Medium-modified jet shapes and other jet observables from in-medium parton shower evolution

The suppression of large transverse momentum (PT) hadrons in heavy-ion (A-A) collisions as compared to their scaled expectation from proton-proton (p-p) collisions due to the interaction of hard partons with the hot and dense QCD medium in A-A collisions is experimentally a well-established phenomenon. Focusing on leading hadrons produced in hard processes, the medium effect appears as energy loss. Beyond that, the question is how the lost energy is redistributed in the medium. With increased experimental statistics and most importantly the kinematic range of the CERN Large Hadron Collider (LHC), studying the properties of full jets rather than leading hadrons is becoming feasible. On the theory side, analytic models and Monte-Carlo (MC) codes for in-medium shower evolution are being developed to describe jets in the medium. In this paper, expectations for medium-modified jet observables, the jet shapes, the thrust distribution, and the n-jet fraction, are computed with the MC code YaJEM for various scenarios of the parton-medium interaction which are all consistent with high-PT hadron suppression data. The computation is done at 20 and 100 GeV jet energy, corresponding to probing the kinematics typical of the BNL Relativistic Heavy Ion Collider (RHIC) and LHC, and the possibility of making an unbiased measurement of the observables is discussed.