Search for new physics using effective field theory in 13 TeV pp collision events that contain a top quark pair and a boosted Z or Higgs boson
A data sample containing top quark pairs (tt over bar ) produced in association with a Lorentz-boosted Z or Higgs boson is used to search for signs of new physics using effective field theory. The data correspond to an integrated luminosity of 138 fb-1 of proton-proton collisions produced at a center-of-mass energy of 13 TeV at the LHC and collected by the CMS experiment. Selected events contain a single lepton and hadronic jets, including two identified with the decay of bottom quarks, plus an additional large-radius jet with high transverse momentum identified as a Z or Higgs boson decaying to a bottom quark pair. Machine learning techniques are employed to discriminate between tt over bar Z or tt over bar H events and events from background processes, which are dominated by tt over bar + jets production. No indications of new physics are observed. The signal strengths of boosted tt over bar Z and tt over bar H production are measured, and upper limits are placed on the tt over bar Z and tt over bar H differential cross sections as functions of the Z or Higgs boson transverse momentum. The effects of new physics are probed using a framework in which the standard model is considered to be the low-energy effective field theory of a higher energy scale theory. Eight possible dimension-six operators are added to the standard model Lagrangian, and their corresponding coefficients are constrained via fits to the data.
WOS:001063259200001
2023-08-10
108
3
032008
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Funder | Grant Number |
Municipal Science amp; Technology Commission | 2288 |
Ministry of Education, Youth and Sports (MEYS) of the Czech Republic | |
Hellenic Foundation for Research and Innovation (HFRI) | EXC 2121 |
Deutsche Forschungsgemeinschaft (DFG) | 390833306 |
Hungarian Academy of Sciences | |
NKFIH Research Grants | K 124850 |
Council of Science and Industrial Research, India | |
Latvian Council of Science | |
Ministry of Education and Science | 2021/41/B/ST2/01369 |
National Science Center | |
Opus | 2021/43/B/ST2/01552 |
National Priorities Research Program by Qatar National Research Fund | MDM-2017-0765 |
ERDF "a way of making Europe | B05F650021 |
Programa Severo Ochoa del Principado de Asturias (Spain) | |
Chulalongkorn Academic into Its 2nd Century Project Advancement Project | |
National Science, Research and Innovation Fund via the Program Management Unit for Human Resources amp; Institutional Development, Research and Innovation | C-1845 |
Kavli Foundation | |
Nvidia Corporation | |
SuperMicro Corporation | |
Welch Foundation | |
Weston Havens Foundation (USA) | |