A search for single top-quark production via flavour-changing neutral current processes from gluon plus up- or charm-quark initial states in proton–proton collisions at the LHC is presented. Data collected with the ATLAS detector in 2012 at a centre-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb (Formula presented.) are used. Candidate events for a top quark decaying into a lepton, a neutrino and a jet are selected and classified into signal- and background-like candidates using a neural network. No signal is observed and an upper limit on the production cross-section multiplied by the (Formula presented.) branching fraction is set. The observed 95 % CL limit is (Formula presented.) and the expected 95 % CL limit is (Formula presented.). The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics (Formula presented.) and (Formula presented.) and on the branching fractions (Formula presented.) and (Formula presented.).
Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
CAVASINNI, VINCENZO;DELL'ORSO, MAURO;DONATI, SIMONE;Francavilla, P.;RODA, CHIARA MARIA ANGELA;Verducci, M.;
2016-01-01
Abstract
A search for single top-quark production via flavour-changing neutral current processes from gluon plus up- or charm-quark initial states in proton–proton collisions at the LHC is presented. Data collected with the ATLAS detector in 2012 at a centre-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb (Formula presented.) are used. Candidate events for a top quark decaying into a lepton, a neutrino and a jet are selected and classified into signal- and background-like candidates using a neural network. No signal is observed and an upper limit on the production cross-section multiplied by the (Formula presented.) branching fraction is set. The observed 95 % CL limit is (Formula presented.) and the expected 95 % CL limit is (Formula presented.). The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics (Formula presented.) and (Formula presented.) and on the branching fractions (Formula presented.) and (Formula presented.).File | Dimensione | Formato | |
---|---|---|---|
EPJC_76_55.pdf
accesso aperto
Tipologia:
Versione finale editoriale
Licenza:
Creative commons
Dimensione
4.97 MB
Formato
Adobe PDF
|
4.97 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.