Observation of the B+→ Jψη′K+ decay

Abstract

The B+ → Jψη′K+ decay is observed for the first time using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb−1. The branching fraction of this decay is measured relative to the known branching fraction of the B+→ ψ(2S)K+ decay and found to beBB+→Jψη′K+BB+→ψ2SK+=4.91±0.47±0.29±0.07×10−2,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{\\mathcal{B}\\left({B}^{+}\ o {J\\psi \\eta}^{\\prime }{K}^{+}\\right)}{\\mathcal{B}\\left({B}^{+}\ o \\psi (2S){K}^{+}\\right)}=\\left(4.91\\pm 0.47\\pm 0.29\\pm 0.07\\right)\ imes {10}^{-2}, $$\\end{document}where the first uncertainty is statistical, the second is systematic and the third is related to external branching fractions. A first look at the J/ψη′ mass distribution is performed and no signal of intermediate resonances is observed.