Production Cross Section In Pp Collisions Research Articles

Measurement of associated J/ψ-ψ(2S) production cross-section in pp collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV

The cross-section of associated J/ψ-ψ(2S) production in proton-proton collisions at a centre-of-mass energy of s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb−1, collected by the LHCb experiment. The measurement is performed for both J/ψ and ψ(2S) mesons having transverse momentum pT< 14 GeV/c and rapidity 2.0 < y < 4.5, assuming negligible polarisation of the J/ψ and ψ(2S) mesons. The production cross-section is measured to be 4.5 ± 0.7 ± 0.3 nb, where the first uncertainty is statistical and the second systematic. The differential cross-sections are measured as functions of several kinematic variables of the J/ψ-ψ(2S) candidates. The results are combined with a measurement of J/ψ-J/ψ production, giving a cross-section ratio between J/ψ-ψ(2S) and J/ψ-J/ψ production of 0.274 ± 0.044 ± 0.008, where the first uncertainty is statistical and the second systematic.

Measurement of the Z boson production cross-section in pp collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 5.02 TeV

The first measurement of the Z boson production cross-section at centre-of-mass energy s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 5.02 TeV in the forward region is reported, using pp collision data collected by the LHCb experiment in year 2017, corresponding to an integrated luminosity of 100 ± 2 pb−1. The production cross-section is measured for final-state muons in the pseudorapidity range 2.0 < η < 4.5 with transverse momentum pT> 20 GeV/c. The integrated cross-section is determined to beσZ→μ+μ−=39.6±0.7stat±0.6syst±0.8lumipb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\sigma}_{Z\ o \\mu +\\mu -}=39.6\\pm 0.7\\left(\ extrm{stat}\\right)\\pm 0.6\\left(\ extrm{syst}\\right)\\pm 0.8\\left(\ extrm{lumi}\\right)\ extrm{pb} $$\\end{document}for the di-muon invariant mass in the range 60 < Mμμ< 120 GeV/c2. This result and the differential cross-section results are in good agreement with theoretical predictions at next-to-next-to-leading order in the strong coupling constant.Based on a previous LHCb measurement of the Z boson production cross-section in pPb collisions at sNN\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s_{NN}} $$\\end{document} = 5.02 TeV, the nuclear modification factor RpPb is measured for the first time at this energy. The measured values are 1.2−0.3+0.5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {1.2}_{-0.3}^{+0.5} $$\\end{document} (stat) ± 0.1(syst) in the forward region (1.53 <yμ∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {y}_{\\mu}^{\\ast } $$\\end{document}< 4.03) and 3.6−0.9+1.6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {3.6}_{-0.9}^{+1.6} $$\\end{document} (stat) ± 0.2(syst) in the backward region (−4.97 <yμ∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {y}_{\\mu}^{\\ast } $$\\end{document}< −2.47), where yμ∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {y}_{\\mu}^{\\ast } $$\\end{document} represents the muon rapidity in the centre-of-mass frame.

Measurement of the toverline{t} production cross-section in pp collisions at sqrt{s} = 5.02 TeV with the ATLAS detector

The inclusive top-quark pair ( toverline{t} ) production cross-section {sigma}_{toverline{t}} is measured in proton–proton collisions at a centre-of-mass energy sqrt{s} = 5.02 TeV, using 257 pb−1 of data collected in 2017 by the ATLAS experiment at the LHC. The toverline{t} cross-section is measured in both the dilepton and single-lepton final states of the toverline{t} system and then combined. The combination of the two measurements yieldsσtt¯=67.5±0.9stat.±2.3syst.±1.1lumi.±0.2beampb,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\sigma}_{t\\overline{t}}=67.5\\pm 0.9\\left(\ extrm{stat}.\\right)\\pm 2.3\\left(\ extrm{syst}.\\right)\\pm 1.1\\left(\ extrm{lumi}.\\right)\\pm 0.2\\left(\ extrm{beam}\\right)\ extrm{pb}, $$\\end{document}where the four uncertainties reflect the limited size of the data sample, experimental and theoretical systematic effects, and imperfect knowledge of both the integrated luminosity and the LHC beam energy, giving a total uncertainty of 3.9%. The result is in agreement with theoretical quantum chromodynamic calculations at next-to-next-to-leading order in the strong coupling constant, including the resummation of next-to-next-to-leading logarithmic soft-gluon terms, and constrains the parton distribution functions of the proton at large Bjorken-x.

