# Observation of ${\overline{B}}_{(s)}^{0}$\rightarrow${}J/$\psi${}$ ${f}_{1}(1285)$ decays and measurement of the ${f}_{1}(1285)$ mixing angle

LHCb Collaboration; Bernet, R; Müller, K; Steinkamp, O; Straumann, U; Vollhardt, A; et al (2014). Observation of ${\overline{B}}_{(s)}^{0}$\rightarrow${}J/$\psi${}$ ${f}_{1}(1285)$ decays and measurement of the ${f}_{1}(1285)$ mixing angle. Physical Review Letters, 112(091802):online.

## Abstract

Decays of ${\overline{B}}_{s}^{0}$ and ${\overline{B}}^{0}$ mesons into $J/$\psi${}$ ${$\pi${}}^{+}$${\pi{}}^{-{}}$${$\pi${}}^{+}$${\pi{}}^{-{}} final states, produced in pp collisions at the LHC, are investigated using data corresponding to an integrated luminosity of 3\text{ }\text{ }\mathrm{fb}{}^{-{}1} collected with the LHCb detector. {\overline{B}}_{(s)}^{0}\rightarrow{}J/\psi{}{f}_{1}(1285) decays are seen for the first time, and the branching fractions are measured. Using these rates, the {f}_{1}(1285) mixing angle between strange and nonstrange components of its wave function in the q\overline{q} structure model is determined to be \pm{}(24.{0}_{-{}2.6-{}0.8}^{+3.1+0.6}). Implications on the possible tetraquark nature of the {f}_{1}(1285) are discussed. Decays of {\overline{B}}_{s}^{0} and {\overline{B}}^{0} mesons into J/\psi{} {\pi{}}^{+}$${$\pi${}}^{$-${}}$${\pi{}}^{+}$${$\pi${}}^{$-${}}$ final states, produced in $pp$ collisions at the LHC, are investigated using data corresponding to an integrated luminosity of $3\text{ }\text{ }\mathrm{fb}{}^{$-${}1}$ collected with the LHCb detector. ${\overline{B}}_{(s)}^{0}$\rightarrow${}J/$\psi${}{f}_{1}(1285)$ decays are seen for the first time, and the branching fractions are measured. Using these rates, the ${f}_{1}(1285)$ mixing angle between strange and nonstrange components of its wave function in the $q\overline{q}$ structure model is determined to be $\pm{}(24.{0}_{$-${}2.6$-${}0.8}^{+3.1+0.6})$. Implications on the possible tetraquark nature of the ${f}_{1}(1285)$ are discussed.

## Citations

7 citations in Web of Science®
7 citations in Scopus®

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Item Type: Journal Article, refereed, original work 07 Faculty of Science > Physics Institute 530 Physics English 2014 24 Feb 2015 15:16 05 Apr 2016 19:03 American Physical Society 0031-9007 https://doi.org/10.1103/PhysRevLett.112.091802
Permanent URL: https://doi.org/10.5167/uzh-108342