LHC releases data about new particle but is it Higgs?
The newest results about Higgs search using 4.9/fb of data were published yesterday and there are many articles in arXiv. The overall view is that there is evidence for something around 125 GeV. Whether this something is Higgs or some other particle decaying to Higgs remains to my opinion an open question. Lubos of course is strong in this faith on Higgs. Somewhat surprisingly Tommaso Dorigo seems the result as a firm evidence for Higgs. Matt Strassler is skeptic. The evidence comes basically from Higgs to γγ decays. There are some ZZ and WW events. CMS represented also data for more rare events. There are also indications about something at higher masses and the interpretation of them depends on the belief system of the blogger.
Bloggers were very active and Phil Gibbs certainly the most active one.
- Phil Gibbs gave online comments and combinations of various data in his blog. In particular, Phil produced a combination of data from ATLAS, CMS, LEP, and Tevatron clearly supporting the existence of bump around 124 GeV. Also the other plots by Phil are very illustrative of the situation: for instance this.
- Tommaso Dorigo commented the results. Tommaso gives many illustrations and sees the results as firm evidence for standard model Higgs and is skeptic about SUSY Higgs.
- Lubos Motl has a nice -albeit over-optimistic from SUSY point of view - summary about the results and useful links to the articles by ATLAS and CMS.
- I liked very much about Matt Strassler's critical comments making clear what is known and what is not known.
- Also Resonaances had added comments on Higgs. And many other bloggers.
It is good to try to summarize what has been found.
- According to ATLAS the bump is at 126 GeV. Altogether gamma-gamma and ZZ events give 3.6 sigma deviation reducing to 2.3-2.5 sigma by look-elsewhere effect.
- According to CMS the bump resides at 124 GeV. CMS has 2.6 sigma deviation reducing to 1.9 sigma when look- elsewhere effect is taken into account.
- The positions of bumps reported by ATLAS and CMS are not quite same so that there is still room for the possibility that the bumps are artifacts.
- Both collaborations publish also the results about signal for Higgs to ZZ decays. Fig 7 in ATLAS eprint reports three candidates Higss to ZZ events at 123.6 GeV, 124.3 GeV , and 124.8 GeV. CMS reports results about decays to bbbar, ττbar, WW, ZZ, γγ, combines the data from various channels, and compares signal cross sections to those predicted by standard model Higgs. There is structure around 145 GeV in some channels. There is also data about higher energies bump like structures both below and above 300 GeV. Maybe the standard model Higgs is not enough. SUSY indeed predicts several Higgs like states and M89 hadron physics entire meson spectroscopy.
The ratio of the γγ signal cross section to the cross section predicted by standard model is given together with 1 and 2 sigma bands describing the background signal without Higgs contributions.
- Fig 8 ATLAS paper gives the observed and expected 95 per cent confidence level limits as a function of hypothesized Higgs boson mass.
- Fig 3 of CMS paper gives bump around 124 GeV.
I wish that I could understand the strange oscillating behavior for the ratio of signal cross section to cross section for signals mimicking Higgs predicted in absence of Higgs. There are bumps around 126 GeV, 139 GeV and 146 GeV. Is this an artifact produced - say - by a discretization in the data processing. There is also a small bump around 113 GeV.
I am a statistical dilettante so that I can make an innocent and possibly stupid question: Could these bumps be something real? For standard model Higgs this is certainly not the case but what about TGD inspired view about new physics at LHC. Going to another extreme: could all bumps with 126 GeV bump included be only data processing artifacts? We do not know yet.
Also the probability p0 that standard model without Higgs could explain the signal cross section is plotted.
- Fig 7 of ATLAS paper gives observed and expected p0 values as a function of the mass of hypothesized Higgs. Small p0 tells that standard model without Higgs contribution requires upwards fluctuation whose probability is p0 to explain the observed signal. There are strong downwards bumps at about 126 GeV and around 145 GeV. They are deeper than the prediction of standard model Higgs which might give rise to worries. There is also something very small at 139 GeV.
- Fig 4 of CMS paper gives similar plot. Now the bumps of p0 are around 123.5 GeV, 137 GeV, and 147.5 GeV.
If taken at face value, also these figures suggest three-bump structure. This might well be a statistical artifact but one can make questions and one fool like me can make more or them than the wise guys are able to answer. Here are two of them.
- Could M89 pion have higher excitations with a mass scale of 10-20 GeV? Could the pion-like state generating the signal besides ground state also excitations with excitation energy scale of order 20 GeV? Could these excitation assigned with the magnetic flux tube structures associated associated with scaled up u and d quarks.
A rough guess for the p-adic prime of scaled up u and d quark in M89 hadron is k=113-18= 95 (k=113 corresponds to Gaussian Mersenne and nuclear p-adic length scale). This corresponds to the p-adic mass scale the estimate 16 GeV from electron's p-adic mass scale about .25 MeV. It however turns out that the actual mass must be by a factor two higher so that one would have 32 GeV mass scale.
