Soft QCD Results from CMS

TL;DR

This paper presents comprehensive measurements of hadron production, correlations, and underlying event activity in proton-proton collisions at various energies, providing valuable data for testing QCD models.

Contribution

It offers new detailed experimental results on hadron spectra, correlations, and underlying activity in p-p collisions at multiple energies, comparing them with QCD Monte Carlo models.

Findings

Identification of structures in two-particle correlations at high multiplicity.

Measurement of Bose-Einstein correlations between identical particles.

Detailed spectra of strange hadrons and underlying event activity.

Abstract

Studies of hadron production in proton-proton collisions, including charged particle transverse momentum, pseudo-rapidity and event-by-event multiplicity distributions at \sqrt{s} = 0.9, 2.36 and 7 TeV are shown. Measured spectra of identified strange hadrons, reconstructed based on their decay topology, are also presented. Comparisons to several QCD Monte Carlo models and tunes are discussed. Results on two-particle angular correlations over a broad range of pseudo-rapidity and azimuthal angle in p-p collisions are presented at both \sqrt{s} = 0.9 and 7 TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate transverse momentum of 1-3 GeV/c. Furthermore, Bose-Einstein correlations between identical particles are measured in samples of proton-proton collisions at \sqrt{s} =0.9 and 7 TeV. Finally, a measurement of the underlying activity in scattering processes with a p_T scale in the several GeV region is also presented.