Measurement of J/\u03c8 production cross-sections in pp collisions at sqrt{s} = 5 TeV

The production cross-sections of J/ψ mesons in proton-proton collisions at a centre-of-mass energy of sqrt{s} = 5 TeV are measured using a data sample corresponding to an integrated luminosity of 9.13 ± 0.18 pb−1, collected by the LHCb experiment. The cross-sections are measured differentially as a function of transverse momentum, pT, and rapidity, y, and separately for J/ψ mesons produced promptly and from beauty hadron decays (nonprompt). With the assumption of unpolarised J/ψ mesons, the production cross-sections integrated over the kinematic range 0 < pT< 20 GeV/c and 2.0 < y < 4.5 areσpromptJ/ψ=8.154±0.010±0.283μb,σnonpromptJ/ψ=0.820±0.003±0.034μb,\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ {\\displaystyle \\begin{array}{c}{\\sigma}_{\\mathrm{prompt}}\\ J/\\psi =8.154\\pm 0.010\\pm 0.283\\ \\upmu \\mathrm{b},\\\\ {}{\\sigma}_{\\mathrm{nonprompt}}\\ J/\\psi =0.820\\pm 0.003\\pm 0.034\\ \\upmu \\mathrm{b},\\end{array}} $$\\end{document}where the first uncertainties are statistical and the second systematic. These cross-sections are compared with those at sqrt{s} = 8 TeV and 13 TeV, and are used to update the measurement of the nuclear modification factor in proton-lead collisions for J/ψ mesons at a centre-of-mass energy per nucleon pair of sqrt{s_{mathrm{NN}}} = 5 TeV. The results are compared with theoretical predictions.

Measurements of W+W\u2212+ \u2265 1 jet production cross-sections in pp collisions at sqrt{s} = 13 TeV with the ATLAS detector

Fiducial and differential cross-section measurements of W+W− production in association with at least one hadronic jet are presented. These measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton-proton collision data collected at sqrt{s} = 13 TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139 fb−1. Events are selected with exactly one oppositely charged electron-muon pair and at least one hadronic jet with a transverse momentum of pT> 30 GeV and a pseudorapidity of |η| < 4.5. After subtracting the background contributions and correcting for detector effects, the jet-inclusive W+W−+ ≥ 1 jet fiducial cross-section and W+W−+ jets differential cross-sections with respect to several kinematic variables are measured. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the W+W− system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced.

Measurement of the Z(\u2192 \u2113+\u2113\u2212)\u03b3 production cross-section in pp collisions at sqrt{s} = 13 TeV with the ATLAS detector

The production of a prompt photon in association with a Z boson is studied in proton-proton collisions at a centre-of-mass energy sqrt{s} = 13 TeV. The analysis uses a data sample with an integrated luminosity of 139 fb−1 collected by the ATLAS detector at the LHC from 2015 to 2018. The production cross-section for the process pp → ℓ+ℓ−γ + X (ℓ = e, μ) is measured within a fiducial phase-space region defined by kinematic requirements on the photon and the leptons, and by isolation requirements on the photon. An experimental precision of 2.9% is achieved for the fiducial cross-section. Differential cross-sections are measured as a function of each of six kinematic variables characterising the ℓ+ℓ−γ system. The data are compared with theoretical predictions based on next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations. The impact of next-to-leading-order electroweak corrections is also considered.

