Breakup corrections to the ${}^3$He beam polarization measurements at the future BNL Electron Ion Collider

TL;DR

This paper evaluates breakup corrections to ${}^3$He beam polarization measurements at the future Electron-Ion Collider, demonstrating that these effects are negligible if certain asymmetries are concurrently measured, thus supporting precise polarimetry.

Contribution

It introduces a method to assess and confirm the negligible impact of ${}^3$He breakup effects on polarization measurements using the HJET technique at EIC.

Findings

Breakup effects are negligible when asymmetries are measured concurrently.

The study uses RHIC Run 16 deuteron data to evaluate corrections.

The ratio of beam and target asymmetries is key to accurate polarization measurement.

Abstract

Requirements for hadron polarimetry at the future Electron-Ion Collider (EIC) include measurements of absolute ${}^3\text{He} (h)$ beam polarization with systematic uncertainties better than $\sigma^\text{syst}_P/P\lesssim1\%$. Due to the successful use, since 2005, of the polarized hydrogen jet target polarimeter (HJET) to measure proton beam polarization at the Relativistic Heavy Ion Collider (RHIC), the HJET technique promises to be suitable for the ${}^3\text{He}$ polarimetry at EIC. For that, however, one needs to know the ratio of the $h^\uparrow{p}$ and $p^\uparrow{h}$ analyzing powers. For elastic scattering, this ratio can be evaluated with sufficient accuracy if $p^\uparrow{p}$ analyzing power is precisely known. In this paper, the deuteron beam data acquired at HJET in RHIC Run 16 was used to evaluate corrections to the measured helion beam polarization due to the ${}^3\text{He}$ breakup. The breakup effect was found to be negligible if the ratio of the beam and target (jet) single spin asymmetries are concurrently measured to determine the ${}^3\text{He}$ beam polarization.