Modification Of Jet Structure Research Articles

Modification of Jet Structure in High-Multiplicity pp Collisions due to Multiple-Parton Interactions and Observing a Multiplicity-Independent Characteristic Jet Size

We study the multiplicity dependence of jet structures in pp collisions using Monte Carlo event generators. We give predictions for multiplicity-differential jet structures and present evidence for a nontrivial jet shape dependence on charged hadron event multiplicity that can be used as a sensitive tool to experimentally differentiate between equally well-preforming simulation tunes. We also propose a way to validate the presence and extent of effects such as multiple-parton interactions (MPI) or color reconnection (CR), based on the detection of nontrivial jet shape modification in high-multiplicity events at high pT. Using multiplicity-dependent jet structure observables in various pT windows might also help understanding the interplay between jet particles and the underlying event (UE). We introduce a multiplicity-independent characteristic jet size measure and use a simplistic model to aid its physical interpretation.

Modification of jet structure in nuclear collisions: theory overview (and pp perspective)

This brief overview of jet structure in heavy-ion collisions touches on analytical and Monte Carlo methods for predicting jet substructure, as well as the question of how new and existing observables can be used to shed light on the dynamics of the interaction of a fragmenting parton with the quark-gluon plasma.

Full jet evolution in quark–gluon plasma and nuclear modification of jet structure in Pb+Pb collisions at 2.76A TeV

We study the evolution of full jet shower in quark-gluon plasma via solving a set of coupled differential transport equations for the three-dimensional momentum distributions of quarks and gluons contained in the full jets. The evolution equations include all partonic splitting processes as well as the collisional energy loss and transverse momentum broadening for both the leading and radiated partons of the full jets. Combining with realistic hydrodynamic simulation for the space-time evolution of the fireball created in Pb+Pb collisions at 2.76A TeV, we calculate the nuclear modification of single inclusive full jet spectra, the momentum imbalance of photon-jet and dijet pairs, and jet shape function (at partonic level). The roles of various jet-medium interaction mechanisms on the modification of full jet energy and internal structure are studied.

Study of high-pT hadron-jet correlations in ALICE

We report the measurement of semi-inclusive pT spectra of charged particle jets that recoil from a high-pT hadron trigger in Pb–Pb and pp collisions at and , respectively. In this analysis, the copious yield of uncorrelated trigger hadron-jet matchings in central Pb–Pb collisions is removed by calculating the difference between two spectra corresponding to exclusive trigger hadron pT ranges. This procedure does not impose any fragmentation bias on the recoil jet population, which is therefore collinear and infrared safe. The resulting distributions obtained for different values of jet resolution parameter are used to study the modification of jet structure in the medium.

Measurements of jet structure and fragmentation from full jet reconstruction in heavy ion collisions at RHIC

Measurements of inclusive hadron suppression and di-hadron azimuthal correlations have provided important insights into jet quenching in hot QCD matter. However, they do not provide access to the energy of the hard scattering and are limited in their sensitivity since they can be affected by biases toward hard fragmentation and small energy loss. Full jet reconstruction in heavy-ion collisions enables a complete study of the modification of jet structure due to energy loss, but is challenging due to the high-multiplicity environment. We present measurements of fully reconstructed di-jets at mid-rapidity in 200 GeV p+p and central Au+Au collisions performed with the STAR detector. We compare fragmentation functions measured in 200 GeV p+p and central Au+Au collisions and assess the systematic uncertainties of their ratio.