Sahibjeet Singh - Top Quarks at the LHC

Thursday 31 Oct 2024, 15:00 → 17:00 US/Eastern

small seminar room

The top quark is the heaviest of all known subatomic particles with a mass similar to that of a Tungsten atom. It is the only quark that can be studied as a “free” quark since it has the shortest lifetime of all quarks. With the discovery of the Higgs boson at the Large Hadron Collider (LHC) in 2012 and no signs of any physics beyond the Standard Model (SM), measurements of the top quark provide an alternate approach to understanding and testing the SM. This talk will discuss two measurements of the top-quark at a center of mass energy of 5.02 TeV using 257  of proton-proton collision data collected by the ATLAS detector. The first topic of discussion is a  cross-section measurement that is used to constrain the gluon Parton Distribution Function (PDF) at high Bjorken ; this cross-section was measured individually in both the dilepton and single-lepton channels of the  decay before being combined. The single-lepton channel is currently the most precise measurement of the  cross-section measured by ATLAS to date. The second measurement is a search for t-channel single top production. The t-channel measurement is the first observation of this process at a center of mass energy of 5.02 TeV. Such precision measurements allow for a test of the SM at energy scales not typically accessed by the LHC while assisting in the understanding of the proton PDFs.