Related papers: B decays with $\tau$-leptons in non-universal left…
Semileptonic $B$ meson decays into the four lightest excited charmed meson states ($D_0^*$, $D_1^*$, $D_1$, and $D_2^*$) and their counterparts with $s$ quarks are investigated, including the full lepton mass dependence. We derive the…
With the expected large increase in data sets, previously not measured decays will be studied at Belle II. We derive standard model predictions for the $B\to X_u \tau\bar\nu$ decay rate and distributions. The region in the lepton energy…
Starting from an Operator Product Expansion in the Heavy Quark Effective Theory up to order 1/m_b^2 we calculate the inclusive semileptonic decays of unpolarized bottom hadrons including lepton mass effects. We calculate the differential…
We address the anomalies in the semi leptonic decays of $B$ mesons in a warped custodial framework. Two possible solutions of lepton non-universality are discussed: A) The muon singlets couple non-universally to NP and B) The…
A class of previously unknown strong-interaction corrections is found to enhance the rate of non-leptonic decays of the b quark by 5-8 percent. This effect decreases the predicted fraction of semi-leptonic decays and brings it into fair…
The full treatment, both nonperturbative - through O(1/m_c^3) - and perturbative - through O(alpha_s) and BLM type O(alpha_s^2) - of the semileptonic lifetime of the D meson is given. A dedicated discussion of the numerics involved is made,…
The measurements of several lepton flavor universality (LFU) violating observables in the decays induced by the quark level transition $b \to c \tau \bar{\nu}$ provide an inkling of plausible physics beyond the standard model of electroweak…
One of the key assumptions of the Standard Model of fundamental particles is that the interactions of the charged leptons, namely electrons, muons, and taus, differ only because of their different masses. While precision tests have not…
We apply the general formalism derived in N. Penalva et al. [Phys. Rev. D 101, 113004 (2020)] to the semileptonic decay of pseudoscalar mesons containing a $b$ quark. While present $B\to D^{(*)}$ data give the strongest evidence in favor of…
We study the exclusive semileptonic $B$-meson decays $B\to K(\pi)\ell^+\ell^-$, $B\to K(\pi)\nu\bar\nu$, and $B\to\pi\tau\nu$, computing observables in the Standard model using the recent lattice-QCD results for the underlying form factors…
The leptonic $\tau$ decays are calculated at the 1-loop level in the Minimal Supersymmetric Standard Model. The deviation from the $\tau - \mu - e$ universality is studied as a function of the supersymmetric parameters and discussed in the…
Several measurements on $R_D, R_{D^*}$, and $R_{J/ \psi}$ by the BaBar, Belle, and LHCb experiments show significant deviations from their Standard Model (SM) predictions, which illustrate the fact that the concept of lepton flavor…
We study the contribution of B_c mesons to the search for B->tau nu decays. We find that at LEP the contributions from B_u and B_c mesons can be comparable. This observation can have a relevant impact on the extraction of constraints on new…
We present a systematic global analysis of dineutrino modes $b \to q \,\nu \bar \nu$, $q=d,s$, and charged dilepton $b \to q \,\ell^+ \ell^-$ transitions. We derive improved or even entirely new limits on dineutrino branching ratios…
Semi-leptonic $B_s \to K \ell \nu$ and $B_s \to D_s \ell \nu$ decays provide an alternative $b$-decay channel to determine the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$ or to obtain $R$-ratios to investigate lepton flavor universality…
New physics models that increase the decay rate of $B_s \to \tau^+ \tau^-$ contribute to the absorptive part of $B_s$--$\bar{B}_s$ mixing, and may enhance $\Delta\Gamma_s$ all the way up to its current experimental bound. In particular, the…
Recently, Qu and Ding, have proposed a formalism where modular invariance is extended to non-supersymmetric scenario considering Yukawa couplings as non-holomorphic functions of modules field $\tau$. Adopting this formalism in this work, we…
We extend the Standard Model (SM) analysis of Ref. [1], which was limited to light leptons in the final state, to the semileptonic $B \to D^* \tau \nu_\tau$ decay. By using quantities that can be analised without the knowledge of $\vert…
We study the effect of non-universal $Z'$ boson on the rare leptonic decay modes of $B_s^*$ mesons, mediated by $b arrow sll$ quark transition. Rare B decays are sensitive to various new physics operators. As B mesons are composite…
We make predictions and propose tests for the semi-leptonic decays $B\to D^{(*)} l \bar{\nu}_l$ and $\Lambda_b\to \Lambda_c l \bar{\nu}_l$, with $l$ = $e$, $\mu$ and $\tau$. Preliminarily, we study such processes according to the $\ell-s$…