4 ms·

So What Is It? The bump on the two-photon plots

zzalpha 11y ago
tl;dr we don't know what it is, or even if its a real signal. But glad to see more content-free coverage of this news...
- qrendel 11y ago
  I wouldn't call it "content-free," since it gives arguments for why it can't be a heavier version of the Higgs, describes multiple hypotheses that will be tested, as well as a timeframe for testing them.
  - zzalpha 11y ago
    Or it could be literally nothing at all because the signal isn't strong enough to conclude anything is actually there to begin with. Which at this point is pretty likely, especially for any hypothesis that doesn't fit with the standard model. The coverage of this has been absurdly breathless given the nature of the "result". The bandwagon jumping (or as the author themselves so elegantly put it, ambulance chasing) is truly something to behold...
    - panic 11y ago
      You should take up Luboš Motl on his bet: http://motls.blogspot.lu/2015/12/a-new-750-gev-boson-is-very-likely-there.html http://motls.blogspot.lu/2015/12/a-new-750-gev-boson-is-very...
- brian-armstrong 11y ago
  I have been excited about the bump, even if later the bump turns out to be false. I wanted to make sure people have a chance to follow the story unfolding if they didn't know about it. I also appreciate the thought exercises surrounding the bump as I'm not scientifically literate enough to do them myself.
deepnet 11y ago
The constraints on the signal are: decays into 2 photons, so must be a boson, integer spin, probably 0, 1 or 2 both signals are 45Gev wide and look like the Higgs signal. ATLAS has a 1.6TeV bump at 2.5 Sigma, potentially a resonance. ATLAS has 747 GeV at 3.6 Sigma, CMS 766 GeV at 2.6 Sigma - combines to 4 Sigma although the Look Elsewhere Effect is disputed. ATLAS run1 at 8TeV did not see the signal. ATLAS has a 2.2 sigma for the 2 TeV excess that CMS saw in Run1, potentially indicating the 750GeV is a composite particle. 4 Sigma diPhoton excesses have turned out to be random fluctuations before. http://resonaances.blogspot.fr/2015/12/a-new-boson-at-750-gev.html http://resonaances.blogspot.fr/2015/12/a-new-boson-at-750-ge... http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-papers-on-new.html http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-p... http://www.math.columbia.edu/~woit/wordpress/?p=8174 http://www.math.columbia.edu/~woit/wordpress/?p=8174
- qrendel 11y ago
  > integer spin, probably 0, 1 or 2 So really 0 or 1. If it had spin 2 that would make it a graviton, which seems... unlikely, to say the least.
  - deleted 11y ago
    [deleted]
  - panic 11y ago
    This article: http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-papers-on-new.html http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-p... also mentions that spin 1 is disallowed by the Landau-Yang Theorem. So it's most likely spin 0.
    - qrendel 11y ago
      It seems this theorem only applies to massive spin 1 particles, though: https://physics.stackexchange.com/questions/38427/proof-of-yangs-theorem https://physics.stackexchange.com/questions/38427/proof-of-y...

tl;dr we don't know what it is, or even if its a real signal. But glad to see more content-free coverage of this news...

qrendel 11y ago
I wouldn't call it "content-free," since it gives arguments for why it can't be a heavier version of the Higgs, describes multiple hypotheses that will be tested, as well as a timeframe for testing them.
- zzalpha 11y ago
  Or it could be literally nothing at all because the signal isn't strong enough to conclude anything is actually there to begin with. Which at this point is pretty likely, especially for any hypothesis that doesn't fit with the standard model. The coverage of this has been absurdly breathless given the nature of the "result". The bandwagon jumping (or as the author themselves so elegantly put it, ambulance chasing) is truly something to behold...
  - panic 11y ago
    You should take up Luboš Motl on his bet: http://motls.blogspot.lu/2015/12/a-new-750-gev-boson-is-very-likely-there.html http://motls.blogspot.lu/2015/12/a-new-750-gev-boson-is-very...
brian-armstrong 11y ago
I have been excited about the bump, even if later the bump turns out to be false. I wanted to make sure people have a chance to follow the story unfolding if they didn't know about it. I also appreciate the thought exercises surrounding the bump as I'm not scientifically literate enough to do them myself.

deepnet 11y ago

The constraints on the signal are: decays into 2 photons, so must be a boson, integer spin, probably 0, 1 or 2 both signals are 45Gev wide and look like the Higgs signal. ATLAS has a 1.6TeV bump at 2.5 Sigma, potentially a resonance. ATLAS has 747 GeV at 3.6 Sigma, CMS 766 GeV at 2.6 Sigma - combines to 4 Sigma although the Look Elsewhere Effect is disputed. ATLAS run1 at 8TeV did not see the signal. ATLAS has a 2.2 sigma for the 2 TeV excess that CMS saw in Run1, potentially indicating the 750GeV is a composite particle. 4 Sigma diPhoton excesses have turned out to be random fluctuations before. http://resonaances.blogspot.fr/2015/12/a-new-boson-at-750-gev.html http://resonaances.blogspot.fr/2015/12/a-new-boson-at-750-ge... http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-papers-on-new.html http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-p... http://www.math.columbia.edu/~woit/wordpress/?p=8174 http://www.math.columbia.edu/~woit/wordpress/?p=8174

qrendel 11y ago
> integer spin, probably 0, 1 or 2 So really 0 or 1. If it had spin 2 that would make it a graviton, which seems... unlikely, to say the least.
- deleted 11y ago
  [deleted]
- panic 11y ago
  This article: http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-papers-on-new.html http://motls.blogspot.co.uk/2015/12/first-batch-of-9-pheno-p... also mentions that spin 1 is disallowed by the Landau-Yang Theorem. So it's most likely spin 0.
  - qrendel 11y ago
    It seems this theorem only applies to massive spin 1 particles, though: https://physics.stackexchange.com/questions/38427/proof-of-yangs-theorem https://physics.stackexchange.com/questions/38427/proof-of-y...