CMS-PAS-BPH-15-003 | ||
Measurements of correlations between J/$\psi$ mesons and jets produced in $\sqrt{s}= $ 8 TeV pp collisions | ||
CMS Collaboration | ||
May 2019 | ||
Abstract: A study of the production of J/$\psi$ mesons in conjunction with jets in pp collisions at $\sqrt{s} = $ 8 TeV is presented. The analysis is based on data corresponding to an integrated luminosity of 19.1 fb$^{-1}$ collected with the CMS detector at the LHC. For events with at least one observed jet, the angular separation between the J/$\psi$ meson and the jet is used to test whether the J/$\psi$ meson is a jet fragment. The differential distributions of jet fragmentation probability as a function of jet energy for a fixed J/$\psi$ energy fraction $z$ are presented. The experimental results are compared to a theoretical model using the fragmenting jet function (FJF) approach. The J/$\psi$ jet fragmentation data agree with the predictions of the FJF calculations that use specific long-distance matrix element parameters. This agreement shows that the combination of data on jet fragmentation to J/$\psi$ mesons and FJF analysis is a new way to test predictions for charmonium production from nonrelativistic quantum chromodynamics and to evaluate long-distance matrix element parameter sets. The analysis also shows that most J/$\psi$ mesons with energy above 15 GeV and rapidity $|y| < $ 1.0 are fragments of jets with pseudorapidity $|\eta_{\mathrm{jet}}| < $ 1. | ||
Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, PLB 804 (2020) 135409. The superseded preliminary plots can be found here. |
Figures | |
![]() png pdf |
Figure 1:
Left: The $\Delta $R for J/$\psi$ events with one observed jet. Right: The $\Delta R_1$ vs. $\Delta R_2$ for two-jet events, where $\Delta R_1$ is associated with the higher-energy jet and $\Delta R_2$ with the lower-energy jet. |
![]() png pdf |
Figure 1-a:
The $\Delta $R for J/$\psi$ events with one observed jet. |
![]() png pdf |
Figure 1-b:
The $\Delta R_1$ vs. $\Delta R_2$ for two-jet events, where $\Delta R_1$ is associated with the higher-energy jet and $\Delta R_2$ with the lower-energy jet. |
![]() png pdf |
Figure 2:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1$ = 0.425, using: (left) the BCKL LDME set [18]; and (right) the BK LDME set [17]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 2-a:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1$ = 0.425, using the BCKL LDME set [18]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 2-b:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1$ = 0.425, using the BK LDME set [17]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 3:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1= $ 0.525, using: (left) the BCKL LDME set [18]; and (right) the BK LDME set [17]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 3-a:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1= $ 0.525, using the BCKL LDME set [18]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 3-b:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1= $ 0.525, using the BK LDME set [17]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 4:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1 = $ 0.625, using: (left) the BCKL LDME set [18]; and (right) the BK LDME set [17]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 4-a:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1 = $ 0.625, using the BCKL LDME set [18]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
![]() png pdf |
Figure 4-b:
Comparison of data (closed circles with vertical bars representing the statistical uncertainty (inner bars) and total uncertainty (outer bars)) with the four LDME terms for $z_1 = $ 0.625, using the BK LDME set [17]. The curves show the jet energy dependence of the FJF model predictions, from which the averages were calculated. |
Tables | |
![]() png pdf |
Table 1:
