• Featured in Physics
  • Editors' Suggestion
  • Open Access

Observation of Two Excited Bc+ States and Measurement of the Bc+(2S) Mass in pp Collisions at s=13TeV

A. M. Sirunyan et al. (CMS Collaboration)
Phys. Rev. Lett. 122, 132001 – Published 2 April 2019
Physics logo See Synopsis: Record LHC Haul Catches Double Meson Signal  

Abstract

Signals consistent with the Bc+(2S) and Bc*+(2S) states are observed in proton-proton collisions at s=13TeV, in an event sample corresponding to an integrated luminosity of 143fb1, collected by the CMS experiment during the 2015–2018 LHC running periods. These excited b¯c states are observed in the Bc+π+π invariant mass spectrum, with the ground state Bc+ reconstructed through its decay to J/ψπ+. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst)MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the Bc+(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(Bc+)MeV, where the last term corresponds to the uncertainty in the world-average Bc+ mass.

  • Figure
  • Figure
  • Figure
  • Received 1 February 2019
  • Revised 18 February 2019

DOI:https://doi.org/10.1103/PhysRevLett.122.132001

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

© 2019 CERN, for the CMS Collaboration

Physics Subject Headings (PhySH)

  1. Research Areas
  1. Physical Systems
Particles & Fields

Synopsis

Key Image

Record LHC Haul Catches Double Meson Signal  

Published 2 April 2019

A huge dataset recorded at the highest particle collision energy so-far observed resolves a puzzle by revealing two meson excited states.

See more in Physics

Authors & Affiliations

Click to Expand

Article Text

Click to Expand

References

Click to Expand
Issue

Vol. 122, Iss. 13 — 5 April 2019

Reuse & Permissions
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

×

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×