相关论文: Low-energy matrix elements of heavy-quark currents
We review lattice determinations of the charm and bottom quark masses and the strong coupling constant obtained by different methods. We explain how effective field theory approaches, such as Non-Relativistic QCD (NRQCD), potential…
The invariant yield of electrons from open-heavy-flavor decays for $1<p_T<8$ GeV/$c$ at midrapidity $|y|<0.35$ in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV has been measured by the PHENIX experiment at the Relativistic Heavy Ion…
We present a new perspective on the study of the behavior of the strong coupling $\alpha_s(Q^2)$ -- the fundamental coupling underlying the interactions between quarks and gluons as described by the Quantum Chromodynamics (QCD) -- in the…
The charm quark has unique properties that make it a very important probe of many facets of the Standard Model. New experimental information on charm decays is becoming available from dedicated experiments at charm factories, and through…
We present a complete analysis of the Heavy Quark Effective Theory Lagrangian at order $1/m^2$ in the leading logarithmic approximation, including effects induced by spectator quarks. At this order new correction terms appear in the…
The framework of the expansion by subgraphs is used to compute asymptotic expansions for the vector and the tensor currents in the limit of large quark masses. We use the results to obtain an estimate for the influence of heavy quarks on…
If quantum chromodynamics (QCD) is renormalized by minimal subtraction (MS), at higher orders, the strong coupling constant alpha_s and the quark masses m_q exhibit discontinuities at the flavour thresholds, which are controlled by…
The theory of the strong force, quantum chromodynamics, describes the proton in terms of quarks and gluons. The proton is a state of two up quarks and one down quark bound by gluons, but quantum theory predicts that in addition there is an…
We systematically derive the analytical expressions of the magnetic moments of the spin-$1\over 2$ singly charmed baryons to the next-to-next-to-leading order in the heavy baryon chiral perturbation theory (HBChPT). We discuss the…
The $O(1/m_Q)$ corrections to masses of excited heavy mesons are studied with sum rules in the heavy quark effective theory. Numerical results for the matrix elements of the heavy quark kinetic energy operator K and chromomagnetic…
We present state-of-the-art results for the matrix elements of flavor diagonal tensor operators within the nucleon state. The calculation of the dominant connected contribution is done using eleven ensembles of gauge configurations…
We determine the charm quark mass $\hat{m}_c$ from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD at ${\cal O} (\hat\alpha_s^3)$. Only experimental data for the charm resonances below the continuum…
We investigate effects of charm-quark interactions in a Quark-Gluon Plasma on the production of $D$ and $J/\psi$ mesons in high-energy heavy-ion collisions. Employing a previously constructed coalescence model that successfully reproduces…
We compute the branching ratios for the rare top quark decays t to c gamma and t to c Z mediated by effective flavor changing neutral couplings at the next-to-leading order in QCD including the effects due to operator mixing. After…
The contribution of the strange-quark current to the electromagnetic form factors of the nucleon is studied using lattice QCD. The strange current matrix elements from our lattice calculation are analyzed in two different ways, the…
The scalar heavy quark content of the nucleon, ${\cal M}_q = \bra{N} m_q \bar q q \ket{N},$ is relevant for computing the interaction of dark matter candidates with ordinary matter, while ${\cal M}_s$ is important for predicting the…
We calculate electromagnetic multipole moments of $\Sigma$-type strange hidden-charm pentaquarks $P^{\Sigma}_{\psi s}$ (isospin triplet $\Sigma^+,\Sigma^0,\Sigma^-$) using QCD light-cone sum rules, with six (spin-1/2) and seven (spin-3/2)…
The spin-dependent operators for heavy quarkonium hybrids have been recently obtained in a nonrelativistic effective field theory approach up to next-to-leading order in the heavy-quark mass expansion. In the effective field theory for…
Quantum chromodynamics (QCD) predicts the existence of both nonperturbative intrinsic and perturbative extrinsic heavy quark contributions to the fundamental structure of hadrons. The existence of intrinsic charm at the 3-standard-deviation…
We examine the leading effects of two-body weak currents from chiral effective field theory on the matrix elements governing neutrinoless double-beta decay. In the closure approximation these effects are generated by the product of a…