Orateur
antoine chapelain
(CEA - Saclay, IRFU/SPP)
Description
The top quark, first observed by the CDF and D0 Col-
laborations in 1995 [1, 2], is the heaviest of all elementary
particles. Due to the large top-quark mass, the measure-
ment of the production and decay properties of top quark
pairs in proton-antiproton collisions provides an im-
portant test of the standard model of particle physics
(SM) that may unveil the presence of new phenomena
beyond the SM (BSM).
Perturbative quantum chromodynamics (pQCD) at
next-to-leading order (NLO) predicts that top quark-antiquark production in quark-antiquark annihilation in the
center of mass frame is forward-backward (FB) asymmet-
ric in the angular distributions of the top and antitop
quarks.
In 2011 results from CDF and D0 [3,4] have driven a lot of attention because some of the measured asymmetries were significantly higher than the predictions based on the SM. Processes beyond the SM can modify the top-antitop production asymmetry and thus predict a higher asymmetry.
I'm going to present the asymmetry measurements I'm involved at the D0 and ATLAS experiments.
[1] F. Abe et al. (CDF Collaboration), Phys. Rev. Lett. 74, 2626 1995).
[2] S. Abachi et al. (D0 Collaboration), Phys. Rev. Lett. 74, 2632 (1995).
[3] T. Aaltonen et al. (CDF Collaboration), Phys. Rev. D 83, 112003 (2011).
[4] V. M. Abazov et al. (D0 Collaboration), Phys. Rev. D 84, 112005 (2011).
Auteur principal
antoine chapelain
(CEA - Saclay, IRFU/SPP)
