HAL: in2p3-00713888, version 1

arXiv: 1207.0364

DOI: 10.1103/PhysRevD.87.011103

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Physical Review D 87 (2013) 011103(R)

Measurement of Leptonic Asymmetries and Top Quark Polarization in ttbar Production

V.M. Abazov, H. Li1, G. Sajot1, J. Stark1, S. Greder2, F. Miconi2, I. Ripp-Baudot2, U. Bassler3, G. Bernardi4, M. Besançon3, D. Brown4, J. Brown4, E. Chapon3, S. Chevalier-Tthéry3, F. Couderc3, A. Croc3, F. Déliot3, C. Deterre3, Y. Enari4, G. Grenier5, A. Grohsjean3, Z. Hubacek3, T. Kurca5, P. Lebrun5, J. Lellouch4, R. Madar3, C. Royon3, V. Shary3, M. Titov3, B. Tuchming3, P. Verdier5, D. Vilanova3, M. C. Cousinou6, A. Duperrin6, W. Geng6, E. Kajfasz6, S. Kermiche6, E. Nagy6, N. Osman6, F. Badaud7, P. Gay7, Ph. Gris7, J.-F. Grivaz8, T. Guillemin8, M. Jaffré8, P. Pétroff8

For the D0 collaboration(s)

(2013)

We present measurements of lepton (l) angular distributions in ttbar -> W+ b W- b -> l+ nu b l- nubar bbar decays produced in ppbar collisions at a center-of-mass energy of sqrt(s)=1.96TeV, where l is an electron or muon. Using data corresponding to an integrated luminosity of 5.4fb^-1, collected with the D0 detector at the Fermilab Collider, we find that the angular distributions of l- relative to anti-protons and l+ relative to protons are in agreement with each other. Combining the two distributions and correcting for detector acceptance we obtain the forward-backward asymmetry A^l_FB = (5.8 +- 5.1(stat) +- 1.3(syst))%, compared to the standard model prediction of A^l_FB (predicted) = (4.7 +- 0.1)%. This result is further combined with the measurement based on the analysis of the l+jets final state to obtain A^l_FB = (11.8 +- 3.2)%. Furthermore, we present a first study of the top-quark polarization.

1:	LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2:	IPHC - Institut Pluridisciplinaire Hubert Curien
3:	IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
4:	LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
5:	IPNL - Institut de Physique Nucléaire de Lyon
6:	CPPM - Centre de Physique des Particules de Marseille
7:	LPC-CLERMONT - Laboratoire de Physique Corpusculaire de Clermont-Ferrand
8:	LAL - Laboratoire de l'Accélérateur Linéaire

Subject(s)

:

Physics/High Energy Physics - Experiment

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From: Emmanuelle Vernay <>

Submitted on: Tuesday, 3 July 2012 08:35:06

Updated on: Monday, 28 January 2013 07:50:46