Compact Muon Solenoid
LHC, CERN
Visit us: CMS Public Website, CMS Physics ;
Contact us: CMS Publications Committee
| CMS-HIN-17-003 ; CERN-EP-2018-076 | ||
| Elliptic flow of charm and strange hadrons in high-multiplicity pPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 8.16 TeV | ||
| CMS Collaboration | ||
| 26 April 2018 | ||
| Phys. Rev. Lett. 121 (2018) 082301 | ||
| Abstract: The elliptic azimuthal anisotropy coefficient ($v_2$) is measured for charm ($ {\mathrm{D^0}} $) and strange ($ {\mathrm{K^0_S}} $, $ \Lambda $, $ \Xi^-$, and $ \Omega^-$) hadrons, using a data sample of pPb collisions collected by the CMS experiment, at a nucleon-nucleon center-of-mass energy ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 8.16 TeV. A significant positive $v_2$ signal from long-range azimuthal correlations is observed for all particle species in high-multiplicity pPb collisions. The measurement represents the first observation of possible long-range collectivity for open heavy flavor hadrons in small systems. The results suggest that charm quarks have a smaller $v_2$ than the lighter quarks, probably reflecting a weaker collective behavior. This effect is not seen in the larger PbPb collision system at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV, also presented. | ||
| Links: e-print arXiv:1804.09767 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; | ||
| Figures | |
png pdf |
Figure 1:
Example of the simultaneous fit to the invariant mass spectrum and $v_{2}^{S+B}(m_{\text {inv}})$ in the $ {p_{\mathrm {T}}} $ interval 4.2-5.0 GeV for events with $185 \leq {N_\text {trk}^\text {offline}} < 250$. |
png pdf |
Figure 2:
Results of elliptic flow ($v_2$) for $ {\mathrm {D^0}} $ mesons, as well as ${\mathrm {K^0_S}}$, $ \Lambda $, ${\Xi ^{-}}$, and ${\Omega ^-}$ particles, as functions of $ {p_{\mathrm {T}}} $ in the multiplicity range 185 $ \leq {N_\text {trk}^\text {offline}} < $ 250 in pPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 8.16 TeV. The error bars correspond to statistical uncertainties, while the shaded areas denote the systematic uncertainties. |
png pdf |
Figure 3:
Upper: the ${v_{2}^\text {sub}}$ results for prompt $ {\mathrm {D^0}} $ meson, as well as for strange hadrons, as functions of $ {p_{\mathrm {T}}} $ in pPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 8.16 TeV with 185 $ \leq {N_\text {trk}^\text {offline}} < $ 250 (left) and PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV with centrality between 30 and 50% (right). Lower: the $n_ {\mathrm {q}}$-scaled ${v_{2}^\text {sub}}$ results. The $ {\mathrm {D^0}} $ $v_2$ data in PbPb are taken from Ref. [43]. The error bars correspond to statistical uncertainties, while the shaded areas denote the systematic uncertainties. |
| Summary |
| In summary, the first measurements of elliptic azimuthal anisotropies for prompt $ {\mathrm{D^0}} $ mesons, as well as $ {\mathrm{K^0_S}} $, $ \Lambda $, $ \Xi^-$, $ \Omega^-$ hadrons, in high-multiplicity pPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 8.16 TeV are presented. Significant positive $v_2$ values are observed for $ {\mathrm{D^0}} $ mesons with ${p_{\mathrm {T}}} > $ 2 GeV. Comparing to strange-hadron results, the $ {\mathrm{D^0}} $ $v_2$ values are found to be smaller at a given $ {p_{\mathrm {T}}} $, or at similar transverse kinetic energy per constituent quark, after normalizing $v_2$ by the number of constituent quarks. The latter effect is not observed in the larger PbPb collision system. It shows that, in high-multiplicity pPb collisions, in contrast to larger nucleus-nucleus collision systems, the collective behavior of charm quarks is weaker than that of the light-flavor quarks. |
