Nuclear Dependence of Charm Production

TL;DR

This study analyzes how charm hadron production varies with atomic number in fixed-target experiments at Fermilab, revealing differences between meson and baryon beam interactions and their nuclear dependence.

Contribution

It provides the first detailed measurement of the nuclear dependence parameter alpha for various charm hadrons across different beam types and kinematic variables.

Findings

Alpha for charm production by pion beams is approximately 0.85.

Alpha for charm production by baryon beams is approximately 0.76.

No dependence of alpha on xF within the studied range.

Abstract

With data taken by SELEX, which accumulated data during the 1996-1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with Sigma-, p, pi-, and pi+ beams. Parameterizing the production cross section A^alpha, A being the atomic number, we determine alpha for D+, D0, Ds+, D+(2010), Lambda_c+, and their respective anti-particles, as a function of their transverse momentum pt and scaled longitudinal momentum xF. Within our statistics there is no dependence of alpha on xF for any charm species for the interval 0.1<xF<1.0. The average value of alpha for charm production by pion beams is alpha_{meson}=0.850+/-0.028. This is somewhat larger than the corresponding average alpha_{baryon}=0.755+/-0.016 for charm production by baryon beams (Sigma-, p).