Speaker
Description
An extraction of the top quark Yukawa coupling ($Y_{t}$) from top quark pair production is presented using proton-proton collisions at $\sqrt{s} = $ 13 TeV, corresponding to an integrated luminosity of 140 $fb^{-1}$, recorded by the ATLAS experiment. Corrections from a Higgs boson exchange between the top quark and top anti-quark can produce non-negligible modifications to differential distributions near the energy threshold of $t\bar{t}$ production. The kinematic distributions sensitive to these modifications at parton level, are the invariant mass of the $t\bar{t}$ system (m$_{tt}$) and the azimuthal angle of the top quark with respect to the beamline in the rest frame of the $t\bar{t}$ system known as $\cos (\theta^*)$ This analysis aims to constrain $Y_{t}$ indirectly using the kinematic distributions of $t\bar{t}$ pair events using the e$\mu$ dilepton final state.
Since we are working in the dilepton channel $t\bar{t}$ $\rightarrow$W$^+$bW$^-$b $\rightarrow \ell^+\nu b\ell^-\nu b$. The ATLAS experiment cannot measure the neutrinos and as such we need to reconstruct the $t\bar{t}$ kinematics sensitive to variations in $Y_{t}$. Machine learning was used to reconstruct the mass of the top quark system as this provides the greatest sensitivity to variations in $Y_{t}$. A binned profile likelihood fit was then implemented to extract a blinded estimation of $Y_{t}$ using Asimov data including a complete set of statistical and systematic uncertainties.
| Apply for student award at which level: | PhD |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |
