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Observation of Z decays to four leptons with the CMS detector at the LHC

Abstract: ABSTRACT: The first observation of the Z boson decaying to four leptons in proton-proton collisions is presented. The analyzed data set corresponds to an integrated luminosity of 5.02 fb?1 at s?=7 TeV collected by the CMS detector at the Large Hadron Collider. A pronounced resonance peak, with a statistical significance of 9.7 ?, is observed in the distribution of the invariant mass of four leptons (electrons and/or muons) with mass and width consistent with expectations for Z boson decays. The branching fraction and cross section reported here are defined by phase space restrictions on the leptons, namely, 80 < m 4? < 100 GeV, where m 4? is the invariant mass of the four leptons, and m ?? > 4 GeV for all pairs of leptons, where m ?? is the two-lepton invariant mass. The measured branching fraction is B(Z?4?)=(4.2+0.9?0.8(stat.)±0.2(syst.))×10?6 and agrees with the standard model prediction of 4.45 × 10?6. The measured cross section times branching fraction is ?(pp?Z)B(Z?4?)=112+23?20(stat.)+7?5(syst.)+3?2(lumi.) fb, also consistent with the standard model prediction of 120 fb. The four-lepton mass peak arising from Z ? 4? decays provides a calibration channel for the Higgs boson search in the H ? ZZ ? 4? decay mode.

Otras publicaciones de la misma revista o congreso con autores/as de la Universidad de Cantabria

 Autoría: Chatrchyan S., Khachatryan V., Sirunyan A.M., Tumasyan A., Adam W., Aguilo E., Bergauer T., Dragicevic M., Erö J., Fabjan C., Friedl M., Frühwirth R., Ghete V.M., Hammer J., Hörmann N., Hrubec J., Jeitler M., Kiesenhofer W., Knünz V., Krammer M., Liko D., Mikulec I., Pernicka M., Rahbaran B., Rohringer C., Rohringer H., Schöfbeck R., Strauss J., Taurok A., Wagner P., Waltenberger W., Walzel G., Widl E., Wulz C.E., Mossolov V.,

 Fuente: Journal of High Energy Physics, 2012, 12, 34

Editorial: Springer Verlag

 Fecha de publicación: 07/12/2012

Nº de páginas: 28

Tipo de publicación: Artículo de Revista

 DOI: 10.1007/JHEP12(2012)034

ISSN: 1126-6708,1029-8479

Url de la publicación: https://doi.org/10.1007/JHEP12(2012)034

Autores/as

SHANHUEI CHUANG

MARTA FELCINI

ALBERTO GRAZIANO

CLARA JORDA LOPE

MARIA AMPARO LOPEZ VIRTO

RAFAEL JOSE MARCO DE LUCAS

FRANCISCA JAVIELA MUÑOZ SANCHEZ

ANA YAIZA RODRIGUEZ MARRERO

MARIA DEL MAR SOBRON SAÑUDO