Production and polarization of ${\Lambda }_c^{+}$ and the charm of the proton

Abstract

We propose a two-component model involving the parton fusion mechanism and recombination of a $ud$ valence diquark with a sea $c$-quark of the incident proton to describe ${\Lambda }_c^{+}$ inclusive production in $pp$ collisions. We also study the polarization of the produced ${\Lambda }_c^{+}$ in the framework of the Thomas Precession Model for polarization. We show that a measurement of the ${\Lambda }_c$ polarization is a sensitive test of its production mechanism. In particular the intrinsic charm model predicts a positive polarization for the ${\Lambda }_c$ within the framework of the Thomas Precession Model, while according to the model presented here the ${\Lambda }_c$ polarization should be negative. The measurement of the ${\Lambda }_c$ polarization provides a close examination of intrinsic charm Fock states in the proton and give interesting information about the hadroproduction of charm.

Comments: references to figures corrected. Final version to appear in Physical Review D