Seminar by A. Hoang Room: Main Auditorium The direct link to the webcast is: https://desy.zoom.us/j/99616528733 Meeting ID: 996 1652 8733 Meeting Password: 733220 Abstract: The top quark mass is currently known from so-called direct measurements with an uncertainty of 300 MeV. This represents a remarkable precision of better than 2 permille, and future measurements at the LHC will reduce this uncertainty even further. In the direct measurements the top quark mass parameter of the MC event generator used in the experimental analysis is determined. There is a general agreement that the this top quark mass parameter is close to the pole mass renormalisation scheme, but at this high level of experimental precision it is eventually mandatory to quantify that relation in a more precise and quantitative manner. In the colloquium I will provide a pedagogical overview on what we currently know about the top quark mass parameter in MC event generators. I discuss a simple framework involving the invariant mass of boosted top quark jets in e+e- collissions in which the question can now be addressed systematically and which also shows which ingredients are needed to answer the question in general. It turns out that aspects such as the implementation of the parton shower or the modelling of hadronization effects need to be controlled at a high precision and affect the answer. It is thus also possible that there is a dependence on the Monte Carlo and the observables used for the top mass measurement. I provide an outlook on ongoing work to generalise the results to observables sensitive to the top quark decay.

Introduction

• Katerina Lipka (DESY and University of Wuppertal)

Room: SR1

Non-relatvistic top quark pairs

• Giovanni Limatola (CMS (CMS Fachgruppe QCD))

Room: SR 1

Prospects for boosted top measurments CMS

• Roman Kogler (DESY FH, CMS)

Room: SR1

Prospects for boosted top measurments ATLAS

• Marcel Vos (IFIC (UVEG/CSIC) Valencia)

Room: SR1

Top quark mass via jet substructure

• Aditya Pathak (DESY)

Room: SR1

bb4l Generator

• Tomas Jezo

Room: SR1

Prospects of top quark mass and width measurements using bb4l in ATLAS

• Katharina Voss (Uni Siegen)

Room: SR1

Prospects of top quark mass and width measurements using bb4l in CMS

• Jiwon Park (CMS (CMS Fachgruppe QCD))

Room: SR1

NNLO tt+jet

• Colomba Brancaccio (University of Turin)

Room: SR1

Off-shell top

• Davide Melini (IFIC)

Room: SR1

Modeling uncertainties with DCTR method

• Valentina Guglielmi (CMS (CMS Fachgruppe QCD))

Room: SR1

Discussion Room: SR1

ATLAS Experimental Results

• Davide Melini (IFIC)

Room: SR1/CFEL SR4

CMS experimental results

• Ana Ventura Barroso (CMS (CMS Fachgruppe QCD))

Room: SR1/CFEL SR4

ATLAS+CMS Combination

• Sebastian Wuchterl (CERN)

Room: SR1/CFEL SR4