A bstract The production cross-sections of J/ψ mesons in proton-proton collisions at a centre-of-mass energy of $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 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, p T , 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 < p T < 20 GeV/ c and 2 . 0 < y < 4 . 5 are $$ {\displaystyle \begin{array}{c}{\sigma}_{\mathrm{prompt}}\ J/\psi =8.154\pm 0.010\pm 0.283\ \upmu \mathrm{b},\\ {}{\sigma}_{\mathrm{nonprompt}}\ J/\psi =0.820\pm 0.003\pm 0.034\ \upmu \mathrm{b},\end{array}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtable> <mml:mtr> <mml:mtd> <mml:msub> <mml:mi>σ</mml:mi> <mml:mtext>prompt</mml:mtext> </mml:msub> <mml:mspace /> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> <mml:mo>=</mml:mo> <mml:mn>8.154</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.010</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.283</mml:mn> <mml:mspace /> <mml:mi>μb</mml:mi> <mml:mo>,</mml:mo> </mml:mtd> </mml:mtr> <mml:mtr> <mml:mtd> <mml:msub> <mml:mi>σ</mml:mi> <mml:mtext>nonprompt</mml:mtext> </mml:msub> <mml:mspace /> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.820</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.003</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.034</mml:mn> <mml:mspace /> <mml:mi>μb</mml:mi> <mml:mo>,</mml:mo> </mml:mtd> </mml:mtr> </mml:mtable> </mml:math> where the first uncertainties are statistical and the second systematic. These cross-sections are compared with those at $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 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 $$ \sqrt{s_{\mathrm{NN}}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>NN</mml:mi> </mml:msub> </mml:msqrt> </mml:math> = 5 TeV. The results are compared with theoretical predictions.
Tópico:
Particle physics theoretical and experimental studies
