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Measurement of the Sigma pi photoproduction line shapes near the Lambda(1405)

K. Moriya R.A. Schumacher K.P. Adhikari D. Adikaram M. Aghasyan M.D. Anderson S. Anefalos Pereira J. Ball 1 N.A. Baltzell M. Battaglieri V. Batourine I. Bedlinskiy M. Bellis A.S. Biselli J. Bono S. Boiarinov W.J. Briscoe V.D. Burkert D.S. Carman A. Celentano S. Chandavar G. Charles 1 P.L. Cole P. Collins V. Crede A. d'Angelo N. Dashyan E. de Sanctis R. de Vita A. Deur B. Dey C. Djalali D. Doughty R. Dupre 2 H. Egiyan L. El Fassi P. Eugenio G. Fedotov S. Fegan R. Fersch J.A. Fleming N. Gevorgyan G.P. Gilfoyle K.L. Giovanetti F.X. Girod 1 J.T. Goetz W. Gohn E. Golovatch R.W. Gothe K.A. Griffioen M. Guidal 2 K. Hafidi H. Hakobyan C. Hanretty N. Harrison D. Heddle K. Hicks D. Ho M. Holtrop C. E. Hyde Y. Ilieva D.G. Ireland B.S. Ishkhanov E.L. Isupov H.S. Jo 2 D. Keller M. Khandaker P. Khetarpal A. Kim W. Kim A. Klein F.J. Klein S. Koirala A. Kubarovsky V. Kubarovsky S.V. Kuleshov N.D. Kvaltine K. Livingston H.Y. Lu I.J.D. Macgregor N. Markov M. Mayer M. Mccracken B. Mckinnon M.D. Mestayer C.A. Meyer M. Mirazita T. Mineeva V. Mokeev R.A. Montgomery E. Munevar C. Munoz Camacho 2 P. Nadel-Turonski R. Nasseripour C.S. Nepali S. Niccolai 2 G. Niculescu I. Niculescu M. Osipenko A.I. Ostrovidov L.L. Pappalardo R. Paremuzyan 2 K. Park S. Park E. Pasyuk E. Phelps J.J. Phillips S. Pisano N. Pivnyuk O. Pogorelko S. Pozdniakov J.W. Price S. Procureur 1 D. Protopopescu D. Rimal M. Ripani B.G. Ritchie G. Rosner P. Rossi F. Sabatié 1 M.S. Saini C. Salgado D. Schott E. Seder H. Seraydaryan Y.G. Sharabian E.S. Smith G.D. Smith D.I. Sober S.S. Stepanyan S. Stepanyan P. Stoler I.I. Strakovsky S. Strauch M. Taiuti W. Tang S. Taylor C.E. Taylor Ye Tian S. Tkachenko B. