Measurement of resonant and $CP$ components in $\overline{B}_s^0\to J/\psi\pi^+\pi^-$ decays

Abstract

The resonant structure of the decay $\overline{B}_s^0\to J/\psi\pi^+\pi^-$ is studied using data corresponding to 3 fb$^{-1}$ of integrated luminosity from $pp$ collisions by the LHC and collected by the LHCb detector. Five interfering $\pi^+\pi^-$ states are required to describe the decay: $f_0(980),~f_0(1500),~f_0(1790),~f_2(1270)$, and $f_2^{\prime}(1525)$. An alternative model including these states and a non-resonant $J/\psi \pi^+\pi^-$ component also provides a good description of the data. Based on the different transversity components measured for the spin-2 intermediate states, the final state is found to be compatible with being entirely $CP$-odd. The $CP$-even part is found to be Structure of the decay B¯s0→J/ψπ+π- is studied using data corresponding to 3 fb−1 of integrated luminosity from pp collisions produced by the LHC and collected by the LHCb detector. Five interfering π+π- states are required to describe the decay: f0(980),f0(1500),f0(1790),f2(1270), and f2′(1525). An alternative model including these states and a nonresonant J/ψπ+π- component also provides a good description of the data. Based on the different transversity components measured for the spin-2 intermediate states, the final state is found to be compatible with being entirely CP odd. The CP-even part is found to be <2.3% at a 95% confidence level. The f0(500) state is not observed, allowing a limit to be set on the absolute value of the mixing angle with the f0(980) of <7.7° at a 90% confidence level, consistent with a tetraquark interpretation of the f0(980) substructure.The resonant structure of the decay \overline{B}_s^0\to J/\psi\pi^+\pi^-$is studied using data corresponding to 3 fb$^{-1}$of integrated luminosity from$pp$collisions by the LHC and collected by the LHCb detector. Five interfering$\pi^+\pi^-$states are required to describe the decay:$f_0(980),f_0(1500),f_0(1790),f_2(1270)$, and$f_2^{\prime}(1525)$. An alternative model including these states and a non-resonant$J/\psi \pi^+\pi^-$component also provides a good description of the data. Based on the different transversity components measured for the spin-2 intermediate states, the final state is found to be compatible with being entirely$CP$-odd. The$CP$-even part is found to be$<2.3$$f_0(500)$state is not observed, allowing a limit to be set on the absolute value of the mixing angle with the$f_0(980)$of$<7.7^{\circ}$at 90$f_0(980)$ substructure