The Surprising Truth About the Higgs Boson 'Discovery' at CERN

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CHAPTERS
0:00 "God Particle Found!"
1:18 What are "particles" really?
3:19 Why heavy particles are not stable
5:17 How do we make a Higgs using lighter particles?
6:48 Why the Higgs is so difficult to detect
8:35 How we really "detect" the Higgs
10:56 Most interesting part of the video
11:08 Special offer from Brilliant
12:26 How the Higgs was made at the LHC

SUMMARY
In 2012, the Higgs boson (the God Particle) was discovered. It's responsible for giving mass to fundamental particles. But the scientists never measured the particle. So how can scientists claim a discovery without ever having seen or measured it? What is a measurement anyway?

The Standard Model shows that all fundamental particles that we know of are an excitation in their own field. Since the Higgs particle has a mass of 125 GeV, you must add 125 GeV worth of energy in the Higgs Field to form a Higgs particle. This is a very high energy level, equivalent to the rest mass of about 244,000 electrons.

Making a Higgs is not easy because heavy particles are not stable. They decay to lower mass particles, because the universe intrinsically favors lower mass/energy particles over higher mass particles. The Higgs particle being heavy is unstable and tends to decay into lighter particles.

But mass is only part of the energy of the particle. The combination of rest mass and kinetic energy of ligher particles can add up to the mass of a heavy particle like the Higgs.

This is the principle behind particle accelerators like the Large Hadron Collider at CERN in Geneva. The LHC actually accelerates protons to do this because it’s a bit easier than electrona since a proton is much heavier at around 1 GeV, so it needs less kinetic energy to create the Higgs particle.

How do you detect the Higgs once it is made? You cannot detect it directly for two reasons. First, two protons collide with the same energy, but in opposite directions. The combined momentum is roughly zero. This means that the created Higgs boson will be roughly stationary in the particle beam. It’s difficult to detect something that doesn’t move because the detectors only picks up particles that fly away from the collision. Secondly, Its lifetime is incredibly short. It decays almost instantly. Thirdly, the Higgs is not a charged particle. Since we generally rely on some electromagnetic interaction to physically detect a particle, it’s not clear how you would detect it even if it could reach the detector.

If all that is true, what did we actually “discover” if no one ever measured a Higgs? You don’t need to measure it to know that it’s there. Essentially, if you smash two protons together and get an event where the sum of the decay products adds up to the mass of the Higgs, then we can reasonably conclude that the event likely created a Higgs particle.

But you might ask, what if the event created random interactions which just happened to yield a decay products equal to the Higgs mass? Yes, that could happen. But if you have many multiple measurements over a long period of time, then you can eliminate the possibility of just random interactions. And in the case of the 2012 announcement, this spike achieved 5 sigma significance, which is the gold standard in particle physics, for determining that a new particle was detected. It is thus as statistically significant discovery.

And it turns out that in there are many other particles, that we also never actually directly measure, because of similar limitations.
For example, the quarks and gluons that make up protons and neutrons, cannot because of the nature of the strong force, ever be directly detected. Yet, scientists still claim we discovered them. They can make this claim because the procedure of their discovery is similar to that of the Higgs.

How is the Higgs Boson produced? The most prominent process used at the Large hadron collider is the gluon fusion process. First, two high energy gluons can be produced by smashing two high energy protons. These can, in some cases, turn into top quarks, and fuse together via a triangle loop. This loop represents top quark, and anti-top quark creation and annihilation. The energy of this annihilation can create a Higgs boson.
#HiggsBoson
#LHC
This Higgs particle of course, as I stated earlier, almost instantly decays. So, what does it decay into? The Higgs decays to form very heavy bottom/anti-bottom quarks, which annihilates into two high energy photons. And the energy of these photons adds up to the mass of the Higgs. The photons is what we actually detect.

[johnmckown]

It was wonderful to hear you say that the universe is inherintly lazy. I fit into this model of existance.

[SabineHossenfelder]

An amazingly clear explanation! I remember learning how to do calculations in quantum field theory without having any idea what it all means. I wish you'd been around then, it'd have been much easier to make sense of the maths.