| References | ||||
| 1 | W. Busza et al. | Charged particle multiplicity in $ \pi^-$-nucleus interactions at 100 and 175 GeV/$c$. | PRL 34 (1975) 836 | |
| 2 | PHOBOS Collaboration | System size dependence of cluster properties from two- particle angular correlations in Cu+Cu and Au+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRC 81 (2010) 024904 | 0812.1172 |
| 3 | STAR Collaboration | Distributions of charged hadrons associated with high transverse momentum particles in pp and Au+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRL 95 (2005) 152301 | nucl-ex/0501016 |
| 4 | STAR Collaboration | Long range rapidity correlations and jet production in high energy nuclear collisions | PRC 80 (2009) 064912 | 0909.0191 |
| 5 | PHOBOS Collaboration | High transverse momentum triggered correlations over a large pseudorapidity acceptance in Au+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRL 104 (2010) 062301 | 0903.2811 |
| 6 | CMS Collaboration | Long-range and short-range dihadron angular correlations in central PbPb collisions at a nucleon-nucleon center of mass energy of 2.76 TeV | JHEP 07 (2011) 076 | CMS-HIN-11-001 1105.2438 |
| 7 | CMS Collaboration | Centrality dependence of dihadron correlations and azimuthal anisotropy harmonics in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV | EPJC 72 (2012) 2012 | CMS-HIN-11-006 1201.3158 |
| 8 | ALICE Collaboration | Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV | PRL 105 (2010) 252302 | 1011.3914 |
| 9 | ATLAS Collaboration | Measurement of the azimuthal anisotropy for charged particle production in $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV lead-lead collisions with the ATLAS detector | PRC 86 (2012) 014907 | 1203.3087 |
| 10 | CMS Collaboration | Measurement of the elliptic anisotropy of charged particles produced in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV | PRC 87 (2013) 014902 | CMS-HIN-10-002 1204.1409 |
| 11 | CMS Collaboration | Studies of azimuthal dihadron correlations in ultra-central PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV | JHEP 02 (2014) 088 | CMS-HIN-12-011 1312.1845 |
| 12 | J.-Y. Ollitrault | Anisotropy as a signature of transverse collective flow | PRD 46 (1992) 229 | |
| 13 | U. Heinz and R. Snellings | Collective flow and viscosity in relativistic heavy-ion collisions | Ann. Rev. Nucl. Part. Sci. 63 (2013) 123 | 1301.2826 |
| 14 | C. Gale, S. Jeon, and B. Schenke | Hydrodynamic modeling of heavy-ion collisions | Int. J. Mod. Phys. A 28 (2013) 1340011 | 1301.5893 |
| 15 | CMS Collaboration | Observation of long-range near-side angular correlations in proton-proton collisions at the LHC | JHEP 09 (2010) 091 | CMS-QCD-10-002 1009.4122 |
| 16 | ATLAS Collaboration | Observation of long-range elliptic azimuthal anisotropies in $ \sqrt{s}= $ 13 and 2.76 TeV pp collisions with the ATLAS Detector | PRL 116 (2016) 172301 | 1509.04776 |
| 17 | CMS Collaboration | Measurement of long-range near-side two-particle angular correlations in pp collisions at $ \sqrt s = $ 13 TeV | PRL 116 (2016) 172302 | CMS-FSQ-15-002 1510.03068 |
| 18 | CMS Collaboration | Observation of long-range near-side angular correlations in proton-lead collisions at the LHC | PLB 718 (2013) 795 | CMS-HIN-12-015 1210.5482 |
| 19 | ALICE Collaboration | Long-range angular correlations on the near and away side in $ \mathrm{pPb}\ $ collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV | PLB 719 (2013) 29 | 1212.2001 |
