Pion-Exchange and Fermi-Motion Effects on the Proton-Deuteron Drell-Yan Process

TL;DR

This paper investigates how pion-exchange and nucleon Fermi-motion influence the proton-deuteron Drell-Yan process, providing a model that aligns well with existing data and offers predictions for future experiments.

Contribution

It introduces a convolution model incorporating c NN components and pion form factors to analyze Drell-Yan ratios, enhancing understanding of nuclear effects in high-energy collisions.

Findings

Pion-exchange and Fermi-motion significantly affect cross-section ratios.

Model predictions agree with 800 GeV data.

Provides forecasts for 120 GeV Fermilab experiments.

Abstract

Within a nuclear model that the deuteron has NN and \pi NN components, we derive convolution formula for investigating the Drell-Yan process in proton-deuteron (pd) reactions. The contribution from the \pi NN component is expressed in terms of a pion momentum distribution that depends sensitively on the \pi NN form factor. With a \pi NN form factor determined by fitting the \pi N scattering data up to invariant mass W = 1.3 GeV, we find that the pion-exchange and nucleon Fermi-motion effects can change significantly the ratios between the proton-deuteron and proton-proton Drell-Yan cross sections, R_{pd/pp} = \sigma^{pd}/(2\sigma^{pp}), in the region where the partons emitted from the target deuteron are in the Bjorken x_2 > 0.4 region. The calculated ratios R_{pd/pp} at 800 GeV agree with the available data. Predictions at 120 GeV for analyzing the forthcoming data from Fermilab are presented.