Virtual Sfermion Effects on Vector-Boson Pair Production at e^+e^- Colliders

We study the quantum effects on vector-boson pair production in e^+e^- annihilation induced by the sleptons and squarks of the minimal supersymmetric extension of the standard model (MSSM) in the one-loop approximation. We list full analytic results, and quantitatively analyze the resulting deviation from the standard-model prediction of e^+e^- -> W^+W^- for the supergravity-inspired MSSM. The latter can be rendered small throughout the whole parameter space by an appropriate choice of renormalization scheme.Comment: 11 pages (Latex), 3 figures (Postscript); MSSM parameter space restricted by imposing experimental search limits, references added; accepted for publication in Phys. Lett.

Soft gluon multiplicity distribution revisited

In this paper the soft gluon radiation from partonic interaction of the type: $2 \to 2$ + gluon has been revisited and a correction term to the widely used Gunion-Bertsch (GB) formula is obtained.Comment: Few typos corrected, to appear in Phys. Rev. D (rapid communication

Measuring radial flow of partonic and hadronic phases in relativistic heavy ion collision

It has been shown that the thermal photon and the lepton pair spectra can be used to estimate the radial velocity of different phases of the matter formed in nuclear collisions at ultra-relativistic energies. We observe a non-monotonic variation of the flow velocity with invariant mass of the lepton pair which is indicative of two different sources of thermal dilepton sources at early and late stage of the dynamically evolving system. We also show that the study of radial velocity through electromagnetic probes may shed light on the nature of the phase transition from hadrons to QGP.Comment: 0ne figure added, minor modification in tex

Probing Quark Gluon Plasma by Heavy Flavors

The drag and diffusion coefficients of charm and bottom quarks propagating through quark gluon plasma (QGP) have been evaluated within the framework of perturbative Quantum Chromodynamics (pQCD). Both radiative and collisional processes of dissipation are included in evaluating these transport coefficients. The dead cone as well as the LPM effects on radiative energy loss of heavy quarks have also been considered. The Fokker Planck equation has been solved to study the dissipation of heavy quarks momentum in QGP. The nuclear suppression factor, $R_{\mathrm AA}$ and the elliptic flow $v_2^{HF}$ of the non-photonic electrons resulting from the semi-leptonic decays of hadrons containing charm and bottom quarks have been evaluated for RHIC and LHC nuclear collision conditions. We find that the observed $R_{\mathrm AA}$ and $v_2$ at RHIC can be reproduced simultaneously within the pQCD framework.Comment: To appear in the proceedings of WPCF, 2011, Tokyo, Japa

Selection from Multivariate Normal Populations

Selection from multivariate normal population