Measurement of the production cross-section of $J/\psi$ and $\psi(2$S$)$ mesons in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
Measurements of the differential production cross-sections of prompt and non-prompt $J/\psi$ and $\psi(2$S$)$ mesons with transverse momenta between 8 and 360 GeV and rapidity in the range $|y|<2$ are reported. Furthermore, measurements of the non-prompt fractions of $J/\psi$ and $\psi(2$S$)$, and the prompt and non-prompt $\psi(2$S$)$-to-$J/\psi$ production ratios, are presented. The analysis is performed using 140 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collision data recorded by the ATLAS detector at the LHC during the years 2015-2018.
29 September 2023
e-print arXiv:2309.17177 - pdf from arXiv - Physics Briefing
Figures
Figure 01a
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01b
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01c
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01d
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01e
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01f
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01g
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 01h
Mass (left) and pseudo-proper decay time (right) projections of the fit result for selected analysis (sub-)bins.
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Figure 02a
Total, statistical, and systematic uncertainties (in %) as functions of pT for the differential (a) prompt J/ψ and (b) non-prompt ψ(2S) cross-sections, and for the non-prompt fractions of (c) J/ψ and (d) ψ(2S), in the rapidity slice 0.00 ≤ |y|<0.75. The main components of the systematic uncertainties are also shown.
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Figure 02b
Total, statistical, and systematic uncertainties (in %) as functions of pT for the differential (a) prompt J/ψ and (b) non-prompt ψ(2S) cross-sections, and for the non-prompt fractions of (c) J/ψ and (d) ψ(2S), in the rapidity slice 0.00 ≤ |y|<0.75. The main components of the systematic uncertainties are also shown.
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Figure 02c
Total, statistical, and systematic uncertainties (in %) as functions of pT for the differential (a) prompt J/ψ and (b) non-prompt ψ(2S) cross-sections, and for the non-prompt fractions of (c) J/ψ and (d) ψ(2S), in the rapidity slice 0.00 ≤ |y|<0.75. The main components of the systematic uncertainties are also shown.
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Figure 02d
Total, statistical, and systematic uncertainties (in %) as functions of pT for the differential (a) prompt J/ψ and (b) non-prompt ψ(2S) cross-sections, and for the non-prompt fractions of (c) J/ψ and (d) ψ(2S), in the rapidity slice 0.00 ≤ |y|<0.75. The main components of the systematic uncertainties are also shown.
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Figure 03a
Differential cross-sections for (a) prompt and (b) non-prompt production of J/ψ mesons. For visual clarity, a scaling factor of 1, 10, or 100 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤ |y|<1.5, and 1.5≤ |y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (obscured by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 03b
Differential cross-sections for (a) prompt and (b) non-prompt production of J/ψ mesons. For visual clarity, a scaling factor of 1, 10, or 100 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤ |y|<1.5, and 1.5≤ |y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (obscured by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 04a
Differential cross-sections for (a) prompt and (b) non-prompt production of ψ(2S) mesons. For visual clarity, a scaling factor of 1, 10, or 100 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤|y|<1.5, and 1.5≤|y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (obscured by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 04b
Differential cross-sections for (a) prompt and (b) non-prompt production of ψ(2S) mesons. For visual clarity, a scaling factor of 1, 10, or 100 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤|y|<1.5, and 1.5≤|y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (obscured by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 05a
Non-prompt production fraction of (a) J/ψ and (b) ψ(2S) mesons. For visual clarity, a vertical shift of 0, 0.2, or 0.4 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤|y|<1.5, and 1.5≤|y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (obscured by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 05b
Non-prompt production fraction of (a) J/ψ and (b) ψ(2S) mesons. For visual clarity, a vertical shift of 0, 0.2, or 0.4 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤|y|<1.5, and 1.5≤|y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (obscured by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 06a
The ψ(2S)-to-J/ψ production ratio for the (a) prompt and (b) non-prompt production mechanisms. For visual clarity, a vertical shift of 0, 0.02, or 0.04 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤|y|<1.5, and 1.5≤|y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (hidden by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 06b
The ψ(2S)-to-J/ψ production ratio for the (a) prompt and (b) non-prompt production mechanisms. For visual clarity, a vertical shift of 0, 0.02, or 0.04 is applied to the rapidity slices 0.00 ≤ |y|<0.75, 0.75≤|y|<1.5, and 1.5≤|y|<2.0, respectively. For each data point, the horizontal bar spans the pT range covered by that bin, with the horizontal position of each point representing the mean pT in that bin. The vertical uncertainty range (hidden by the marker for some values) combines both the statistical (the inner bar) and total uncertainty. Uncertainties related to spin alignment or integrated luminosity are not included. Data up to 60 GeV were taken with a dimuon trigger with integrated luminosity 2.6 fb-1; data above 60 GeV were taken with a single-muon trigger with integrated luminosity 140 fb-1.
