The production of J/psi mesons is studied with the LHCb detector using data from pp collisions at sqrt(s)=2.76 TeV corresponding to an integrated luminosity of 71 nb^1. The differential crosssection for inclusive J/psi production is measured as a function of its transverse momentum pT. The crosssection in the fiducial region 0<pT<12 GeV/c and rapidity 2.0<y<4.5 is measured to be 5.6 +/ 0.1(stat) +/ 0.4 (syst) mub, with the assumption of unpolarised J/psi production. The fraction of J/psi production from bhadron decays is measured to be (7.1 +/ 0.6 (stat) +/ 0.7 (syst)) .
Dimuon mass distributions, with fit results superimposed, in bins of $p_{\rm T}$ . Results for $ p_{\rm T} >7 {\mathrm{ Ge V /}c} $ are merged in the last bin. 
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Distributions of the data with projections of the fit superimposed for (left) the dimuon invariant mass and (right) $t_z$. The thick blue line is the total fit function and the hatched area the background component. 
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Acceptance (orange circles), reconstruction (upwardfacing red triangles), trigger (downwardfacing green triangles) and total (blue squares) $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ efficiency, as a function of $p_{\rm T}$ . The efficiencies are evaluated from a Monte Carlo simulation in which the $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ is produced unpolarised. 
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Differential production crosssection for inclusive $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ production in the rapidity range $2.0<y<4.5$ as a function of $p_{\rm T}$ . The vertical error bars are the quadratic sums of the statistical and systematic uncertainties. 
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Animated gif made out of all figures. 
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Relative systematic uncertainties on the luminosity (%). 
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Relative systematic uncertainties on the crosssection results and on the fraction of $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ mesons from $b$hadron decay (%). 
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Differential crosssection ${\rm d}\sigma / {\rm d} p_{\rm T} $ at $\sqrt{s}=2.76\mathrm{ Te V} $ for inclusive $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ production in bins of $p_{\rm T}$ . The rapidity range covered is $2.0<y<4.5$. The first uncertainty is statistical and the second is systematic. 
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Created on 05 March 2021.