Publication
Observation of the Z$\to\psi\ell^+\ell^-$ decay in pp collisions at $\sqrt{s}=$ 13 TeV
| dc.contributor.author | CMS collaboration (2298 authors) | |
| dc.contributor.author | Nayak, Aruna | |
| dc.contributor.author | Bargassa, Pedrame | |
| dc.contributor.author | Beirão da Cruz e Silva, Cristóvão | |
| dc.contributor.author | Di Francesco, Agostino | |
| dc.contributor.author | Faccioli, Pietro | |
| dc.contributor.author | Galinhas, Bruno | |
| dc.contributor.author | Gallinaro, Michele | |
| dc.contributor.author | Hollar, Jonathan | |
| dc.contributor.author | Leonardo, Nuno | |
| dc.contributor.author | Iglesias, Lara Lloret | |
| dc.contributor.author | Seixas, Joao | |
| dc.contributor.author | Strong, Giles | |
| dc.contributor.author | Toldaiev, Oleksii | |
| dc.contributor.author | Vadruccio, Daniele | |
| dc.contributor.author | Varela, Joao | |
| dc.contributor.author | Vischia, Pietro | |
| dc.contributor.author | David Tinoco Mendes, Andre | |
| dc.contributor.author | Silva, Pedro | |
| dc.contributor.author | Musella, Pasquale | |
| dc.date.accessioned | 2019-02-05T16:33:32Z | |
| dc.date.available | 2019-02-05T16:33:32Z | |
| dc.date.issued | 2018-10-10 | |
| dc.date.updated | 2019-02-05T16:33:32Z | |
| dc.description.abstract | This Letter presents the observation of the rare Z boson decay Z $\to\psi\ell^+\ell^-$. Here, $\psi$ represents contributions from direct J/$\psi$ and $\psi$(2S) $\to$ J/$\psi X$, $\ell^+\ell^-$ is a pair of electrons or muons, and the J/$\psi$ meson is detected via its decay to $\mu^+\mu^-$. 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 $\psi$(2S) $\to$ J/$\psi X$ contribution, the ratio of the branching fraction of the exclusive decay Z $\to\psi\ell^+\ell^-$ to the decay Z $\to\mu^+\mu^-\mu^+\mu^-$ within a fiducial phase space is measured to be $\mathcal{B}($Z $\to\psi\ell^+\ell^-) / \mathcal{B}($Z $\to\mu^+\mu^-\mu^+\mu^-) =$ 0.67 $\pm$ 0.18 (stat) $\pm$ 0.05 (syst). | |
| dc.description.version | Peer Reviewed | |
| dc.identifier | Phys.Rev.Lett. 121 (2018) 141801 Phys. Rev. Lett. 121, 141801 (2018); DOI 10.1103/PhysRevLett.121.141801 | |
| dc.identifier.uri | http://dx.doi.org/10.1103/PhysRevLett.121.141801 | |
| dc.identifier.uri | http://hdl.handle.net/10400.26/27665 | |
| dc.language.iso | eng | |
| dc.title | Observation of the Z$\to\psi\ell^+\ell^-$ decay in pp collisions at $\sqrt{s}=$ 13 TeV | |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| rcaap.rights | openAccess | pt |
| rcaap.type | article |