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One quick question about Higgs boson and supersymmetry...

by No-where-man
Tags: boson, higgs, supersymmetry
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No-where-man
#1
Oct23-13, 02:48 PM
P: 184
Peter Higgs is going to get a Nobel prize for physics, since Higgs boson's existence was confirmed in the experiments in CERN.
But I do have some questions:
I read the following, but I'm not qualified to say if this is true or not, so I'm asking you for help, and if the following statement is crackpotism or not:

I found this:
Even if the Higgs mechanism incorporated into the Standard Model does correctly describe the properties of the particle mediating the decay of fundamental particle quantum mass fields, that does not prove that the Higgs field based mechanism of imparting rest mass to fundamental particles is correct - only that the mechanism of its dissipation upon particle disintegration is properly described and correct.

Is this true or false?

Also I found on CERN's own website:
http://home.web.cern.ch/about/update...le-higgs-boson

"To determine if this is the Standard Model Higgs boson, the collaborations have, for example, to measure precisely the rate at which the boson decays into other particles and compare the results to the predictions. The detection of the boson is a very rare event – it takes around 1 trillion (10^12) proton-proton collisions for each observed event. To characterize all of the decay modes will require much more data from the LHC."

So what do you think? I actually thought that story with Higgs boson is over, I mean Peter Higgs will have Nobel prize for this discovery and confirmation.
I do not understand what else should be experimented when it comes to Higgs boson?

Also, supersymmetry has not been proven yet:
http://www.theguardian.com/science/2...fers-discovery

Are there going to be any problems for Standard Model theory since there is no any confirmation for the existence of supersymmetry which seems to be very elusive, and what would this mean for Standard Model theory, which is he most successful to this day?

http://abcnews.go.com/Technology/god...ry?id=19574423
"CERN is looking to do more with the Higgs boson than simply confirm its existence. Lincoln says that there's a very large discrepancy that still needs to be addressed. The Higgs-boson-like particle observed at the LHC a year ago has about 100 trillion times less than energy than what the Standard Model predicts.

Unfortunately, he will have to wait awhile until he sees that issue resolved. The LHC is currently turned off for maintenance issues and is not scheduled to be turned back on until late 2014 at the earliest."

I don't understand this part:
The Higgs-boson-like particle observed at the LHC a year ago has about 100 trillion times less than energy than what the Standard Model predicts.
What does this mean?
That Higgs-boson particle is not what they thought it would be since its mass unexpectedly; is so small, actually to small according to this?

They also say that: "Since last July, physicists have had their hands full, analyzing a newer and bigger set of data from CERN's Large Hadron Collider (LHC), the world's most powerful particle accelerator. It was the LHC that first provided researchers with evidence of the Higgs boson's existence, and the new data fits in line with Higgs's theory and provides even more evidence that CERN has truly found the Higgs boson."

I thought this story is over and that Higgs boson is definitely 100% proven, I didn't expect this, I'm confused, the way they say this is like they are not still sure or over with experiments which definitely proves the existence of Higgs boson.
Big thanks to all.
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mfb
#2
Oct23-13, 05:38 PM
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Quote Quote by No-where-man View Post
Peter Higgs is going to get a Nobel prize for physics, since Higgs boson's existence was confirmed in the experiments in CERN.
Don't forget Englert. And Brout would have gotten the prize as well, but he died in 2011.

I found this:
Even if the Higgs mechanism incorporated into the Standard Model does correctly describe the properties of the particle mediating the decay of fundamental particle quantum mass fields, that does not prove that the Higgs field based mechanism of imparting rest mass to fundamental particles is correct - only that the mechanism of its dissipation upon particle disintegration is properly described and correct.
Where did you find that? It does not look right.

Also I found on CERN's own website:
http://home.web.cern.ch/about/update...le-higgs-boson

"To determine if this is the Standard Model Higgs boson, the collaborations have, for example, to measure precisely the rate at which the boson decays into other particles and compare the results to the predictions. The detection of the boson is a very rare event it takes around 1 trillion (10^12) proton-proton collisions for each observed event. To characterize all of the decay modes will require much more data from the LHC."