The values of the $\chi ^2$ and the $\chi ^2$ probability (in parentheses) for 7 degrees of freedom in the comparison of the data and the FJF prediction for each LDME term with $z_1$ = 0.425. |
![]() png pdf |
Table 2:
The values of the $\chi ^2$ and the $\chi ^2$ probability (in parentheses) for 7 degrees of freedom in the comparison of the data and the FJF prediction for each LDME term with $z_1$ = 0.525. |
![]() png pdf |
Table 3:
The values of the $\chi ^2$ and the $\chi ^2$ probability (in parentheses) for 7 degrees of freedom in the comparison of the data and the FJF prediction for each LDME term with $z_1 = $ 0.625. |
Summary |
The first analysis comparing data for J/$\psi$ mesons produced as fragmentation products of a central gluonic jet with a theoretical analysis based on Fragmenting Jet Function (FJF) approach has been presented. The data were collected by the CMS Collaboration from $\mathrm{pp}$ collisions at $\sqrt{s}= $ 8 TeV, corresponding to an integrated luminosity of 19.1 fb$^{-1}$. The agreement between the data and the FJF predictions over a wide range of $z$, where $z$ is the J/$\psi$ fraction of the jet energy, validates the FJF approach for gluon fragmentation. For the three $z$ values, 0.425, 0.525, and 0.625, the nonrelativistic quantum chromodynamic long-distance matrix element (LDME) terms for the $^{3}S_{1}^{(8)}$ and $^3P_{J}^{(8)}$ configurations are not dominant for either the Bodwin, Chung, Kim and Lee (BCKL) [18] or Butenschoen and Kniehl (BK) [17] parameter sets, ie, these terms are not the main contributors to J/$\psi$ production by jet fragmentation. For the BCKL LDME parameters, the $^{1}S_{0}^{(8)}$ term dominates jet fragmentation to J/$\psi$ for all three $z$ values studied. This could explain the small J/$\psi$ polarization at large ${p_{\mathrm{T}}}$ observed in high energy hadronic collisions at the Tevatron and LHC. However, the possible role of the $^{3}S_{1}^{(1)}$ term using the BK parameters, with its implied large J/$\psi$ polarization, has to be addressed theoretically. It has almost the same jet energy dependence as the BCKL $^{1}S_{0}^{(8)}$ term for $z > $ 0.5, but not for lower $z$. For events with one observed jet, 84% of J/$\psi$ mesons with $E > $ 15 GeV and $|y| < $ 1 are fragments of a jet produced in the angular region $|\eta| < $ 1.0. We have also demonstrated that some J/$\psi$ mesons are fragments of jets that fail the requirement ${p_{\mathrm{T}}}|_{\mathrm{jet}} > $ 25 GeV. Using a simple model to estimate the fraction of J/$\psi$ mesons that are fragments of unobserved jets, we find that jet fragmentation can be the source of $ > $ 80% of the J/$\psi$ mesons produced in this kinematic region. |
References | ||||
1 | E598 Collaboration | Experimental observation of a heavy particle $ J $ | PRL 33 (1974) 1404 | |
2 | J.-E. Augustin et al. | Discovery of a narrow resonance in e$ ^{+} $e$ ^{-} $ annihilation | PRL 33 (1974) 1406 | |
3 | C.-H. Chang | Hadronic production of $ J/\psi $ associated with a gluon | NPB 172 (1980) 425 | |
4 | R. Baier and R. Ruckl | Hadronic production of J/$ \psi $ and $ {\Upsilon} $: transverse momentum distributions | PLB 102 (1981) 364 | |
5 | CDF Collaboration | $ J/\psi $, $ \psi^\prime \to \mu^{+} \mu^{-} $ and $ B \to J/\psi $, $ \psi^\prime $ cross-sections | in 27th International Conference on High-energy Physics (ICHEP 94) Glasgow, Scotland, July 20-27, 1994 1994 | hep-ex/9412013 |
6 | CDF Collaboration | $ J/\psi $ and $ \psi(2S) $ production in $ \mathrm{p}\bar{\mathrm{p}} $ collisions at $ \sqrt{s} = $ 1.8 TeV | PRL 79 (1997) 572 | |
7 | P. Cho and A. K. Leibovich | Color-octet quarkonia production | PRD 53 (1996) 150 | |
8 | P. Cho and A. K. Leibovich | Color-octet quarkonia production. II | PRD 53 (1996) 6203 | |
9 | P. Artoisenet et al. | $ {\Upsilon} $ Production at Fermilab Tevatron and LHC energies | PRL 101 (2008) 152001 | |
