A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7fb−1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. A differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26±0.03(stat)±0.10(syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.
Measurement of top quark polarisation in t-channel single top quark production
SOLA, VALENTINA;AMAPANE, Nicola Carlo;ARGIRO', Stefano;BELLAN, Riccardo;COSTA, Marco;COVARELLI, Roberto;MIGLIORE, Ernesto;MONACO, Vincenzo;OBERTINO, Maria Margherita;PACHER, LUCA;PELLICCIONI, Mario;PINNA ANGIONI, GIAN LUCA;RAVERA, FABIO;ROMERO, Alessandra;SACCHI, Roberto;SOLANO, Ada Maria;
2016-01-01
Abstract
A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7fb−1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. A differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26±0.03(stat)±0.10(syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.File | Dimensione | Formato | |
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