Light Cone Distribution Amplitude for the $\Lambda$ Baryon from Lattice QCD

TL;DR

This paper computes the light-cone distribution amplitudes of the $\Lambda$ baryon using lattice QCD with large momentum effective theory, providing foundational results for understanding baryon structure and decay processes.

Contribution

It introduces a lattice QCD approach to calculate the $\Lambda$ baryon LCDAs within the large momentum effective theory framework, a novel application for baryon studies.

Findings

Computed the three-dimensional momentum fraction distribution for light quarks in $\Lambda$

Validated the analytic properties of baryon quasi-distribution amplitudes in coordinate space

Provided results that can inform phenomenological models of $\Lambda_b$ decays

Abstract

We calculate the leading-twist light-cone distribution amplitudes of the light $\Lambda$ baryon using lattice methods within the framework of large momentum effective theory. Our numerical computations are conducted employing $N_f=2+1$ stout smeared clover fermions and a Symanzik gauge action on a lattice with spacing $a=0.077\;\rm{fm}$, and a pion mass of 303 MeV. To approach the large momentum regime, we simulate the equal-time correlations with the hadron momentum $P^z = \{2.52, 3.02, 3.52\}$ GeV. By investigating the potential analytic characteristics of the baryon quasi-distribution amplitude in coordinate space, we validate these findings through our lattice calculations. After renormalization and extrapolation, we present results for the three-dimensional distribution of momentum fractions for the two light quarks. Based on these findings the paper briefly discusses the phenomenological impact on weak decays of $\Lambda_b$, and outlines potential systematic uncertainties that can be improved in the future. This work lays the theoretical foundation for accessing baryon LCDAs from lattice QCD.