Could stringy excitations with string tension determined by 32 GeV scale be in question? If so then also ordinary pion should have similar fine structure in mass spectrum with energy scale of 31 MeV assignable with u and d quarks with k=113. I have a vague memory that Tommaso Dorigo had reported something about low energy excitations of pion but I failed to find anything about this in web and concluded that I must have been hallucinating.
- Shnoll effect is something which main stream colleagues certainly refuse to take seriously. In TGD framework one can develop a p-adic model for Shnoll effect which can be justified in terms of quantum arithmetics giving a first principle justification for the canonical identification playing a key role in p-adic mass calculations. The model predicts a number theoretic deformation of probability distributions characterized p-adic prime p. The modification replaces the rational valued parameters of distribution by quantum rationals. Typically a probabiity distribution with single bump decomposes to several ones and the phenomenon occurs also in nuclear physics.
Could this deformation be at work even in particle physics? If so, it could cause the splitting of single very wide resonance bump around 125 GeV to several sharper bumps. Even the bump like structure at 113 GeV could correspond to this wide resonance bump. The original resonance bump could be rather wide: something like 30-40 GeV. Very naive guess would be that the width of leptopion obeys able to decay to ordinary quarks Γ ∼ αs(89) m(π89). Already for αs=.1 one could have a bump with width of about 15 GeV. For ordinary pion the impossibility of strong decays would not allow Shnoll effect. The splitting into sub-bumps by Shnoll effect would make this wide bump visible.
After a painful web search I managed to find an article titled Search for low-mass exotic mesonic structures: II. Attempts to understand the experimental results reporting that there is experimental support for narrow excited states of pion at masses 62, 80, 100, 140, 181, 198, 215, 227.7, and 235 MeV (authors mention that the last might be uncertain). The states at 100, 140, and 198 MeV are half octaves of the lightest state. The article fits the states to Regge trajectories but it is not possible to use single slope for all states. The mass differences vary between 10 and 40 GeV so that the scale is what one would expect from the above string argument. Also Shnoll effect might explain the existence of the bumps and if the explanations are consistent the spectrum of the pion states is dictated by number theoretical arguments to a high degree.
Combination of signals from all channels
CMS has also a preprint about the combination of signals from all decay channels of Higgs.
- CMS gives also a figure combination of all CMS searches (γγ, bbbar,ττbar, WW, ZZ).
- Figure 1 of CMS article shows a clear structure around 124 GeV. There is another structure around about 145 GeV. In standard model Higgs scenario the structure at 145 GeV would not be taken seriously since the cross section need to produce the bump would be much below the predicted one but if one accepts super-symmetric M89 hadron physics, the situation changes. There is also structure around 325 GeV and in the range 260-285 GeV. M89 hadron physics would assign these structures to vector mesons ρ and ω89 and corresponding smesons consisting of squark and anti-squark.
- CMS gives a plot comparing the ratio of best fit for signal cross section to the predicted cross section for Higgs to bbar, ττbar, γγ, ZZ, WW. The fit is rather satisfactory: for Higgs to γγ the signal cross section is about 1.7 times higher than predicted. One cannot deny that this can be seen as a strong support for standard model Higgs.
The original idea behind M89 hadron physics was that it effectively replaces Higgs. If one takes the CMS result seriously this idea must be realized rather concretely: the predicted signal cross sections must be rather near to those predicted by standard model Higgs. The crucial tests are decay rates to fermion pairs and the possibly existing other resonances.
Lubos has written a new post were he makes the strange assumption that if there is a signal it must be Higgs. Lubos also uses as a "proof" of Higgsyness the fit of Phil for which the gamma-gamma signal cross section at maximum equals to the prediction. This holds true because the fit forces it to hold true! For some reason Lubos "forgets" this!
By inspecting the figure more closely one finds that the observed cross section has a long tail unlike the predicted cross section. This long tail could correspond to the large width of resonance splitting into sub-bumps if Shnoll effect is present. If Higgs option is correct, this tail should disappear as statistics improves. Also the other structures which are present, should disappear.
What is of course remarkable that CMS paper shows that H→ γγ cross section is of the same order of magnitude and only about 1.7 times higher than the predicted cross section. This gives a constraint on M89 hadron physics, which it of course might fail to satisfy unless the idea about replacement of Higgs with M89 hadron physics is true at a rather quantitative level.
One should also keep in mind that the value of Higgs mass is at the lower bound for the range with stable Higgs vacuum. This is not a good sign. An interesting question is whether the mass for pion-like state of M89 hadron physics is in some sense also minimal and what this minimality could mean physically: some kind of criticality - maybe on instance of quantum criticality of TGD Universe- but not criticality against the decay of Higgs vacuum?
To sum up, one can agree with the official statement: the situation remains open. What is nice that there very probably is a signal and from TGD point view the nice thing is that this signal is still consistent with M89 hadron physics.