Hadronic Production of Lambda_c from 600 GeV/c pion, sigma and proton beams

TL;DR

This paper reports on the measurement of hadroproduction asymmetry of Lambda_c baryons versus anti-Lambda_c using different beams at Fermilab, revealing the influence of beam type and kinematic variables on charm baryon production.

Contribution

It provides new experimental data on Lambda_c production asymmetries with pion, sigma, and proton beams at high energies, supporting the leading quark model.

Findings

Strong charm baryon production asymmetry in forward hemisphere for baryon beams.

Pion beam shows smaller asymmetry compared to sigma and proton beams.

Beam fragments significantly influence Lambda_c formation at these energies.

Abstract

We present data from Fermilab experiment E781 (SELEX) on the hadroproduction asymmetry for anti-Lambda_c compared to Lambda_c+ as a function of xF and pt2 distributions for Lambda_c+. These data were measured in the same apparatus using incident pi-, sigma- beams at 600 GeV/c and proton beam at 540 GeV/c. The asymmetry is studied as a function of xF. In the forward hemisphere with xF >= 0.2 both baryon beams exhibit very strong preference for producing charm baryons rather than charm antibaryons, while the pion beam asymmetry is much smaller. In this energy regime the results show that beam fragments play a major role in the kinematics of Lambda_c formation, as suggested by the leading quark picture.