What We REALLY See at Particle Detectors
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- เผยแพร่เมื่อ 15 เม.ย. 2023
- Since the era of particle colliders, physicists claim to have discovered many different types of elementary particles and with the latest discovery of the Higgs boson in 2012 at the Large Hadron Collider (LHC) the standard model of particle physics is complete. The lifespan of such exotic particles however is in the order of 10^(-25) seconds which is a much smaller time interval humanity measured so far. What gives the physicists the right to claim they have discovered such particles? In this video, I am going to talk about how such particles are detected and what it truly means when physicists say they detected a new particle.
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As someone who works in CERN, I can say that this is probably the best explanation in TH-cam about how our detectors work! It is a shame that CERN official channels don't upload this type of educational content. Keep it up!
Wow, thank you! Means a lot from someone who works there. I envy your job :)
I posted a concept on r/grandunifiedtheory and I’m looking for feedback
I've heard about the "bump" they were looking for in the statistics to confirm the stats, but never understood it fully and why it had to be done like that. Thanks so much for explaining it.
Every article you google just uses layman's terms.
I am glad this video helped :)
Thank you for this! I've never seen a video explaining the detectors at all or what we're seeing with the diagrams of lines shooting and curving everywhere.
Never have i seen a clearer explanation at this level of description. As with your other videos - and they are getting better and better - you are doing a great service. THANK YOU Lukas!
Wow thank you for these kind words and the support it keeps me motivated to create more :)
If anybody are interested in this topic I can recommend book. "The Quantum Frontier. The Large Hadron Collider" by Don Lincoln. If I recall correctly it describe same topic and engineering achievement of LHC as well.
I was amazed how clever is design of LHC was and how many restriction was during building it.
From your video I have understood a whole lot more about how experimental particle physics is conducted that I have not gleaned from anywhere else.
Excellent job you do here on TH-cam. Thank you so much :) :)
Thank you so much for this vid. This is the best explanation on TH-cam. Simple but not oversimplified.
you are awesome at explaining things
More about elementary particle physics, please😃
there is a plan for 2 more so far :)
Bros hair density is going up
I wish that was the case :D
17:14 It's rather impossible because the process must produce a pair : lepton and antilepton of the same kind.
Hence, Zeton may only decay in the following schemes:
Z0 -> e+ + e-;
Z0 -> mi+ + mi- .
And, I suppose, also:
Z0 -> ni_e- +ni_e+
Decay into taon tau+ and antitaon tau- seems to me impossible due to the "huge" mass of taons.
Amazing video 👏 Underrated channel
Thanks! :)
Not really related, but I assume higgs particles would be created when high-energy cosmic rays hit the atmosphere. Would it be possible to build some kind of airborne or orbiting detector that could study these interactions closely enough to detect any exotic particles formed in them? Or is the density of interactions simply orders of magnitude too low for it to be feasible?
Thank you, interesting.
Impressive video. Thank you.
Thanks :)
Great video! I enjoyed it a lot!
Awesome, thank you!
Very well explained.
thanks!
Perfect video!
So, muon's presence is detected, but not its energy, so how can you get any kind of invariant mass out of muon detection? Especially if its the last layer of the detector apparatus?
Thank you!
Thanks!
In comments in another video, regarding higgs, why did fermions need to be described as massless in order to maintain symmetry?
Is there possibly some relation in that because quarks/gluons seem to have an attractive spring like relation, similarly to how an astronaut at a certain distance feels massless (even though they are still bound to Earth's gravity system)?
Also, if you take a random (or a bunch of random) volumes of intergalactic (and/or interstellar) space, let's say cubic volumes of 1 mm:
What percent of these volumes are full of each field?
How can each volume be 100% full of EM field, 100% full of Gravity field, 100% full of higgs field, etc. (I have heard of pauli exclusion, but I don't think that relevantly approaches this question)
I think there are some misconceptions involved here. Let me work backwards and see if I can help.
A "field" in quantum physics isn't like a physical object. Don't think of it as water filling the volume of space occupied by the ocean. Rather, each field is an independent entity that can coexist in a variety of superpositions. Any two fields may or may not interact with each other at various strengths. How strongly and in what ways they interact is called "coupling strength". For example, the electron field is very strongly coupled to the electromagnetic field. This manifests in particle physics as the electron carrying an electromagnetic charge; those two statements are equivalent: the electron is an electromagnetically charged particle; the electron field is strongly coupled to the electromagnetic field.
The Pauli Exclusion Principle only applies to particles (a.k.a. wave packets) _within_ a field. So two electrons, which you can sort of visualize as two hill-like fluctuations in the electron field, can't get too close together or they will repel each other. This is not due to their like charge-that interaction is mediated by the electromagnetic field, via virtual photons. So two electrons sort of near each other will interact via each electron coupling to the EM field, exchanging virtual photons within the EM field, and then re-coupling back to the electron field to feel the effects. But two electrons _extremely_ close to each other will _inherently_ be unable to occupy the same state. Don't ask me what force causes them to repel each other in that case... nobody has ever been able to answer that.
