Narrow Results

A possible SU(15) process at HERA is investigated. The process that we consider is through the exchange of new heavy gauge bosons X^- and X^-- which are predicted in SU(15). This process produces two easily observable like-sign muons in the final state. The cross-section of this process is calculated by using HELAS and VEGAS programs, and PDF-library functions. The cross-section turns out to be small to be observed in the near future.

The dilepton decays of the top quark are a powerful laboratory for probing the Standard Model and searching for hints of a more fundamental theory. We present a detailed analysis of the production cross section and the kinematic qualities of top quark pair candidate events in collisions at = 1.96 TeV collected by the CDF detector which include two leptons in the final state, suggesting the decay . We describe the selection of candidate events to suppress major backgrounds and present the number of observed events over background. As a test of the top quark hypothesis, the kinematics of the events are analyzed via a measurement of M_top with unprecedented precision.

We report a measurement of the production cross section using dilepton events with jets and missing transverse energy in collisions at . Using 197 pb^-1 of data recorded by the upgraded Collider Detector at Fermilab (CDF II), we use two complementary techniques to select candidate events. The combined result yields a production cross section of which is consistent with the Standard Model.

We extend the previous study of dilepton production using [S. Somorendro Singh and Y. Kumar, Can. J. Phys.92 (2014) 31] based on a simple quasiparticle model of quark–gluon plasma (QGP). In this model, finite value of quark mass uses temperature dependent chemical potential the so-called Temperature Dependent Chemical Potential Quark Mass (TDCPQM). We calculate dilepton production in the relevant range of mass region. It is observed that the production rate is marginally enhanced from the earlier work. This is due to the effect of TDCPQM and its effect is highly significant in the production of dilepton.

The Beam Energy Scan Phase II at RHIC, BES-II, is scheduled from year 2019 to 2020 and will explore the high baryon density region of the QCD phase diagram with high precision. The program will focus on the interesting energy region determined from the results of BES-I. Some of the key measurements anticipated are the chiral symmetry restoration and QGP thermal radiation in the dilepton and direct photon channels. The measurements will be possible with an order of magnitude better statistics provided by the electron cooling upgrade of RHIC and with the detector upgrades planned to extend STAR experimental reach. The upgrades are: the inner Time Projection Chamber sectors (iTPC), the Event Plane Detector (EPD), and the end-cap Time of Flight (eTOF). We present the BES-II program details and the physics opportunities in the dilepton and direct photon channels enabled by the upgrades.