Measurement of {psi {(2S)}} production cross-sections in proton-proton collisions at sqrt{s} =7 and 13text { TeV}

The cross-sections of psi {(2S)} meson production in proton-proton collisions at sqrt{s} =13text { TeV} are measured with a data sample collected by the LHCb detector corresponding to an integrated luminosity of 275text { pb} ^{-1} . The production cross-sections for prompt psi {(2S)} mesons and those for psi {(2S)} mesons from b-hadron decays ({psi {(2S)}} text{-from- }{b} ) are determined as functions of the transverse momentum, p_{mathrm {T}}, and the rapidity, y, of the psi {(2S)} meson in the kinematic range 2<p_{mathrm {T}} <20text { GeV/}c and 2.0<y<4.5. The production cross-sections integrated over this kinematic region are σ(promptψ(2S),13TeV)=1.430±0.005(stat)±0.099(syst)μb,σ(ψ(2S)-from-b,13TeV)=0.426±0.002(stat)±0.030(syst)μb.\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$\\begin{aligned} \\begin{aligned}&\\sigma (\\text{ prompt } {\\psi {(2S)}},13\\text { TeV})\\\\&\\quad =1.430\\pm 0.005\\text { (stat)} \\pm 0.099\\text { (syst)} \\,\\upmu \\text {b} ,\\\\&\\sigma ({\\psi {(2S)}} \\text{-from- }{b},13\\text { TeV})\\\\&\\quad =0.426\\pm 0.002\\text { (stat)} \\pm 0.030\\text { (syst)} \\,\\upmu \\text {b} . \\end{aligned} \\end{aligned}$$\\end{document}A new measurement of psi {(2S)} production cross-sections in pp collisions at sqrt{s}=7text { TeV} is also performed using data collected in 2011, corresponding to an integrated luminosity of 614text { pb} ^{-1} . The integrated production cross-sections in the kinematic range 3.5<p_{mathrm {T}} <14text { GeV/}c and 2.0<y<4.5 are σ(promptψ(2S),7TeV)=0.471±0.001(stat)±0.025(syst)μb,σ(ψ(2S)-from-b,7TeV)=0.126±0.001(stat)±0.008(syst)μb.\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$\\begin{aligned} \\begin{aligned}&\\sigma (\\text{ prompt } {\\psi {(2S)}},7\\text { TeV})\\\\&\\quad =0.471\\pm 0.001\\text { (stat)} \\pm 0.025\\text { (syst)} \\,\\upmu \\text {b} ,\\\\&\\sigma ({\\psi {(2S)}} \\text{-from- }{b},7\\text { TeV})\\\\&\\quad =0.126\\pm 0.001\\text { (stat)} \\pm 0.008\\text { (syst)} \\,\\upmu \\text {b} . \\end{aligned} \\end{aligned}$$\\end{document}All results show reasonable agreement with theoretical calculations.

Measurement of W^{pm }-boson and Z-boson production cross-sections in pp collisions at sqrt{s}=2.76\xa0TeV with the ATLAS detector

