CMS-PAS-HIN-16-016 | ||
Studies of beauty suppression via measurements of nonprompt D0 mesons in PbPb collisions at √sNN= 5.02 TeV | ||
CMS Collaboration | ||
May 2018 | ||
Abstract: The transverse momentum spectra of D0 mesons from b hadron decays are measured in pp and PbPb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The measurement is performed in the D0 pT range of 2-100 GeV/c and in the rapidity range of |y|< 1. The D0 mesons from b hadron decays are distinguished from prompt D0 mesons by their decay topologies. In PbPb collisions, the B→D0 yield is found to be suppressed in most of the measured pT range compared to pp collisions. The suppression is weaker than that of prompt D0 mesons and charged hadrons for pT around 10 GeV/c. While theoretical calculations incorporating partonic energy loss in the quark gluon plasma can successfully describe the measured B→D0 suppression at higher pT, the data show an indication of larger suppression than the model predictions in the range of 2 <pT< 5 GeV/c. | ||
Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, PRL 123 (2019) 022001. The superseded preliminary plots can be found here. |
Figures | Summary | Additional Figures | References | CMS Publications |
---|
Figures | |
![]() png pdf |
Figure 1:
a): three-component invariant mass fit for an example D0 DCA bin for pT of 6-7 GeV/c in PbPb collisions; b): DCA distributions for D0 candidates in the signal invariant mass region and in the sidebands (scaled by 0.5) for D0 pT of 6-7 GeV/c in pp collisions; c): Signal D0 DCA distribution obtained with the invariant mass fit for each D0 DCA bin, and a prompt + nonprompt two-component fit to it, for D0 pT of 6-7 GeV/c in PbPb collisions; d): Signal D0 DCA distribution obtained with sideband subtraction, and a prompt + nonprompt two-component fit to it, for D0 pT of 6-7 GeV/c in pp collisions. |
![]() png pdf |
Figure 2:
Upper panel: B→D0 pT-differential cross section in pp collisions and invariant yield in PbPb collisions normalized with the nuclear overlap function TAA, at √sNN= 5.02 TeV. The cross section in pp is compared to calculations using FONLL [28]. Lower panel: The FONLL/data ratio for the B→D0 pT spectra in pp collisions. |
![]() png pdf |
Figure 3:
B→D0 nuclear modification factor RAA for PbPb collisions at √sNN= 5.02 TeV compared to B mesons [15], J/ψ from b hadron decays [16], prompt D0 [13] and charged hadrons [21] (upper panel), and to various theoretical predictions [29,30,31,32,33,34,35,36] (lower panel). |
Summary |
To conclude, this note presents the transverse momentum spectra of D0 mesons from B decay measured in pp and PbPb collisions at √sNN= 5.02 TeV with the CMS detector at the LHC. The D0 from B decay are distinguished from prompt D0 by the DCA of their flight path relative to the primary vertex. The measured spectrum in pp collisions is close to the upper limit of the pQCD FONLL calculation. In PbPb collisions, the B→D is suppressed in most of the measured pT range from 2 to 100 GeV/c. The B→D nuclear modification factor RAA is higher than prompt D0 and charged hadrons around 10 GeV/c, which is in line with the predicted mass ordering of suppression. Comparing to theoretical predictions, the measured RAA is consistent with some models at higher pT, but shows a hint of stronger suppression than the models available at low pT. |
Additional Figures | |
![]() png pdf |
Additional Figure 1:
B→D0 nuclear modification factor RAA for PbPb collisions at √sNN= 5.02 TeV compared to B mesons [15], J/ψ from b hadron decays [16], prompt D0 [13] and charged hadrons [21]. |
![]() png pdf |
Additional Figure 2:
B→D0 nuclear modification factor RAA for PbPb collisions at √sNN= 5.02 TeV compared to various theoretical predictions [29, 30, 31, 32, 33, 34, 35, 36]. |
References | ||||
1 | \'E. V. Shuryak | Theory of hadron plasma | Sov. Phys. JETP 47 (1978)212 | |
2 | J. C. Collins and M. J. Perry | Superdense matter: Neutrons or asymptotically free quarks? | PRL 34 (1975) 1353 | |
3 | F. Karsch and E. Laermann | Thermodynamics and in-medium hadron properties from lattice QCD | in Quark-Gluon Plasma III, R. Hwa, ed 2003 | hep-lat/0305025 |
4 | STAR Collaboration | Experimental and theoretical challenges in the search for the quark gluon plasma: The STAR Collaboration's critical assessment of the evidence from RHIC collisions | NP A 757 (2005) 102 | nucl-ex/0501009 |
