On the shape of the $\bar{d}-\bar{u}$ asymmetry

Abstract

Using data from a recent reanalysis of neutron structure functions extracted from inclusive proton and deuteron deep-inelastic scattering (DIS), we re-examine the constraints on the shape of the $\bar{d}-\bar{u}$ asymmetry in the proton at large parton momentum fractions $x$. A global analysis of the proton-neutron structure function difference from BCDMS, NMC, SLAC and Jefferson Lab DIS measurements, and of Fermilab Drell-Yan lepton-pair production cross sections, suggests that existing data can be well described with $\bar{d}>\bar{u}$ for all values of $x$ currently accessible. We compare the shape of the fitted $\bar{d}-\bar{u}$ distributions with expectations from nonperturbative models based on chiral symmetry breaking, which can be tested by upcoming Drell-Yan data from the SeaQuest experiment at larger values of $x$.

Comments: 17 pages, 6 figures