The production cross-sections for W^{pm } and Z bosons are measured using ATLAS data corresponding to an integrated luminosity of 4.0 pb^{-1} collected at a centre-of-mass energy sqrt{s}=2.76 TeV. The decay channels W rightarrow ell nu and Z rightarrow ell ell are used, where ell can be an electron or a muon. The cross-sections are presented for a fiducial region defined by the detector acceptance and are also extrapolated to the full phase space for the total inclusive production cross-section. The combined (average) total inclusive cross-sections for the electron and muon channels are: σW+→ℓνtot=2312±26(stat.)±27(syst.)±72(lumi.)±30(extr.)pb,σW-→ℓνtot=1399±21(stat.)±17(syst.)±43(lumi.)±21(extr.)pb,σZ→ℓℓtot=323.4±9.8(stat.)±5.0(syst.)±10.0(lumi.)±5.5(extr.)pb.\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$\\begin{aligned} \\sigma ^{\\text {tot}}_{W^{+}\\rightarrow \\ell \\nu }= & {} 2312 \\pm 26\\ (\\text {stat.})\\\\&\\pm 27\\ (\\text {syst.}) \\pm 72\\ (\\text {lumi.}) \\pm 30\\ (\\text {extr.})~\\text {pb} , \\\\ \\sigma ^{\\text {tot}}_{W^{-}\\rightarrow \\ell \\nu }= & {} 1399 \\pm 21\\ (\\text {stat.})\\ \\pm 17\\ (\\text {syst.}) \\\\&\\pm 43\\ (\\text {lumi.}) \\pm 21\\ (\\text {extr.})~\\text {pb} , \\\\ \\sigma ^{\\text {tot}}_{Z \\rightarrow \\ell \\ell }= & {} 323.4 \\pm 9.8\\ (\\text {stat.}) \\pm 5.0\\ (\\text {syst.})\\\\&\\pm 10.0\\ (\\text {lumi.}) \\pm 5.5 (\\text {extr.}) ~\\text {pb} . \\end{aligned}$$\\end{document}Measured ratios and asymmetries constructed using these cross-sections are also presented. These observables benefit from full or partial cancellation of many systematic uncertainties that are correlated between the different measurements.

Measurement of heavy-flavour production, correlations and jets with ALICE

In this article, recent ALICE measurements of the RAA and v2 of electrons at mid-rapidity (|y|&lt;0.6) and muons at forward rapidity (2.5&lt;y&lt;4), from semi-leptonic decays of heavy-flavour hadrons in Pb–Pb collisions at [see formula in PDF] = 5.02 TeV are shown. The results of D-tagged jet production cross-section in pp collisions at √s =7 TeV are presented. In addition, the azimuthal correlation of D mesons with charged particles in p–Pb collisions at [see formula in PDF] = 5.02 TeV, and electrons from semi-leptonic decays of heavyflavour hadrons with charged particles in p–Pb and Pb–Pb collisions at [see formula in PDF] = 5.02 TeV are reported.

Measurement of the B\xb1 production cross-section in pp collisions at sqrt{s}=7 and 13 TeV

The production of B± mesons is studied in pp collisions at centre-of-mass energies of 7 and 13 TeV, using B± → J/ψ K± decays and data samples corresponding to 1.0 fb−1 and 0.3 fb−1, respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range 0 < pT < 40 GeV/c and the rapidity range 2.0 < y < 4.5 are measured to beσpp→B±X,s=7TeV=43.0±0.2±2.5±1.7μb,σpp→B±X,s=13TeV=86.6±0.5±5.4±3.4μb,\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ \\begin{array}{l}\\sigma \\left( pp\\to {B}^{\\pm }X,\\sqrt{s}=7\\kern0.5em \\mathrm{T}\\mathrm{e}\\mathrm{V}\\right)=43.0\\pm 0.2\\pm 2.5\\pm 1.7\\kern0.5em \\upmu \\mathrm{b},\\hfill \\\\ {}\\sigma \\left( pp\\to {B}^{\\pm }X,\\sqrt{s}=13\\kern0.5em \\mathrm{T}\\mathrm{e}\\mathrm{V}\\right)=86.6\\pm 0.5\\pm 5.4\\pm 3.4\\kern0.5em \\upmu \\mathrm{b},\\hfill \\end{array} $$\\end{document}where the first uncertainties are statistical, the second are systematic, and the third are due to the limited knowledge of the B± → J/ψ K± branching fraction. The ratio of the cross-section at 13 TeV to that at 7 TeV is determined to be 2.02 ± 0.02 (stat) ± 0.12 (syst). Differential cross-sections are also reported as functions of pT and y. All results are in agreement with theoretical calculations based on the state-of-art fixed next-to-leading order quantum chromodynamics.

