arXiv subjects

José Manuel Morgado Chávez

Publications and source records attributed to José Manuel Morgado Chávez.

4 recordsLinked to original sources

arXiv2024

The distribution amplitude of the $η_c$-meson at leading twist from Lattice QCD

Distribution amplitudes are functions of non-perturbative matrix elements describing the hadronization of quarks and gluons. Thanks to factorization theorems, they can be used to compute the scattering amplitude of high-energy processes. Recently, new ideas have allowed their computation using lattice QCD, which should provide us with a general, fully relativistic determination. We present the first lattice calculation of the $η_c$-meson distribution amplitude at leading twist. Starting from the relevant matrix element in discrete Euclidean space on a set of $N_f=2$ CLS ensembles, we explain the method to connect to continuum Minkowski spacetime. After addressing several sources of systematic uncertainty, we compare to Dyson-Schwinger and non-relativistic QCD determinations of this quantity. We find significant deviations between the latter and our result even at small Ioffe times.

hep-lat↗

arXiv2024

The $η_c$-meson leading-twist distribution amplitude

In this project, we employ the short-distance factorization to compute the distribution amplitude of the $η_c$-meson from Lattice QCD at leading twist. We employ a set of CLS $N_f=2$ ensembles at three lattice spacings and various quark masses to extrapolate the pseudo distribution to the physical point in the isospin limit. We solve the inverse problem modeling the distribution amplitude, and we match our results to the light-cone in the $\overline{\text{MS}}$-scheme. We include a complete error budget, and we compare to two alternative approaches: non-relativistic QCD and Dyson-Schwinger equations, finding good agreement with the latter but not with the former.

hep-lat↗

arXiv2024

The distribution amplitude of the $η_c$-meson

In this proceeding we determine the distribution amplitude of the $η_c$-meson from first principles. This quantity appears as a consequence of factorization theorems, and it is necessary to compute the amplitude of multiple exclusive processes. Since it is defined along a light-cone, its calculation via lattice QCD was impossible until recently, when a generalization to Euclidean metric was proposed, and a connection to the physical limit was established. We briefly explain the method of short distance factorization, which allows us to compute the distribution amplitude, and our lattice setup. After summarizing the steps for the continuum and chiral extrapolation, we present our results and compare them to two alternative determinations, one using non-relativistic QCD and another solving the Dyson-Schwinger equations; we find a large discrepancy with the former.

hep-lat↗

arXiv2023

The distribution amplitude of the $η_c$ meson

We report on the first lattice determination of the pseudoscalar meson $η_c$ light-cone distribution amplitude, using a set of three CLS $N_f=2$ ensembles at a pion mass $m_π \sim 270~\text{MeV}$ and lattice spacings $a \sim 0.076~\text{fm}$, $0.066~\text{fm}$ and $0.049~\text{fm}$. Employing Short Distance Factorization, we extract the pseudo-DA on the lattice for Ioffe times $ν\leq 4.5$, and the various lattice spacings allow us to take the continuum limit. We employ a basis of Jacobi polynomials to parametrize the distribution amplitude, which allows to express the matching to the pseudo distribution in closed form, and we observe a strong effect which we attribute to the heavy charm-quark mass.

hep-lat↗