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


The CMS collaboration C., Khachatryan V., Sirunyan A., Tumasyan A., Adam W., Asilar E., ...Daha Fazla

JOURNAL OF HIGH ENERGY PHYSICS, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: Konu: 4
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1007/jhep04(2016)073
  • Dergi Adı: JOURNAL OF HIGH ENERGY PHYSICS

Özet

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 8TeV corresponding to an integrated luminosity of 19.7 fb(-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.