Jet Properties from Dihadron Correlations in p+p Collisions at sqrt(s)=200 GeV

TL;DR

This study measures jet properties in proton-proton collisions at 200 GeV using two-particle correlations, determining key parameters like jet fragmentation transverse momentum and partonic transverse momentum, consistent across different trigger momenta.

Contribution

It provides new measurements of jet fragmentation and partonic transverse momentum in p+p collisions at 200 GeV, using a correlation method and combining data with e+e- fragmentation functions.

Findings

Jet fragmentation transverse momentum sqrt(<j_T^2>) = 585 MeV/c

Partonic transverse momentum sqrt(<k_T^2>) = 2.68 GeV/c

Both parameters are independent of trigger particle transverse momentum

Abstract

The properties of jets produced in p+p collisions at sqrt(s)=200 GeV are measured using the method of two particle correlations. The trigger particle is a leading particle from a large transverse momentum jet while the associated particle comes from either the same jet or the away-side jet. Analysis of the angular width of the near-side peak in the correlation function determines the jet fragmentation transverse momentum j_T . The extracted value, sqrt(<j_T^2>)= 585 +/- 6(stat) +/- 15(sys) MeV/c, is constant with respect to the trigger particle transverse momentum, and comparable to the previous lower sqrt(s) measurements. The width of the away-side peak is shown to be a convolution of j_T with the fragmentation variable, z, and the partonic transverse momentum, k_T . The <z> is determined through a combined analysis of the measured pi^0 inclusive and associated spectra using jet fragmentation functions measured in e^+e^-. collisions. The final extracted values of k_T are then determined to also be independent of the trigger particle transverse momentum, over the range measured, with value of sqrt(<k_T^2>) = 2.68 +/- 0.07(stat) +/- 0.34(sys) GeV/c.