Search for flavor-changing neutral currents in top-quark decays t to Zq in pp collisions at sqrt(s)=8 TeV
S. Chatrchyan
,
S. Baffioni
(1)
,
F. Beaudette
(1)
,
P. Busson
(1)
,
C. Charlot
(1)
,
N. Daci
(1)
,
T. Dahms
(1)
,
M. Dalchenko
(1)
,
L. Dobrzynski
(1)
,
A. Florent
(1)
,
R. Granier de Cassagnac
(1)
,
M. Haguenauer
(1)
,
P. Mine
(1)
,
C. Mironov
(1)
,
I.N. Naranjo
(1)
,
M. Nguyen
(1)
,
C. Ochando
(1)
,
P. Paganini
(1)
,
D. Sabes
(1)
,
R. Salerno
(1)
,
Y. Sirois
(1)
,
C. Veelken
(1)
,
Y. Yilmaz
(1)
,
A. Zabi
(1)
,
J.-L. Agram
(2)
,
J. Andrea
(2)
,
D. Bloch
(2)
,
J.-M. Brom
(2)
,
E.C. Chabert
(2)
,
C. Collard
(2)
,
E. Conte
(2)
,
F. Drouhin
(2)
,
J.-C. Fontaine
(2)
,
D. Gele
(2)
,
U. Goerlach
(2)
,
C. Goetzmann
(2)
,
P. Juillot
(2)
,
A.-C. Le Bihan
(2)
,
P. van Hove
(2)
,
S. Gadrat
(3)
,
S. Beauceron
(4)
,
N. Beaupere
(4)
,
G. Boudoul
(4)
,
S. Brochet
(4)
,
J. Chasserat
(4)
,
R. Chierici
(4)
,
D. Contardo
(4)
,
P. Depasse
(4)
,
H. El Mamouni
(4)
,
J. Fan
(4)
,
J. Fay
(4)
,
S. Gascon
(4)
,
M. Gouzevitch
(4)
,
B. Ille
(4)
,
T. Kurca
(4)
,
M. Lethuillier
(4)
,
L. Mirabito
(4)
,
S. Perries
(4)
,
J.D. Ruiz Alvarez
(4)
,
L. Sgandurra
(4)
,
V. Sordini
(4)
,
M. Vander Donckt
(4)
,
P. Verdier
(4)
,
S. Viret
(4)
,
H. Xiao
(4)
S. Chatrchyan
- Function : Author
S. Baffioni
- Function : Author
- PersonId : 20331
- IdHAL : stephanie-barrillon
- ORCID : 0000-0002-7075-1673
P. Busson
- Function : Author
- PersonId : 741166
- IdHAL : phbusson
- ORCID : 0000-0001-6027-4511
- IdRef : 033562466
R. Granier de Cassagnac
- Function : Author
- PersonId : 739189
- IdHAL : raphgrandecass
- ORCID : 0000-0002-1275-7292
- IdRef : 132136651
C. Mironov
- Function : Author
- PersonId : 1196248
- IdHAL : camelia-mironov
P. Paganini
- Function : Author
- PersonId : 739173
- IdHAL : pascal-paganini
- ORCID : 0000-0001-9580-683X
- IdRef : 183219406
J.-L. Agram
- Function : Author
- PersonId : 1147753
- IdHAL : j-l-agram
- ORCID : 0000-0001-7476-0158
- IdRef : 090333748
C. Collard
- Function : Author
- PersonId : 753602
- IdHAL : caroline-collard
- ORCID : 0000-0002-5230-8387
- IdRef : 223465992
E. Conte
- Function : Author
- PersonId : 755000
- IdHAL : eric-conte
- ORCID : 0000-0003-3154-3123
- IdRef : 122530209
P. van Hove
- Function : Author
- PersonId : 742701
- IdHAL : pierre-van-hove
- ORCID : 0000-0002-2431-3381
- IdRef : 264250834
M. Gouzevitch
- Function : Author
- PersonId : 741096
- IdHAL : maxime-gouzevitch
- ORCID : 0000-0002-5524-880X
- IdRef : 13627160X
M. Lethuillier
- Function : Author
- PersonId : 740178
- IdHAL : morgan-lethuillier
- ORCID : 0000-0001-6185-2045
- IdRef : 090177835
V. Sordini
- Function : Author
- PersonId : 739810
- IdHAL : viola-sordini
- ORCID : 0000-0003-0885-824X
- IdRef : 128184035
Abstract
A search for flavor-changing neutral currents in top-quark decays t to Zq is performed in events produced from the decay chain t t-bar to Zq+Wb, where both vector bosons decay leptonically, producing a final state with three leptons (electrons or muons). A dataset collected with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 19.7 inverse femtobarns of proton-proton collisions at a center-of-mass energy of 8 TeV. No excess is seen in the observed number of events relative to the standard model prediction; thus no evidence for flavor-changing neutral currents in top-quark decays is found. A combination with a previous search at 7 TeV excludes a t to Zq branching fraction greater than 0.05% at the 95% confidence level.