Measurements of prompt charm production cross-sections in pp collisions at sqrt{s}=5 TeV

Production cross-sections of prompt charm mesons are measured using data from pp collisions at the LHC at a centre-of-mass energy of 5 TeV. The data sample corresponds to an integrated luminosity of 8.60 ± 0.33 pb−1 collected by the LHCb experiment. The production cross-sections of D0, D+, Ds+, and D∗+ mesons are measured in bins of charm meson transverse momentum, pT, and rapidity, y. They cover the rapidity range 2.0 < y < 4.5 and transverse momentum ranges 0 < pT< 10 GeV/c for D0 and D+ and 1 < pT< 10 GeV/c for Ds+ and D∗+ mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1 < pT< 8 GeV/c are determined to beσpp→D0X=1004±3±54μb,σpp→D+X=402±2±30μb,σpp→Ds+X=170±4±16μb,σpp→D∗+X=421±5±36μb,\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ \\begin{array}{l}\\sigma \\left( pp\\to {D}^0X\\right)=1004\\pm 3\\pm 54\\mu \\mathrm{b},\\\\ {}\\sigma \\left( pp\\to {D}^{+}X\\right)=402\\pm 2\\pm 30\\mu \\mathrm{b},\\\\ {}\\sigma \\left( pp\\to {D}_s^{+}X\\right)=170\\pm 4\\pm 16\\mu \\mathrm{b},\\\\ {}\\sigma \\left( pp\\to {D}^{\\ast +}X\\right)=421\\pm 5\\pm 36\\mu \\mathrm{b},\\end{array} $$\\end{document}where the uncertainties are statistical and systematic, respectively.

Measurement of the J/\u03c8 pair production cross-section in pp collisions at sqrt{s}=13 TeV

The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of sqrt{s}=13 TeV, corresponding to an integrated luminosity of 279 ±11 pb−1. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 ± 1.0 ± 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions.

Measurement of the prompt J/psi pair production cross-section in pp collisions at sqrt{s} = 8\xa0TeV with the ATLAS detector

The production of two prompt J/psi mesons, each with transverse momenta p_{mathrm {T}}>8.5 GeV and rapidity |y| < 2.1, is studied using a sample of proton-proton collisions at sqrt{s} = 8 TeV, corresponding to an integrated luminosity of 11.4 fb^{-1} collected in 2012 with the ATLAS detector at the LHC. The differential cross-section, assuming unpolarised J/psi production, is measured as a function of the transverse momentum of the lower-p_{mathrm {T}}J/psi meson, di-J/psi p_{mathrm {T}} and mass, the difference in rapidity between the two J/psi mesons, and the azimuthal angle between the two J/psi mesons. The fraction of prompt pair events due to double parton scattering is determined by studying kinematic correlations between the two J/psi mesons. The total and double parton scattering cross-sections are compared with predictions. The effective cross-section of double parton scattering is measured to be sigma _{mathrm {eff}} = 6.3 pm 1.6 mathrm {(stat)} pm 1.0 mathrm {(syst)} mb.

Erratum to: Measurements of prompt charm production cross-sections in pp collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

C. Baesso, M. Cruz Torres, C. Gobel, J. Molina Rodriguez are associated to Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil Y. Xie, J. Yu are associated to Center for High Energy Physics, Tsinghua University, Beijing, China D. A. Milanes, I. A. Monroy, J. A. Rodriguez Lopez are associated to LPNHE, Universite Pierre et Marie Curie, Universite Paris Diderot, CNRS/IN2P3, Paris, France O. Grunberg, M. Hes, C. Vos, R. Waldi are associated to Physikalisches Institut, Ruprecht-Karls-Universitat Heidelberg, Heidelberg, Germany T. Likhomanenko, A. Malinin, V. Shevchenko, A. Ustyuzhanin are associated to Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia D. Derkach, E. Khairullin, T. Likhomanenko, A. Ustyuzhanin are associated to Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia F. Martinez Vidal, A. Oyanguren, P. Ruiz Valls, C. Sanchez Mayordomo are associated to Universitat de Barcelona, Barcelona, Spain C. J. G. Onderwater is associated to Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands Deceased (T. M. Karbach)

