The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric Standard Model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of "benchmark" models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter tan β and, in some scenarios, on the masses of neutral Higgs bosons.

No abstract

No abstract

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0:3 < p T < 9 GeV=c at midrapidity (jyj < 0:35) from heavy-flavor (charm and bottom) decays in Au Au collisions at s NN p 200 GeV. The nuclear modification factor R AA relative to p p collisions shows a strong suppression in central Au Au collisions, indicating substantial energy loss of heavy quarks in the medium produced at RHIC energies. A large azimuthal anisotropy v 2 with respect to the reaction plane is observed for 0:5 < p T < 5 GeV=c indicating substantial heavy-flavor elliptic flow. Both R AA and v 2 show a p T dependence different from those of neutral pions. A comparison to transport models which simultaneously describe R AA p T and v 2 p T suggests that the viscosity to entropy density ratio is close to the conjectured quantum lower bound, i.e., near a perfect fluid.