Related papers: Lepton polarization effects in "Lambda_b -> Lambda…
This study investigates the influence of the fourth generation quarks on the double lepton polarizations in B \rar K \ell^+ \ell^- decay. Taking |V_{t's}V_{t'b}|\sim \{0.01-0.03\} with phase about 100^\circ, which is consistent with the…
The kinematic distributions of the lepton pairs produced in the decay of the Standard Model Higgs to ZZ and WW are related to the polarization fractions of the virtual vector bosons. The full amplitude can be decomposed analytically into a…
The study of polarized branching ratio and different lepton polarization asymmeteries in the exclusive rare decays $B\rightarrow K^{\ast}\ell^{+}\ell^{-}$ ($\ell=\mu , \tau$) have been made in the standard model (SM) and in type III of the…
We consider two-body and quasi-two-body decays of the type $f_1 \to f_2 B$, where $f_1$ and $f_2$ are spin-1/2 fermions and $B$ a spin-0 or spin-1 boson. After recalling the non-covariant formalism for decay amplitudes, we derive the…
We investigate the exclusive $B\to \gamma \ell^+ \ell^- $ decay in the general two Higgs doublet model (model III) including the neutral Higgs boson effects with an emphasis on possible CP-violating effects. For this decay, we analyse the…
The decay width, forward-backward asymmetry and tau lepton longitudinal and transversal polarization for the exclusive (B -> K tau^+ tau^-) decay in a two Higgs doublet model are computed. It is shown that the forward-backward asymmetry and…
The longitudinal polarization, the transverse polarization, and the forward-backward asymmetry of Lambda baryons have been measured using a sample of 4.34 million hadronic Z^0 decays collected with the OPAL detector at LEP between 1990 and…
The paper gives the polarization of the tau lepton in the semileptonic B decays with respect to the direction of the virtual W boson. The result is given including the nonperturbative HQET corrections.The perturbative QCD corrections are…
We analyze the possibility of universality violation in diagonal leptonic decays of the $Z$ boson, in the context of interfamily "see-saw" models. In a minimal extension of the Standard Model with right-handed neutrino fields, we find that…
A Monte Carlo study of the polar and azimuthal angular distributions of the lepton pair arising from the decay of a $W$ or $Z$ boson produced at high transverse momentum in hadronic collisions is presented. In the absence of cuts on the…
We use a sample of 384 million BBbar decays collected with the Babar detector at the PEP-II asymmetric e+e- storage ring to study the flavor-changing neutral current decays B->K(*)l+l-, where l+l- is either e+e- or mu+mu-. We present…
Semileptonic B meson decays induced by $b \to s(d) l^+ l^-$ flavour changing neutral current (FCNC) transitions are very important to probe the quark-flavour sector of the standard model (SM) and also offer a probe to test new physics (NP).…
Rare B decays of the type $b \to s~\ell^+\ell^-(\nu\bar\nu)$ are analyzed in a generic scenario where New Physics effects enter predominantly via $Z$ penguin contributions. We show that this possibility is both phenomenologically allowed…
We study the charmless baryonic three-body decays of B mesons: B+ to p Lambdabar gamma, B+ to p Lambdabar pi0 and B0 to p Lambdabar pi-. The partial branching fractions as a function of the baryon-antibaryon mass and the polar angle…
We study anomalous couplings among neutral gauge bosons in $ZZ$ production at the LHC for $\sqrt{s}=13$ TeV in $4$-lepton final state. We use the cross section and polarization asymmetries of the $Z$ boson to estimate simultaneous limits on…
The transverse lepton polarization asymmetry in pi_l2gamma decays may probe T-violating interactions beyond the Standard Model. Dalitz plot distributions of the expected effects are presented and compared to the contribution from the…
We have calculated the branching ratio and CP asymmetry of B-->X_s +gamma decay within the family--nonuniversal Z' models. We have established certain bounds on the model parameters using the present experimental bounds. We also comment on…
The weak decays of $B \to K^{\ast}_0(1430) l^{+} l^{-}$ ($l=\mu, \tau$) are investigated in Minimal Supersymmetric Standard Model (MSSM) and also in Supersymmetric (SUSY) SO(10) Grand Unified Models. Neutral Higgs bosons are the point of…
New BABAR measurements are presented for the exclusive rare decays B -> K(*) l+ l- including branching fractions, isospin asymmetries, direct CP violation, and lepton flavor universality for dilepton masses below and above the J/psi…
Having taken the QED radiative correction and one-loop weak corrections into account, we have computed the unpolarized forward-backward asymmetry in the process $e^+e^- -> \mu^+\mu^-$ at a very reasonable accuracy. Special attention to the…