Measurement of the forward Z boson production cross-section in pp collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

A measurement of the production cross-section of Z bosons in pp collisions at $\sqrt{s} = 13$ TeV is presented using dimuon and dielectron final states in LHCb data. The cross-section is measured for leptons with pseudorapidities in the range $2.0 < \eta < 4.5$, transverse momenta $p_\text{T} > 20$ GeV and dilepton invariant mass in the range $60<m(\ell\ell)<120$ GeV. The integrated cross-section from averaging the two final states is \begin{equation*}\sigma_{\text{Z}}^{\ell\ell} = 194.3 \pm 0.9 \pm 3.3 \pm 7.6\text{ pb,}\end{equation*} where the first uncertainty is statistical, the second is due to systematic effects, and the third is due to the luminosity determination. In addition, differential cross-sections are measured as functions of the Z boson rapidity, transverse momentum and the angular variable $\phi^*_\eta$.

Simultaneous measurements of the [formula omitted], W+W−, and Z/γ⁎ → ττ production cross-sections in pp collisions at [formula omitted] with the ATLAS detector

Simultaneous measurements of the tt‾, W+W−, and Z/γ⁎→ττ production cross-sections using an integrated luminosity of 4.6 fb-1 of pp collisions at s=7 TeV collected by the ATLAS detector at the LHC are presented. Events are selected with two high transverse momentum leptons consisting of an oppositely charged electron and muon pair. The three processes are separated using the distributions of the missing transverse momentum of events with zero and greater than zero jet multiplicities. Measurements of the fiducial cross-section are presented along with results that quantify for the first time the underlying correlations in the predicted and measured cross-sections due to proton parton distribution functions. These results indicate that the correlated NLO predictions for tt‾ and Z/γ⁎→ττ significantly underestimate the data, while those at NNLO generally describe the data well. The full cross-sections are measured to be σ(tt‾)=181.2±2.8−9.5+9.7±3.3±3.3 pb, σ(W+W−)=53.3±2.7−8.0+7.3 and σ(Z/γ⁎→ττ)=1174±24−87+72±21±9 pb, where the cited uncertainties are due to statistics, systematic effects, luminosity and the LHC beam energy measurement, respectively.

Measurements of prompt charm production cross-sections in pp collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

Production cross-sections of prompt charm mesons are measured with the first data from $pp$ collisions at the LHC at a centre-of-mass energy of $13\,\mathrm{TeV}$. The data sample corresponds to an integrated luminosity of $4.98 \pm 0.19\,\mathrm{pb}^{-1}$ collected by the LHCb experiment. The production cross-sections of $D^{0}$, $D^{+}$, $D_{s}^{+}$, and $D^{*+}$ mesons are measured in bins of charm meson transverse momentum, $p_{\mathrm{T}}$, and rapidity, $y$, and cover the range $0 < p_{\mathrm{T}} < 15\,\mathrm{GeV}/c$ and $2.0 < y < 4.5$. The ratios of the integrated cross-sections between charm mesons agree with previously measured fragmentation fractions. The inclusive $c\overline{c}$ cross-section within the range of $0 < p_{\mathrm{T}} < 8\,\mathrm{GeV}/c$ is found to be \[ \sigma(pp \to c\overline{c}X) = 2940 \pm 3 \pm 180 \pm 160\,\mu\mathrm{b} \] where the uncertainties are due to statistical, systematic and fragmentation fraction uncertainties, respectively.

