Iso-spin asymmetry of quark distributions and implications for single top-quark production at the LHC

S. Alekhin; J. Bluemlein; S. Moch; R. Placakyte

Paper

Iso-spin asymmetry of quark distributions and implications for single top-quark production at the LHC

Abstract

We present an improved determination of the up- and down-quark distributions in the proton using recent data on charged lepton asymmetries from

gauge-boson production at the LHC and Tevatron. The analysis is performed in the framework of a global fit of parton distribution functions. The fit results are consistent with a non-zero iso-spin asymmetry of the sea,

, at small values of Bjorken

indicating a delayed onset of the Regge asymptotics of a vanishing

-asymmetry at small-

. We compare with up- and down-quark distributions available in the literature and provide accurate predictions for the production of single top-quarks at the LHC, a process which can serve as a standard candle for the light quark flavor content of the proton.