New New Particle Rumour

There is a new rumour about a new particle doing the rounds of the physics blogs. So far it is reported at Not Even Wrong, Resonaances and The Reference Frame.

I do not claim to be the best source of details about new phenomenology,but sometimes my intuition is good so here are a few points.

  • This is not a hoax. It was revealed in an internal memo that was apparently more pubic than it should have been.
  • The memo described a bump in diphoton channel at 115 GeV
  • This is where SUSY prefers the Higgs, but said Higgs does not give such a high rate of diphoton decays.
  • As seen recently bumps can be made to disappear by adjusting the analysis, and this analysis is not completed and approved so it could go away.
  • However, the signal seems to be consistent with the old LEP observation and with faint hints in Tevatron results, so this suggests something real.
  • If it is real then CMS must see it too. Therefore Tommaso Dorigo must remain silent.
  • Although the old LEP result was always considered a hint of a Higgs and this seems likely to be the same thing, we should be open-minded about what it really is.
  • On the one hand I want it to be SUSY and this is possible. We expect to hear about variants of SUSY that fit the bill at the next arXiv hep-ph update.
  • On the other hand, a high photon coupling suggests a neutral composite particle made of charged constituents, like a meson. I don’t know if this is plausible but someone will be suggesting such possibilities soon.
  • Whatever it is, if it is real it is almost certainly Beyond Standard Model and therefore very exciting.
  • The data collected by ATLAS is already quite a bit more than the amount used in this analysis and it will increase by a factor in the coming weeks. There will be more news soon.

Update: Well I was wrong about Tommaso remaining silent. He is sceptical because of comparison with Tevatron and also because of look-elsewhere effect, but the Tevatron can just about accommodate this and there is no look-elsewhere effect if you were specifically looking for a state at 115 GeV :)

Update 23-Apr-2011: Tommaso is now willing to offer $1000 against your $500 that this is not a genuine observation. If you are tempted to take him on you should consider that he may have access to data from CMS that would decisively resolve the question :)

Update 25-Apr-2011: Channel 4 news UK picked up this story and included a well balanced interview with John Butterworth


15 Responses to New New Particle Rumour

  1. If it is real then CMS must see it too. Therefore Tomasso Dorigo must reamin silent. :-)

    Pls spell “remain” betterer.

  2. Luboš Motl says:

    My impressions about the meson, BSM, and other observations are almost exactly identical. Thanks. Of course, aside from compositeness, there can be all kinds of new states that increase the decay rate.

    I have some problems to imagine a silent Dorigo.

    • Philip Gibbs says:

      Yes indeed, this time it will actually be worth while to see what hep-ph can come up with. I suppose even composite Higgs is possible but yes, lots of other possibilities I am sure.

  3. Well, I have suggested the existence of pion like states already for 15 years ago, which is quite soon;-). Worth of the meson sector of entire hadron physics actually. Nice if colleagues gradually start to wake up! Maybe also bloggers could do so;-).

    AS I have explained, TGD predicts scaled up variant of hadron physics at TeV energy range. The CDF bump could be interpreted as the decay of charged pion and width estimate makes sense. This interpretation is however not consistent with neutral pion having so much lower mass. Mass difference between charged and neutral pions should be of order .5 GeV, not 30 GeV.

    Just at this moment the only reasonable interpretation allowing both states as mesons would be that kaon of new hadron physics i-if anything- is detected at CDF and neutral pion at ATLAS. The experimenters could kill the interpretation as neutral pion easily by estimating two-photon production rate from axial current anomaly and using reasonable estimate for the production rate of neutral pions.

    For TGD based interpretation see my blog posting and the previous postings about CDF bump.

  4. alexander dosher says:

    Well, if it was “more pubic than it should have been”, i certainly *hope* it was kept internal. We had proper physics in my day, none of this filthy smut. ;-)

  5. [...] Gibbs también se ha hecho eco de esta noticia en “New Particle Rumour,” viXra log, 22th April, 2011. Como ya he comentado en mi entrada, podría tratarse de una [...]

  6. What is interesting and encouraging from the point of view of TGD is that the total decay rate of exotic pion to gamma pairs is of the same order of magnitude as that using the facts that gamma-gamma branching fraction of standard Higgs is about 2*10^(-3) and scaled up now by factor 30, and that the t total decay width of Higgs is around .3* 10^(-3) GeV. See the blog article. This assuming that exotic gluons appearing in the triangle loop describing decay to gammas form flavor SU(3) octet (fermion generations form the triplet) meaning additional factor 64 in the rate determined by anomaly considerations.

    The total decay width of exotic pion is however several orders of magnitude higher than the width of Higgs like particle which is below 10^(-2) GeV in the mass regions considered. See the figure 4 of of this article. If experimentalists have really been able to conclude that the decay width is indeed of this order of magnitude, the identification as exotic pion is definitely excluded.

    The decay width 10^(-2) GeV is quite a small number as compared to the width of the peak like structure at 120 GeV appearing in D0 data represented by Tommaso: it is measured in GeVs. How the experimentalists are able to deduce the decay width or are they able to actually able to do this at all?

    What is the contribution of the measurement uncertainties to the width of the bump- say the width coming from the uncertainty in the measurement of gamma energies? If it is of order GeV meaning 1 per cent uncertainty in the measurement of gamma energy or even .1 GeV, how the experimentalists manage to conclude that Higgs candidate with decay width below 10^(-2) GeV is in question? Is this just an assumption motivated by expectations?

    In any case, if the experimenters have managed to determine the decay width so accurately, the interpretation as pion of scaled up hadron physics is definitely excluded since the decay width should be measured using GeV or even 10 GeV as a unit. Even as a dummy non-professional I dare to be skeptic. Also the fact that 115 GeV happens to be just what is expected from SUSY according to Lubos raises strong suspicions that experimentalists tend to see what theoreticians tell they should see;-). I am also wondering the completely uncritical attitude of Lubos concerning the interpretation as SUSY Higgs.

    Matti Pitkanen

  7. [...] Gibbs también se ha hecho eco de esta noticia en “New Particle Rumour,” viXra log, 22th April, 2011. Como ya he comentado en mi entrada, podría tratarse de una nueva [...]

  8. D R Lunsford says:

    I wonder what Tony Smith’s E8 model says about this?

    -drl

  9. [...] Gibbs también se ha hecho eco de esta noticia en “New Particle Rumour,” viXra log, 22th April, 2011. Como ya he comentado en mi entrada, podría tratarse de una nueva [...]

  10. [...] Atlas, al CERN, c’era una sorpresa? Sì, un’altra gobba come al Tevatron! Sarà mica il bos…? No, no,  semmai diverso, ma come si permette questo [...]

  11. [...] again the latest rumour of a new particle has proven too good to be true. With the first public plots using 2011 data at the LHC the ATLAS [...]

Follow

Get every new post delivered to your Inbox.

Join 281 other followers

%d bloggers like this: