CMS logoCMS event Hgg
Compact Muon Solenoid
LHC, CERN

CMS-PAS-HIN-19-013
Study of in-medium modification of dijets in PbPb collisions at 5.02 TeV
Abstract: Modifications to the distribution of charged particles with respect to high transverse momentum $(p_{\mathrm{T}})$ jets passing through a quark-gluon plasma are explored. Jets corresponding to dijet selection where the leading and subleading jets are back-to-back are studied in lead-lead (PbPb) and proton-proton (pp) collisions. Correlations of charged particles are measured in relative pseudorapidity and relative azimuth from the jet axes. Jet momentum density profiles ("jet shapes") are determined. The events are categorized in bins of collision centrality, charged particle $p_{\mathrm{T}}$ and dijet momentum balance $x_{j}$, which is the ratio between the subleading and leading jet $p_{\mathrm{T}}$. In comparing the PbPb and pp collision results, modifications to the charged particle yields is found to depend on the $x_{j}$ value. Modifications to both the charged-particle pseudorapidity dependence and the jet momentum density profile are observed to be greater for the leading jet in more momentum balanced conditions. The modifications become more pronounced with respect to the subleading jet for events with a larger dijet momentum imbalance.
Figures & Tables Summary Additional Figures References CMS Publications
Figures

png pdf
Figure 1:
Distributions of charged particle yields correlated to leading jets as a function of $|\Delta \eta |$ for pp (first column) and PbPb collisions in different centrality bins (second to fifth column), shown differentially for all $p_{\rm T}^{\rm trk}$ bins. The first row shows the charged particle yields without any selection on $x_{j}$, while other rows show the charged particle yields in different bins of $x_{j}$, starting with the most unbalanced 0 $ < x_{j} < $ 0.6 (second row) to most balanced 0.8 $ < x_{j} < $ 1.0 (fourth row) dijet events.

png pdf
Figure 2:
Distributions of charged particle yields correlated to subleading jets as a function of $|\Delta \eta |$ for pp (first column) and PbPb collisions in different centrality bins (second to fifth column), shown differentially for all $p_{\rm T}^{\rm trk}$ bins. The first row shows the charged particle yields without any selection on $x_{j}$, while other rows show the charged particle yields in different bins of $x_{j}$, starting with the most unbalanced 0 $ < x_{j} < $ 0.6 (second row) to most balanced 0.8 $ < x_{j} < $ 1.0 (fourth row) dijet events.

png pdf
Figure 3:
Jet radial momentum profile $\mathrm {P}(\Delta r)$ for pp (first column) and PbPb collisions in different centrality bins (second to fifth column), shown differentially in $p_{\rm T}^{\rm trk}$ for leading (top row) and subleading (bottom row) jets.

png pdf
Figure 4:
PbPb to pp ratio of the jet radial momentum distributions, $\mathrm {P} (\Delta r)_{\rm PbPb}/\mathrm {P} (\Delta r)_{\rm pp}$, for different centrality bins for the leading jets (top row) and subleading jets (bottom row).

png pdf
Figure 5:
Leading jet shapes $\rho (\Delta r)$ (normalized to unity over $\Delta r < $ 1) for pp (first column) and PbPb collisions in different centrality bins (second to fifth columns), shown differentially in $p_{\rm T}^{\rm trk}$ for inclusive $x_{j}$ bin (first row) and in differential bins 0 $ < x_{j} < $ 0.6 (second row), 0.6 $ < x_{j} < $ 0.8 (third row), and 0.8 $ < x_{j} < $ 1.0 (fourth row).

png pdf
Figure 6:
PbPb to pp ratio for leading jet shapes $\rho (\Delta r)_{\rm PbPb} / \rho (\Delta r)_{\rm pp}$, in different centrality bins for 0 $ < x_{j} < $ 0.6 (top row), 0.6 $ < x_{j} < $ 0.8 (middle row) and 0.8 $ < x_{j} < $ 1.0 (bottom row) dijet selections. The leading jet shape ratio for all dijets, i.e. without any selection on the dijet momentum balance are also shown in each row for comparison.

