to the neutrinos and if it is also related to inflation or dark energy all of these connections are really open-ended these are questions these are this this need a program uh an experimental program both a precision program and the discovery program now let me show you the stability let's not read the words but let's see the plot there this is the little part of the of the pant of the of the of the higgs uh uh mexican hut the punt that it is on the on the bottom of a of a bottle and as i will change it you see that when the trough the trough was very well lined up but then as i change the potential i can make it turn around so the mexican hut can go around so what i thought was a stable state could actually be a state like on the bottom right plot where i can tunnel from a false vacuum to a true vacuum because my mexican heart potential turned around so now in fact the opposite can happen as well but in this case i i am i'm saying that if i go from the from the from the false vacuum to a better energetically favored vacuum the universe would bubble away and it will appear in a different vacuum of course this sounds it would be 10 to 100 years and this sounds like big nonsense but in fact if i consider no other physics this is what i'm led to with with the quantum mechanics that i know and of course this is something that we need to investigate if i put supersymmetry of course this is in the plot that is showing here the meta stability is shown in in yellow and it is given as a function of the mass of the higgs and the mash of the top of course if i put new uh news new the new symmetry super symmetry and new particles this plot on the left goes away and i have no problem uh with with with the universe or the vacuum i'm not going to bubble away so i'm going to now talk the last section is about matters the dark matter and how it is connected also with the higgs so um well that's luminous matter um we see it from all the observations in the sky and this is dark matter we don't see it um it's it's it's also not exactly transparent but if i put dark matter in front of luminous matter i will see uh distortions of luminous matter as if the dark matter is a lens dark matter interacts gravitationally the first dark matter the first let's say discovery i would say of the dark matter was by zviki theodor zwiki uh who was a hungarian physicist at caltech and he was really nasty and nobody liked him and therefore when he published the paper that in a cluster of galaxies there were not galaxies then they were called nebula in a cluster of galaxies he calculated with a viral theorem from the gas how much mass that would have um and that's the virile theorem is talking about potential energy and kinetic energy and he found a factor of 500 more than the calculation with the luminous matter so he wrote the paper and this is the paper and and nobody believed him because he was so nasty not because they didn't want to consider him to consider his findings now that was the dynamics of many galaxies the clusters of galaxies for the galaxies themselves the the the how galaxies are being comprised they're being comprised by stars and gas and dust the black hole in the middle huge black hole in the middle and also dark matter and this was inferred by measurements of the stars we call them the rotation curves of the stars in the galaxy and the rotational curve is on the on the y-axis and the r as far as we go from the middle of the galaxy outside is on the y-axis and just with newtonian mechanics you would expect that the rotation curves would would slow down as as you go out of the galaxy in fact the data is observed to be flattening there and so came the the the whole headache about what it is that the the baryonic matter in the stars in the galaxies is scaffolding too so that you get this stabilization there and the thing that first people did is they assumed that the galaxies are are embedded the galaxies are flat and they're embedded in a big dark matter halo and we didn't know what dark matter is but we knew that from this that it interacts gravitationally for the astronomers that's pretty much the end of the story because they don't care what it is so the discovery is done there is dark matter we've got it here it is um veera rubin was the first one to uh to do this uh rotation curves and again this is showing the same diagram and the keplerian expectation and and this is showing the actual data that she measured so there's another way that you can see it that you can observe it in the sky that there is dark matter and this is with lensing this will be explained in the last lecture a little more but gravity if you put a big gravity big mass gravity it will the light from a far away star system galaxies and clusters of galaxies will be distorted as if you go in the distortion mirrors so you will see in the sky images that have little lines around them of galaxies like this one and this is a simulation of which kind of distribution the dark matter would have in order to get this type of distortions the distortions are these little lines that you see which are not which are showing you that there is what we call gravitational lensing um now the best how is this why am i talking to you about the skies and dark matter and astrophysical observations the best clue we got for what dark matter is um is the particle a kind of particle like the particle that susie that is the sushi the supersymmetric lightest supersymmetric particle which is a very weird uh thing because supersymmetry was not built in order to have this particle in um on the left here it