Production of Mesons and Baryons at High Rapidity and High Pt in Proton-Proton Collisions at sqrt(s) = 200 GeV

TL;DR

This study measures charged hadron spectra at forward rapidities in proton-proton collisions at 200 GeV, revealing large proton-to-pion ratios and testing perturbative QCD predictions with mixed success.

Contribution

First measurement of particle spectra at forward rapidities in pp collisions at 200 GeV, providing new data on proton and meson production at high rapidity and transverse momentum.

Findings

Large proton to pion ratios up to 4 GeV/c transverse momentum.

NLO pQCD describes pions and kaons well but not protons.

Proton yields and $ar{p}/p$ ratios are not fully explained by models.

Abstract

We present particle spectra for charged hadrons $\pi^\pm, K^\pm, p$ and $\bar{p}$ from pp collisions at $\sqrt{s}=200$ GeV measured for the first time at forward rapidities (2.95 and 3.3). The kinematics of these measurements are skewed in a way that probes the small momentum fraction in one of the protons and large fractions in the other. Large proton to pion ratios are observed at values of transverse momentum that extend up to 4 GeV/c, where protons have momenta up to 35 GeV. Next-to-leading order perturbative QCD calculations describe the production of pions and kaons well at these rapidities, but fail to account for the large proton yields and small $\bar{p}/p$ ratios.