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Figure 07a
Spin-alignment hypothesis correction factors for the jpsi (a) differential cross-section and (b) non-prompt production fraction, for a number of spin-alignment scenarios. The correction factors are approximately the same for jpsi and psip, for the prompt and non-prompt production mechanisms, and also for the three rapidity regions. The discontinuities at pT=60 GeV are due to the transition from a low-pT dimuon trigger to a high-pT single-muon trigger, and the corresponding change in event acceptance.
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Figure 07b
Spin-alignment hypothesis correction factors for the jpsi (a) differential cross-section and (b) non-prompt production fraction, for a number of spin-alignment scenarios. The correction factors are approximately the same for jpsi and psip, for the prompt and non-prompt production mechanisms, and also for the three rapidity regions. The discontinuities at pT=60 GeV are due to the transition from a low-pT dimuon trigger to a high-pT single-muon trigger, and the corresponding change in event acceptance.
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Figure 08a
Ratios of various theoretical predictions (described in the text) to the data points from this measurement, for the prompt production of (a) J/ψ and (b) ψ(2S) in the central rapidity region. In each pT bin, the shaded area represents the ratio of the theoretical prediction to the measured value, with the vertical spread showing the uncertainties of the respective model. Error bars on the black dots show fractional uncertainties of this measurement.
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Figure 08b
Ratios of various theoretical predictions (described in the text) to the data points from this measurement, for the prompt production of (a) J/ψ and (b) ψ(2S) in the central rapidity region. In each pT bin, the shaded area represents the ratio of the theoretical prediction to the measured value, with the vertical spread showing the uncertainties of the respective model. Error bars on the black dots show fractional uncertainties of this measurement.
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Figure 09a
Ratios of various theoretical predictions (described in the text) to the data points from this measurement, for non-prompt production of (a) J/ψ and (b) ψ(2S) in the central rapidity region. In each pT bin, the shaded area represents the ratio of the theoretical prediction to the measured value, with the vertical spread showing the uncertainties of the respective model. Error bars on the black dots show fractional uncertainties of this measurement.
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Figure 09b
Ratios of various theoretical predictions (described in the text) to the data points from this measurement, for non-prompt production of (a) J/ψ and (b) ψ(2S) in the central rapidity region. In each pT bin, the shaded area represents the ratio of the theoretical prediction to the measured value, with the vertical spread showing the uncertainties of the respective model. Error bars on the black dots show fractional uncertainties of this measurement.
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Tables
Table 01
Parameterisation of the fit model. Here G, CB, E and P denote Gaussian, Crystal Ball, exponential and second-order polynomial functions, respectively, with different indices corresponding to different parameters. The parameterisation of the i=1 term is modified as described in the text and shown in Eq. (4).
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Table 02
Correction factors for an assumed angular dependence propto 1+λθ cos2θ in the helicity frame, for several values of the parameter λθ. The correction factors were found to be the same (within 1%-2%) for jpsi and psip mesons, for prompt and non-prompt production mechanisms, and for the three rapidity intervals considered in this paper.
