# Measurement of top quark polarisation in t-channel single top quark production

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 19.7 inverse-femtobarns. 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.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01226175
Contributor : Sylvie Flores <>
Submitted on : Monday, November 9, 2015 - 7:34:04 AM
Last modification on : Thursday, June 17, 2021 - 3:19:05 PM

### Citation

V. Khachatryan, M. Besançon, F. Couderc, M. Dejardin, D. Denegri, et al.. Measurement of top quark polarisation in t-channel single top quark production. Journal of High Energy Physics, Springer Verlag (Germany), 2016, 04, pp.073. ⟨10.1007/JHEP04(2016)073⟩. ⟨in2p3-01226175⟩

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