5 | PHENIX Collaboration | Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration | NP A 757 (2005) 184 | nucl-ex/0410003 |
6 | B. Muller, J. Schukraft, and B. Wyslouch | First Results from Pb+Pb collisions at the LHC | Ann. Rev. Nucl. Part. Sci. 62 (2012) 361 | 1202.3233 |
7 | M. L. Miller, K. Reygers, S. J. Sanders, and P. Steinberg | Glauber modeling in high energy nuclear collisions | Ann. Rev. Nucl. Part. Sci. 57 (2007) 205 | nucl-ex/0701025 |
8 | STAR Collaboration | Observation of D0 meson nuclear modifications in Au+Au collisions at √sNN= 200 GeV | PRL 113 (2014) 142301 | 1404.6185 |
9 | ALICE Collaboration | Centrality dependence of high-pT D meson suppression in Pb-Pb collisions at √sNN= 2.76 TeV | JHEP 11 (2015) 205 | 1506.06604 |
10 | ALICE Collaboration | Transverse momentum dependence of D-meson production in Pb-Pb collisions at √sNN= 2.76 TeV | JHEP 03 (2016) 081 | 1509.06888 |
11 | ALICE Collaboration | Production of charged pions, kaons and protons at large transverse momenta in pp and PbPb collisions at √sNN= 2.76 TeV | PLB 736 (2014) 196 | 1401.1250 |
12 | ALICE Collaboration | Centrality dependence of charged particle production at √sNN= 2.76 TeV | PLB 720 (2013) 52 | 1208.2711 |
13 | CMS Collaboration | Nuclear modification factor of D0 mesons in PbPb collisions at √sNN= 5.02 TeV | Submitted to PLB | CMS-HIN-16-001 1708.04962 |
14 | CMS Collaboration | Suppression and azimuthal anisotropy of prompt and nonprompt J/ψ production in PbPb collisions at √sNN= 2.76 TeV | EPJC 77 (2017) 252 | CMS-HIN-14-005 1610.00613 |
15 | CMS Collaboration | Measurement of B+/− meson differential production cross sections in pp and PbPb collisions at √sNN= 5.02 TeV | PRL 119 (2017) 152301 | CMS-HIN-16-011 1705.04727 |
16 | CMS Collaboration | Nuclear modification factor of charmonia in pbpb collisions at 5.02 tev | Submitted to EPJC | CMS-HIN-16-025 1712.08959 |
17 | Particle Data Group | Review of Particle Physics | CPC 40 (2016) 100001 | |
18 | 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 |
19 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
20 | CMS Collaboration | CMS luminosity calibration for the pp reference run at √s= 5.02 TeV | CMS-PAS-LUM-16-001 | CMS-PAS-LUM-16-001 |
21 | CMS Collaboration | Charged-particle nuclear modification factors in PbPb and pPb collisions at √sNN= 5.02 TeV | JHEP 04 (2017) 039 | CMS-HIN-15-015 1611.01664 |
22 | CMS Collaboration | Transverse momentum and pseudorapidity distributions of charged hadrons in pp collisions at $√s= $ 0.9 and 2.36 TeV | JHEP 02 (2010) 041 | CMS-QCD-09-010 1002.0621 |
23 | T. Sjostrand et al. | An Introduction to PYTHIA 8.2 | CPC 191 (2015) 159 | 1410.3012 |
24 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
25 | GEANT4 Collaboration | GEANT4 --- a simulation toolkit | NIMA 506 (2003) 250 | |
26 | I. P. Lokhtin and A. M. Snigirev | A model of jet quenching in ultrarelativistic heavy ion collisions and high-pT hadron spectra at RHIC | EPJC 45 (2006) 211 | hep-ph/0506189 |
27 | CMS Collaboration | Measurement of Tracking Efficiency | CMS-PAS-TRK-10-002 | |
28 | M. Cacciari, M. Greco, and P. Nason | The pT spectrum in heavy flavor hadroproduction | JHEP 05 (1998) 007 | hep-ph/9803400 |
29 | 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 |
30 | J. Xu, A. Buzzatti, and M. Gyulassy | Azimuthal jet flavor tomography with CUJET2.0 of nuclear collisions at RHIC and LHC | JHEP 08 (2014) 063 | 1402.2956 |
31 | J. Xu, J. Liao, and M. Gyulassy | Consistency of perfect fluidity and jet quenching in semi-quark-gluon monopole plasmas | Chin. PL32 (2015) 092501 | 1411.3673 |
32 | P. B. Gossiaux et al. | Gluon radiation by heavy quarks at intermediate energies and consequences for the mass hierarchy of energy loss | NP A931 (2014) 581--585 | 1409.0900 |
33 | M. He, R. J. Fries, and R. Rapp | Heavy-quark diffusion and hadronization in quark-gluon plasma | PRC 86 (2012) 014903 | 1106.6006 |
34 | 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 |
35 | T. Song et al. | Tomography of the quark-gluon-plasma by charm quarks | PRC 92 (2015) 014910 | 1503.03039 |
36 | T. Song et al. | Charm production in Pb + Pb collisions at energies available at the CERN Large Hadron Collider | PRC 93 (2016) 034906 | 1512.00891 |
![]() |
Compact Muon Solenoid LHC, CERN |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |