Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR

TL;DR

This study assesses the feasibility of measuring proton electromagnetic form factors in the time-like region at FAIR using the PANDA detector, through detailed simulations of signal and background processes.

Contribution

It demonstrates that precise measurements of the differential cross section and individual form factor moduli are achievable up to high momentum transfer values with PANDA at FAIR.

Findings

Proton form factors can be measured up to q^2 ≈ 14 (GeV/c)^2.

Total cross section can be determined up to q^2 ≈ 28 (GeV/c)^2.

Simulation results align with existing data and explore two-photon exchange sensitivity.

Abstract

The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the annihilation of $\bar p +p $ into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction $\bar p +p \to e^++ e^-$ can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of $q^2\simeq 14$ (GeV/c)$^2$. The total $\bar p +p\to e^++e^-$ cross section will be measured up to $q^2\simeq 28$ (GeV/c)$^2$. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.