Related papers: Calculation of P-Wave Charmonium Decay Rates Using…
We estimate the decay rates of $\eta_c\rightarrow 2\gamma$, $\eta_c'\rightarrow 2\gamma$, and $J/\psi\rightarrow e^+ e^-$, $\psi^\prime\rightarrow e^+e^-$, by taking into account both relativistic and QCD radiative corrections. The decay…
We compute O(alpha^3 ln alpha) corrections to the decay rates of para- and orthopositronium into two and three photons, respectively. For this calculation we employ the nonrelativistic QED regularized dimensionally and we explain how in…
The nature of resonances and excited states near decay thresholds is encoded in scattering amplitudes, which can be extracted from single-particle and multiparticle correlators in finite volumes. Lattice calculations have only recently…
Two-photon decay rates of pseudoscalar, scalar and tensor states of charmonium and bottomonium are calculated in the framework of the relativistic quark model. Both relativistic effects and one-loop radiative corrections are taken into…
Precision tests of the Standard Model and searches for New Physics in the quark flavor sector depend on accurate theoretical calculations of decay rates and spectra for rare, flavor-changing processes. The theoretical status and recent…
We investigate the form factors of $B_c$ meson into $S$-wave charmonium within the nonrelativistic QCD effective theory and obtain the next-to-leading order relativistic corrections to the form factors, where both the $B_c$ meson and the…
Partial decay widths of the heavy-light mesons, $D, D_s, B,$ and $B_s$, emitting one chiral particle ($\pi$ or $K$) are evaluated in the framework of a relativistic potential model. Decay amplitudes are calculated by keeping the Lorentz…
Despite measurements which date more than 20 years ago, no straightforward solution of the ratio of the parity-conserving (P-wave) to parity- violating (S-wave) decays of the hyperons has been obtained. Here we use two 2-point methods in…
A rigorous QCD analysis of the inclusive annihilation decay rates of heavy quarkonium states is presented. The effective-field-theory framework of nonrelativistic QCD is used to separate the short-distance scale of annihilation, which is…
We compute the complete imaginary part of the NRQCD Lagrangian at order 1/M^4 in the heavy-quark mass expansion, which includes center of mass operators, and at order alpha_s^2 in the matching coefficients. We also compute the imaginary…
In this work, we use the $C^3P_{\,0}$ model to calculate the decay widths of the low lying charmonium $J^{PC}=1^{--}$ states, nominally $J/\psi(1S)$ and $\psi(2S)$, in the following common channels: $\rho\,\pi$, $\omega\,\eta$,…
The study of the $B^{+}\to p \bar p K^{+}$ decay channel at LHCb offers great opportunities to study different aspects of the Standard Model and possibly Beyond Standard Model physics. In particular it can be interesting not only for the…
We propose a new strategy for the determination of the QCD coupling. It relies on a coupling computed in QCD with $N_{\rm f} \geq 3$ degenerate heavy quarks at a low energy scale $\mu_{\rm dec}$, together with a non-perturbative…
We investigate decay constants of P and D-wave heavy-light mesons within the mock-meson approach. Numerical estimates are obtained using the relativistic quark model. We also comment on recent calculations of heavy-light pseudo-scalar and…
We investigate $J/\psi$ decays into octet baryon-antibaryons pairs. The decay amplitudes are computed within the collinear QCD factorisation framework. The subleading amplitude, which describes the decay of longitudinally polarised…
We employ ptychography, a phase-retrieval imaging technique, to show experimentally for the first time that a partially coherent high-energy matter (electron) wave emanating from an extended source can be decomposed into a set of mutually…
In this work, we investigate the spectroscopy and decay rates of charmonia within the framework of non-relativistic Schr\"{o}dinger equation by employing an approximate inter quark-antiquark potential. The spin hyperfine, spin-orbit and…
The charm quark density-density correlation is calculated for $1S$ and $1P$ conventional charmonia and $J^{PC}=1^{-+},0^{+-}$ charmoniumlike states from lattice QCD and are interpreted as spatial wave functions of these states with some…
Within the framework of nonrelativistic QCD (NRQCD) factorization,and based on the Collins--Soper operator definition of fragmentation functions, we present a systematic calculation of the fragmentation functions for a heavy quark…
In this paper, a study of two-photon and two-gluon decays in the context of p-wave heavy quarkonia is presented. Within the covariant light-front framework, the annihilation rates of scalar and tensor quarkonium states are derived. In the…