Neutrinos are the Worst Particles in the Universe - Ask a Spaceman!

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subscription speaking of subscriptions the first 1 000 of my subscribers to click the link in the description of this video we'll get a free trial of premium membership so you can just do it neutrinos neutrinos are the worst particle in the universe they're the worst i i neutrinos annoy me neutrinos give me a headache i mean and they've given everyone a headache since they were first discovered they weren't even discovered on purpose they were discovered on accident when we're looking at something called beta decay where we realize that a neutron in a nucleus transforms into a proton and electron it just decays it just changes and this is uh triggers a lot of radioactive decay when we're looking at these kinds of reactions way back in like the 1920s we're looking at these reactions we realize that the energy and momentum that the original neutron had was not matched up by the total energy and momentum of the proton and electron that that came out it just didn't add up so something had to to give and what we came up with was the existence of a new particle that was involved in this reaction but stole away some of the energy and momentum and yet we couldn't directly see it we knew it had to be neutrally charged like no charge at all and we knew that because uh the proton in the electron that came out a positive and negative that balanced the electrical charge coming into the reaction which was a neutral neutron so you can't just add or create electric charges we knew it had to be tiny because these differences in energy and momentum were just very very tiny and we knew it couldn't interact with the electromagnetic force because we would have seen it so we came up with like a cute name for it uh neutrino little neutral one it's italian for a little neutral one and that's like when a particle gets a name as has half of a joke you know it's just gonna be bad news now neutrinos by themselves so so they were introduced in the 1930s and then discovered a couple decades later experimentally verified like yep we've got neutrinos there's this new kind of particle which is annoying but we can deal with it and it took part in all sorts of reactions but then we discovered that there are different flavors of neutrinos another word for flavor here is species the most common word that physicists use is flavor i don't know why when species or kind or type would work better but here we are we discovered there are more flavors of neutrinos and this went along with the discovery that there are different flavors of the electron so you have uh your electron has its charge has its mass has its spin it does all of its electron things there is a version of the electron that he has the exact same electric charge exact same spin behaves exactly like the electron does except it has a much heavier mass we call the muon and that's a different kind of electrons like the like the older sibling of the electron and then we discovered that there is a third type or flavor or species called the tau particle which is a like the electron and the muon but heavier still so to go along with these three flavors of electrons there are three flavors of neutrinos there is the electron neutrino the muon neutrino and the tau neutrino and these flavors pair up so if you have some sort of complicated physics interaction going on at the subatomic level if there are electrons involved in the reaction you're going to get electron neutrinos along with it if there are tau particles you're going to get the tau neutrinos and if there are muons you're gonna get the muon neutrinos so they pair up flavor to flavor then there there's the whole antimatter thing so not only are there the neutrinos in the three kinds there are three kinds of anti-neutrinos so like that's six new particles to add to the universe which is super annoying because that's a lot of bookkeeping that's a lot to keep track of these neutrinos are weird for a long time we thought they have no mass but i'll get into that in a little bit they only interactive by the weak nuclear force so they don't participate in strong nuclear force they don't participate in electromagnetic yes technically they participate in gravity because everything partici participates in gravity but like it's so barely there it doesn't even count it's just the weak nuclear force the only way to see a neutrino is with a weak nuclear force which is super weak and super short range and and that's a whole other set of headaches right there the weak nuclear force and you got these six particles that we've had to add to the the table of the list of particles in the universe but we're kind of sort of able to deal with that like okay fine there are more particles but then in the 1960s with the homestake experiment we were detecting neutrinos produced by the sun neutrinos anytime there's like a nuclear reaction neutrinos are somehow involved they always get in the way of things and in the sun is a giant nuclear reactor so it's constantly spitting out neutrinos and we know from nuclear physics of what's happening inside the core of the sun then it spits out electron type neutrinos electron neutrinos but then when we went to measure this the actual amount of neutrinos bombarding the earth and they're like trillions of neutrinos passing through your body right now by the way uh we so we build this big detector it is only saw like a third to a half of the neutrinos that we knew that the sun was creating so that was a problem that was way back in the 1960s it took a long time for us to come up with an answer and the answer is so annoying the answer to why is the sun when we know the sun is producing this many neutrinos but we only see half of them or a third of them we did constant double checks like no we are getting the physics of the sun right we do understand nuclear reactions we know it's producing electron neutrinos we know the distance like we double checked everything and then we started to build some other kinds of experiments and we realized that neutrinos do one of the most annoying things possible which is change identity identity as they travel neutrinos can do something that we call mixing if i were to have an electron neutrino gun and i were to shoot you with the electron neutrino gun as these electron neutrinos travel some of them which will just transform into muon neutrinos or town neutrinos and then maybe back to electron neutrinos and then back into muon and so by the time they hit you some of them will be electrons some of them will be tau some of them will be muon neutrinos and if your detector is only set up if your body is only set up to detect electron type neutrinos then all the muons and tau neutrinos are just going to sail right by you you're not set up to see it once we were able to set our up our experiments to see this kind of thing we saw all the neutrinos all over the place but