[JthaPTV]

I wish I had a teacher like this growing up. Enthusiastic, to the point and very matter of fact about these complex topics. In the same breath he acknowledges common doubts and questions with a positive and non confrontational ease. I'm just some regular dude pushing 40 with a wife and family but these videos make my brain tingle in a way that just feels great and brings me back to a time where I was excited to learn but never was afforded during my time in the educational system.

[SolveEtCoagula]

One of THE best videos on particle physics I have ever seen. Like many others, when I struggled through my Physics degree we had a backboard and, usually, very badly hand written OHP's (don't worry if you don't know what these are - dreadful things!) to deal with. Not only does AA explain things extremely well, the animations add a new dimension which helps the text tremendously. I envy the new generations of students and hope they appreciate just how valuable these productions are.

Thanks Alvin!

[alfadog]

Outstanding animations as usual, Professor Ash. After watching your videos, I feel like Neo when he learned jiu jitsu.

[steviejd]

Arvin, you are simply brilliant, thank you so much for giving us your time and enthusiasm.

[SamWitney]

Arvin, this is amazing. Thank you for doing this video as I think a lot of people forget that we don't necessarily have to see something directly to know it's there. This is becoming so much more important as there is so much now in physics we can't directly see, but need to find a way to indeed conclude something is there. I hope the science community keeps going with ways to find things that we can't directly see and each of these discoveries is huge. We will always question things and that's good, but we have to learn to make sure we follow the science that's already been concluded. If something is 5 or 6 sigma we can't dismiss it and say it doesn't exist and do some totally different stuff. The only way we make progress is by following what we have found and building on that. As hard as it is. You can find a billion ways to not find something, but the hardest part is finding the one way to find something. This is where I don't agree with experimentalist that all tests are good as they say the result is progress regardless. But it is not now a days as science has become very difficult and very expensive. ITER

[RacerRich]

Great explanation. I was fortunate to tour CERN prior to the official announcement and could read between lines to see that they had made the discovery and were in the process of collecting the statistically significant quantity before making it official. Data processing was impressive in terms of the quantity and that it was processed overnight.

[KnightmareFrame]

Really loved the Feynman Diagram explanation and animation at the end, good stuff!

[JasonPF]

I genuinely look forward to these videos every week, thanks Arvin :)

[jasonjoon]

I love your videos. I have learnt so much from you. I have honestly contemplated quitting my comfortable job to pursue particle physics just because of your videos.

[kajeralocse]

How you simplified this very complex concept is amazing. Thank you.

[emergentform]

Great stuff! Yea we always need to remember that we aren't seeing reality directly but rather our interpretation of reality through the lens of our senses and our own mind. Could be that there are alien civilizations out there that have a while differently model, every bit as valid as our own, completely depending on how they are measuring and interpreting the results of their inquires. The mental map is not the territory, but rather only a representation of it with varying/unknown degrees of accuracy.

[MWTGoldenGun]

I appreciate how you are honest about what we don't know about physics. Many people teach these subjects as immutable fact, when in actuality there is still so much unknown that could upend everything we currently know. It makes you more relatable as a regular person seeking knowledge rather than just another know it all scientist. (Still acknowledging that you are in fact very informed and knowledgeable and a great teacher)

[prolixescalation]

I have no idea how I bumped onto this channel, but it is a blessing

[gdeamonlord]

the channel that keeps on giving, great video, keep it up!

[LQhristian]

Finally, a detailed explanation of the 'actual' discovery!

[GregTateHome]

Great format and presentation style on a pretty complex topic, good job Arvin!

[mandelbraught]

Yeah after I learned more about physics, and science in general, I realized what does "seeing" something even mean. But, of course, we're human and it's natural. Like the JWST, we can't "see" anything it's seeing, although I wish we could 😃 Another excellent one Arvin, thanks!

[PowerScissor]

Another great video!

The number one confusing thing for people in my experience that I get asked the most when they watch videos like this is the heavy use of phrases like "10 times 3 to the power of negative 6".

People that don't deal with numbers written like that, have no idea if that's a big number, a small number, and everything said after that is lost because they can't follow along anymore.

Just a quick explanation of that, even though it might seem silly, would go a long way of helping even more people follow along in these videos.