Finite-Q2corrections to parity-violating DIS

Abstract

Parity-violating deep inelastic scattering (PVDIS) has been proposed as an important new tool to extract the flavor and isospin dependence of parton distributions in the nucleon. We discuss finite-Q 2 effects in PVDIS asymmetries arising from subleading kinematical corrections and longitudinal contributions to the γZ interference. For the proton, these need to be accounted for in order to accurately extract the d/u ratio at large x; for the deuteron they are important to consider when searching for evidence of charge symmetry violation in parton distributions or signals for physics beyond the standard model. We further explore the dependence of PVDIS asymmetries for polarized targets on the u and d helicity distributions at large x.

Examination of higher-order twist contributions in parity-violating deep-inelastic electron-deuteron scattering

“…[21]. Noting that the contribution of O µν ud (x) to the electroweak structure functions satisfies the Callan-Gross relation at leading order in the strong coupling, we find that…”

“…In terms of the former, it was recently suggested that HT contributions to the Y 1 term in the deuterium asymmetry may be too large and too theoretically uncertain to utilize this term as a probe of CSV [21]. These suggestions were based on the possibility that R γ and R γ Z could differ substantially.…”

“…Detailed phenomenological and theoretical analyses of CSV effects can be found in Refs. [21,41,42]. In Fig.…”

“…The general expression for the asymmetry A RL is given in terms of the five structure functions F γ 1,2 and F γ Z 1,2,3 takes the form [21],…”

“…More recently, higher twist effects to the asymmetry were estimated by the authors of Ref. [21], who considered the possibility that R γ and R γ Z receive substantially different contributions from finite-Q 2 effects. These authors argued that such a difference could introduce hadronic uncertainties that might impede the extraction of CSV effects from A RL .…”