First measurement of the {Lambda}_c^{+} → pη′ decay

Abstract

We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay {Lambda}_c^{+} → pη′ with η′ → ηπ+π−, using a data sample corresponding to an integrated luminosity of 981 fb−1, collected by the Belle detector at the KEKB e+e− asymmetric-energy collider. A significant {Lambda}_c^{+} → pη′ signal is observed for the first time with a signal significance of 5.4σ. The relative branching fraction with respect to the normalization mode {Lambda}_c^{+} → pK−π+ is measured to beBΛc+→pη′BΛc+→pK−π+=7.54±1.32±0.73×10−3,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{\\mathcal{B}\\left({\\Lambda}_c^{+}\ o p\\eta^{\\prime}\\right)}{\\mathcal{B}\\left({\\Lambda}_c^{+}\ o {pK}^{-}{\\pi}^{+}\\right)}=\\left(7.54\\pm 1.32\\pm 0.73\\right)\ imes {10}^{-3}, $$\\end{document}where the uncertainties are statistical and systematic, respectively. Using the world-average value of mathcal{B}left({Lambda}_c^{+}to {pK}^{-}{pi}^{+}right) = (6.28 ± 0.32) × 10−2, we obtainBΛc+→pη′=4.73±0.82±0.46±0.24×10−4,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{B}\\left({\\Lambda}_c^{+}\ o p\\eta^{\\prime}\\right)=\\left(4.73\\pm 0.82\\pm 0.46\\pm 0.24\\right)\ imes {10}^{-4}, $$\\end{document}where the uncertainties are statistical, systematic, and from mathcal{B}left({Lambda}_c^{+}to {pK}^{-}{pi}^{+}right) , respectively.