shows you the the the mass energy budget of the universe and we are the special um little tiny percentage of the of the of the two slices one is the neutrino slice and one is the rest of all the of all the baryonic matter and the rest is dark matter 23 and 73 dark energy for which um when you don't know what it is don't even speak of it but we do anyways and look how much we speak about it in the past five years we have gotten a renaissance of theories of dark matter because we haven't found which particle it is we have been looking for it as a particle with experiments in the sky experiments underground and the collider experiments and we haven't found it yet and so to understand which space is there still to explore we have made that tons of theories of dark mothers warm dark matter axion dark matter solid and dark matter sugra gravity no cubals also sterile neutrinos all sorts of different kinds of particles and all sorts of extensions of the standard model so the dark matter interaction with mater what we know is via gravity and this is the famous bullet cluster you will get a good explanation about it but in this case the dark matter does nothing when when galaxies collide and the normal matter dust and gas they they scatter um could it be however that dark matter interacts with normal matter with the weak interactions for example with the z it could but we excluded it we have experimental data that we excluded could it be that it is actually interacting with normal matter through the higgs yes it could and we haven't excluded it and we're very close to getting there on all the experiments the experiments underground and the experiments and the and the collider experiments could it be that there is something else of course always there is something else that it could be but right now it's the time to actually we have cornered ourselves in a situation that we will have enough experimental data to actually speak definitively about dark matter even better to discover it i'm not going to go through this slide except to say that there is a miracle there and the miracle is the coincidence the coincidence you can say that the neutralino the lightest supersymmetric particle fits the bill to cover the dark matter of the universe the relic abundance for the dark matter of the universe here is in here is in plot the words that i told you that we are almost there here the experiments are the experiments of the future that will explore dark matter interaction with normal matter the rate these experiments have not been done and these experiments up to here have been done and this is where it would be if food was via the higgs so we are going down here and we will know very soon from these experiments whether the area where the higgs is the way the dark matter speaks to matter is and is and so this is extremely important time there are all sorts of dark matter evidences you hear it in the news nothing is definitive there are many anomalies nothing is definitive and this is a totally open-ended puzzle and i think dark matter and new physics is the biggest absolutely the biggest problem in physics today this is a this is a a network that represents the the dark matter in the universe and it looks like indeed the scaffolding where matter the luminous matter is hanging on to it's gravitational for the moment and we don't know anything else other than that this is the last slide um i i want to emphasize for the higgs connection to the beyond um the the major important big topics are the dark matter whether the higgs is a portal to the dark matter is the electro weak bariogenesis and you're going to hear a little bit about that and the electro weak phase transition this is the first real cosmic event in the evolution of the universe where we actually have the phase transition and we have mass and out to the particles and also the the principle that creates and stabilizes the the electro weak scale how the the higgs talks to the neutrinos specifically with their little masses and the dynamical origins do we have more higgs's the dynamical origins of all the flavor of all the flavor flavor and and the masses the mixings and and cp violation and of course when we solve all of the above extra credit comes if we figure out what is the connection of the higgs with dark energy namely the connect this is going to be covered in the cosmology lecture about the acceleration the exp the the expansion of the universe at an acceleration so this needs a multi-decade global experimental effort on many fronts particle physics nuclear physics astrophysics even precision astronomy can give input and and of course cosmology i have told you this i have made the prediction that we will find that we can find supersymmetry at the lhc so the the so far we haven't and if we don't on the next run you will hear me being at the pose because i think we need to have new ideas if we don't find super super partners at the next run at the energy scales that we expect them then we're going to be looking for new ideas in this field that's the end thank you

Channel: World Science Festival

Views: 7,074

Rating: 4.9075146 out of 5

Keywords: Maria Spiropulu, Higgs particle, Standard Model, the future of particle physics, Higgs boson, quantum excitation, the god particle, Peter Higgs, Higgs mechanism, why particles have mass, LHC, CERN, World Science U, University, science unplugged, New York City, NYC, Physics, Stephen Hawking, Albert Einstein, Quantum Mechanics, General Relativity, black hole, WSU

Id: wPt3f7yRYUE

Length: 71min 50sec (4310 seconds)

Published: Thu Jul 30 2020