Null-test signal for T-invariance violation in $pd$ scattering

TL;DR

This paper investigates the null-test signal for T-invariance violation in proton-deuteron scattering using Glauber theory, focusing on meson exchanges and Coulomb effects, to identify potential signals of time-reversal violation.

Contribution

The study provides a detailed theoretical analysis of the null-test observable in $pd$ scattering, including spin dependence and meson exchange contributions, highlighting the role of the $h_1$ meson and Coulomb interactions.

Findings

The $ ho$-meson exchange contribution to the null-test signal is zero.

The $h_1$ meson exchange produces a non-zero contribution.

Coulomb interaction does not cause divergence in the cross section.

Abstract

The integrated proton-deuteron cross section $\widetilde\sigma$ for the case of the incident proton vector polarization $p_y^p$ and tensor polarization $P_{xz}$ of the deuteron target provides a null test signal for time-reversal invariance violating but P-parity conserving (TVPC) effects. We study the null-test observable $\widetilde\sigma$ within the Glauber theory of the double-polarized $pd$ scattering. Full spin dependence of the ordinary strong $pN$ scattering amplitudes and different types of the hypothetical TVPC pN-amplitudes are taken into account. We show that the contribution from the exchange of the lowest-mass meson allowed in the TVPC interaction, i.e. the $\rho$-meson, to the null-test observable $\widetilde\sigma$ is zero. The axial $h_1$ meson exchange makes a non-zero contribution. We find that inclusion of the Coulomb interaction does not lead to divergence of the cross section $\widetilde\sigma$ and calculate its energy dependence at the proton beam energy 100-1000 MeV.