Measurement of the forward-backward asymmetry in the distribution of leptons in $t\bar{t}$ events in the lepton+jets channel
V.M. Abazov
,
G. Bernardi
(1)
,
D. Brown
(1)
,
Y. Enari
(1)
,
S. Greder
(2)
,
G. Grenier
(3)
,
T. Kurca
(3)
,
P. Lebrun
(3)
,
J. Lellouch
(1)
,
D. Li
(1)
,
F. Miconi
(2)
,
I. Ripp-Baudot
(2)
,
L. Zivkovic
(1)
,
J.-F. Grivaz
(4)
,
T. Guillemin
(4)
,
M. Jaffré
(4)
,
P. Pétroff
(4)
,
F. Badaud
(5)
,
Ph. Gris
(5)
,
G. Sajot
(6)
,
J. Stark
(6)
,
M.-C. Cousinou
(7)
,
A. Duperrin
(7)
,
W. Geng
(7)
,
E. Kajfasz
(7)
,
S. Kermiche
(7)
,
E. Nagy
(7)
,
N. Osman
(7)
1
LPNHE -
Laboratoire de Physique Nucléaire et de Hautes Énergies
2 DRS-IPHC - Département Recherches Subatomiques
3 IPNL - Institut de Physique Nucléaire de Lyon
4 LAL - Laboratoire de l'Accélérateur Linéaire
5 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
6 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
7 CPPM - Centre de Physique des Particules de Marseille
2 DRS-IPHC - Département Recherches Subatomiques
3 IPNL - Institut de Physique Nucléaire de Lyon
4 LAL - Laboratoire de l'Accélérateur Linéaire
5 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
6 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
7 CPPM - Centre de Physique des Particules de Marseille
V.M. Abazov
- Function : Author
G. Bernardi
- Function : Author
- PersonId : 1374140
- ORCID : 0000-0002-2837-2442
- IdRef : 088561623
P. Lebrun
- Function : Author
- PersonId : 741027
- IdHAL : patrice-jean-marie-lebrun
- ORCID : 0000-0001-6115-5856
E. Kajfasz
- Function : Author
- PersonId : 742630
- IdHAL : eric-kajfasz
- ORCID : 0000-0002-8575-405X
- IdRef : 150389043
Abstract
We present measurements of the forward-backward asymmetry in the angular distribution of leptons from decays of top quarks and antiquarks produced in proton-antiproton collisions. We consider the final state containing a lepton and at least three jets. The entire sample of data collected by the D0 experiment during Run II of the Fermilab Tevatron Collider, corresponding to 9.7 inverse fb of integrated luminosity, is used. The asymmetry measured for reconstructed leptons is $A_{FB}^l = \big(2.9 \pm 2.1(stat.) ^{+1.5}_{-1.7}(syst.) \big)$%. When corrected for efficiency and resolution effects within the lepton rapidity coverage of $|y_l|<1.5$, the asymmetry is found to be $A_{FB}^l = \big(4.2 \pm 2.3(stat.) ^{+1.7}_{-2.0}(syst.) \big)$%. Combination with the asymmetry measured in the dilepton final state yields $A_{FB}^l = \big(4.2 \pm 2.0(stat.) \pm 1.4(syst.) \big)$%. We examine the dependence of $A_{FB}^l$ on the transverse momentum and rapidity of the lepton. The results are in agreement with predictions from the next-to-leading-order QCD generator \mcatnlo, which predicts an asymmetry of $A_{FB}^l = 2.0$% for $|y_l|<1.5$.