2022-10-052022-10-052016-04-06Ablikim, M. vd. (2016). "Observation of an anomalous line shape of the η′π+π− mass spectrum near the p ̄p mass threshold in J/ψ → γη′π+π−". Physical Review Letters, 117(4).0031-90071079-7114https://doi.org/10.1103/PhysRevLett.117.042002https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.042002http://hdl.handle.net/11452/28970Çalışmada 437 yazar bulunmaktadır. Bu yazarlardan sadece Bursa Uludağ Üniversitesi mensuplarının girişleri yapılmıştır.Using 1.09 x 10(9) J/psi events collected by the BESIII experiment in 2012, we study the J / psi -> gamma eta'pi(+)pi(-) process and observe a significant abrupt change in the slope of the eta'pi(+)pi(-) invariant mass distribution at the proton-antiproton (p (p) over bar) mass threshold. We use two models to characterize the eta'pi(+)pi(-) line shape around 1.85 GeV/c(2): one that explicitly incorporates the opening of a decay threshold in the mass spectrum (Flatte formula), and another that is the coherent sum of two resonant amplitudes. Both fits show almost equally good agreement with data, and suggest the existence of either a broad state around 1.85 GeV/c(2) with strong couplings to the c final states or a narrow state just below the p (p) over bar mass threshold. Although we cannot distinguish between the fits, either one supports the existence of a p (p) over bar moleculelike state or bound state with greater than 7 sigma significance.eninfo:eu-repo/semantics/openAccessPhysicsBaryonıumGlueballX(1835)StateQcdMass spectrometryBound stateFinal stateInvariant mass distributionLine shapeMass spectraProton-antiprotonResonant amplitudeStrong couplingMass spectrometersArticle0003801234000032-s2.0-84979517843117427494467Physics, multidisciplinaryAntiprotons; Spectroscopy; Annihilation