Publicação
Observation of Z decays to four leptons with the CMS detector at the LHC
| dc.contributor.author | CMS collaboration (2189 authors) | |
| dc.contributor.author | Hollar, Jonathan | |
| dc.contributor.author | Nayak, Aruna | |
| dc.contributor.author | Almeida, Nuno | |
| dc.contributor.author | Bargassa, Pedrame | |
| dc.contributor.author | David Tinoco Mendes, Andre | |
| dc.contributor.author | Faccioli, Pietro | |
| dc.contributor.author | Ferreira Parracho, Pedro Guilherme | |
| dc.contributor.author | Gallinaro, Michele | |
| dc.contributor.author | Seixas, Joao | |
| dc.contributor.author | Varela, Joao | |
| dc.contributor.author | Vischia, Pietro | |
| dc.contributor.author | Lloret Iglesias, Lara | |
| dc.contributor.author | Musella, Pasquale | |
| dc.contributor.author | Rodrigues Antunes, Joao | |
| dc.contributor.author | Silva, Pedro | |
| dc.contributor.author | Pela, Joao | |
| dc.contributor.author | Leonardo, Nuno | |
| dc.date.accessioned | 2019-02-03T21:24:59Z | |
| dc.date.available | 2019-02-03T21:24:59Z | |
| dc.date.issued | 2012-10 | |
| dc.date.updated | 2019-02-03T21:24:59Z | |
| dc.description.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 inverse femtobarns at sqrt(s) = 7 TeV collected by the CMS detector at the Large Hadron Collider. A pronounced resonance peak, with a statistical significance of 9.7 sigma, 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[4l] < 100 GeV, where m[4l] is the invariant mass of the four leptons, and m[ll] > 4 GeV for all pairs of leptons, where m[ll] is the two-lepton invariant mass. The measured branching fraction is B(Z to 4l) = (4.2 /+0.9/-0.8 (stat.) +/- 0.2 (syst.)) 10E-6 and agrees with the standard model prediction of 4.45 10E-6. The measured cross section times branching fraction is sigma(pp to Z) B(Z to 4 l) = 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 to 4 l decays provides a calibration channel for the Higgs boson search in the H to ZZ to 4 l decay mode. | |
| dc.description.version | Peer Reviewed | |
| dc.identifier | JHEP 1212 (2012) 034; DOI 10.1007/JHEP12(2012)034 | |
| dc.identifier.uri | http://dx.doi.org/10.1007/JHEP12(2012)034 | |
| dc.identifier.uri | http://hdl.handle.net/10400.26/26294 | |
| dc.language.iso | eng | |
| dc.title | Observation of Z decays to four leptons with the CMS detector at the LHC | |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| rcaap.rights | openAccess | pt |
| rcaap.type | article |