Are all quarks nearly massless in a QGP

Are all quarks nearly massless in a QGP? A fundamental test of the Higgs Yukawa coupling? M. J. Tannenbaum Brookhaven National Laboratory Upton, NY 11973 USA 4 th International Conference on Hard and Electromagnetic Probes of High Energy Nuclear Collisions--Hard Probes 2010 Eilat, Israel October 10 -15, 2010 Hard. Probes 2010 1

CCR at the CERN-ISR Discovery of high p. T 0 production in p-p F. W. Büsser, et al. , CERN, Columbia, Rockefeller Collaboration Phys. Lett. 46 B, 471 (1973) Bjorken scaling PR 179(1969)1547 Berman. Bj. Kogut scaling PRD 4(71)3388 Blankenbecler, Brodsky, Gunion x. T=2 p. T/ s Scaling PL 42 B, 461 (1972) neff gives the form of the force-law between constituents: neff=4 for QED • e-6 p. T breaks to a power law at high p. T with characteristic s dependence • Large rate indicates that partons interact strongly (>> EM) with other. • Data follow x. T=2 p. T/ s scaling but with neff=8!, not neff=4 as expected for QED Hard. Probes 2010 2

CCOR 1978 --Discovery of “REALLY high p. T>7 Ge. V/c” at ISR CCOR A. L. S. Angelis, et al, Phys. Lett. 79 B, 505 (1978) 8 QCD: Cahalan, Geer, Kogut, Susskind, PRD 11, 1199 (1975) 5 neff=5 (=4++) as predicted for QCD Hard. Probes 2010 3

ISR 0 vs RHIC p-p RHIC pp vs Au. Au 0 are suppressed in Au+Au eg 200 Ge. V p-p Nuclear Modification Factor 0 invariant cross section in p-p at s=200 Ge. V is a pure power law for p. T > 3 Ge. V/c, n=8. 1 0. 1 Hard. Probes 2010 4

Suppression of 0 is arguably the major discovery at RHIC. Energy loss in medium? particle ID is crucial different particles behave differently Original 0 discovery, PHENIX PRL 88 (2002) 022301; Latest PRL 101 (2008) 232301 Direct are not suppressed. 0 and suppressed even at high p. T Implies a strong medium effect (energy loss) since not affected. Hard. Probes 2010 5

QM 2006 -Direct e in Au+Au indicate a theoretical crisis Au+Au p-p beautiful agreement of e with c b production PHENIX PRL 97(2006)252002 Au+Au PHENIX PRL 98 (2007)172301 heavy quarks suppressed the same as light quarks, and they flow, but less. This disfavors the hypothesis of energy loss by gluon bremsstrahlung in medium but brings string theorists into the game, see references in PRL 98 (2007) 172301. Hard. Probes 2010 6

From CERN Courier, September 2007 • I read an article “Yukawa's gold mine” by Nino Zichichi taken from his talk at INPC 2007 in Tokyo, Japan, in which he proposed: “We know that confinement produces masses of the order of a Ge. V. Therefore, according to our present understanding, the QCD ‘colourless’ condition could not explain the heavy quark mass. However, since the origin of the quark masses is still not known, it cannot be excluded that in a QCD coloured world (i. e. QGP), the six quarks are all nearly massless and that the colourless condition doesn’t give quarks is ‘flavour’ dependent. ” • • Higgsisn’t flavor-blind mass !!! QCD • MJT: “Wow! Massless b and c quarks in a color-charged medium would be the simplest way to explain the apparent equality of gluon, light and heavy quark suppression indicated by the equality of RAA for 0 and direct-single e± in regions where both c and b quarks dominate. ” Hard. Probes 2010 7

Why would I be so quick to believe Zichichi? Proc. 12 th ICHEP, Dubna 1964 Hard. Probes 2010 UA 1, UA 2, CERN 1983 W boson discovery 8

In my opinion Zichichi’s idea is much more reasonable than Ad. S/CFT! How to prove it? First, comments from some distinguished physicists: • Stan Brodsky: “Oh, you mean the Higgs Field can’t penetrate the QGP. ” • Rob Pisarski: “You mean that the propagation of heavy and light quarks through the medium is the same” • Chris Quigg (Moriond 08): “The Higgs coupling to vector bosons , W, Z is specified in the standard model and is a fundamental issue. One big question to be answered by the LHC is whether the Higgs gives mass to fermions or only to gauge bosons? The ‘Yukawa’ couplings to fermions are put in by hand are not required. ” “What sets fermion masses, mixings? ” Hard. Probes 2010 9

Opinions of distinguished physicists, cont’d • I asked Steve Weinberg (4/15/10) whether the standard model would still work in the vector boson sector if the Higgs didn’t couple to Fermions, or the Higgs Yukawa coupling was much smaller than now considered standard; and could this possibly explain the absence of the Higgs detected in the and + - decay modes. • He didn’t say yes, He didn’t say no. • But he did say that he and Lenny Susskind had a model, Technicolor, that worked well in the vector boson sector but didn’t give mass to the Fermions. • Hmm. Hard. Probes 2010 10

Does this affect the m. W-mt-m. H relationship? • Bill Marciano: “No change here if no Yukawa coupling; but there could be other changes” (? ) Hard. Probes 2010 11

My Proposal: use the VTX to be installed in 2010 • Map out, on an event-by-event basis, the di-hadron correlations from identified di-jets, and light quark and gluon di-jets, which originate from the vertex and can be measured with 0 -hadron correlations. These measurements will confirm in detail (or falsify) whether the different flavors of quarks behave as if they have the same mass in a color-charged medium. First try: e -h corelations see Jiayin Sun: Mon. Oct 11 -IIB FVTX Endcaps MJT-Erice 08 NCC A. Zichichi INPC 07 VTX Barrel Hard. Probes 2010 12

h -h correlations in Au+Au: Away-side yield vs x. E p. Ta/p. Tt is steeper in Au+Au than p-p indicating energy loss The away side p. Ta/p. Tt x. E distribution triggered by a leading particle with p. Tt was thought to be equal to the fragmentation function but we found that it is NOT sensitive to the shape of the fragmentation function but only to the shape of the inclusive p. Tt spectrum with power n (=8. 1). Formula derived in PRD 74 (2006) 072002 works for pp and AA h (4

First try IAA for e. HF-h in Au+Au-Looks the same as 0 -h ! PHENIX e. HF-h J. Sun IIB PHENIX IAA 0 -h, PRL 104 (2010) 252301 They look the same because NLO parton opposite to e. g. c or b quark is mostlikely a gluon. Need both c-cbar and b-bar identified Hard. Probes 2010 14

Jet shape (FF) prediction and measurement Borghini & Wiedemann, hep-ph/0506218 PHENIX PRD 82(2010)072001 Isolated -h correlation Improving Borghini & Wiedemann x. E distribution for isolated- -h correlation from the reaction g+q +q should be the u quark fragmentation function (FF). Excellent agreement with Tasso fragmentation function from e+e- q+qbar supports this and shows that FF can be determined without Jet reconstruction in p-p (and A+A) from direct- -h correlations Hard. Probes 2010 15

From “Why build the ILC’’-Rolf-Dieter Heuer Hard. Probes 2010 16