Abstract: | Top quark production in the forward region in proton-proton collisions is
observed for the first time. The $W!+!b$ final state with $W omu
u$ is
reconstructed using muons with a transverse momentum, $p_{
m T}$, larger than
25 GeV in the pseudorapidity range $2.0<eta<4.5$. The $b$ jets are required to
have $50 < p_{
m T} < 100$ GeV and $2.2 < eta < 4.2$, while the transverse
component of the sum of the muon and $b$-jet momenta must satisfy $p_{
m T} >
20$ GeV. The results are based on data corresponding to integrated luminosities
of 1.0 and $2.0$ fb$^{-1}$ collected at center-of-mass energies of 7 and 8 TeV
by LHCb. The inclusive top quark production cross-sections in the fiducial
region are $sigma({
m top})[7
m{TeV}] = 239pm53({
m stat})pm38({
m
syst}),{
m fb}$ and $sigma({
m top})[8
m{TeV}] = 289pm43({
m
stat})pm46({
m syst}),{
m fb}$. These results, along with the observed
differential yields and charge asymmetries, are in agreement with
next-to-leading order Standard Model predictions. |