TY - JOUR
T1 - Search for flavor-changing neutral-current couplings between the top quark and the Z boson with proton-proton collisions at s=13 TeV with the ATLAS detector
AU - ATLAS Publications
AU - Clark, Philip James
AU - Farrington, Sinead
AU - Gao, Yanyan
AU - Leonidopoulos, Christos
AU - Martin, Victoria Jane
AU - Mijovic, Liza
AU - Wynne, Benjamin
AU - Alderweireldt, Sara
AU - Carter, T.M.
AU - Hasib, A.
AU - Heath, M.P.
AU - Palazzo, S.
AU - Parrish, V.A.
AU - Takeva, E.P.
AU - Themistokleous, N.
AU - Villhauer, E.M.
AU - Zaid, E.
PY - 2023/8/30
Y1 - 2023/8/30
N2 - A search for flavor-changing neutral-current couplings between a top quark, an up or charm quark, and a Z boson is presented, using proton–proton collision data at √s=13 TeV collected by the ATLAS detector at the Large Hadron Collider. The analyzed data set corresponds to an integrated luminosity of 139 fb−1. The search targets both single-top-quark events produced as gq→tZ (with q=u, c) and top-quark-pair events, with one top quark decaying through the t→Zq channel. The analysis considers events with three leptons (electrons or muons), a b-tagged jet, possible additional jets, and missing transverse momentum. The data are found to be consistent with the background-only hypothesis and 95% confidence-level limits on the t→Zq branching ratios, assuming only tensor operators of the Standard Model effective field theory framework contribute to the tZq vertices. These are 6.2×10−5 (13×10−5) for t→Zu (t→Zc) for a left-handed tZq coupling, and 6.6×10−5 (12×10−5) in the case of a right-handed coupling. These results are interpreted as 95% CL upper limits on the strength of the corresponding couplings, yielding limits for |C(13)*uW| and |C(13)*uB| (|C(31)uW| and |C(31)uB|) of 0.15 (0.16), and limits for |C(23)*uW| and |C(23)*uB| (|C(32)uW| and |C(32)uB|) of 0.22 (0.21), assuming a new-physics energy scale ΛNP of 1 TeV.
AB - A search for flavor-changing neutral-current couplings between a top quark, an up or charm quark, and a Z boson is presented, using proton–proton collision data at √s=13 TeV collected by the ATLAS detector at the Large Hadron Collider. The analyzed data set corresponds to an integrated luminosity of 139 fb−1. The search targets both single-top-quark events produced as gq→tZ (with q=u, c) and top-quark-pair events, with one top quark decaying through the t→Zq channel. The analysis considers events with three leptons (electrons or muons), a b-tagged jet, possible additional jets, and missing transverse momentum. The data are found to be consistent with the background-only hypothesis and 95% confidence-level limits on the t→Zq branching ratios, assuming only tensor operators of the Standard Model effective field theory framework contribute to the tZq vertices. These are 6.2×10−5 (13×10−5) for t→Zu (t→Zc) for a left-handed tZq coupling, and 6.6×10−5 (12×10−5) in the case of a right-handed coupling. These results are interpreted as 95% CL upper limits on the strength of the corresponding couplings, yielding limits for |C(13)*uW| and |C(13)*uB| (|C(31)uW| and |C(31)uB|) of 0.15 (0.16), and limits for |C(23)*uW| and |C(23)*uB| (|C(32)uW| and |C(32)uB|) of 0.22 (0.21), assuming a new-physics energy scale ΛNP of 1 TeV.
KW - Plus Plus
KW - Parton Distributions
KW - Pair Production
KW - Physics
KW - Decay
U2 - 10.1103/PhysRevD.108.032019
DO - 10.1103/PhysRevD.108.032019
M3 - Article
SN - 2470-0010
VL - 108
SP - 1
EP - 34
JO - Physical Review D
JF - Physical Review D
IS - 3
M1 - 032019
ER -