So what do you think? I actually thought that story with Higgs boson is over, I mean Peter Higgs will have Nobel prize for this discovery and confirmation.
I do not understand what else should be experimented when it comes to Higgs boson?
There are still some models that predict a new particle very similar to the standard model higgs, but different in some other aspects. And there might be some completely new thing that has not been thought of yet. It is always useful to test existing theories. This is done with all particles, even the well-known ones. For the Higgs, there are just more tests left to do, and the precision is not so good yet.

Also, supersymmetry has not been proven yet:
http://www.theguardian.com/science/2...fers-discovery
This is a big understatement. There is not even a sign of SUSY. There are some theoretical arguments why SUSY is nice, but nothing has been found yet.

Are there going to be any problems for Standard Model theory since there is no any confirmation for the existence of supersymmetry which seems to be very elusive, and what would this mean for Standard Model theory, which is he most successful to this day?
The SM does not need SUSY.

http://abcnews.go.com/Technology/god...ry?id=19574423
"CERN is looking to do more with the Higgs boson than simply confirm its existence. Lincoln says that there's a very large discrepancy that still needs to be addressed. The Higgs-boson-like particle observed at the LHC a year ago has about 100 trillion times less than energy than what the Standard Model predicts.
This is plain wrong. Don't read articles that have "god particle" in their title, it is not worth the time. I could guess what the original statement was (probably related to the hierarchy problem), but it is certainly not what the article says.

I thought this story is over and that Higgs boson is definitely 100% proven
There are no proofs in physics. Even for the best theories, there could be some experiment tomorrow that shows a deviation. The existence of a particle has been shown beyond reasonable doubt, in all measurements done so far the particle agrees very well with the predictions for the SM higgs boson, so it is expected that it is the SM higgs boson.
Bill_K
#3
Oct23-13, 06:19 PM
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Quote Quote by No-where-man View Post
To determine if this is the Standard Model Higgs boson, the collaborations have, for example, to measure precisely the rate at which the boson decays into other particles and compare the results to the predictions.
What everyone wants to find, of course, is something that the Standard Model does not predict. The radical optimists thought this kind of evidence would turn up almost immediately, possibly involving exotic new particles. Not the case, all we have found so far is the Higgs boson.

But the story is far from over, now we must examine the details. Further analysis will involve a much larger data set, to confirm that the particle we observe behaves exactly as predicted. This is expected to take at least 5-10 years.

No-where-man
#4
Oct24-13, 12:47 AM
P: 184
One quick question about Higgs boson and supersymmetry...

Quote Quote by mfb View Post
Don't forget Englert. And Brout would have gotten the prize as well, but he died in 2011.

Where did you find that? It does not look right.
But how do you than explain Higgs boson and what exactly was confirmed?

There are still some models that predict a new particle very similar to the standard model higgs, but different in some other aspects. And there might be some completely new thing that has not been thought of yet. It is always useful to test existing theories. This is done with all particles, even the well-known ones. For the Higgs, there are just more tests left to do, and the precision is not so good yet.

This is a big understatement. There is not even a sign of SUSY. There are some theoretical arguments why SUSY is nice, but nothing has been found yet.

The SM does not need SUSY.
They always say that supersymmetry is needed in standard model, I guess the are wrong...
But they also say that standard model is incomplete, in what way I'm not sure if they mean on dark matter and dark energy?

This is plain wrong. Don't read articles that have "god particle" in their title, it is not worth the time. I could guess what the original statement was (probably related to the hierarchy problem), but it is certainly not what the article says.

There are no proofs in physics. Even for the best theories, there could be some experiment tomorrow that shows a deviation. The existence of a particle has been shown beyond reasonable doubt, in all measurements done so far the particle agrees very well with the predictions for the SM higgs boson, so it is expected that it is the SM higgs boson.
Thanks for all the answers, and I actually thought this, I even saw that it will take another 10 years to actually prove that this truly a Higgs boson.
You're right about this: There are no proofs in physics. Even for the best theories, there could be some experiment tomorrow that shows a deviation.

But what about protons, electron and all other known particles which we know for quite a long time-so neither they are actually proven-I mean their existence (if I understood correctly)?

I guess the only way actually prove anything in physics is to have gigantic microscope which will put entire universe under its "eye" and observe what's going on, unfortunately this is impossible.