Measurement of forward J/ψ production cross-sections in pp collisions at s = 13 $$ \sqrt{s}=13 $$ TeV

The production of $J/\psi$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV is studied with the \lhcb detector. Cross-section measurements are performed as a function of the transverse momentum $p_\mathrm{T}$ and the rapidity $y$ of the $J/\psi$ meson in the region $p_\mathrm{T}<14\mathrm{GeV}/c$ and $2.0<y<4.5$, for both prompt $J/\psi$ mesons and $J/\psi$ mesons from $b$-hadron decays. The production cross-sections integrated over the kinematic coverage are $15.03\pm 0.03\pm 0.94$ $\mu$b for prompt $J/\psi$ and $2.25\pm 0.01\pm 0.14$ $\mu$b for $J/\psi$ from $b$-hadron decays, assuming zero polarization of the $J/\psi$ meson. The first uncertainties are statistical and the second systematic. The cross-section reported for $J/\psi$ mesons from $b$-hadron decays is used to extrapolate to a total $b\bar{b}$ cross-section. The ratios of the cross-sections with respect to $\sqrt{s}=8$ TeV are also determined.

Measurement of the exclusive Υ production cross-section in pp collisions at s = 7 $$ \sqrt{s}=7 $$ TeV and 8 TeV

A study is presented of central exclusive production of $\Upsilon(nS)$ states, where the $\Upsilon(nS)$ resonances decay to the $\mu^+\mu^-$ final state, using $pp$ collision data recorded by the LHCb experiment. The cross-section is measured in the rapidity range $2<y(\Upsilon)<4.5$ where the muons are reconstructed in the pseudorapidity range $2<\eta(\mu^\pm)<4.5$. The data sample corresponds to an integrated luminosity of 2.9 fb$^{-1}$ and was collected at centre-of-mass energies of $7$ TeV and $8$ TeV. The measured $\Upsilon(1S)$ and $\Upsilon(2S)$ production cross-sections are \begin{eqnarray} \sigma(pp \to p\Upsilon(1S)p) &=& 9.0 \pm 2.1 \pm 1.7\textrm{ pb and}\nonumber\\ \sigma(pp \to p\Upsilon(2S)p) &=& 1.3 \pm 0.8 \pm 0.3\textrm{ pb},\nonumber \end{eqnarray} where the first uncertainties are statistical and the second are systematic. The $\Upsilon(1S)$ cross-section is also measured as a function of rapidity and is found to be in good agreement with Standard Model predictions. An upper limit is set at 3.4 pb at the 95\% confidence level for the exclusive $\Upsilon(3S)$ production cross-section, including possible contamination from $\chi_b(3P)\to\Upsilon(3S)\gamma$ decays.

Measurement of the forward Z boson production cross-section in pp collisions at s = 7 $$ \sqrt{s}=7 $$ TeV

A measurement of the production cross-section for $Z$ bosons that decay to muons is presented. The data were recorded by the LHCb detector during $pp$ collisions at a centre-of-mass energy of 7 TeV, and correspond to an integrated luminosity of 1.0 fb$^{-1}$. The cross-section is measured for muons in the pseudorapidity range $2.0 < \eta < 4.5$ with transverse momenta $p_{T} > 20$ GeV/c. The dimuon mass is restricted to $60 < M_{\mu^{+}\mu^{-}} < 120$ GeV/c$^{2}$. The measured cross-section is $$\sigma_{Z\rightarrow\mu^{+}\mu^{-}} = (76.0 \pm 0.3 \pm 0.5 \pm 1.0 \pm 1.3) \, \text{pb}$$ where the uncertainties are due to the sample size, systematic effects, the beam energy and the luminosity. This result is in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. The cross-section is also measured differentially as a function of kinematic variables of the $Z$ boson. Ratios of the production cross-sections of electroweak bosons are presented using updated LHCb measurements of $W$ boson production. A precise test of the Standard Model is provided by the measurement of the ratio $$\frac{\sigma_{W^{+}\rightarrow\mu^{+}\nu_{\mu}} + \sigma_{W^{-}\rightarrow\mu^{-}\bar{\nu}_{\mu}}}{\sigma_{Z\rightarrow\mu^{+}\mu^{-}}} = 20.63\pm0.09\pm0.12\pm0.05,$$ where the uncertainty due to luminosity cancels.