10 | P. Faccioli et al. | Quarkonium production in the LHC era: a polarized perspective | PLB 736 (2014) 98 | 1403.3970 |
11 | M. Procura and I. W. Stewart | Quark fragmentation within an identified jet | PRD 81 (2010) 074009 | 0911.4980 |
12 | A. Jain, M. Procura, and W. J. Waalewijn | Parton fragmentation within an identified jet at NNLL | JHEP 05 (2011) 035 | 1101.4953 |
13 | M. Procura and W. J. Waalewijn | Fragmentation in jets: cone and threshold effects | PRD 85 (2012) 114041 | 1111.6605 |
14 | M. Baumgart, A. K. Leibovich, T. Mehen, and I. Z. Rothstein | Probing quarkonium production mechanisms with jet substructure | JHEP 1411 (2014) 003 | 1406.2295 |
15 | G. Altarelli and G. Parisi | Asymptotic freedom in parton language | NPB126 (1977) 298--318 | |
16 | L. Dai and P. Shrivastava | Quarkonium polarization and the long distance matrix elements hierarchies using jet substructure | 1707.08629 | |
17 | M. Butenschoen and B. A. Kniehl | Next-to-leading-order tests of NRQCD factorization with J/$ \psi $ yield and polarization | MPLA 28 (2013) 1350027 | 1212.2037 |
18 | G. T. Bodwin, H. S. Chung, U.-R. Kim, and J. Lee | Fragmentation contributions to $ J/\psi $ production at the Tevatron and the LHC | PRL 113 (2014) 022001 | 1403.3612 |
19 | K.-T. Chao et al. | J/$ {\psi} $ polarization at hadron colliders in nonrelativistic QCD | PRL 108 (Jun, 2012) 242004 | 1201.2675 |
20 | LHCb Collaboration | Study of J/$ \psi $ production in jets | PRL 118 (2017) 192001 | 1701.05116 |
21 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
22 | CMS Collaboration | $ J/\psi $ and $ \psi $(2S) production in $ \mathrm{pp} $ collisions at $ \sqrt{s}= $ 7 TeV | JHEP 02 (2012) 011 | CMS-BPH-10-014 1111.1557 |
23 | CMS Collaboration | Measurement of J/$ \psi $ and $ \psi $(2S) prompt double-differential cross sections in $ \mathrm{pp} $ collisions at $ \sqrt{s}= $ 7 TeV | PRL 114 (2015) 191802 | CMS-BPH-14-001 1502.04155 |
24 | CMS Collaboration | Measurements of the $ \Upsilon $(1S), $ \Upsilon $(2S), and $ \Upsilon $(3S) differential cross sections in $ \mathrm{pp} $ collisions at $ \sqrt{s}= $ 7 TeV | PLB 749 (2015) 14 | CMS-BPH-12-006 1501.07750 |
25 | CMS Collaboration | Performance of CMS muon reconstruction in $ \mathrm{pp} $ collision events at $ \sqrt{s}= $ 7 TeV | JINST 7 (2012) P10002 | CMS-MUO-10-004 1206.4071 |
26 | CMS Collaboration | Particle-flow reconstruction and global event description with the cms detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
27 | CMS Collaboration | Determination of jet energy calibration and transverse momentum resolution in CMS | JINST 6 (2011) P11002 | CMS-JME-10-011 1107.4277 |
28 | D. Lange | The EvtGen particle decay simulation package | NIMA 462 (2001) 152 | |
29 | E. Barberio, B. van Eijk, and Z. W\cas | $ PHOTOS: $ A universal Monte Carlo for QED radiative corrections in decays | CPC 66 (1991) 115 | |
30 | S. Agostinelli et al. | GEANT4 -- a simulation toolkit | Nucl. Instr. Meth. A 506 (2003) 250 | |
31 | CMS Collaboration | Muon ID Performance: low-$ \rm{p_T} $ muon efficiencies | CMS DP-2014/020 | |
32 | T. Adye | Unfolding algorithms and tests using RooUnfold | in Proceedings, PHYSTAT 2011 Workshop on Statistical Issues Related to Discovery Claims in Search Experiments and Unfolding, CERN,Geneva, Switzerland 17-20 January 2011, pp. 313--318, CERN CERN, Geneva | 1105.1160 |
33 | CDF Collaboration | Polarizations of $ J/ {\psi} $ and $ {\psi}(2S) $ mesons produced in $ \mathrm{p}\overline{\mathrm{p}} $ Collisions at $ \sqrt{s}=1.96\text{}\text{}\mathrm{TeV} $ | PRL 99 (2007) 132001 | |
34 | CMS Collaboration | Measurement of the prompt J/$ \psi $ and $ \psi $(2S) polarizations in $ \mathrm{pp} $ collisions at $ \sqrt{s} = $ 7 TeV | PLB 727 (2013) 381 | CMS-BPH-13-003 1307.6070 |
![]() |
Compact Muon Solenoid LHC, CERN |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |