1207.0181 (T. -S. H. Lee et al.)

Fermi motion and pion-exchange effects on Drell-Yan processes    [PDF]

T. -S. H. Lee, H. Kamano

Within the framework of relativistic quantum mechanics, convolution formula are developed for calculating the Drell-Yan process in proton(p)-deuteron(d) reactions. We find that the Fermi motion and pion-exchange effects in the deuteron can change significantly the ratios of the Drell-Yan cross sections R_{pd/pp} = \sigma^{pd}/(2\sigma^{pp}) in the region where the partons emitted from the target are in the Bjorken x_2 > 0.4 region. The predicted pion-exchange effects are sensitive to the \pi NN form factor and the parton distribution \bar{u} and \bar{d} of the proton and pion at large x. Using the \pi NN form factor determined from fitting the \pi N phase shifts up to 1.4 GeV, the predicted ratios at 800 GeV agree with the available data. Predictions at 120 GeV for analyzing the forthcoming data from Fermilab are presented.

View original: http://arxiv.org/abs/1207.0181