png pdf
Figure 7:
Subleading jet shapes $\rho (\Delta r)$ (normalized to unity over $\Delta r < $ 1) for pp (first column) and PbPb collisions in different centrality bins (second to fifth columns), shown differentially in $p_{\rm T}^{\rm trk}$ for inclusive $x_{j}$ bin (first row) and in differential bins 0 $ < x_{j} < $ 0.6 (second row), 0.6 $ < x_{j} < $ 0.8 (third row), and 0.8 $ < x_{j} < $ 1.0 (fourth row).

png pdf
Figure 8:
PbPb to pp ratio for subleading jet shapes $\rho (\Delta r)_{\rm PbPb} / \rho (\Delta r)_{\rm pp}$, in different centrality bins for 0 $ < x_{j} < $ 0.6 (top row), 0.6 $ < x_{j} < $ 0.8 (middle row) and 0.8 $ < x_{j} < $ 1.0 (bottom row) dijet selections. The subleading jet shape ratio for all dijets, i.e. without any selection on the dijet momentum balance are also shown in each row for comparison.

png pdf
Figure 9:
Ratio of momentum unbalanced jet shapes 0.0 $ < x_{j} < $ 0.6 (top row) and balanced jet shapes 0.8 $ < x_{j} < $ 1.0 (bottom row) to $x_{j}$ integrated jet shapes for leading jets in pp collisions and different PbPb centrality bins.

png pdf
Figure 10:
Ratio of momentum unbalanced jet shapes 0.0 $ < x_{j} < $ 0.6 (top row) and balanced jet shapes 0.8 $ < x_{j} < $ 1.0 (bottom row) to $x_{j}$ integrated jet shape for subleading jets in pp collisions and different PbPb centrality bins.

png pdf
Figure 11:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a generator level $x_{j}$ for a given reconstructed $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 11-a:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a generator level $x_{j}$ for a given reconstructed $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 11-b:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a generator level $x_{j}$ for a given reconstructed $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 11-c:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a generator level $x_{j}$ for a given reconstructed $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 11-d:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a generator level $x_{j}$ for a given reconstructed $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 11-e:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a generator level $x_{j}$ for a given reconstructed $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 12:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a reconstructed $x_{j}$ for a given generator level $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 12-a:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a reconstructed $x_{j}$ for a given generator level $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 12-b:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a reconstructed $x_{j}$ for a given generator level $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 12-c:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a reconstructed $x_{j}$ for a given generator level $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 12-d:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a reconstructed $x_{j}$ for a given generator level $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.

png pdf
Figure 12-e:
Generator level $x_{j}$ versus reconstructed $x_{j}$ in the analysis $x_{j}$ bins. The plots show the probability to find a reconstructed $x_{j}$ for a given generator level $x_{j}$. Pythia8 simulation is on the leftmost column in the top row while the most central Pythia+Hydjet in on the right of the bottow row.
Tables

png pdf
Table 1:
Number of events for pp and for different PbPb centrality bins within stated $x_{j}$ ranges. The numbers in parentheses show the fraction of events in each $x_{j}$ bin for a given centrality.

png pdf
Table 2:
Systematic uncertainties for the leading jet shape components, integrated in $\eta $, and $\Delta r$, and shown for pp and centrality binned PbPb collisions. The ranges correspond to the $p_{\mathrm {T}}$ dependence of the uncertainty.

png pdf
Table 3:
Systematic uncertainties for the subleading jet shape components, integrated in $\eta $, and $\Delta r$, and shown for pp and centrality binned PbPb collisions. The ranges correspond to the $p_{\mathrm {T}}$ dependence of the uncertainty.
Summary
CMS has measured charged particle yields in events containing back-to-back leading and subleading jet pairs around the respective jet axes using data from pp and PbPb collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV collected in 2017 and 2018. Using a momentum weighting, jet shapes are also determined. When comparing the charged particle yields around the jet axes, there is an excess of low ${p_{\mathrm{T}}}{}$ particles in PbPb collisions with respect to pp collisions. This excess is larger in the subleading side compared to leading side. The excess is also found to have a different $x_{j}$ dependence for the leading and subleading sides. The leading jets show the strongest modifications effects in balanced events, where the transverse momenta of the two jets are close to each other. However, subleading jets experience the greatest modifications in events with a large jet momentum imbalance between the leading and subleading jets. This indicates that in balanced events both jets lose a comparable amount of energy, while in events with a momentum imbalance the leading jet loses significantly less energy. A possible explanation for the imbalance is that the leading jet is produced near the surface of the plasma while the subleading jet needs to traverse a long distance through the plasma.

