Measurement of nuclear modification factors of ϒ(1S), ϒ(2S), and ϒ(3S) mesons in PbPb collisions at TeV
Here, the cross sections for $$\Upsilon$$(1S), $$\Upsilon$$(2S), and $$\Upsilon$$(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at $$\sqrt{s_{_\mathrm{NN}}} =$$ 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, R$$_\mathrm{AA}$$, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, R$$_\mathrm{AA}$$($$\Upsilon$$(1S)) $$>$$ R$$_\mathrm{AA}$$($$\Upsilon$$(2S)) $$>$$ R$$_\mathrm{AA}$$($$\Upsilon$$(3S)) . The suppression of $$\Upsilon$$(1S) is larger than that seen at $$\sqrt{s_{_\mathrm{NN}}} =$$ 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the R$$_\mathrm{AA}$$ of $$\Upsilon$$(3S) integrated over $$p_\mathrm{T}$$ and rapidity is 0.094 at 95% confidence level, which is the strongest suppression observed for any hadron species in heavy ion collisions to date.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- The CMS Collaboration
- Grant/Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1615170
- Alternate ID(s):
- OSTI ID: 1454708
- Report Number(s):
- FERMILAB-PUB-18-271-CMS; CMS-HIN-16-023; CERN-EP-2018-110; arXiv:1805.09215; S037026931930022X; PII: S037026931930022X
- Journal Information:
- Physics Letters B, Journal Name: Physics Letters B Vol. 790 Journal Issue: C; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
Web of Science
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