Abstract
The energy loss of fast partons traversing the strongly interacting matter produced in high-energy nuclear collisions is one of the most interesting observables to probe the nature of the produced medium. The multipurpose compact muon solenoid (CMS) detector is well designed to measure these hard scattering processes with its high-resolution calorimeters and high precision silicon tracker. In central Pb–Pb collisions, a center-of-mass energy of 2.76 TeV parton energy loss is observed as a significant dijet transverse momentum imbalance, when comparing to a reference distribution corresponding to pp collisions at the same energy. To gain further understanding of the parton energy loss mechanism, the redistribution of the quenched jet energy was studied using the transverse momentum balance of charged tracks projected onto the direction of the leading jet. In contrast to pp collisions, a large fraction of the momentum balance for asymmetric dijets is found to be carried by low momentum particles at large angular distance to the axis of the recoiling jet. Further, the fragmentation functions for leading and subleading jets were reconstructed and were found to be unmodified compared to measurements in pp collisions. The results yield a detailed picture of parton propagation in the hot QCD medium.
Highlights
Heavy ion collisions at the Large Hadron Collider (LHC) are expected to produce matter at energy densities exceeding any previously explored in experiments conducted at particle accelerators
Analyzing data from pp and PbPb collisions at a center-of-mass energy of 2.76 TeV parton energy loss is observed as a significant imbalance of dijet transverse momentum
No visible modification of the dijet azimuthal correlation due to the nuclear medium was observed while a strong increase in the fraction of highly unbalanced jets has been seen in central PbPb collisions compared with peripheral collisions and model calculations
Summary
Heavy ion collisions at the Large Hadron Collider (LHC) are expected to produce matter at energy densities exceeding any previously explored in experiments conducted at particle accelerators. One of the key experimental signatures suggested to study the quark-gluon plasma(QGP), which is expected to be formed at these high energy densities, is the energy loss of high-transverse-momentum partons passing through the medium [1]. This parton energy loss is often referred to as “jet quenching”. The energy lost by a parton provides fundamental information on the thermodynamical and transport properties of the traversed medium
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Physics G: Nuclear and Particle Physics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
