Abstract: | The associated production of a $W$ boson with a jet originating from either a
light parton or heavy-flavor quark is studied in the forward region using
proton-proton collisions. The analysis uses data corresponding to integrated
luminosities of 1.0 and $2.0,{
m fb}^{-1}$ collected with the LHCb detector
at center-of-mass energies of 7 and 8 TeV, respectively. The $W$ bosons are
reconstructed using the $W omu
u$ decay and muons with a transverse
momentum, $p_{
m T}$, larger than 20 GeV in the pseudorapidity range
$2.0<eta<4.5$. The partons are reconstructed as jets with $p_{
m T} > 20$ GeV
and $2.2 < eta < 4.2$. The sum of the muon and jet momenta must satisfy
$p_{
m T} > 20$ GeV. The fraction of $W+$jet events that originate from beauty
and charm quarks is measured, along with the charge asymmetries of the
$W!+!b$ and $W!+!c$ production cross-sections. The ratio of the $W+$jet to
$Z+$jet production cross-sections is also measured using the $Z omumu$
decay. All results are in agreement with Standard Model predictions. |