Also if you said the following is correct:
"There are still some models that predict a new particle very similar to the standard model higgs, but different in some other aspects. And there might be some completely new thing that has not been thought of yet. It is always useful to test existing theories. This is done with all particles, even the well-known ones. For the Higgs, there are just more tests left to do, and the precision is not so good yet."

Why than would Peter Higgs or anyone else get a Nobel prize for physics if you cannot really prove anything?
Is not that contradictory?
I mean only a definite 100% irrefutable evidences is what it should matter, nothing less.
No-where-man
#5
Oct24-13, 12:51 AM
P: 184
Quote Quote by Bill_K View Post
What everyone wants to find, of course, is something that the Standard Model does not predict. The radical optimists thought this kind of evidence would turn up almost immediately, possibly involving exotic new particles. Not the case, all we have found so far is the Higgs boson.

But the story is far from over, now we must examine the details. Further analysis will involve a much larger data set, to confirm that the particle we observe behaves exactly as predicted. This is expected to take at least 5-10 years.
Jeez, another 10 years?
I actually suspected that, but I was hoping that this will not be the case after all, I was too optimistic.
But like mfb said you cannot really prove 100% anything in physics, so one experiment could change everything.
mfb
#6
Oct24-13, 02:18 PM
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Quote Quote by No-where-man View Post
But how do you than explain Higgs boson and what exactly was confirmed?
There are many possible explanations, the SM higgs boson is the easiest one.
It was confirmed that there is a particle which agrees very well with the SM higgs.

They always say that supersymmetry is needed in standard model, I guess the are wrong...
Who says that?
But they also say that standard model is incomplete, in what way I'm not sure if they mean on dark matter and dark energy?
Dark matter, dark energy and gravity. And baryogenesis is another unsolved puzzle.

But what about protons, electron and all other known particles which we know for quite a long time-so neither they are actually proven-I mean their existence (if I understood correctly)?
Their existence is shown beyond reasonable doubt, and that is true for the new particle as well.

Why than would Peter Higgs or anyone else get a Nobel prize for physics if you cannot really prove anything?
You cannot prove that the sun exists. But it is a really good model.

I mean only a definite 100% irrefutable evidences is what it should matter, nothing less.
Then do mathematics.

"Further tests need x years" is a bit like Sorites paradox. How many grains of sand do you need to have "a heap"? If you start with a single grain of sand (a single measurement) and just keep adding more and more grains (more measurements), when does it start to become a heap (a confirmation that the new particle is the SM higgs)?
Bill_K
#7
Oct24-13, 02:58 PM
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Quote Quote by mfb View Post
"Further tests need x years" is a bit like Sorites paradox. How many grains of sand do you need to have "a heap"? If you start with a single grain of sand (a single measurement) and just keep adding more and more grains (more measurements), when does it start to become a heap (a confirmation that the new particle is the SM higgs)?
No, come on. That's why we use the five-sigma criterion.
mfb
#8
Oct24-13, 03:02 PM
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Quote Quote by Bill_K View Post
No, come on. That's why we use the five-sigma criterion.
For the existence of a deviation from some hypothesis, sure. But how do you want to show "this particle is the SM higgs boson" in that way? With a deviation from... what?
Bill_K
#9
Oct24-13, 03:37 PM
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What remains to be done to confirm the 126 GeV particle really is the standard Higgs? How much data will it require? How long will it take? Here's some of the answers.

So far, the LHC has accumulated about 25 fb-1 of data. The second run (starting in 2015) is expected to produce 300 fb-1. The upgraded HI-LHC (planned for 2020) will aim for 3000 fb-1.

To-do list:

Higgs production by vector boson fusion (WW, WZ and ZZ) not yet confirmed.

Search for possible exotic decay modes.

Search for other Higgs-like particles.

Determination of Higgs spin/parity - Spin 0 has been verified to 2-3 sigma. Negative parity is disfavored but not yet ruled out.

Higgs self-coupling - you have to create two Higgs at once! Estimated to require 1000 fb-1.
mfb
#10
Oct24-13, 06:30 PM
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More ToDo:
  • measure the coupling constants more precise (will hit systematic limits in most measurements at 3000/fb)
  • measure the production channels more precise
  • measure differential cross-sections (the angular and momentum distribution of the Higgs)
  • make a clear observation of H->ττ (~100-300/fb)
  • find H->μμ (will require >1000/fb for 5 sigma)


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