Observation of the Z →ψ + - Decay in pp Collisions at s =13 TeV

(CMS Collaboration)

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

This Letter presents the observation of the rare Z boson decay Z→ψ + -. Here, ψ represents contributions from direct J/ψ and ψ(2S)→J/ψX, + - is a pair of electrons or muons, and the J/ψ meson is detected via its decay to μ+μ-. The sample of proton-proton collision data, collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponds to an integrated luminosity of 35.9 fb-1. The signal is observed with a significance in excess of 5 standard deviations. After subtraction of the ψ(2S)→J/ψX contribution, the ratio of the branching fraction of the exclusive decay Z→J/ψ + - to the decay Z→μ+μ-μ+μ- within a fiducial phase space is measured to be B(Z→J/ψ + -)/B(Z→μ+μ-μ+μ-)=0.67±0.18(stat)±0.05(syst).

Original languageEnglish (US)
Article number141801
JournalPhysical review letters
Volume121
Issue number14
DOIs
StatePublished - Oct 4 2018

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Observation of the Z →ψ + - Decay in pp Collisions at s =13 TeV'. Together they form a unique fingerprint.

  • Cite this