From the discovery of direct-single-electrons at the CERN ISR to a fundamental test of the Higgs Yukawa coupling in Heavy Ion collisons

by Michael Tannenbaum (Brookhaven National Laboratory)

Tuesday 5 May 2009, 11:00 → 12:00 Europe/Zurich

40-S2-C01 (CERN)

Direct single electrons in pp collisions were discovered by the CERN-Columbia-Rockefeller-Saclay Collaboration at the CERN-ISR in 1974 (before the discovery of the J/Psi) and shown by Hinchliffe and Llewellyn Smith in 1976 to be the result of the production and decay of charm particles. This technique was used at RHIC to measure the production of the heavy c and b quarks and their suppression in Au+Au collisions at the same level as pizeroes from light quarks and gluons. This dramatic and unexpected result is incompatible with the most likely explanation of suppression as due to radiational energy loss. Zichichi has suggested that ``since the origin of the quark masses is still not known, it cannot be excluded that in a QCD coloured world (QGP), the six quarks are all nearly massless''. Since the Yukawa coupling of the Higgs Boson to Fermions is not a key feature of the standard model, but is put in by hand, massless b and c quarks in a QGP are not necessarily excluded and would be the simplest way to explain the apparent equality of light and heavy quark suppression in Heavy Ion Collisions. Forthcoming precision measurements of light and heavy quark energy loss in A+A collisions at RHIC and LHC should confirm in detail (or falsify) whether the different flavors of quarks behave as if they have the same mass in a color-charged medium, which would be a unique contribution of Relativistic Heavy Ion Physics at a fundamental level to the standard model. Title: Heavy Ion Forum Description: Heavy Ion Forum, U. Wiedenann, Y. Foka Community: ALICE Meeting Access Information: - Meeting URL http://evo.caltech.edu/evoGate/koala.jnlp?meeting=eueneevav2aDa9IiaBIu - Phone Bridge ID: 948056