Measurement of the underlying event activity using charged-particle jets in proton-proton collisions at sqrt(s) = 2.76 TeV

Understand

A measurement of the underlying event (UE) activity in proton-proton collisions is performed using events with charged-particle jets produced in the central pseudorapidity region (abs(eta[jet]) < 2) and with transverse momentum 1<= pt[jet] < 100 GeV.

• The analysis uses a data sample collected at a centre-of-mass energy of 2.76 TeV with the CMS experiment at the LHC.
• The UE activity is measured as a function of pt[jet] in terms of the average multiplicity and scalar sum of transverse momenta (pt) of charged particles, with abs(eta) < 2 and pt > 0.5 GeV, in the azimuthal region transverse to the highest pt jet direction.
• By further dividing the transverse region into two regions of smaller and larger activity, various components of the UE activity are separated.