Towards the time-like pion form factor beyond the elastic regime using domain-wall QCD

TL;DR

This paper explores the time-like pion form factor beyond the elastic regime using lattice QCD with domain-wall fermions, aiming to understand inelastic contributions relevant for hadron physics.

Contribution

It introduces a novel lattice QCD approach to access the inelastic region of the time-like pion form factor beyond the elastic limit.

Findings

Preliminary results on one ensemble demonstrate the method's feasibility.

The spectral density analysis provides insights into inelastic pion interactions.

The formalism extends the understanding of hadron form factors in non-elastic regimes.

Abstract

In this work, we investigate the time-like pion form factor from lattice QCD in the isosymmetric limit, a quantity that plays an important role in understanding hadron physics with substantial phenomenological applications. This observable can be calculated in the elastic region using the finite-volume approach, up to the first (four-particle) open channel. With the goal of accessing the exclusive two-pion form factor in the inelastic region, starting from a three-point correlator involving the vector current and two (temporally-displaced) pion interpolating operators, we examine the associated underlying spectral density and calculate the form factor using a formalism based on the LSZ reduction. A preliminary analysis on one ensemble generated by the RBC/UKQCD collaboration using domain-wall fermions is presented.