Compact Muon Solenoid
LHC, CERN
Visit us: CMS Public Website, CMS Physics ;
Contact us: CMS Publications Committee
| CMS-PAS-HIN-18-006 | ||
| Jet shapes for isolated photon-tagged jets in PbPb and pp collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}}= $ 5.02 TeV | ||
| CMS Collaboration | ||
| May 2018 | ||
| Abstract: The modification of jet shapes in PbPb collision, relative to those in pp collision, is studied for jets associated with an isolated photon, using data collected with the CMS detector at the CERN LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Jet shapes are constructed in annuli around the axes of jets of transverse momentum $p_\mathrm{T}^\mathrm{jet} > $ 30 GeV/$c$ that are associated with an isolated photon of $p_\mathrm{T}^\gamma > $ 60 GeV/$c$, using charged particles of $p_\mathrm{T}^\mathrm{trk} > $ 1 GeV/$c$. The jet shape distributions are consistent between peripheral PbPb collisions and pp collisions, and they become more different for more central PbPb collisions. The modifications are indicative of a larger fraction of the jet momenta being carried at larger distances from the jet axes, following the interaction between the medium and the traversing partons. | ||
|
Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, PRL 122 (2019) 152001. The superseded preliminary plots can be found here. |
||
| Figures | Summary | Additional Figures | References | CMS Publications |
|---|
| Figures | |
png pdf |
Figure 1:
Top: The differential jet shape, $ {\rho (r)} $, for jets associated with an isolated photon for 50-100%, 30-50%, 10-30%, 0-10% PbPb (full crosses), pp (open crosses) collisions, and PYTHIA MC (histogram). Middle: The ratios of the PbPb over pp distributions. Bottom: The ratios of the MC over pp distributions. The vertical lines through the points represent statistical uncertainties, while the colored boxes indicate systematic uncertainties in data. |
| Summary |
| In summary, the differential jet shapes for jets associated with isolated photons are measured in pp and PbPb collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV for the first time. They are constructed using charged particles with $p_\mathrm{T}^\mathrm{trk} > $ 1 GeV/$c$, for jets with $p_\mathrm{T}^\mathrm{jet} > $ 30 GeV/$c$, which are associated with an isolated photon with $p_\mathrm{T}^\gamma > $ 60 GeV/$c$. While the distribution from the most peripheral (50--100%) PbPb collisions are consistent with pp, a modification of the PbPb jet shape is observed in central collisions, where the 0--10% (10--30%) PbPb $\rho (r)$ is enhanced for $r \geq $ 0.15 ($r \geq $ 0.2 ). No significant suppression is seen at intermediate $r$. The modifications demonstrate conclusively that for hard scatterings which produce dominantly quarks with very similar momentum distribution in pp and PbPb, as identified by the photon tag, the jet momentum is distributed fractionally at greater radial distance in PbPb. This significant redistribution of energy observed in central PbPb collisions, compared with pp and peripheral PbPb collisions, is interpreted as a direct observation of jet broadening in the QGP. |
| Additional Figures | |
png pdf |
Additional Figure 1:
Top: The centrality dependence of differential jet shape, $ {\rho (r)} $, for jets associated with an isolated photon for PbPb (full markers) and pp (open markers) collisions. Bottom: The ratios of the PbPb over pp distributions. The vertical lines through the points represent statistical uncertainties, while the colored boxes indicate systematic uncertainties. |
png pdf |
Additional Figure 2:
Top: The differential jet shape, $ {\rho (r)} $, for jets associated with an isolated photon for pp (full markers) collisions compared to {pythia} MC (histogram). Bottom: The ratios of the MC over pp data distributions. The vertical lines through the points represent statistical uncertainties, while the colored boxes indicate systematic uncertainties in data. |
png pdf |
Additional Figure 3:
Top: The differential jet shape, $ {\rho (r)} $, from two event centralities for jets associated with an isolated photon for PbPb (full markers) and pp (open markers) collisions Bottom: The ratios of the PbPb over pp distributions. The vertical lines through the points represent statistical uncertainties, while the colored boxes indicate systematic uncertainties. |
png pdf |
Additional Figure 4:
The ratio of PbPb over pp differential jet shape, $ {\rho (r)} $, for 0-10% centrality interval. |
png pdf |
Additional Figure 5:
Comparison of the ratios of PbPb over pp differential jet shape, $ {\rho (r)} $, for 0-10% centrality interval with $\text {SCET}_\text {G}$ [1,2,3] and LBT [4] theoretical models. The $\text {SCET}_\text {G}$ band represents the variation of physics scale. |