For the jet shapes, a redistribution of energy is observed from small angles with respect to the jet axis to larger angles when comparing PbPb collisions to pp events. The difference between the PbPb and pp results is larger for the leading jet compared to the subleading jets, which can be explained by the fact that the subleading jet distribution in pp collisions is significantly wider than that for leading jets. When studying the $x_{j}$ bins for the subleading jet, there is a peak in the PbPb to pp ratio for unbalanced dijet momentum events that disappears for balanced events. This peak can be attributed to a third jet contribution that is needed in pp events to conserve momentum for events where there is a large dijet momentum imbalance.

When comparing jet shape plots corresponding to different dijet momentum balance conditions, the distributions for leading jets are found to be broader for events with balanced jet momenta compared to those where there is a momentum imbalance. For subleading jets, the situation changes with the events with a significant momentum imbalance found to be broader. These observations are consistent with the previous hypothesis given to interpret the particle yield measurements, namely that the average path length inside the medium for leading jets is larger for momentum balanced events, while for subleading jets it is larger in unbalanced events. These data can be used to constrain models of the production point of the dijet within the quark-gluon plasma.
Additional Figures

png pdf
Additional Figure 1:
Distributions of charged particle yields correlated to leading jets as a function of $|\Delta \eta |$ for pp (first column) and 0-10 % central PbPb collisions (second column), shown differentially for all charged particle transverse momentum $(p_{\rm T}^{\rm ch})$ bins. The first row shows the charged particle yields without any selection on $x_{j} = {{p_{\mathrm {T}}} {}^{\mathrm {subleading}}}/{{p_{\mathrm {T}}} {}^{\mathrm {leading}}}$, while other rows show the charged particle yields in different bins of $x_{j}$, starting with the most unbalanced 0 $ < x_{j} < $ 0.6 (second row) to the most balanced 0.8 $ < x_{j} < $ 1.0 (third row) dijet events.

png pdf
Additional Figure 2:
Distributions of charged particle yields correlated to subleading jets as a function of $|\Delta \eta |$ for pp (first column) and 0-10 % central PbPb collisions (second column), shown differentially for all charged particle transverse momentum $(p_{\rm T}^{\rm ch})$ bins. The first row shows the charged particle yields without any selection on $x_{j} = {{p_{\mathrm {T}}} {}^{\mathrm {subleading}}}/{{p_{\mathrm {T}}} {}^{\mathrm {leading}}}$, while other rows show the charged particle yields in different bins of $x_{j}$, starting with the most unbalanced 0 $ < x_{j} < $ 0.6 (second row) to the most balanced 0.8 $ < x_{j} < $ 1.0 (third row) dijet events.

png pdf
Additional Figure 3:
Leading jet shapes $\rho (\Delta r)$ (normalized to unity over $\Delta r < $ 1) for pp (first column) and 0-10 % central PbPb collisions (second column), shown differentially in charged particle transverse momentum $(p_{\rm T}^{\rm ch})$ for inclusive $x_{j} = {{p_{\mathrm {T}}} {}^{\mathrm {subleading}}}/{{p_{\mathrm {T}}} {}^{\mathrm {leading}}}$ bin (first row) and in $x_{j}$ bins 0 $ < x_{j} < $ 0.6 (second row) and 0.8 $ < x_{j} < $ 1.0 (third row).

png pdf
Additional Figure 4:
Subleading jet shapes $\rho (\Delta r)$ (normalized to unity over $\Delta r < $ 1) for pp (first column) and 0-10 % central PbPb collisions (second column), shown differentially in charged particle transverse momentum $(p_{\rm T}^{\rm ch})$ for inclusive $x_{j} = {{p_{\mathrm {T}}} {}^{\mathrm {subleading}}}/{{p_{\mathrm {T}}} {}^{\mathrm {leading}}}$ bin (first row) and in $x_{j}$ bins 0 $ < x_{j} < $ 0.6 (second row) and 0.8 $ < x_{j} < $ 1.0 (third row).

