Hard diffractive electroproduction of two pions

TL;DR

This paper calculates the leading order amplitude for hard diffractive electroproduction of two pions, revealing isoscalar dominance in certain kinematic regions and linking production mechanisms to gluonic components.

Contribution

It provides a theoretical calculation of the amplitude and insights into the production mechanisms of pion pairs, highlighting the role of gluons in the process.

Findings

Isoscalar pion pairs dominate at x_{Bj}>0.3 near threshold and f_2 resonance.

Production is mainly via two collinear gluons.

Comparison of charged and neutral pion production reveals gluonic contributions.

Abstract

We have calculated the leading order amplitude of hard diffractive electroproduction of two pions in lepton nucleon scattering. At the leading twist level a pion pair can be produced only in an isospin one or zero state. We have shown that isoscalar states are produced dominantly for x_{Bj}>0.3 and with an invariant mass of the two pions close to the threshold (S-wave) and in the f_2 resonance region (D-wave). These isoscalar pion pairs are dominantly produced by two collinear gluons. Comparing the production of charged and neutral pion pairs as a function of x_{Bj} and m_pipi one can get information about the gluonic component of two-pion distribution amplitudes.