| 20 | ATLAS Collaboration | Observation of associated near-side and away-side long-range correlations in $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 tev proton-lead collisions with the ATLAS detector | PRL 110 (2013) 182302 | 1212.5198 |
| 21 | LHCb Collaboration | Measurements of long-range near-side angular correlations in $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5 TeV proton-lead collisions in the forward region | PLB 762 (2016) 473 | 1512.00439 |
| 22 | R. D. Weller and P. Romatschke | One fluid to rule them all: viscous hydrodynamic description of event-by-event central p+p, p+Pb and Pb+Pb collisions at $ \sqrt{s}= $ 5.02 TeV | PLB 774 (2017) 351 | 1701.07145 |
| 23 | J. L. Nagle and W. A. Zajc | Small system collectivity in relativistic hadron and nuclear collisions | Submitted to Ann. Rev. Nucl. Part. Sci | 1801.03477 |
| 24 | S. Voloshin and Y. Zhang | Flow study in relativistic nuclear collisions by Fourier expansion of azimuthal particle distributions | Z. Phys. C 70 (1996) 665 | hep-ph/9407282 |
| 25 | B. H. Alver, C. Gombeaud, M. Luzum, and J.-Y. Ollitrault | Triangular flow in hydrodynamics and transport theory | PRC 82 (2010) 034913 | 1007.5469 |
| 26 | B. Schenke, S. Jeon, and C. Gale | Elliptic and triangular flow in event-by-event D=3+1 viscous hydrodynamics | PRL 106 (2011) 042301 | 1009.3244 |
| 27 | Z. Qiu, C. Shen, and U. Heinz | Hydrodynamic elliptic and triangular flow in Pb-Pb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV | PLB 707 (2012) 151 | 1110.3033 |
| 28 | ALICE Collaboration | Long-range angular correlations of pi, K and p in p--Pb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV | PLB 726 (2013) 164 | 1307.3237 |
| 29 | CMS Collaboration | Long-range two-particle correlations of strange hadrons with charged particles in pPb and PbPb collisions at LHC energies | PLB 742 (2015) 200 | CMS-HIN-14-002 1409.3392 |
| 30 | CMS Collaboration | Evidence for collectivity in pp collisions at the LHC | PLB 765 (2017) 193 | CMS-HIN-16-010 1606.06198 |
| 31 | CMS Collaboration | Evidence for collective multi-particle correlations in pPb collisions | PRL 115 (2015) 012301 | CMS-HIN-14-006 1502.05382 |
| 32 | ATLAS Collaboration | Measurement of multi-particle azimuthal correlations in pp, pPb and low-multiplicity PbPb collisions with the ATLAS detector | EPJC 77 (2017) 428 | 1705.04176 |
| 33 | ATLAS Collaboration | Measurement of long-range multiparticle azimuthal correlations with the subevent cumulant method in pp and p+Pb collisions with the ATLAS detector at the CERN Large Hadron Collider | PRC 97 (2018) 024904 | 1708.03559 |
| 34 | PHENIX Collaboration | Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central d+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRL 114 (2015) 192301 | 1404.7461 |
| 35 | STAR Collaboration | Long-range pseudorapidity dihadron correlations in d+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PLB 747 (2015) 265 | 1502.07652 |
| 36 | PHENIX Collaboration | Measurements of multiparticle correlations in d+Au collisions at 200, 62.4, 39, and 19.6 GeV and p+Au collisions at 200 GeV and implications for collective behavior | PRL 120 (2018) 062302 | 1707.06108 |
| 37 | PHENIX Collaboration | Measurements of elliptic and triangular flow in high-multiplicity $ ^{3} \mathrm{He}$ + Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRL 115 (2015) 142301 | 1507.06273 |
| 38 | K. Dusling, W. Li, and B. Schenke | Novel collective phenomena in high-energy proton--proton and proton--nucleus collisions | Int. J. Mod. Phys. E 25 (2016) 1630002 | 1509.07939 |
