5 DEC 2022
11:00 - 12:00

Abstract:

The first measurements of production cross sections of polarized same-sign W^± W^± boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb^(-1) . Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W^± W^± scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88) fb is set on the production cross section for longitudinally polarized same-sign W^± W^± boson pairs. The electroweak production of same-sign W^± W^± boson pairs with at least one of the W bosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.

Based on
doi:10.1016/j.physletb.2020.136018

Meeting Link
https://meet.google.com/jyc-uqyh-bmq


Link: https://meet.google.com/jyc-uqyh-bmq

7 DEC 2022
11:00 - 12:00

Abstract:

In this work, we study the heavy-ion collisions in high energy scales. we employ the EMC effect to extract the parton distribution functions (PDF s) inside the Lead (Pb) and Gold (Au) nuclei. Calculated PDFs are used to achieve the transverse momentum dependent (TMD) ones, using the Pythia 8 and MCFM-10 codes. Through this procedure TMDPDFs for charm and bottom quarks in Au at $\sqrt{S_{NN}} = 200$ GeV, Pb at $\sqrt{S_{NN}} = 2.76$ TeV and $\sqrt{S_{NN}} = 5.02$ TeV are calculated. To evaluate the validity of results and investigate the influence of nuclear EMC effects, achieved TMDs are used as input to calculate the heavy quark modification factor $R_{AA}$ at transverse plane $P_T$. This observable is calculated through numerical solution of the Fokker-Planck equation by extracting the drag and diffusion coefficients, using the hard thermal loop correction in the frame work of the relativistic hydrodynamics up to the third order approximation of gradient expansion. The results are compared with same solution when the input PDFs are considered inside the unbounded protons. Some predictions for future experiments are also presented.

Indico Link
https://indico.hep.ipm.ir/e/j.sheibani

Meeting Link
https://meet.google.com/gwq-hepa-cpy

Link: https://meet.google.com/gwq-hepa-cpy