Prasanta Kumar Das

Data for polarization in charmless B{yields}{phi}K*: A signal for new physics?

The recent observations of sizable transverse fractions of B{yields}{phi}K* may hint for the existence of new physics. We analyze all possible new-physics four-quark operators and find that two classes of new-physics operators could offer resolutions to the B{yields}{phi}K* polarization anomaly. The operators in the first class have structures (1-{gamma}{sub 5})x(1-{gamma}{sub 5}), {sigma}(1-{gamma}{sub 5})x{sigma}(1-{gamma}{sub 5}), and in the second class (1+{gamma}{sub 5})x(1+{gamma}{sub 5}), {sigma}(1+{gamma}{sub 5})x{sigma}(1+{gamma}{sub 5}). For each class, the new-physics effects can be lumped into a single parameter. Two possible experimental results of polarization phases, arg(A{sub perpendicular})-arg(A{sub parallel}){approx_equal}{pi} or 0, originating from the phase ambiguity in data, could be separately accounted for by our two new-physics scenarios: the first (second) scenario with the first (second) class new-physics operators. The consistency between the data and our new-physics analysis suggests a small new-physics weak phase, together with a large(r) strong phase. We obtain sizable transverse fractions {lambda}{sub parallel{sub parallel}}+{lambda}{sub perpendicular{sub perpendicular}}{approx_equal}{lambda}{sub 00}, in accordance with the observations. We find {lambda}{sub parallel{sub parallel}}{approx_equal}0.8{lambda}{sub perpendicular{sub perpendicular}} in the first scenario but {lambda}{sub parallel{sub parallel}} > or approx. {lambda}{sub perpendicular{sub perpendicular}} in the second scenario. We discuss the impact of the new-physics weak phase on observations.

Unparticle effects in Supernovae cooling

Recently H. Georgi suggested that a scale-invariant unparticle U sector with an infrared fixed point at high energy can couple with the standard model matter via a higher-dimensional operator suppressed by a high cutoff scale. Intense phenomenological search of this unparticle sector in the collider and flavor physics context has already been made. Here we explore its impact in cosmology, particularly its possible role in the supernovae cooling. We found that the energy-loss rate (and thus the cooling) is strongly dependent on the effective scale {lambda}{sub U} and the anomalous dimension d{sub U} of this unparticle theory.

Moller and Bhaba scattering in the noncommutative SM

We study the Moeller and Bhabha scattering in the noncommutative extension of the standard model using the Seiberg-Witten maps of this to first order of the noncommutative parameter {theta}{sub {mu}}{sub {nu}}. We look at the angular distribution d{sigma}/d{omega} to explore the noncommutativity of space-time at around {lambda}{sub NC}{approx}TeV and find that the distribution deviates significantly from the one obtained from the commutative version of the standard model.

COSMIC BIREFRINGENCE WITHIN THE FRAMEWORK OF HETEROTIC STRING THEORY

Low energy string theory predicts the existence of an axion field which can lead to cosmic birefringence. We solve the electromagnetic wave equations in the presence of such an axion and a dilaton field in order to determine their effect on the polarization of light. We find that the presence of dilaton field leads to a nontrivial modification of the final result. We comment on the possibility of discovering such an effect by observations of radio wave polarizations from distant radio galaxies and quasars. We have also determined the limits on the string theory parameters that are imposed by the current polarization data from distant quasars and radio galaxies.

e+e−→μ+μ−scattering in the noncommutative standard model

We study muon pair production

Neutral Higgs boson pair production at the LC in the Noncommutative Standard Model

e^+ e^- \to \mu^+ \mu^-

On distinguishing radions from Higgs bosons

in the noncommutative(NC) extension of the standard model using the Seiberg-Witten maps of this to the second order of the noncommutative parameter

Neutral Z boson pair production due to radion resonance in the Randall-Sundrum model: Prospects at the CERN LHC

\Theta_{\mu \nu}

Working group report: High energy and collider physics

. Using

ρ parameter constraints on radion phenomenology and a lower bound on Higgs mass

\mathcal{O}(\Theta^2)