Measurement of charged-particle distributions sensitive to the underlying event in ps = 13 TeV proton?proton collisions with the ATLAS detector at the LHC

G. OTERO Y GARZON, ET. AL., THE ATLAS COLLABORATION

JOURNAL OF HIGH ENERGY PHYSICS

SPRINGER

Lugar: Berlin; Año: 2017

1126-6708

We present charged-particle distributions sensitive to the underlying event, measured by theATLAS detector in proton?proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb −1 .The distributions were constructed using charged particles with absolute pseudorapidity lessthan 2.5 and with transverse momentum greater than 500 MeV, in events with at least onesuch charged particle with transverse momentum above 1 GeV. These distributions charac-terise the angular distribution of energy and particle flows with respect to the charged particlewith highest transverse momentum, as a function of both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are comparedto the predictions of various Monte Carlo event generators, experimentally establishing thelevel of underlying-event activity at LHC Run 2 energies and providing inputs for the devel-opment of event generator modelling. The current models in use for UE modelling typicallydescribe this data to 5% accuracy, compared with data uncertainties of less than 1%.