png pdf |
Additional Figure 6:
The ratio of PbPb over pp differential jet shape, $ {\rho (r)} $, for 30-100% (left) and 0-30% (right) centrality intervals. |
| References | ||||
| 1 | F. Karsch | The phase transition to the quark gluon plasma: recent results from lattice calculations | NP A 590 (1995) 367 | hep-lat/9503010 |
| 2 | D. A. Appel | Jets as a probe of quark-gluon plasmas | PRD 33 (1986) 717 | |
| 3 | J. P. Blaizot and L. D. McLerran | Jets in expanding quark-gluon plasmas | PRD 34 (1986) 2739 | |
| 4 | M. Gyulassy and M. Plumer | Jet quenching in dense matter | PLB 243 (1990) 432 | |
| 5 | X.-N. Wang and M. Gyulassy | Gluon shadowing and jet quenching in $ A+A $ collisions at $ \sqrt{s} = 200A $ GeV | PRL 68 (1992) 1480 | |
| 6 | R. Baier et al. | Radiative energy loss and $ p_{\perp} $-broadening of high energy partons in nuclei | NPB 484 (1997) 265 | hep-ph/9608322 |
| 7 | B. G. Zakharov | Radiative energy loss of high-energy quarks in finite-size nuclear matter and quark-gluon plasma | JEPTL 65 (1997) 615 | hep-ph/9704255 |
| 8 | J. Casalderrey-Solana and C. A. Salgado | Introductory lectures on jet quenching in heavy ion collisions | Acta Phys. Polon. B 38 (2007) 3731 | 0712.3443 |
| 9 | D. d'Enterria | Jet quenching | in Springer Materials - The Landolt-B\"ornstein Database, R. Stock, ed., volume 23: Relativistic Heavy Ion Physics, p. 99 Springer-Verlag | 0902.2011 |
| 10 | U. A. Wiedemann | Jet quenching in heavy ion collisions | Landolt-Bornstein (2010) 521 | 0908.2306 |
| 11 | A. Majumder and M. Van Leeuwen | The theory and phenomenology of perturbative QCD based jet quenching | Prog. Part. NP 66 (2011) 41 | 1002.2206 |
| 12 | JET Collaboration | Extracting the jet transport coefficient from jet quenching in high-energy heavy-ion collisions | PRC 90 (2014) 014909 | 1312.5003 |
| 13 | ATLAS Collaboration | Measurement of the jet radius and transverse momentum dependence of inclusive jet suppression in lead-lead collisions at $ \sqrt{s_{NN}} = $ 2.76 TeV with the ATLAS detector | PLB 719 (2013) 220 | 1208.1967 |
| 14 | ALICE Collaboration | Measurement of charged jet suppression in Pb-Pb collisions at $ \sqrt{s_{NN}} = $ 2.76 TeV | JHEP 03 (2014) 013 | 1311.0633 |
| 15 | ATLAS Collaboration | Measurements of the nuclear modification factor for jets in Pb+Pb collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV with the ATLAS detector | PRL 114 (2015) 072302 | 1411.2357 |
| 16 | ALICE Collaboration | Measurement of jet suppression in central Pb-Pb collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 2.76 TeV | PLB 746 (2015) 1 | 1502.01689 |
| 17 | CMS Collaboration | Measurement of inclusive jet cross sections in pp and PbPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV | PRC 96 (2017) 015202 | CMS-HIN-13-005 1609.05383 |
| 18 | CMS Collaboration | Measurement of jet fragmentation into charged particles in $ pp $ and PbPb collisions at $ \sqrt{s_{NN}}= $ 2.76 TeV | JHEP 10 (2012) 087 | CMS-HIN-11-004 1205.5872 |
| 19 | CMS Collaboration | Modification of jet shapes in PbPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 2.76 TeV | PLB 730 (2014) 243 | CMS-HIN-12-002 1310.0878 |
| 20 | CMS Collaboration | Measurement of jet fragmentation in PbPb and pp collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV | PRC 90 (2014) 024908 | CMS-HIN-12-013 1406.0932 |
| 21 | ATLAS Collaboration | Measurement of inclusive jet charged-particle fragmentation functions in Pb+Pb collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV with the ATLAS detector | PLB 739 (2014) 320 | 1406.2979 |
| 22 | CMS Collaboration | Measurement of transverse momentum relative to dijet systems in PbPb and pp collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV | JHEP 01 (2016) 006 | CMS-HIN-14-010 1509.09029 |
| 23 | CMS Collaboration | Decomposing transverse momentum balance contributions for quenched jets in PbPb collisions at $ \sqrt{s_{\mathrm{N}\;\mathrm{N}}}= $ 2.76 TeV | JHEP 11 (2016) 055 | CMS-HIN-15-011 1609.02466 |
| 24 | CMS Collaboration | Correlations between jets and charged particles in PbPb and pp collisions at $ \sqrt{s_{\mathrm{NN}}}= $ 2.76 TeV | JHEP 02 (2016) 156 | CMS-HIN-14-016 1601.00079 |
| 25 | ALICE Collaboration | First measurement of jet mass in Pb-Pb and p-Pb collisions at the LHC | PLB 776 (2018) 249 | 1702.00804 |
| 26 | CMS Collaboration | Measurement of the Splitting Function in $ pp $ and Pb-Pb Collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 5.02 TeV | PRL 120 (2018) 142302 | CMS-HIN-16-006 1708.09429 |