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Auxiliary material
Figure 01
Comparison of the differential cross-section of prompt J/ψ production measured by ATLAS in the central rapidity range with the CMS [20] and ALICE [28] result in the closest-matching rapidity ranges.
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Figure 02a
Differential cross sections of (a) prompt J/ψ and (b) prompt ψ(2S) overlaid with the predictions of NLO NRQCD model [51] with LDMEs pre-determined in Ref. [52,53]. Model uncertainties include variations of renormalisation, factorisation and NRQCD scales.
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Figure 02b
Differential cross sections of (a) prompt J/ψ and (b) prompt ψ(2S) overlaid with the predictions of NLO NRQCD model [51] with LDMEs pre-determined in Ref. [52,53]. Model uncertainties include variations of renormalisation, factorisation and NRQCD scales.
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Figure 03a
Differential cross sections of prompt J/ψ (a) and prompt ψ(2S) (b) overlaid with predictions from the kT-factorisation model [54,55], obtained with the PEGASUS event generator [56] using the LDMEs determined in Ref. [57]. Theoretical uncertainties are due to variation in the renormalisation scale alone. The range of comparison is limited by the availability of the transverse-momentum-dependent gluon PDF [58].
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Figure 03b
Differential cross sections of prompt J/ψ (a) and prompt ψ(2S) (b) overlaid with predictions from the kT-factorisation model [54,55], obtained with the PEGASUS event generator [56] using the LDMEs determined in Ref. [57]. Theoretical uncertainties are due to variation in the renormalisation scale alone. The range of comparison is limited by the availability of the transverse-momentum-dependent gluon PDF [58].
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Figure 04a
Differential cross sections of (a) prompt J/ψ and (b) prompt ψ(2S), overlaid with predictions of the Improved Colour Evaporation Model [59], with parameters and their uncertainties previously determined from fits to LHCb data at 7 TeV [60,61].
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Figure 04b
Differential cross sections of (a) prompt J/ψ and (b) prompt ψ(2S), overlaid with predictions of the Improved Colour Evaporation Model [59], with parameters and their uncertainties previously determined from fits to LHCb data at 7 TeV [60,61].
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Figure 05a
The non-prompt differential cross-section overlaid with FONLL [62] predictions, shown for (a) J/ψ mesons, and (b) ψ(2S) mesons. The spread of the FONLL prediction band covers the effects of variation of hard scale and charm quark mass.
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Figure 05b
The non-prompt differential cross-section overlaid with FONLL [62] predictions, shown for (a) J/ψ mesons, and (b) ψ(2S) mesons. The spread of the FONLL prediction band covers the effects of variation of hard scale and charm quark mass.
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Figure 06a
Differential cross sections of non-prompt J/ψ (a) and non-prompt ψ(2S) (b) overlaid with predictions of the model based on the next-to-leading order QCD calculation in the general-mass-variable-flavor-number scheme (GM-VFNS) [63]. Parameters of the model were determined in Ref. [52,64], with uncertainties due to renormalisation scale dependence.
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Figure 06b
Differential cross sections of non-prompt J/ψ (a) and non-prompt ψ(2S) (b) overlaid with predictions of the model based on the next-to-leading order QCD calculation in the general-mass-variable-flavor-number scheme (GM-VFNS) [63]. Parameters of the model were determined in Ref. [52,64], with uncertainties due to renormalisation scale dependence.
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Figure 07a
Differential cross sections of non-prompt J/ψ (a) and non-prompt ψ(2S) (b) overlaid with predictions of the NRQCD model with kT-factorisation [65,56]. The range of comparison is limited by the availability of the transverse-momentum-dependent gluon PDF [58].
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Figure 07b
Differential cross sections of non-prompt J/ψ (a) and non-prompt ψ(2S) (b) overlaid with predictions of the NRQCD model with kT-factorisation [65,56]. The range of comparison is limited by the availability of the transverse-momentum-dependent gluon PDF [58].
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