Subtracting the Underlying-Event Energy in Reconstructed Jets in √s_NN = 200 GeV Proton+Proton Collisions at the STAR experiment

C. Ostberg, for the STAR Collaboration

Senior, Physics Department, San Francisco State University

REU Student at the Cyclotron Institute, Texas A&M University

Mentor: Dr. Saskia Mioduszewski

Jets resulting from hard scatterings (i.e. scatterings with large momentum transfer) provide insight into parton energy loss in the hot, dense medium produced by ultra-relativistic heavy-ion collisions. Complementary measurements in the medium-free proton-proton environment establish a vacuum fragmentation reference.  In a collision, energy that goes into the production of particles not originating from the hard scattering is background (referred to as the underlying event) that must be subtracted from the measured jet-energy.  We present a study of different methods to subtract the underlying-event energy in 200 GeV proton-proton collisions recorded at the STAR experiment at RHIC.