Makale detayı · 2018
title Observation of the math display=”inline” mrow miZ/mi mo stretchy=”false”→/mo miψ/mi msup mrow moℓ/mo /mrow mrow mo/mo /mrow /msup msup mrow moℓ/mo /mrow mrow mo−/mo /mrow /msup /mrow /math Decay in math display=”inline” mip/mi mip/mi /math Collisions at math display=”inline” msqrt mis/mi /msqrt mo=/mo mn13/mn mtext /mtext mtext /mtext miTeV/mi /math/title
- Yıl
- 2018
- ISSN
0031-9007- Tür
- article
Veri kaynağı ayrımı
- YÖKSİS YÖKSİS makale kaydı
- OpenAlex OpenAlex zenginleştirmesi (özet, atıf, konular)
Özet
İngilizce (OpenAlex)
This Letter presents the observation of the rare $Z$ boson decay $Z\ensuremath{\rightarrow}\ensuremath{\psi}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$. Here, $\ensuremath{\psi}$ represents contributions from direct $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}J/\ensuremath{\psi}X$, ${\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ is a pair of electrons or muons, and the $J/\ensuremath{\psi}$ meson is detected via its decay to ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. 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 $35.9\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The signal is observed with a significance in excess of 5 standard deviations. After subtraction of the $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}J/\ensuremath{\psi}X$ contribution, the ratio of the branching fraction of the exclusive decay $Z\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ to the decay $Z\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ within a fiducial phase space is measured to be $\mathcal{B}(Z\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}})/\phantom{\rule{0ex}{0ex}}\mathcal{B}(Z\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})=0.67\ifmmode\pm\else\textpm\fi{}0.18(\text{stat})\ifmmode\pm\else\textpm\fi{}0.05(\text{syst})$.
Konular
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
Birincil konu Particle physics theoretical and experimental studies