Same-sign WW production in proton-nucleus collisions at the LHC as a signal for double parton scattering

TL;DR

This paper investigates same-sign W-boson pair production in proton-lead collisions at the LHC as a clear signal of double parton scattering, providing estimates of cross sections and potential for measuring parton distributions.

Contribution

It presents the first detailed calculation of DPS WW production in p-Pb collisions at the LHC, highlighting its potential as an unambiguous DPS signal.

Findings

DPS WW cross section in p-Pb is about 150 pb at 8.8 TeV.

DPS WW rate is 600 times higher than in pp collisions.

Expected 10 fully leptonic WW events in 2 pb^{-1} data.

Abstract

The production of same-sign W-boson pairs from double parton scatterings (DPS) in proton-lead (p-Pb) collisions at the CERN Large Hadron Collider is studied. The signal and background cross sections are estimated with next-to-leading-order perturbative QCD calculations using nuclear parton distribution functions for the Pb ion. At sqrt(sNN) = 8.8 TeV the cross section for the DPS process is about 150 pb, i.e. 600 times larger than that in proton-proton collisions at the same centre-of-mass energy and 1.5 times higher than the pPb --> WW+2-jets single-parton background. The measurement of such a process, where 10 events with fully leptonic W's decays are expected after cuts in 2 pb^{-1}, would constitute an unambiguous DPS signal and would help determine the effective sigma_eff parameter characterising the transverse distribution of partons in the proton.