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

(CMS Collaboration)

Research output: Contribution to journalArticle

1 Citation (Scopus)

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
Article number141801
JournalPhysical Review Letters
Volume121
Issue number14
DOIs
Publication statusPublished - 4 Oct 2018

Fingerprint

collisions
decay
protons
subtraction
center of mass
muons
standard deviation
bosons
mesons
luminosity
electrons
energy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Observation of the Z →ψ + - Decay in pp Collisions at s =13 TeV. / (CMS Collaboration).

In: Physical Review Letters, Vol. 121, No. 14, 141801, 04.10.2018.

Research output: Contribution to journalArticle

@article{96b903ff14df4e658cc648f3dbb387fc,
title = "Observation of the Z →ψ + - Decay in pp Collisions at s =13 TeV",
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).",
author = "{(CMS Collaboration)} and Sirunyan, {A. M.} and A. Tumasyan and W. Adam and F. Ambrogi and E. Asilar and T. Bergauer and J. Brandstetter and E. Brondolin and M. Dragicevic and J. Er{\"o} and {Escalante Del Valle}, A. and M. Flechl and R. Fr{\"u}hwirth and Ghete, {V. M.} and J. Hrubec and M. Jeitler and N. Krammer and I. Kr{\"a}tschmer and D. Liko and T. Madlener and I. Mikulec and N. Rad and H. Rohringer and J. Schieck and R. Sch{\"o}fbeck and M. Spanring and D. Spitzbart and A. Taurok and W. Waltenberger and J. Wittmann and Wulz, {C. E.} and M. Zarucki and V. Chekhovsky and V. Mossolov and {Suarez Gonzalez}, J. and {De Wolf}, {E. A.} and {Di Croce}, D. and V. Danilov and J. Kim and J. Kim and J. Kim and A. Zarubin and Y. Ivanov and V. Kim and V. Oreshkin and S. Vavilov and V. Popov and A. Ershov and A. Babaev and S. Baidali",
year = "2018",
month = "10",
day = "4",
doi = "10.1103/PhysRevLett.121.141801",
language = "English",
volume = "121",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "14",

}

TY - JOUR

T1 - Observation of the Z →ψ + - Decay in pp Collisions at s =13 TeV

AU - (CMS Collaboration)

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Ambrogi, F.

AU - Asilar, E.

AU - Bergauer, T.

AU - Brandstetter, J.

AU - Brondolin, E.

AU - Dragicevic, M.

AU - Erö, J.

AU - Escalante Del Valle, A.

AU - Flechl, M.

AU - Frühwirth, R.

AU - Ghete, V. M.

AU - Hrubec, J.

AU - Jeitler, M.

AU - Krammer, N.

AU - Krätschmer, I.

AU - Liko, D.

AU - Madlener, T.

AU - Mikulec, I.

AU - Rad, N.

AU - Rohringer, H.

AU - Schieck, J.

AU - Schöfbeck, R.

AU - Spanring, M.

AU - Spitzbart, D.

AU - Taurok, A.

AU - Waltenberger, W.

AU - Wittmann, J.

AU - Wulz, C. E.

AU - Zarucki, M.

AU - Chekhovsky, V.

AU - Mossolov, V.

AU - Suarez Gonzalez, J.

AU - De Wolf, E. A.

AU - Di Croce, D.

AU - Danilov, V.

AU - Kim, J.

AU - Kim, J.

AU - Kim, J.

AU - Zarubin, A.

AU - Ivanov, Y.

AU - Kim, V.

AU - Oreshkin, V.

AU - Vavilov, S.

AU - Popov, V.

AU - Ershov, A.

AU - Babaev, A.

AU - Baidali, S.

PY - 2018/10/4

Y1 - 2018/10/4

N2 - 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).

AB - 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).

UR - http://www.scopus.com/inward/record.url?scp=85054666594&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85054666594&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.121.141801

DO - 10.1103/PhysRevLett.121.141801

M3 - Article

VL - 121

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 14

M1 - 141801

ER -