Measurement of the resonant and CP components in $\overline{B}^0\rightarrow J/ψπ^+π^-$ decays

Journal article

The resonant structure of the reaction $\overline{B}^0\rightarrow J/\psi \pi^+\pi^-$ is studied using data from 3 fb$^{-1}$ of integrated luminosity collected by the LHCb experiment, one-third at 7 Tev center-of-mass energy and the remainder at 8 Tev. The invariant mass of the $\pi^+\pi^-$ pair and three decay angular distributions are used to determine the fractions of the resonant and non-resonant components. Six interfering $\pi^+\pi^-$ states: $\rho(770)$, $f_0(500)$, $f_2(1270)$, $\rho(1450)$, $\omega(782)$ and $\rho(1700)$ are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative CP fractions of each of the resonant final states are determined. The $f_0(980)$ meson is not seen and the upper limit on its presence, compared with the observed $f_0(500)$ rate, is inconsistent with a model of tetraquark substructure for these scalar mesons at the eight standard deviation level. In the $q\overline{q}$ model, the absolute value of the mixing angle between the $f_0(980)$ and the $f_0(500)$ scalar mesons is limited to be less than $17^{\circ}$ at 90% confidence level.

Authors: collaboration, L; Aaij, R; Adeva, B; Adinolfi, M; Affolder, A

• Publication status: Published
• Journal: Phys. Rev. D
• Volume: 90
• Issue: 1
• Pages: 012003
• Publication date: 2014-04-23
• DOI: 10.1103/PhysRevD.90.012003
• EISSN: 1550-2368
• ISSN: 1550-7998
• Keywords: hep-ex; nucl-ex; hep-ph