Has the Higgs Boson Particle Been Discovered at Cern?

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SUMMARY

The Higgs boson particle has been confirmed with a mass of approximately 125 GeV, with a significance level of 4.9 sigma reported by the CMS collaboration at CERN. Leading physicists, including Joe Incandela, have stated that there is strong evidence for the particle's existence, which is crucial for validating the Standard Model of particle physics. The discovery indicates that the Higgs boson may play a fundamental role in giving mass to elementary particles, marking a significant milestone in modern physics.

PREREQUISITES
  • Understanding of particle physics concepts, particularly the Standard Model
  • Familiarity with the Higgs mechanism and its implications for mass generation
  • Knowledge of statistical significance in experimental physics, specifically the meaning of sigma levels
  • Experience with data analysis techniques used in high-energy physics experiments
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  • Research the implications of the Higgs boson discovery on the Standard Model of particle physics
  • Learn about the methods used in particle detection and analysis at CERN, particularly the ATLAS and CMS experiments
  • Explore the concept of supersymmetry and its relation to the Higgs boson
  • Investigate the ongoing studies regarding the properties of the Higgs boson, including its spin and decay channels
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Physicists, researchers in high-energy physics, students studying particle physics, and anyone interested in the implications of the Higgs boson discovery for our understanding of the universe.

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God particle is 'found': Scientists at Cern expected to announce on Wednesday Higgs boson particle has been discovered


Scientists 'will say they are 99.99% certain' the particle has been found
Leading physicists have been invited to event - sparking speculation that Higgs boson particle has been found
'God Particle' gives particles that make up atoms their mass


http://www.dailymail.co.uk/sciencet...iggs-boson-particle-discovered-Wednesday.html
 
Physics news on Phys.org


Oh damn. Something is about to go down. Hopefully, they have yet to discover the Higgs. I want to work at ATLAS! :-/
 


there'll be other things to discover; you'll still get to work at ATLAS :)
 


How big a result would finding the Higgs be? It seems like a lot of speculation would have made it a very likely find, just a matter of getting enough data.
 


schaefera said:
How big a result would finding the Higgs be? It seems like a lot of speculation would have made it a very likely find, just a matter of getting enough data.

We will then have gained scientific proof that humans are material beings.
That is something to be celebrated!
:smile:
 


schaefera said:
How big a result would finding the Higgs be? It seems like a lot of speculation would have made it a very likely find, just a matter of getting enough data.

Depending on whose analysis you believe, 125 gig Higgs favors a supersymmetric extension of the standard model over a vanilla standard model. Based masses of top quark, and W boson, standard model would prefer Higgs over 130 gig (according to some).
 


If they have already found it, why should they wait another day to announce that they will find it?

:devil:
 
  • #10


PAllen said:
Depending on whose analysis you believe, 125 gig Higgs favors a supersymmetric extension of the standard model over a vanilla standard model. Based masses of top quark, and W boson, standard model would prefer Higgs over 130 gig (according to some).
I saw a number of 122 GeV/c2 today. I'm not sure of the validity. Lot's of rumors/guesses/speculations on the part of outsiders are flying across the internet.

So let's wait for the announcement later this evening or morning or afternoon in Australia/NZ.
 
  • #11


Transcription of the first few minutes of the video which was temporarily accessible online:

Joe Incandela, the CMS Spokesperson, on CMS progress on the search for the Higgs Boson, 4 July 2012:

We've observed a new particle. We have quite strong evidence that there's something there. Its properties are still going to take us a little bit of time. But we can see that it decays to two photons, for example, which tells us it's a boson, it's a particle with integer spin. And we know its mass is roughly 100 times the mass of the proton. And this is very significant. This is the most massive such particle that exists, if we confirm all of this, which I think we will.

And this is very, very significant. It's something that may, in the end, be one of the biggest observations of any new new phenomena in our field in the last 30 or 40 years, going way back to the discovery of quarks, for example. We see very, very strong evidence of the decay to two photons, and a very very narrow peak in the distribution. We see also the evidence of the decay to two Z-particles, which are like heavy photons, in this particular theory of elementary physics. And then we've studied the number of other channels that have reported, but these are less sensitive and are therefore less conclusive at the moment. But we are very excited. I'm extremely tired at the moment, so I may not appear to be as excited as I really am, but the significance of this observation could be very very great.

It could be ultimately seen that its properties are very consistent with the Standard Model Higgs, or it could be found out that its properties don't exactly match the predictions for the Standard Model.
And if that's the case, then we have something really quite profound here. It could be a gateway, if you like, to the next phase of exploring the deepest fabric of the universe, which is pretty profound when you think about it.

