Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of forward $toverline{t}$, $W+boverline{b}$ and $W+coverline{c}$ production in $pp$ collisions at $sqrt{s}=8$ TeV
58
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The production of $toverline{t}$, $W+boverline{b}$ and $W+coverline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $pm$ 0.02 $mbox{fb}^{-1}$. The $W$ bosons are reconstructed in the decays $Wrightarrowell u$, where $ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.
rate research
Read More
A measurement of the cross-section for $W to e u$ production in $pp$ collisions is presented using data corresponding to an integrated luminosity of $2,$fb$^{-1}$ collected by the LHCb experiment at a centre-of-mass energy of $sqrt{s}=8,$TeV. The electrons are required to have more than $20,$GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive $W$ production cross-sections, where the $W$ decays to $e u$, are measured to be begin{equation*} sigma_{W^{+} to e^{+} u_{e}}=1124.4pm 2.1pm 21.5pm 11.2pm 13.0,mathrm{pb}, end{equation*} begin{equation*} sigma_{W^{-} to e^{-}bar{ u}_{e}}=,,,809.0pm 1.9pm 18.1pm,,,7.0pm phantom{0}9.4,mathrm{pb}, end{equation*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The $W^{+}/W^{-}$ cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of $W$ boson branching fractions is determined to be begin{equation*} mathcal{B}(W to e u)/mathcal{B}(W to mu u)=1.020pm 0.002pm 0.019, end{equation*} where the first uncertainty is statistical and the second is systematic.
A measurement of the inclusive $W to mu u$ production cross-section using data from $pp$ collisions at a centre-of-mass energy of $sqrt{s} = 7 {rm , TeV}$ is presented. The analysis is based on an integrated luminosity of about $1.0 {rm , fb}^{-1}$ recorded with the LHCb detector. Results are reported for muons with a transverse momentum greater than $20 {rm , Gekern -0.1em V!/}c$ and pseudorapidity between 2.0 and 4.5. The $W^{+}$ and $W^{-}$ production cross-sections are measured to be $$sigma_{W^{+} to mu^{+} u} = 861.0 pm 2.0 pm 11.2 pm 14.7 {rm , pb},$$ $$sigma_{W^{-} to mu^{-}overline{ u}} = 675.8 pm 1.9 pm 8.8 pm 11.6 {rm , pb},$$ where the first uncertainty is statistical, the second is systematic and the third is due to the luminosity determination. Cross-section ratios and differential distributions as functions of the muon pseudorapidity are also presented. The ratio of $W^{+}$ to $W^{-}$ cross-sections in the same fiducial kinematic region is determined to be $$frac{sigma_{W^{+} to mu^{+} u}}{sigma_{W^{-} to mu^{-}overline{ u}}} = 1.274 pm 0.005 pm 0.009,$$ where the uncertainties are statistical and systematic, respectively. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics.
The production of $W$ and $Z$ bosons in association with jets is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $pm$ 0.02 fb$^{-1}$. The $W$ boson is identified using its decay to a muon and a neutrino, while the $Z$ boson is identified through its decay to a muon pair. Total cross-sections are measured and combined into charge ratios, asymmetries, and ratios of $W+$jet and $Z$+jet production cross-sections. Differential measurements are also performed as a function of both boson and jet kinematic variables. All results are in agreement with Standard Model predictions.
The decay $Z rightarrow b bar{b}$ is reconstructed in $pp$ collision data, corresponding to 2 fb$^{-1}$ of integrated luminosity, collected by the LHCb experiment at a centre-of-mass energy of $sqrt{s}=8$ TeV. The product of the $Z$ production cross-section and the $Z rightarrow b bar{b}$ branching fraction is measured for candidates in the fiducial region defined by two particle-level $b$-quark jets with pseudorapidities in the range $2.2 < eta < 4.2$, with transverse momenta $p_{T}>20$ GeV and dijet invariant mass in the range $45 < m_{jj} < 165$ GeV. From a signal yield of $5462 pm 763$ $Z rightarrow b bar{b}$ events, where the uncertainty is statistical, a production cross-section times branching fraction of $332 pm 46 pm 59$ pb is obtained, where the first uncertainty is statistical and the second systematic. The measured significance of the signal yield is 6.0 standard deviations. This measurement represents the first observation of the $Z rightarrow b bar{b}$ production in the forward region of $pp$ collisions.
Measurements are presented of electroweak boson production using data from $pp$ collisions at a centre-of-mass energy of $sqrt{s} = 8mathrm{,Tekern -0.1em V}$. The analysis is based on an integrated luminosity of $2.0mathrm{,fb}^{-1}$ recorded with the LHCb detector. The bosons are identified in the $Wrightarrowmu u$ and $Zrightarrowmu^{+}mu^{-}$ decay channels. The cross-sections are measured for muons in the pseudorapidity range $2.0 < eta < 4.5$, with transverse momenta $p_{rm T} > 20{mathrm{,Gekern -0.1em V!/}c}$ and, in the case of the $Z$ boson, a dimuon mass within $60 < M_{mu^{+}mu^{-}} < 120{mathrm{,Gekern -0.1em V!/}c^{2}}$. The results are begin{align*} sigma_{W^{+}rightarrowmu^{+} u} &= 1093.6 pm 2.1 pm 7.2 pm 10.9 pm 12.7{rm ,pb} , , sigma_{W^{-}rightarrowmu^{-}bar{ u}} &= phantom{0}818.4 pm 1.9 pm 5.0 pm phantom{0}7.0 pm phantom{0}9.5{rm ,pb} , , sigma_{Zrightarrowmu^{+}mu^{-}} &= phantom{00}95.0 pm 0.3 pm 0.7 pm phantom{0}1.1 pm phantom{0}1.1{rm ,pb} , , end{align*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. The evolution of the $W$ and $Z$ boson cross-sections with centre-of-mass energy is studied using previously reported measurements with $1.0mathrm{,fb}^{-1}$ of data at $7mathrm{,Tekern -0.1em V}$. Differential distributions are also presented. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