So... to answer your question about how full a given volume of space is with each field, that simply isn't the right question. Each field is basically just information. It's a number or collection of numbers that are defined in every infinitesimal volume of space. A scalar field, like the Higgs Field, only has one number at each point in space that tells us the "scale" of the energy of the Higgs Field at that point, hence "scalar". A vector field will have four numbers per point in space, one for its magnitude and three defining its directionality. So with the Higgs field, you can only ask, "How much Higgs-ness is there here?" With the electromagnetic field (a vector field), you can ask, "How strong is the EM field here and in what direction?" Gravity a.k.a. the curvature of spacetime is a rank 2 _tensor_ field. It has a magnitude, a directionality, and then for each combination of magnitude and direction it also has a _curvature_ or rate of change.
How does this answer the question? Well... imagine if you were to consider a city to be a volume of interest in space, let's say Tokyo. What is the temperature in Tokyo? What is the wind speed and direction? What is the population density? What is the average elevation? These are all numbers, all types of information. They can all coexist, and none of them "fill" the volume of the city that is Tokyo, and yet all of them also fill it because if we're thinking of these properties as fields (temperature as a scalar field, wind velocity as a vector field, etc), each field occupies the entire volume of the city.
Thus, the answer to "What percent of these volumes are full of each field" is: That's just not a sensible question to ask, because that's not how fields work.
So now we're _kind of_ equipped to talk about your first question. See, physics is a grand process of hypothesizing about how the universe works, developing models, and then testing those models to see if they are correct and can predict the outcomes of various experiments. One of our most advanced theories is called Gauge Theory, and models the universe's fundamental particles and forces and fields, and their interactions, as a very simple, elegant mathematical relationship. You may have come across "SU(3) x SU(2) x U(1)" in videos about that.
In that simplistic model, symmetry is extremely important, and with those symmetries, bosons are predicted to be massless.
Experiment, however, shows that they definitely are _not_ massless. Thus that symmetry is _broken;_ it does not hold in the real universe. This means our theory is definitely incorrect in some way, but so far we haven't found any clean modification to it that makes it match experiment. So we instead sort of tack on little modifications, or _perturbations_ of our model to account for the real behavior. With those perturbations, it's an _extremely_ successful theory. It can predict some experimental results and values of universal constants to as much as thirteen significant figures, which is incredible! It also predicts other values such as the energy of an empty volume of space in perfect vacuum, with an error of over 120 orders of magnitude. So it includes both the best and worst predictions ever made in science.
We have been hoping to be able to "quantize" gravity and add General Relativity into the Standard Model to get a full theory of the universe, but it doesn't work. It hasn't been working for over a century now, with thousands and thousands of our best and brightest working on it. The tweaks we have to make are getting increasingly ugly and ad-hoc, and while simplicity isn't _always_ correct, it's been a consistently good signpost for us up until now. New models like String Theory can come up with much more mathematically elegant models that do work, but the problem with those is that the possibility space is absolutely enormous; so big that the chances of stumbling upon the exact parameterization of the exact model that actually describes _our_ universe is all but impossible, sort of like playing "guess the number I'm thinking" when the possibility space is "all the rational numbers between zero and infinity".
Anyway, not sure if this helped or only added more confusion, but it's how I understand the subject at this point.
I think only e+/e- or u+/u- are posible!
yes there is the so called lepton number conservation law :) electron and muon have different lepton numbers and since the original particle is not a lepton its lepton number is 0 but the electron and muon lepton numbers would not cancel out to zero in the final state
How do we go from there is more light at a certain energy, to a particle that give matter mass , I think the property of giving particles mass should be measured.
How do they know that the energy of light produced is related to the particles mass .
The particle mass thing is in the mathematics of standard model. Standard model is based on the requirements for local symmetry of the lagrangian that describe dynamics of the quantum fields. But the problem was that the only way we could have local SU(2) symmetry for fermions was if they were masless because the mass term in the lagrangian broke it. This is the reason the higgs mechanism was invented which lead to the prediction for scalar particle (higgs boson) The LHC comfirmed the existence of such particles that has all the required properties in 2012
@@lukasrafajpps So the higgs boson is necessary for the standard model to work. Is that the evidence for the higgs boson property of giving particles mass ?
There's some things you can only be certain by the law that nothing can violates logic go with that that's a universal law and everything will come up clear like human concepts do not apply on any way to physics like time it is a concept time never exist and never will it's just a concept of our mind same thing with the space space empty if you put something in it even geometry got to take it immediately out for space keeps be in space with nothing in it means concept space can have many things in it like feels objects and by being a concept so it doesn't bend or anything so basically take this two concept out of any equation every revelation you get. taking this thing out it is unbelievable difficult to do but take him out and you'll see everything a little bit clearer
I like this guy. Who is he?
How we detect susy particles if those things even exist ,,,?
well, it depends on their mass if they exist. If it is very high we need very powerfull collider.
@@lukasrafajpps Because of unstable economics and political situations and the contribution of some "physicists" in the last couple of decades or so there are an ever growing number of anti-collider and anti-string or anti-supersymmetry related folks or even anti-science people in general that resulted in an ever increasing pressure to scientific related budgets so it seems like the prospect of us building a FCC or CLIC scale collider in the foreseeable future looks unlikely considering the price tag. But on the other hand in the high energy physics community the number of research on new collider technologies such as PWFA and LWFA also increases with the premise of higher accelerator gradients from 1 GV/m to as high as 100 TV/m (even theoretically an accelerator gradients in the range of petavolts per meter can be achieved with plasmonics) do you think that the new type of accelerators worth pursuing, and can we build one to probe peta or even exaelectronvolts phenomenology regimes?
...LSD particles...
this is why particle physics is a laughing stock. please nobody build another collider.