| 27 | ATLAS Collaboration | Measurement of jet fragmentation in Pb+Pb and pp collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 2.76 TeV with the ATLAS detector at the LHC | EPJC 77 (2017) 379 | 1702.00674 |
| 28 | CMS Collaboration | Jet properties in PbPb and pp collisions at $ \sqrt{s_\mathrm{NN}} = $ 5.02 TeV | CMS-HIN-16-020 1803.00042 |
|
| 29 | X.-N. Wang, Z. Huang, and I. Sarcevic | Jet quenching in the opposite direction of a tagged photon in high-energy heavy ion collisions | PRL 77 (1996) 231--234 | hep-ph/9605213 |
| 30 | X.-N. Wang and Z. Huang | Medium-induced parton energy loss in $ {\gamma} $+jet events of high-energy heavy-ion collisions | PRC 55 (1997) 3047 | hep-ph/9701227 |
| 31 | W. Dai, I. Vitev, and B.-W. Zhang | Momentum imbalance of isolated photon-tagged jet production at RHIC and LHC | PRL 110 (2013) 142001 | 1207.5177 |
| 32 | R. B. Neufeld, I. Vitev, and B. W. Zhang | Physics of $ Z^0/\gamma^* $-tagged jets at energies available at the CERN Large Hadron Collider | PRC 83 (2011) 034902 | 1006.2389 |
| 33 | J. Casalderrey-Solana et al. | Predictions for boson-jet observables and fragmentation function ratios from a hybrid strong/weak coupling model for jet quenching | JHEP 03 (2016) 053 | 1508.00815 |
| 34 | Z.-B. Kang, I. Vitev, and H. Xing | Vector-boson-tagged jet production in heavy ion collisions at energies available at the CERN Large Hadron Collider | PRC 96 (2017) 014912 | 1702.07276 |
| 35 | CMS Collaboration | Studies of jet quenching using isolated-photon+jet correlations in PbPb and $ pp $ collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV | PLB 718 (2013) 773 | CMS-HIN-11-010 1205.0206 |
| 36 | CMS Collaboration | Study of jet quenching with isolated-photon+jet correlations in PbPb and pp collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 5.02 TeV | Submitted to \it PLB | CMS-HIN-16-002 1711.09738 |
| 37 | CMS Collaboration | Study of jet quenching with Z+jet correlations in Pb-Pb and pp Collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 5.02 TeV | PRL 119 (2017) 082301 | CMS-HIN-15-013 1702.01060 |
| 38 | CMS Collaboration | Observation of medium induced modifications of jet fragmentation in PbPb collisions using isolated-photon-tagged jets | Submitted to PRLett | CMS-HIN-16-014 1801.04895 |
| 39 | I. Vitev, S. Wicks, and B.-W. Zhang | A Theory of jet shapes and cross sections: From hadrons to nuclei | JHEP 11 (2008) 093 | 0810.2807 |
| 40 | Y.-T. Chien and I. Vitev | Towards the understanding of jet shapes and cross sections in heavy ion collisions using soft-collinear effective theory | JHEP 05 (2016) 023 | 1509.07257 |
| 41 | CMS Collaboration | Observation and studies of jet quenching in PbPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 2.76 TeV | PRC 84 (2011) 024906 | CMS-HIN-10-004 1102.1957 |
| 42 | CMS Collaboration | Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV | PRL 109 (2012) 022301 | CMS-HIN-11-012 1204.1850 |
| 43 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
| 44 | CMS Collaboration | Charged-particle nuclear modification factors in PbPb and pPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 5.02 TeV | JHEP 04 (2017) 039 | CMS-HIN-15-015 1611.01664 |
| 45 | CMS Collaboration | Measurement of isolated photon production in pp and PbPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}} = $ 2.76 TeV | PLB 710 (2012) 256 | CMS-HIN-11-002 1201.3093 |
| 46 | CMS Collaboration | Measurement of the isolated prompt photon production cross section in pp collisions at $ \sqrt{s} = $ 7 TeV | PRL 106 (2011) 082001 | CMS-QCD-10-019 1012.0799 |
| 47 | CMS Collaboration | Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV | JINST 10 (2015) P08010 | CMS-EGM-14-001 1502.02702 |
| 48 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
| 49 | T. Sjostrand, S. Mrenna, and P. Z. Skands | A brief introduction to PYTHIA 8.1 | CPC 178 (2008) 852 | 0710.3820 |
| 50 | I. P. Lokhtin and A. M. Snigirev | A model of jet quenching in ultrarelativistic heavy ion collisions and high-$ p_{\mathrm{T}} $ hadron spectra at RHIC | EPJC 45 (2006) 211 | hep-ph/0506189 |
| 51 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
| 52 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ k_{t} $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
| 53 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
| 54 | 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 | |
| 55 | CMS Collaboration | Jet momentum dependence of jet quenching in PbPb collisions at $ \sqrt{s_{_{\mathrm{NN}}}}= $ 2.76 TeV | PLB 712 (2012) 176 | CMS-HIN-11-013 1202.5022 |
| 56 | CMS Collaboration | Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV | JINST 12 (2017) P02014 | CMS-JME-13-004 1607.03663 |
|
|
Compact Muon Solenoid LHC, CERN |
|
|
|
|
|
|