png pdf
Additional Figure 5:
PbPb to pp ratio for leading jet shapes $\rho (\Delta r)_{\rm PbPb} / \rho (\Delta r)_{\rm pp}$ for events in the 0-10 % centrality class. The gray points show $x_{j} = {{p_{\mathrm {T}}} {}^{\mathrm {subleading}}}/{{p_{\mathrm {T}}} {}^{\mathrm {leading}}}$ integrated ratio, while the red points are the ratio in 0 $ < x_{j} < $ 0.6 bin and blue points in 0.8 $ < x_{j} < $ 1.0 bin. Error bars are statistical uncertainties while the shaded areas show systematic uncertainties.

png pdf
Additional Figure 6:
PbPb to pp ratio for subleading jet shapes $\rho (\Delta r)_{\rm PbPb} / \rho (\Delta r)_{\rm pp}$ for events in the 0-10 % centrality class. The gray points show $x_{j} = {{p_{\mathrm {T}}} {}^{\mathrm {subleading}}}/{{p_{\mathrm {T}}} {}^{\mathrm {leading}}}$ integrated ratio, while the red points are the ratio in 0 $ < x_{j} < $ 0.6 bin and blue points in 0.8 $ < x_{j} < $ 1.0 bin. Error bars are statistical uncertainties while the shaded areas show systematic uncertainties.
References
1 J. D. Bjorken Energy loss of energetic partons in qgp: possible extinction of high $ p_{\rm t} $ jets in hadron-hadron collisions FERMILAB-PUB-82-059-THY
2 STAR Collaboration Direct observation of dijets in central Au+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV PRL 97 (2006) 162301 nucl-ex/0604018
3 PHENIX Collaboration Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV: Jet-quenching and the response of partonic matter PRC 77 (2008) 011901 0705.3238
4 ATLAS Collaboration Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV with the ATLAS Detector at the LHC PRL 105 (2010) 252303 1011.6182
5 CMS Collaboration Observation and studies of jet quenching in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV PRC 84 (2011) 024906 CMS-HIN-10-004
1102.1957
6 CMS Collaboration Jet momentum dependence of jet quenching in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 2.76 TeV PLB 712 (2012) 176 CMS-HIN-11-013
1202.5022
7 ALICE Collaboration Measurement of jet suppression in central Pb-Pb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV PLB 746 (2015) 1 1502.01689
8 CMS Collaboration Measurement of jet fragmentation in PbPb and pp collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 2.76 TeV PRC 90 (2014) 024908 CMS-HIN-12-013
1406.0932
9 ATLAS Collaboration Measurement of inclusive jet charged-particle fragmentation functions in Pb+Pb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 2.76 TeV with the ATLAS detector PLB739 (2014) 320--342 1406.2979
10 CMS Collaboration Modification of jet shapes in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV PLB 730 (2014) 243 CMS-HIN-12-002
1310.0878
11 CMS Collaboration Measurement of transverse momentum relative to dijet systems in PbPb and pp collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV JHEP 01 (2016) 6 CMS-HIN-14-010
1509.09029
12 CMS Collaboration Correlations between jets and charged particles in PbPb and pp collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV JHEP 02 (2016) 156 CMS-HIN-14-016
1601.00079
13 CMS Collaboration Decomposing transverse momentum balance contributions for quenched jets in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 2.76 TeV JHEP 11 (2016) 055 CMS-HIN-15-011
1609.02466
14 CMS Collaboration Jet properties in PbPb and pp collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 5.02 TeV JHEP 05 (2018) 006 CMS-HIN-16-020
1803.00042
15 L. Apolinario, N. Armesto, and L. Cunqueiro An analysis of the influence of background subtraction and quenching on jet observables in heavy-ion collisions JHEP 02 (2013) 022 1211.1161
16 A. Ayala, I. Dominguez, J. Jalilian-Marian, and M. E. Tejeda-Yeomans Jet asymmetry and momentum imbalance from $ 2 \to 2 $ and $ 2 \to 3 $ partonic processes in relativistic heavy-ion collisions PRC92 (2015), no. 4, 044902 1503.06889