| 39 | P. Braun-Munzinger | Quarkonium production in ultra-relativistic nuclear collisions: Suppression versus enhancement | JPG 34 (2007) S471 | nucl-th/0701093 |
| 40 | STAR Collaboration | Measurement of $ {\mathrm{D^0}}\ $ azimuthal anisotropy at midrapidity in Au+Au collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRL 118 (2017) 212301 | 1701.06060 |
| 41 | ALICE Collaboration | Azimuthal anisotropy of D meson production in Pb-Pb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 2.76 TeV | PRC 90 (2014) 034904 | 1405.2001 |
| 42 | ALICE Collaboration | $ D $-meson azimuthal anisotropy in midcentral Pb-Pb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV | PRL 120 (2018) 102301 | 1707.01005 |
| 43 | CMS Collaboration | Measurement of prompt D$ ^{0} $ meson azimuthal anisotropy in PbPb collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV | Submitted to PRLett | CMS-HIN-16-007 1708.03497 |
| 44 | STAR Collaboration | Mass, quark-number, and $ \sqrt{s_{NN}} $ dependence of the second and fourth flow harmonics in ultra-relativistic nucleus-nucleus collisions | PRC 75 (2007) 054906 | nucl-ex/0701010 |
| 45 | PHENIX Collaboration | Scaling properties of azimuthal anisotropy in Au+Au and Cu+Cu collisions at $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 200 GeV | PRL 98 (2007) 162301 | nucl-ex/0608033 |
| 46 | 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 |
| 47 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
| 48 | CMS Collaboration | Constraints on the chiral magnetic effect using charge-dependent azimuthal correlations in pPb and PbPb collisions at the LHC | Submitted to PRC | CMS-HIN-17-001 1708.01602 |
| 49 | CMS Collaboration | Observation of correlated azimuthal anisotropy fourier harmonics in pp and p+Pb collisions at the LHC | PRL 120 (2018) 092301 | CMS-HIN-16-022 1709.09189 |
| 50 | CMS Collaboration | Multiplicity and rapidity dependence of strange hadron production in pp, pPb, and PbPb collisions at the LHC | PLB 768 (2017) 103 | CMS-HIN-15-006 1605.06699 |
| 51 | Particle Data Group, C. Patrignani et al. | Review of particle physics | CPC 40 (2016) 100001 | |
| 52 | T. Sjostrand, S. Mrenna and P. Skands | A brief introduction to PYTHIA 8.1 | CPC 178 (2008) 852 | 0710.3820 |
| 53 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
| 54 | T. Pierog et al. | EPOS LHC: Test of collective hadronization with data measured at the CERN Large Hadron Collider | PRC 92 (2015) 034906 | 1306.0121 |
| 55 | CMS Collaboration | Multiplicity and transverse momentum dependence of two- and four-particle correlations in pPb and PbPb collisions | PLB 724 (2013) 213 | CMS-HIN-13-002 1305.0609 |
| 56 | M. Nahrgang et al. | Elliptic and triangular flow of heavy flavor in heavy-ion collisions | PRC 91 (2015) 014904 | 1410.5396 |
| 57 | M. He, R. J. Fries, and R. Rapp | Heavy flavor at the Large Hadron Collider in a strong coupling approach | PLB 735 (2014) 445 | 1401.3817 |
| 58 | J. Xu, J. Liao, and M. Gyulassy | Bridging soft-hard transport properties of quark-gluon plasmas with CUJET3.0 | JHEP 02 (2016) 169 | 1508.00552 |
| 59 | D. Molnar and S. A. Voloshin | Elliptic flow at large transverse momenta from quark coalescence | PRL 91 (2003) 092301 | nucl-th/0302014 |
| 60 | V. Greco, C. M. Ko, and P. Levai | Parton coalescence and antiproton/pion anomaly at RHIC | PRL 90 (2003) 202302 | nucl-th/0301093 |
| 61 | R. J. Fries, B. Muller, C. Nonaka, and S. A. Bass | Hadronization in heavy ion collisions: Recombination and fragmentation of partons | PRL 90 (2003) 202303 | nucl-th/0301087 |
|
|
Compact Muon Solenoid LHC, CERN |
|
|
|
|
|
|