What's new in
Note: Newest contributions are at the top!
New results have been published on properties of what is conventionally called quark gluon plasma (QGP) . As a matter fact, this phase does not resemble plasma at all. The decay patterns bring in mind decays of string like objects parallel to the collision axes rather than isotropic blackbody radiation. The initial state looks like a perfect fluid rather than plasma and thus more like a particle like object.
The results of QGP - or color glass condensate (CGC) as it is also called - come from three sources and are very similar. The basic characteristic of the collisions is the cm energy s1/2of nucleon pair. The data sources are Au-Au collisions at RHIC, Brookhaven with s1/2=130 GeV, p-p collisions and p-nucleus collisions at LHC with s1/2=200 GeV and d-Au collisions at RHIC with s1/2=200 GeV studied by PHENIX collaboration.
According to the popular article telling about the findings of PHENIX collaboration the collisions are believed to involve a creation of what is called hot spot. In Au-Au collisions this hot spot has size of order Au nucleus. In d-Au collisions it is reported to be much, much smaller. What does this mean? The size of deuteron nucleus or of nucleon? Or something even much smaller? Hardly so if one believes in QCD picture. If this is however the case, the only reasonable candidate for its size would be the longitudinal size scale of colliding nucleon-nucleon system of order L=hbar/s1/2 if an object with this size is created in the collision. I did my best to find some estimate for the very small size of the hot spot from articles some related to the study but failed (see this, this and this): if I were a paranoid I would see this as a conspiracy to keep this as a state secret;-).
How to understand the findings?
I have already earlier considered the basic characteristics of the collisions. What is called QGP does not behave at all like plasma phase for which one would expect particle distributions mimicking blackbody radiation of quarks and gluons. Strong correlations are found between charged particles created in the collision and the best manner to describe them is in terms of a creation of longitudinal string-like objects parallel to the collision axes.
In TGD framework this observation leads to the proposal that the string like objects could be assigned with M89 hadron physics introduced much earlier to explain strange cosmic ray events like Centauro. The p-adic mass scale assignable to M89 hadron physics is obtained from that of electron (given by p-adic thermodynamics in good approximation by m127= me/51/2) as m89= 2(127-89)/2× me/51/2. This gives m89= 111.8 GeV. This is conveniently below the cm mass of nucleon pair in all the experiments.
In standard approach based on QCD the description is completely different. The basic parameters are now thermodynamical. One assumes that thermalized plasma phase is created and is parametrized by the energy density assignable to gluon fields for which QCD gives the estimate ε ≥ 1 GeV/fm3 and by temperature which is about T=170 GeV and more or less corresponds to QCD Λ. One can think of the collision regions as highly flattened pancake (Lorentz contraction) containing very density gluon phase called color glass condensate, which would be something different from QGP and definitely would not conform with the expectations from perturbative QCD since QGP would be precisely a manifestation of perturbative QGP (see this).
Also a proposal has been made that this phase could be described by AdS/CFT correspondence non-perturbatively - again in conflict with the basic idea that perturbative QCD should work. It has however turned out that this approach does not work even qualitatively as Bee ludicly explains this in her blog article Whatever happened to AdS/CFT and the Quark Gluon Plasma?.
Strangely enough, this failure of QGP and AdS/CFT picture has not created any fuss although one might think that the findings challenging the basic pillars of standard model should be seen as sensational and make happy all those who have publicly told that nothing would be more well-come than the failure of standard model. Maybe particle theorists have enough to do with worrying about the failure of standard SUSY and super string inspired particle phenomenology that they do not want to waste their time to the dirty problems of low energy phenomenology.
A further finding mentioned in the popular article is stronger charm-anticharm suppression in head-on collisions than in peripheral collisions (see this). What is clear that if M89 hadrons are created, they consist of lightest quarks present in the lightest hadrons of M89 hadron physics - that is u and d (and possibly also s) of M89 hadrons, which are scaled variants of ordinary u and d quarks and decay to u and d (and possibly s) quarks of M107 hadron physics. If the probability of creating a hot M89 spot is higher in central than peripheral collisions the charm suppression is stronger. Could a hot M89 spot associated with a nucleon-nucleon pair heat some region around it to M89 hadronic phase so that charm suppression would take place inside larger volume than in periphery?
There is also the question whether the underlying mechanism relies on specks of hot QGP or some inherent property of nuclei themselves. At the first sight, the latter option could not be farther from the TGD inspired vision. However, in nuclear string model inspired by TGD nuclei consists of nucleons connected by color bonds having quark and antiquark at their ends. These bonds are characterized by rather large p-adic prime characterizing current quark mass scale of order 5-20 GeV for u and d quarks (the first rough estimate for the p-adic scales involved is p≈ 2^k, k=121 for 5 MeV and k= 119 for 20 MeV). These color bonds Lorentz contract in the longitudinal direction so that nearly longitudinal color bonds would shorten to M89 scale whereas transversal color bonds would get only thinner. Could they be able to transform to color bonds characterized by M89 and in this manner give rise to M89 mesons decaying to ordinary hadrons?
Flowers to the grave of particle phenomenology
The recent situation in theoretical particle physics and science in general does not raise optimism. Super string gurus are receiving gigantic prizes from a theory that was a failure. SUSY has failed in several fronts and cannot be anymore regarded as a manner to stabilize the mass of Higgs. Although the existence of Higgs is established, the status of Higgs mechanism is challenged by its un-naturality: the assumption that massivation is due to some other mechanism and Higgs has gradient coupling provides a natural explanation for Higgs couplings. The high priests are however talking about "challenges" instead of failures. Even evidence for the failure of even basic QCD is accumulating as explained above. Peter Higgs, a Nobel winner of this year, commented the situation ironically by saying that he would have not got a job in the recent day particle physics community since he is too slow.
The situation is not much better in the other fields of science. Randy Scheckman, also this year's Nobel prize winner in physiology and medicine has declared boycott of top science journals Nature, Cell and Science. Schekman said that the pressure to publish in "luxury" journals encourages researchers to cut corners and pursue trendy fields of science instead of doing more important work. The problem is exacerbated, he said, by editors who were not active scientists but professionals who favoured studies that were likely to make a splash.
Theoretical and experimental particle physics is a marvellous creation of humankind. Perhaps we should bring flowers to the grave of the particle physics phenomenology and have a five minutes' respectful silence. It had to leave us far too early.
For background see the chapter "New particle physics predicted by TGD" of "p-Adic Physics".
For background see the chapter "New particle physics predicted by TGD".
This note was inspired by very interesting posting "Storm in IceCube" by Jester. IceCube is a neutrino detector located at South Pole. Most of the neutrinos detected are atmospheric neutrinos originating from Sun but what one is interested in are neutrinos from astrophysical sources.
For background see the chapter "New particle physics predicted by TGD" of "p-Adic length scale hypothesis and dark matter hierarchy".