Search for CP violation in events with top quarks and Z bosons at √s=13 and 13.6 TeV
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10511262" target="_blank" >RIV/00216208:11320/25:10511262 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=1Ukzt_finy" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=1Ukzt_finy</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.physletb.2025.139857" target="_blank" >10.1016/j.physletb.2025.139857</a>
Alternative languages
Result language
angličtina
Original language name
Search for CP violation in events with top quarks and Z bosons at √s=13 and 13.6 TeV
Original language description
A search for the violation of the charge-parity (CP) symmetry in the production of top quarks in association with Z bosons is presented, using events with at least three charged leptons and additional jets. The search is performed in a sample of proton-proton collision data collected by the CMS experiment at the CERN LHC in 2016-2018 at a center-of-mass energy of 13 TeV and in 2022 at 13.6 TeV, corresponding to a total integrated luminosity of 173 fb(-1). For the first time in this final state, observables that are odd under the CP transformation are employed. Also for the first time, physics-informed machine-learning techniques are used to construct these observables. While for standard model (SM) processes the distributions of these observables are predicted to be symmetric around zero, CP-violating modifications of the SM would introduce asymmetries. Two CP-odd operators O-Wt(I) and O-tZ(I) in the SM effective field theory are considered that may modify the interactions between top quarks and electroweak bosons. The obtained results are consistent with the SM prediction within two standard deviations, and exclusion limits on the associated Wilson coefficients of -2.7 < c(tW)(I) < 2.5 and -0.2 < c(tZ)(I) < 2.0 are set at 95% confidence level. The largest discrepancy is observed in CtZI where data is consistent with positive values, with an observed local significance with respect to the SM hypothesis of 2.5 standard deviations, when only linear terms are considered.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10300 - Physical sciences
Result continuities
Project
<a href="/en/project/LM2023040" target="_blank" >LM2023040: Research infrastructure for experiments at CERN</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
ISSN
0370-2693
e-ISSN
1873-2445
Volume of the periodical
869
Issue of the periodical within the volume
Aug 25
Country of publishing house
NL - THE KINGDOM OF THE NETHERLANDS
Number of pages
16
Pages from-to
139857
UT code for WoS article
001617228300001
EID of the result in the Scopus database
2-s2.0-105017450573