Related papers: Tau Decays Beyond the Standard Model
We study the doubly-polarized lepton pair forward-backward asymmetries in (Lambda_b -> Lambda l^+ l^-) decay using a general, model independent form of the effective Hamiltonian. We present the general expression for nine…
Tau-lepton decays with up to two $\pi^0$'s in the final state, $\tau^+ \to \pi^+ \bar{\nu}_\tau$, $\rho^+ (\pi^+\pi^0) \bar{\nu}_\tau$, $a^+_1 (\pi^+\pi^0\pi^0) \bar{\nu}_\tau$, are used to study the performance of the barrel part of the…
The TauSpinner algorithm is a tool that allows to modify the physics model of the Monte Carlo generated samples due to the changed assumptions of event production dynamics, but without the need of re-generating events. With the help of…
We explore the prospects for searches at the LHC for sparticle decays that violate $\tau$ lepton number, in the light of neutrino oscillation data and the seesaw model for neutrino masses and mixing. We analyse the theoretical and…
The presence of tau leptons in the final state is an important signature in searches for physics beyond the Standard Model. Hadronically decaying tau leptons can be reconstructed over a wide kinematic range at ATLAS. The reconstruction…
We perform a study of the $B^{(*)}$, $D^{(*)}$ semileptonic decays, using a different method than in conventional approaches, where the matrix elements of the weak operators are evaluated and a detailed spin-angular momentum algebra is…
The semileptonic decay $\Lambda_c \to \Lambda \ell \nu$ is considered in the framework of heavy quark effective theory beyond the leading order in the $1/m_c$ expansion. According to our estimate the polarization variable will receive only…
We study CP violation in semi-leptonic $\tau$ decays and we determine the conditions necessary to be able to define a observable CP asymmetry. We apply these conditions in both models, the standard model for the electroweak interactions and…
The hadronic decays of the tau lepton can be used to determine the effective charge alpha_tau(m^2_tau') for a hypothetical tau-lepton with mass in the range 0 < m_tau' < m_tau. This definition provides a fundamental definition of the QCD…
Many models for physics beyond the Standard Model predict lepton-flavour violating decays of charged leptons at a level which may become observable very soon. We investigate the decays of a Tau-lepton into three charged leptons (Tau ->…
We present the study of the semileptonic decay \Lambda_c to \Lambda\ell^+\nu by using the light-cone sum rule approach. Distribution amplitudes (DAs) for the \Lambda baryon are discussed to the leading order conformal spin, and QCD sum rule…
The possible anomalous New Physics contributions to electric and magnetic dipole moments of the $\tau$ lepton has brought renewed interest in development of new charge-parity violating signatures in the $\tau$-pair production at Belle II…
Recently, several indications of lepton non-universality observables have been perceived in semileptonic $B$ meson decay processes, both in the neutral-current ($b \to s ll $) and charged-current ($b \to c l \bar \nu_l$) transitions.…
This thesis presents a study of the decays $\tau\rightarrow e\nu\overline{\nu}$ identified after a selection of $\tau^+\tau^-$ events produced in $e^+e^-$ collisions at LEP. These collisions, predominantly mediated by a $Z^0$ boson, offer a…
Precise measurements of the tau lepton properties provide stringent tests of the Standard Model structure and accurate determinations of its parameters. We overview the present status of a few selected topics: lepton universality, QCD tests…
Establishing CP violation in B0 (bar{B0}) --> l+ l- decays requires a measurement of polarization of the final lepton pair, or a precise determination of the B0 --> l+ l- and bar{B0} --> l+ l- rates. We first argue that if the amplitudes of…
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…
In a recent paper we studied the effect of new-physics operators with different Lorentz structures on the semileptonic $\Lambda_b \to \Lambda_c \tau \bar{\nu}_{\tau}$ decay. This decay is of interest in light of the $R({D^{(*)}})$ puzzle in…
The tau-lepton plays an important role in the physics program at the Large Hadron Collider (LHC). It offers a probe in searches for New Physics and to measure parameters of the Standard Model. Spin of tau lepton is an interesting…
In supersymmetry with large tan(beta) the decays B0(B0bar) -> l+l- are dominated by the scalar and pseudoscalar Higgs penguin diagrams leading to strong enhancement of leptonic decay rates with potentially large CP asymmetries in the…