Measurement of the normalized Z/gamma*->mu+mu- transverse momentum distribution in p\bar{p} collisions at sqrt{s}=1.96 TeV

TL;DR

This paper reports the first measurement of the Z/gamma* transverse momentum distribution in proton-antiproton collisions at 1.96 TeV using muon pairs, providing data that tests QCD predictions and improves modeling of collider events.

Contribution

It presents the first measurement of Z/gamma* transverse momentum at the particle level in par{p} collisions at this energy, reducing model dependence.

Findings

QCD predictions show varied success in describing the data

Provides data to improve theoretical models and event generators

Enhances understanding of initial state radiation in hadron collisions

Abstract

We present a new measurement of the Z/gamma* transverse momentum distribution in the range 0 - 330GeV, in proton-antiproton collisions at sqrt{s}=1.96 TeV. The measurement uses 0.97 fb-1 of integrated luminosity recorded by the D0 experiment and is the first using the Z/gamma*->mu+mu- + X channel at this center-of-mass energy. This is also the first measurement of the Z/gamma* transverse momentum distribution that presents the result at the level of particles entering the detector, minimizing dependence on theoretical models. As any momentum of the Z/gamma* in the plane transverse to the incoming beams must be balanced by some recoiling system, primarily the result of QCD radiation in the initial state, this variable is an excellent probe of the underlying process. Tests of the predictions of QCD calculations and current event generators show they have varied success in describing the data. Using this measurement as an input to theoretical predictions will allow for a better description of hadron collider data and hence it will increase experimental sensitivity to rare signals.