Related papers: Long-distant contribution and $\chi_{c1}$ radiativ…
We revisit the calculation of the width for the radiative decay of a $1^{+-}$ heavy $Q \bar Q$ meson via the channel $1^{+-} \to 0^{-+} +\gamma$ in the covariant light-front quark model. We carry out the reduction of the light-front…
In this study, we conduct an enhanced investigation of pure annihilation-type charmless hadronic B-decays within the framework of the PQCD approach. Specifically, we account for the quark-loop enhanced contribution to various decay…
In this work, we discuss the contribution of the mesonic loops to the decay rates of $\chi_{c1}\to \phi\phi,\,\omega\omega$ which are suppressed by the helicity selection rules and $\chi_{c1}\to \phi\omega$ which is a double-OZI forbidden…
Radiative decays $D^*_{(s)}\to D_{(s)}\gamma$ are revisited in light of new experimental data from the \textit{BABAR} and BESIII collaborations. The radiative couplings $g_{D^*D\gamma}$ encoding nonperturbative QCD effects are calculated in…
Using the 1/N_C expansion scheme and truncating the hadronic spectrum to the lowest-lying resonances, we match a meromorphic approximation to the < S P P > Green function onto QCD by imposing the correct large-momentum falloff, both…
We present leading logarithmic QCD corrections to the decay B_s --> \gamma\gamma in the Standard Model. Further, the form factor F_{1}(0) of B_s --> \phi\gamma is calculated in the framework of QCD sum rules and found to be in agreement…
We study the radiative (E1 and M1) decays of P-wave quarkonia in a strong magnetic field based on the Lagrangian of potential nonrelativistic QCD. To investigate their properties, we implement a polarized wave function basis justified in…
Until present the study of the form factors associated to the vector and axial-vector components of the hadronic weak current has been carried out with a plethora of modelizations of the underlying strong interactions. While of importance…
The electromagnetic decays of the ground state baryon multiplets with one heavy quark are calculated using Heavy Hadron Chiral Perturbation Theory. The M1 and E2 amplitudes for S^{*}--> S gamma, S^{*} --> T gamma and S --> T gamma are…
The decay of the Higgs boson into two photons, $h \to \gamma \gamma$, is a loop-induced process within the Standard Model, predominantly mediated by loops of $W$ bosons and top quarks. While these leading contributions are well understood,…
Based on the framework of nonrelativistic Quantum Chromodynamics (NRQCD), we carry out next-to-leading order (NLO) QCD corrections to the decay of $Z$ boson into $\chi_c$ and $\chi_b$, respectively. The branching ratio of $Z \to…
General one-loop contributions to the decay amplitudes $H\rightarrow \nu_l\bar{\nu}_l\gamma$ are presented, considering all possible contributions of additional heavy vector gauge bosons, fermions, and charged (and also neutral) scalar…
Recently, the BESIII Collaboration reported the first observation of the decays $\chi_{cJ} \to \eta \eta \eta^\prime$ in order to search for the $1^{-+}$ exotic state $\eta_1(1855)$. A partial wave analysis of the $\eta \eta^\prime$…
Various exclusive and inclusive decays of B mesons are studied, at present, with dedicated experiments at ``B factories''. In order to compete with the experimental accuracy, we need a reliable theoretical framework to compute strong…
Adding a hard photon to the final state of a leptonic pseudoscalar-meson decay lifts the helicity suppression and can provide sensitivity to a larger set of operators in the weak effective Hamiltonian. Furthermore, radiative leptonic $B$…
A lattice QCD approach to the calculation of the long-distance contributions to $\epsilon_K$ is presented. This parameter describes indirect CP violation in $K\to\pi\pi$ decay. While the short-distance contribution to $\epsilon_K$ can be…
We discuss exclusive charmless B decays within the Standard Model of particle physics. In particular, we consider hadronic two-body decays as B -> pi pi and perform a conceptual analysis of heavy-to-light form factors which encode the…
The two-loop QCD radiative corrections to the $B_c$ meson leptonic decay rate are calculated in the framework of NRQCD factorization formalism. Two types of master integrals appearing in the calculation are obtained analytically for the…
We apply the perturbative QCD factorization theorem developed recently for nonleptonic heavy meson decays to the radiative decay $B\to K^*\gamma$. In this formalism the evolution of the Wilson coefficients from the $W$ boson mass down to…
We calculate the contribution of the weak annihilation to the $B\rightarrow \rho\gamma$ decay amplitude by means of QCD sum rules using the photon light-cone wave function. We find that this long-distance contribution amounts to about 10\%…