Search

We present the result of an indirect search for high energy neutrinos from Weakly Interacting Massive Particle (WIMP) annihilation in the Sun using upward-going muon (upmu) events at Super-Kamiokande. Data sets from SKI-SKIII (3109.6 days) were used for the analysis. We looked for an excess of neutrino signal from the Sun as compared with the expected atmospheric neutrino background in three upmu categories: stopping, non-showering, and showering. No significant excess was observed. The 90% C.L. upper limits of upmu flux induced by WIMPs of 100 GeV c-2 were 6.4 x 10-15 cm-2 s-1 and 4.0 x 10-15 cm-2 s-1 for the soft and hard annihilation channels. respectively. These limits correspond to upper limits of 4.5 x 10-39 cm-2 and 2.7 x 10-40 cm-2 for spin-dependent WIMP-nucleon scattering cross sections in the soft and hard annihilation channels, respectively. [ABSTRACT FROM AUTHOR]

Based on Conesa del Valle et al (2008 Phys. Lett. B 663 202), we present the results for the nuclear modification factors RAA and RCP of the high transverse momentum (5 < pt < 60 GeV/c) distribution of muons in Pb-Pb collisions at LHC energies, in which two pseudo-rapidity ranges covered by the LHC experiments, |e| < 2.5 and 2.5 < e < 4, are investigated. Heavy-quark energy loss is taken into account by mass-dependent BDMPS quenching weights. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. The muons from W and Z, that dominates the high pt, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks. [ABSTRACT FROM AUTHOR]