17 J.-P. Blaizot, Y. Mehtar-Tani, and M. A. C. Torres Angular structure of the in-medium QCD cascade PRL 114 (2015), no. 22, 222002 1407.0326
18 M. A. Escobedo and E. Iancu Event-by-event fluctuations in the medium-induced jet evolution JHEP 05 (2016) 008 1601.03629
19 J. Casalderrey-Solana et al. Angular Structure of Jet Quenching Within a Hybrid Strong/Weak Coupling Model JHEP 03 (2017) 135 1609.05842
20 Y. Tachibana, N.-B. Chang, and G.-Y. Qin Full jet in quark-gluon plasma with hydrodynamic medium response PRC95 (2017), no. 4, 044909 1701.07951
21 CMS Collaboration Jet momentum dependence of jet quenching in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 2.76 TeV PLB712 (2012) 176--197 CMS-HIN-11-013
1202.5022
22 CMS Collaboration Description and performance of track and primary-vertex reconstruction with the CMS tracker JINST 9 (2014), no. 10, P10009 CMS-TRK-11-001
1405.6569
23 CMS Collaboration The CMS Experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
24 M. Cacciari, G. P. Salam, and G. Soyez The anti-$ k_t $ jet clustering algorithm JHEP 04 (2008) 063 0802.1189
25 O. Kodolova, I. Vardanyan, A. Nikitenko, and A. Oulianov The performance of the jet identification and reconstruction in heavy ions collisions with CMS detector EPJC50 (2007) 117--123
26 CMS Collaboration Dependence on pseudorapidity and centrality of charged hadron production in PbPb collisions at a nucleon-nucleon centre-of-mass energy of 2.76 TeV JHEP 08 (2011) 141 CMS-HIN-10-001
1107.4800
27 T. Sjostrand et al. An Introduction to PYTHIA 8.2 CPC 191 (2015) 159--177 1410.3012
28 CMS Collaboration Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements CMS-GEN-17-001
1903.12179
29 NNPDF Collaboration Parton distributions from high-precision collider data EPJC 77 (2017), no. 10, 663 1706.00428
30 GEANT4 Collaboration GEANT4: A Simulation toolkit NIMA506 (2003) 250--303
31 I. P. Lokhtin et al. Heavy ion event generator HYDJET++ (HYDrodynamics plus JETs) CPC 180 (2009) 779--799 0809.2708
32 M. Cacciari, G. P. Salam, and G. Soyez FastJet User Manual EPJC72 (2012) 1896 1111.6097
33 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017), no. 10, P10003 CMS-PRF-14-001
1706.04965
34 D. Bertolini, T. Chan, and J. Thaler Jet Observables Without Jet Algorithms JHEP 04 (2014) 013 1310.7584
35 A. J. Larkoski, D. Neill, and J. Thaler Jet Shapes with the Broadening Axis JHEP 04 (2014) 017 1401.2158
36 O. Kodolova, I. Vardanian, A. Nikitenko, and A. Oulianov The performance of the jet identification and reconstruction in heavy ions collisions with CMS detector EPJC 50 (2007) 117
37 CMS Collaboration Measurement of the elliptic anisotropy of charged particles produced in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV PRC87 (2013), no. 1, 014902 CMS-HIN-10-002
1204.1409
38 P. Berta, M. Spousta, D. W. Miller, and R. Leitner Particle-level pileup subtraction for jets and jet shapes JHEP 06 (2014) 092 1403.3108
39 CMS Collaboration Description and performance of track and primary-vertex reconstruction with the CMS tracker JINST 9 (2014) P10009 CMS-TRK-11-001
1405.6569
40 CMS Collaboration Charged-particle nuclear modification factors in PbPb and pPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 5.02 TeV JHEP 04 (2017) 039 CMS-HIN-15-015
1611.01664
41 CMS Collaboration Measurement of jet fragmentation into charged particles in pp and PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 2.76 ~TeV JHEP 10 (2012) 087 CMS-HIN-11-004
1205.5872
42 CMS Collaboration Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV JINST 12 (2017), no. 02, P02014 CMS-JME-13-004
1607.03663
Compact Muon Solenoid
LHC, CERN