2012/06/25 by Belle Collaboration, C. C. Zhang, H. Aihara +108 · 1 citation
Physics and Astronomy · #Collider #Crystallography #Energy (signal processing) #High-Energy Particle Collisions Research #KEKB #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #hep-ex
paper · pdf · doi:10.1103/physrevd.86.052002
13 pages, 7 figures, submitted to PRD
arxiv created 2012/06/25 · openalex publication_date 2012/09/10 · arxiv updated 2015/06/05 · openalex created_date 2017/03/16 · openalex updated_date 2026/08/05
The invariant mass spectrum of the \ensuremathη^\ensuremath'\ensuremathπ+\ensuremathπ^\ensuremath- final state produced in two-photon collisions is obtained using a 673 fb^\ensuremath-1 data sample collected in the vicinity of the \ensuremathΥ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e^\ensuremath- collider. We observe a clear signal of the \ensuremathηc(1S) and measure its mass and width to be M(\ensuremathηc(1S))=(2982.7\ifmmode±\else\textpm\fi1.8(stat)\ifmmode±\else\textpm\fi2.2(syst)\ifmmode±\else\textpm\fi0.3(model)) MeV/c2 and \ensuremathΓ(\ensuremathηc(1S))=(37.8_\ensuremath-5.3+5.8(stat)\ifmmode±\else\textpm\fi2.8(syst)\ifmmode±\else\textpm\fi1.4(model)) MeV/c2. The third error is an uncertainty due to possible interference between the \ensuremathηc(1S) and a nonresonant component. We also report the first evidence for \ensuremathη(1760) decay to \ensuremathη^\ensuremath'\ensuremathπ+\ensuremathπ^\ensuremath-; we find two solutions for its parameters, depending on the inclusion or not of the X(1835), whose existence is of marginal significance in our data. From a fit to the mass spectrum using coherent X(1835) and \ensuremathη(1760) resonant amplitudes, we set a 90% confidence level upper limit on the product \ensuremathΓ_\ensuremathγ\ensuremathγB(\ensuremathη^\ensuremath'\ensuremathπ+\ensuremathπ^\ensuremath-) for the X(1835).