Related papers: $b \to c$ semileptonic sum rule: orbitally excited…
The $b \to c$ semileptonic sum rules provide relations between the decay rates of $B \to D^{(*)} \tau\bar\nu$ and $\Lambda_b \to \Lambda_c \tau\bar\nu$. Starting from the heavy quark and zero-recoil limits, we revisit the derivation of the…
We investigate semileptonic sum rules in heavy-to-light charm decays, motivated by analogous relations in $b \to c$ and $b \to u$ transitions. Focusing on the $c \to d\overline{\ell}\nu$ decays, $D \to \pi\overline{\ell}\nu$, $D \to…
We study heavy-hadron semileptonic decays proceeding via $b \to c$ transition, such as $B \to D^{(*)}\tau\bar{\nu}_\tau$ and $\Lambda_b \to \Lambda_c\tau\bar{\nu}_\tau$. In the heavy-quark limit, where the heavy-quark symmetry holds, we…
Lepton flavor universality is a key prediction of the Standard Model of particle physics and any violation of it immediately indicates the existence of new physics. Given the recent more than $4\sigma$ discrepancy in charged current…
Lepton flavor universality violations in semileptonic $b \to c$ transitions have garnered attention over a decade. For $R_{H_c}={\rm{BR}}(H_b\to H_c \tau\bar\nu_\tau)/{\rm{BR}}(H_b\to H_c \ell\bar\nu_\ell)$ with $\ell$ being $e,\, \mu$, a…
The form factors of the semileptonic $B_c\to S(AV)\ell\nu$ $(\ell=\tau, \mu, e)$ transitions, where S and AV denote the scalar $X_{c0}$ and axial vector $(X_{c1}, h_{c})$ mesons, are calculated within the framework of the three-point QCD…
Exclusive semileptonic $B$ decays into excited charmed mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. Two universal Isgur-Wise functions \tau and \zeta for semileptonic B decays into four lowest…
The sum rule for charmless inclusive semileptonic B-meson decays allows a theoretically clean and experimentally efficient determination of |V_{ub}|. The leading twist contribution to the sum rule is known in QCD. We compute higher twist…
We derive a Bjorken sum rule for semileptonic $\Omega_b$ decays to ground and low-lying negative-parity excited charmed baryon states, in the heavy quark limit. We discuss the restriction from this sum rule on form factors and compare it…
Motivated by the claimed possibility of a large contribution of the first radial excitation of the $D^{(\ast )}$ to the $B$ semileptonic decay into charmed mesons, also invoked to solve the "$1/2$ vs. $3/2$ semileptonic puzzle", we discuss…
We present a sum rule relating the electron energy spectrum and the hadron mass distribution in semileptonic b -> u decays close to threshold. The relation found is free from non-perturbative effects and the theoretical error is expected to…
We explicitly check quark-hadron duality to order $(m_b-m_c)\Lambda/m_b^2$ for $b \to c l\nu$ decays in the limit $m_b-m_c \ll m_b$ including ground state and orbitally excited hadrons. Duality occurs thanks to a new sum rule which…
Taking into account the gluon condensate contributions, the form factors of the semileptonic $B_c^- \to D^{*0}\ell\nu$ transition with $l=\tau, e$ are calculated in the framework of the three point QCD sum rules. The heavy quark effective…
The form factors of weak decays of the B_c meson to orbitally excited charmonium, D, B_s and B mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. Relativistic effects…
Exclusive semileptonic B decays to the lightest excited charmed mesons are investigated at order $\Lambda_{QCD}/m_Q$ in the heavy quark effective theory. At zero recoil, $\Lambda_{QCD}/m_Q$ corrections to the matrix elements of the weak…
We derive new sum rules for the form factors of the $B_c\to J/\psi\, \ell \bar{\nu}_\ell$ semileptonic transitions, employing the vacuum-to-$B_c$ correlation function of the $J/\psi$-interpolating and $b\to c$ weak currents. In the heavy…
Considering the gluon condensate corrections, the form factors relevant to the semileptonic rare $B_c \rar D,D_s(J^{P}=0^{-}) l^{+}l^{-}$ with $l=\tau,\mu,e$ and $B_c \rar D,D_s(J^{P}=0^{-})\nu\bar{\nu}$ transitions are calculated in the…
We study the semileptonic decays of the $B_c$ meson into final charmonium states within the standard model and beyond. The relevant hadronic transition form factors are calculated in the framework of the covariant confined quark model…
We investigate the semileptonic decays of charmed mesons to light vector mesons within the framework of light-cone sum rules. Our calculation is performed at leading order in QCD coupling, incorporating contributions up to twist-five…
We study the heavy quark effective theory prediction for semileptonic $B$ decays into an orbital excited $F$-wave charmed doublet, the ($2^{+}$, $3^{+}$) states ($D^{*'}_{2}$, $D_{3}$), at the leading order of heavy quark expansion. The…