And the other thing I would like to say is that obviously all of this is extremely preliminary. What we've looked for is a few grains on a beach, in one sense. I did some calculations, and if you replaced every event, every collision of the beams that we've scanned or had take place in our experiment over the last two years, if you let each one of those be represented by a grain of sand, you'd have enough sand to fill an Olympic-sized swimming pool. And the number of events that we've collected that we claim represent this observation are on the order of tens, or dozens. So it's an incredibly difficult task, and it takes a lot of care and cross-checking. We're re-calibrating, and we'll have better results, even on the current data, when we release at the end of the month. But it's very exciting.
http://blogs.telegraph.co.uk/news/t...like-the-higgs-boson-has-been-found-probably/

(The bold is mine)

Hans
 
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  • #12


Whats so fascinating about the Higgs particle, is that it is the first example that we know of what seems to be a fundamental elementary scalar in nature.

The only other examples that we know about, are always arranged (by hand) by some experimentalist somewhere (say in condensed matter).

What's really quite astonishing about the whole thing, is that scalar field theory is quite sick theoretically. It's the first thing you learn about in a course on quantum field theory, but in some sense its the theory that we have the least control over, and in many ways has the most mysterious and drastic consequences for physics. Thus, it is also one of the last things you end up studying as well.
 
  • #13


Astronuc said:
... So let's wait for the announcement later this evening or morning or afternoon in Australia/NZ.

There was a thread exactly like this that got locked because the mentors wanted to wait until the actual findings were announced to avoid speculation.
 
  • #14


Here's live coverage of the press conference, it starts in 20 minutes or so: http://webcast.web.cern.ch/webcast/play_higgs.html
 
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  • #15


CMS presented a 4.9sigma-signal using the 3 sensitive channels.

The H->gamma gamma channel is very convincing (with a significance of 4 sigma), here is the summary plot for this channel:

snlw2333.jpg
 
  • #16


Result from the conference:
They observed a new boson with mass of 125.3 ± 0.6 GeV at 4.9\sigma significance.
 
  • #17


Is there any chance this is not the Higgs but something else?
 
  • #18


I do not know of any reasonable alternative, and it fits very well to the expectation of the Standard Model Higgs. It could be something else, but I would not expect anything surprising there.

Edit: Here is the corresponding ATLAS plot, giving (local) 4.5 sigma in the H->gamma gamma channel.

68or2i9m.jpg
 
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  • #19


schaefera said:
How big a result would finding the Higgs be? It seems like a lot of speculation would have made it a very likely find, just a matter of getting enough data.



It's BIG. It's confirming the veracity of the Standard Model, which certain circles doubted because of the hypotethical nature of the Higgs(until now).
 
  • #20


Can someone explain to me how they know this particle is a boson?
 
  • #21


This cannot be verified from the data now, but further studies might study the spin, too, by analysing the angular distributions of the decay products.
Apart from that, theory requires that the Higgs particle is a boson. If it is not, it has to be something else, it cannot be the particles which corresponds to the field responsible for electroweak symmetry breaking.

Edit: Combined significance at ATLAS is 5.0 Sigma.
They quote 126.5 GeV as mass.
 
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  • #22


What are the properties they already analysed that leads them to conclude it is the Higgs? I thought they had the spin 0 already?
 
  • #23


The decay channels H \to \gamma \gamma and H \to Z (\to ll) Z^* (\to ll) with the predicted cross-section*branching fraction and the rough mass, consistent with precision SM experiments with other particles. At the same time, no unexpected excess elsewhere.
 
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  • #24


mfb said:
This cannot be verified from the data now, but further studies might study the spin, too, by analysing the angular distributions of the decay products.
Apart from that, theory requires that the Higgs particle is a boson. If it is not, it has to be something else, it cannot be the particles which corresponds to the field responsible for electroweak symmetry breaking.

Edit: Combined significance at ATLAS is 5.0 Sigma.
They quote 126.5 GeV as mass.

I'm pretty sure I heard someone say that they knew it was a boson, maybe I misheard.
 
  • #26


Do they have really a proof or they are interpreting the result that can be the unexpected signal coming from the mass 126 GeV?
 
  • #27


b/c of the decay channel → 2γ, 2Z° it must be a boson
 
  • #28


Is already anything in arXiv ?
 
  • #29


ammalakinki said:
Do they have really a proof or they are interpreting the result that can be the unexpected signal coming from the mass 126 GeV?

You don't have a proof through experiment. ATLAS and CMS have a 99.9999% certainty that there they have found a new boson with a mass of 125 GeV- consistent with the Higgs. But there are several variants of the higgs.

This is just the beginning: the discovery of a new particle. The future is rich with further discoveries on this new particle.
 
  • #30


In other words, it looks like a duck, and it's where we would expect to find a duck (according to the predictions of QAD = quantum aviodynamics), but we have to do further study to verify that it walks like a duck and quacks like a duck.
 
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