Polarisation observables in lepton antilepton to proton antiproton reactions including lepton mass

Abstract

General expressions, including the lepton mass, for the spin averaged differential cross section for the annihilation reaction lepton antilepton to proton antiproton are given, as well as general formulae for the single and double spin asymmetries in the centre of mass frame. In particular we discuss the single spin asymmetry, normal to the scattering plane, which measures the relative phase difference between nucleon electromagnetic form factors $G_E$ and $G_M$. Recent experimental investigations of these form factors in the space and time like region are reviewed. It is thought that measurements of the phase of these form factors will provide fundamental information on the internal nucleon structure. The phases between $G_E$ and $G_M$ are accessible through polarisation observables measured in the antiproton proton to lepton antilepton reaction, or in its time reversed process.

arXiv comment14 pages, to be submitted to EPJA

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Cited by in corpus (6)

• The electromagnetic form factors of the proton in the timelike region
• The electromagnetic form factors of the $\Lambda$ in the timelike region
• Polarization observables in the $e^{+}{e}^{-}\to \bar{\Lambda }\Lambda$ reaction
• Proton-antiproton annihilation into massive leptons
• Helicity amplitudes and crossing relations for antiproton proton reactions
• Novel method to extract the femtometer structure of strange baryons using the vacuum polarization effect