Nuclear parton distributions and the Drell-Yan process

Abstract

We study the nuclear parton distribution functions on the basis of our recently developed semimicroscopic model, which takes into account a number of nuclear effects including nuclear shadowing, Fermi motion and nuclear binding, nuclear meson-exchange currents and off-shell corrections to bound nucleon distributions. We discuss in details the dependencies of nuclear effects on the type of parton distribution (nuclear sea vs. valence) as well as on the parton flavour (isospin).We apply the resulting nuclear parton distributions to calculate ratios of cross sections for protoninduced Drell-Yan production off different nuclear targets. We obtain a good agreement on the magnitude, target and projectile x and the dimuon mass dependence of proton-nucleus Drell-Yan process data from the E772 and E866 experiments at Fermilab. We also provide nuclear corrections for the Drell-Yan data from the E605 experiment.

Determination of strange sea quark distributions from fixed-target and collider data

“…This ratio offers a large cancellation of both experimental and theoretical uncertainties, including the nuclear corrections related to the Fetarget estimated employing the Kulagin-Petti (KP) model [37][38][39]. Indeed, a detailed calculation for the NOMAD kinematics taking into account the flavor dependence of the different PDFs [40] shows that the overall nuclear correction on the ratio R μμ is < 1%, which is much smaller than the corresponding experimental uncertainties in data, cf. Fig.…”

Nuclear parton distributions

“…. in a hadron h. Following [7,8] we write the nuclear PDF q a/A as (for brevity, we suppress explicit dependencies on x and Q 2 )…”

“…We then expand the off-shell PDF q(x, Q 2 , p 2 ) in (2) about the on-shell value p 2 = M 2 in series in v [14]. Keeping the leading terms we have [7,8]:…”

“…Here we briefly review the approach followed in [7,8,18] and consider constraints on the common nuclear meson cloud coming from the nuclear light-cone momentum sum rule together with the meson contribution to the nuclear potential energy. We write the MEC correction in a convolution form similar to (2):…”

“…The model incorporates a number of nuclear corrections including the smearing with the energy-momentum distribution of bound nucleons (Fermi motion and binding), the off-shell correction to bound nucleon structure functions, corrections from nuclear meson exchange currents (MEC) and the propagation of the hadronic component of the virtual intermediate boson in the nuclear environment. In [8] this approach was applied to compute individual NPDFs. In Sec.2 we briefly review the approach in context of nuclear DIS.…”