Impact of Z′Z^{\prime} and UED parameters on different asymmetries in Bs→ϕℓ+ℓ−B_{s} \to \phi \ell^{+} \ell^{-} decays

A comprehensive study of the impact of new-physics on different observables for $B_{s}\to \phi \ell^{+}\ell^{-}$ has been done. We examine the new physics models such as $Z^{\prime}$ and UED models, where the effects of new physics coming through the modification of Wilson coefficients. We have analyzed these effects through the theoretical prediction of the branching ratio, the forward-backward asymmetry, lepton polarization asymmetries and the helicity fractions of the final state meson. These all observables will definitely be measured in present and future colliders with great precision. We also pointed out that hadronic uncertainties in various physical observables are small which make them an ideal probe to establish new physics. Therefore, the measurements of these observables for the same decay would permit the detection of physics beyond the Standard Model and will also help us to distinguish between different new physics scenarios.Comment: 28 pages, 14 figure

K_1(1270)-K_1(1400) mixing and the fourth generation SM effects in B-->K_1l^+l^- decays

The implications of the fourth generation quarks in the B-->K_{1}(1270,1400)l^{+}l^{-} with l=mu, tau decays are studied, where the mass eigenstates K_{1}(1270) and K_{1}(1400) are the mixture of ^{1}{P}_{1} and ^{3}{P}_{1} states with the mixing angle \theta_{K}. In this context, we have studied various observables like branching ratio (BR), forward backward asymmetry (A_{FB}) and longitudinal and transverse helicity fractions (f_{L,T}) of K_{1} meson in B-->K_{1}l^{+}l^{-} decays. To study these observables, we have used the Light Cone QCD sum rules form factors and set the mixing angle \theta_{K}=-34^{o}. It is noticed that the BR is suppressed for K_{1}(1400) as a final state meson compared to that of K_{1}(1270). Same is the case when the final state leptons are tauons rather than muons. In both the situations all the above mentioned observables are quite sensitive to the fourth generation effects. Hence the measurements of these observables at LHC, for the above mentioned processes can serve as a good tool to investigate the indirect searches for the existence of fourth generation quarks.Comment: 17 pages, 14 figures, resembles with the PRD published versio

Pakistan's trade competitiveness & complementarities in South Asia

Over the past decade Pakistan remained involved in two major trade agreements with in the South Asia (Pakistan & Sri-Lanka FTA and SAFTA). It is meaningful from an operational and policy perspective to evaluate Pakistan's trade performance in South Asia against its objectives of greater trade integration and suggest policy interventions to improve its effectiveness. In order to achieve this objective, current study evaluates the Pakistan’s overall and chapter-wise trade performance with SAARC major SAARC economies for the last seven years (2003-09). This study has been disaggregated into two parts: In the first part of the study, an assessment of trade performance of SAARC members is carried out with respect to the rest of the world. Pakistan's trade performance vis-à-vis other SAARC members is the focus of this part. In the second part Pakistan’s trade performance in South Asia has been analyzed and policy interventions have been suggested to improve its effectiveness. Certain trade indicators like Trade Complementarity Index (TCI), Trade Specialization Index (TSI), Grubel Lloyd Index (GLI), Revealed Comparative Analysis (RCA), Bilateral Revealed Comparative Analysis BRCAs and Revealed Market Access (RMA) have been employed to achieve the above objectives.International Trade, Regionalism

Insights into the quark-gluon vertex from lattice QCD and meson spectroscopy

By comparing successful quark-gluon vertex interaction models with the corresponding interaction extracted from lattice-QCD data on the quark's propagator, we identify common qualitative features which could be important to tune future interaction models beyond the rainbow ladder approximation. Clearly, a quantitative comparison is conceptually not simple, but qualitatively the results suggest that a realistic interaction should be relatively broad with a strong support at about $0.4-0.6$~GeV and infrared-finite