Measurement of the Z+b-jet cross-section in pp collisions at $\sqrt{s}=7{\mathrm{\,Te\kern -0.1em V}}$ in the forward region
R. Aaij
(1)
,
Y. Amhis
(2)
,
S. Barsuk
(2)
,
M. Borsato
(2)
,
O. Kochebina
(2)
,
J. Lefrançois
(2)
,
F. Machefert
(2)
,
A. Martin Sanchez
(2)
,
Marie Nicol
(2)
,
P. Robbe
(2)
,
M.-H. Schune
(2)
,
M. Teklishyn
(2)
,
A. Vallier
(2)
,
B. Viaud
(2)
,
L. Beaucourt
(3)
,
M. Chefdeville
(3)
,
D. Decamp
(3)
,
N. Déléage
(3)
,
Ph. Ghez
(3)
,
J.-P. Lees
(3)
,
J.F. Marchand
(3)
,
M.-N. Minard
(3)
,
B. Pietrzyk
(3)
,
W. Qian
(3)
,
S. t'Jampens
(3)
,
V. Tisserand
(3)
,
E. Tournefier
(3)
,
S. Akar
(4)
,
E. Aslanides
(4)
,
J. Cogan
(4)
,
W. Kanso
(4)
,
R. Legac
(4)
,
O. Leroy
(4)
,
G. Mancinelli
(4)
,
A. Mordà
(4)
,
J. Serrano
(4)
,
A. Tsaregorodtsev
(4)
,
Ziad Zj Ajaltouni
(5)
,
M. Baalouch
(5)
,
E. Cogneras
(5)
,
O. Deschamps
(5)
,
I. El Rifai
(5)
,
G. Gazzoni
(5)
,
M. Grabalosa Gándara
(5)
,
Pierre Henrard
(5)
,
M. Hoballah
(5)
,
R. Lefèvre
(5)
,
J. Maratas
(5)
,
S. Monteil
(5)
,
V. Niess
(5)
,
P. Perret
(5)
M. Chefdeville
- Function : Author
- PersonId : 741874
- IdHAL : maximilien-chefdeville
- ORCID : 0000-0002-6553-6493
S. t'Jampens
- Function : Author
- PersonId : 736045
- IdHAL : stephane-tjampens
- ORCID : 0000-0003-4249-6641
J. Cogan
- Function : Author
- PersonId : 750510
- IdHAL : julien-cogan
- ORCID : 0000-0001-7194-7566
- IdRef : 078779014
O. Leroy
- Function : Author
- PersonId : 171866
- IdHAL : olivier-leroy
- ORCID : 0000-0002-2589-240X
- IdRef : 169871835
J. Serrano
- Function : Author
- PersonId : 175327
- IdHAL : justine-serrano
- ORCID : 0000-0003-2489-7812
- IdRef : 127525521
Ziad Zj Ajaltouni
- Function : Author
- PersonId : 903794
E. Cogneras
- Function : Author
- PersonId : 743220
- IdHAL : eric-cogneras
- ORCID : 0000-0002-8933-9427
O. Deschamps
- Function : Author
- PersonId : 12089
- IdHAL : olivier-deschamps
- ORCID : 0000-0002-7047-6042
- IdRef : 161447368
Pierre Henrard
- Function : Author
- PersonId : 829303
M. Hoballah
- Function : Author
- PersonId : 1174785
- IdHAL : mostafa-adam-hoballah-hobart
P. Perret
- Function : Author
- PersonId : 739797
- IdHAL : pascal-perret
- ORCID : 0000-0002-5732-4343
Abstract
The associated production of a Z boson or an off-shell photon $\gamma^*$ with a bottom quark in the forward region is studied using proton-proton collisions at a centre-of-mass energy of $7{\mathrm{\,Te\kern -0.1em V}}$. The Z bosons are reconstructed in the ${\text{Z}/\gamma^*}\rightarrow{\mu^{+}\mu^{-}}$ final state from muons with a transverse momentum larger than $20{\mathrm{\,Ge\kern -0.1em V}}$, while two transverse momentum thresholds are considered for jets ($10{\mathrm{\,Ge\kern -0.1em V}}$ and $20{\mathrm{\,Ge\kern -0.1em V}}$). Both muons and jets are reconstructed in the pseudorapidity range $2.0 < \eta < 4.5$. The results are based on data corresponding to $1.0{\,{fb}^{-1}}$ recorded in 2011 with the LHCb detector. The measurement of the Z+b-jet cross-section is normalized to the Z+jet cross-section. The measured cross-sections are $ \sigma(\text{$\text{Z}/\gamma^*(\mu^{+}\mu^{-})$+b-jet}) = 330 \pm 68 (\text{stat}) \pm 58 (\text{syst}) \pm 12 (\text{lumi}) {\,{fb}}$ for ${$p_{\rm T}$}$(jet)$>10{\mathrm{\,Ge\kern -0.1em V}}$, and $ \sigma(\text{$\text{Z}/\gamma^*(\mu^{+}\mu^{-})$+b-jet}) = 167 \pm 47 (\text{stat}) \pm 29 (\text{syst}) \pm 6 (\text{lumi}) {\,{fb}} $ for ${$p_{\rm T}$}$(jet)$>20{\mathrm{\,Ge\kern -0.1em V}}$.