this neutrino mixing is weird there are there are a couple other particles that do this in the universe but not the ones that you interact with on a daily basis not ones flying through your body right now and the fact that neutrinos can mix that they can shift their identities led us to conclude that neutrinos have mass the way it works is that what we call an electron neutrino or a tau neutrino or a muon neutrino isn't the entire story there are these three flavors of neutrinos there are also three masses of neutrinos the physicists label them m1 m2 and m3 which is not very helpful or descriptive or flowery but at least it's simple and straightforward there are three flavors of neutrinos and three masses of neutrinos and these flavors and the masses do not line up they do not describe the same thing which is i mean come on who does this who does this like if you look at an electron you have the charge of the electron you have the flavor of the electron you have the mass of the electron and that's it you name any one of those things and you've completely described the you know who you're talking and talking about you're talking about the electron same as the top quark same as the neutron same whatever particle you want but the neutrino the flavor in the mass do not line up if i say here's a tau neutrino it's really a combination of the three masses of neutrinos the three mass identities of the neutrino if i give you an electron neutrino it's really a mixture of the three mass identities a different mixture but still a mixture of m1 m2 and m3 combine together to give you the electron neutrino they combine together in a different way to give you the muon nutrient combined together in a different way to give you the tau neutrino it also works in reverse like if i were to somehow to give you like here's an m1 neutrino tada it's really a mixture of the electron the muon and the tau neutrinos blending together to give you the m1 these the flavor identities and the mass identities do not line up no other particle that you interact with on a daily basis acts like that the chaon does in case you're wondering but we're not going to talk about the k on today and so that's the reason the reason we think they have mass is the three mass identities they have the different masses m1 is different than m2 and it's different than m3 they travel through space at slightly different speeds and so they like phase in and out of each other as they travel like sometimes m1 is a little bit stronger and sometimes m2 is a little bit sometimes m3 and depending on the ratio of the masses it's that changes what you detect so if there's a certain ratio of m1 m2 and m3 you might get an electron neutrino but if you put take your detector and move it back like a foot then the neutrinos can travel another extra foot and change their identity just a little bit because the ratios of masses will be a little bit different now it's a town you don't see it at all the fact that neutrinos have mass is a huge problem huge we cannot we can't explain it and there's the reason we can't explain is there's one other property of neutrinos that i haven't told you about yet yeah this is this i told you neutrinos are the worst because it just keeps getting worse and worse every uh every particle has something we call a handedness or uh helicity or or somewhat equivalent uh chirality there's various words that we associate with this like if if i shot you with a bullet i know there's a lot of violence involved in this episode please forgive me if i shot with you with the ball and the bullet is spinning it can spin in one direction as it's flying to you or it can spin in in the opposite direction as it's flying to you and it doesn't care we call one of these arrangements right-handed and the other arrangement left-handed okay every single particle as it travels can spin in one direction or the other as it travels who cares there's right-handed versions and left-handed versions neutrinos only come in left-handed form that's right every single neutrino that we've ever observed is only left-handed its spin is always in the opposite direction as its direction of travel every anti-neutrino by the way is always right-handed why is this a problem well particles all particles in physics don't have mass on their own they instead acquire mass by interacting with something called the higgs field the higgs field permeates all the space of time space and time the particles start talking to the higgs field in the higgs field says yeah you can have some mass here's some mass for you electron here's some mass for you top quark you know et cetera et cetera that actual interaction in order to get the math work out and all the symmetries to go right the higgs field has to talk to both right-handed and left-handed versions of the particles say like okay we got a right-handed electron over here and a left-handed electron over here okay i'm going to talk to both of you at the same time and i'm going to give both of you mass and you're going to go on with about your day so if the neutrino is only left-handed there's no right-handed version of the neutrino there's nothing for the higgs bos the higgs field to talk to and so the neutrino can't acquire mass by talking to the higgs field because it doesn't have its opposite-handed counterpart and yet the neutrino has mass do you see why i have a headache now the explanation for why neutrinos have mass is beyond our current understanding of physics it could be it could be that there is a right-handed version of the neutrino but for some reason has some incredibly high mass and so we never see it in our experiments and it never interacts with us on a daily basis we call this a sterile neutrino like it's even less of a neutrino than a neutrino is and that's saying a lot in which case okay you got your left hand you got your right-handed you use the higgs boson mechanism higgs field mechanism you get some mass but we happen to not see the uh the opposite-handed counterpart it could be that neutrinos are their own antiparticle in which case there are some mathematical ways in order to give it mass this is called the myharana mass if you're curious it could be both there could be like right-handed versions and the neutrino could be its its own anti-particle in which case neutrinos would occasionally collide and blow each other up but they so rarely interact it like never happens honestly we don't know honestly we don't know and this is why neutrinos are the worst particle in the universe thank you so much for watching i'll see you next time please go to patreon.com like share subscribe and and i just need a break from neutrinos

Channel: Paul M. Sutter

Views: 28,286

Keywords: space, cosmos, universe, astronomy, physics, astrophysics, cosmology, science, neutrinos, higgs field, neutrino mixing, particle physics, subatomic physics, solar neutrino problem

Id: 0-VgesDOr9E

Length: 16min 36sec (996 seconds)

Published: Wed Apr 21 2021