PHENIX Measurement of Parity-Violating Single Spin Asymmetry in W Production in p+p Collisions at 500 GeV

TL;DR

This paper reports the measurement of parity-violating single spin asymmetry in W boson production in polarized proton-proton collisions at 500 GeV, providing insights into the flavor-separated polarized parton distribution functions.

Contribution

It presents the first measurement of electron single spin asymmetry in W production at 500 GeV, offering new data on polarized parton distributions.

Findings

Measured electron energy spectrum from W decays.

Observed parity-violating single spin asymmetry.

Provides data for flavor-separated polarized PDFs.

Abstract

The flavor-separated polarized parton distribution functions for light quarks and anti-quarks in the proton can be studied in the production of $W$ bosons in $p$+$p$ collisions. The $W$s are produced in processes like $u+\bar{d}\rightarrow W^+$ and $\bar{u}+ d \rightarrow W^-$ and we observe the lepton (an electron or muon) from the decay channel $W^{\pm}\rightarrow l^{\pm}\nu$. The electron energy spectrum from $W$ decays measured with an integrated luminosity of approximately 10 pb$^{-1}$ will be shown, with a measurement of the electron single spin asymmetry in central rapidity.