Analysis of polarization observables and radiative effects for the reaction $\bar p+p\rightarrow e^++e^-$

TL;DR

This paper derives expressions for polarization observables and radiative corrections in the antiproton-proton to electron-positron reaction, considering polarization states and providing numerical estimates relevant for the PANDA experiment.

Contribution

It presents new formulas for polarization observables and radiative effects in the reaction, including angle-dependent corrections in the laboratory frame, with numerical estimates for experimental conditions.

Findings

Radiative corrections depend on scattering angle in the lab system.

Formulas for polarization observables are derived for polarized initial and final states.

Numerical estimates provided for PANDA experiment conditions.

Abstract

The expressions for the differential cross section and of the polarization observables for the reaction $\bar p+p\rightarrow e^++e^-$ are given in terms of the nucleon electromagnetic form factors in the laboratory system. Radiative corrections due to the emission of virtual and real soft photons from the leptons are also calculated. Unlike the center-of- mass system case, they depend on the scattering angle. Polarization effects are derived in the case when the antiproton beam, the target and the electron in the final state are polarized. Numerical estimations have been done for all observables for the PANDA experimental conditions using models for the nucleon electromagnetic form factors in the time-like region. The radiative corrections to the differential cross section are calculated as function of the beam energy and of the electron angle.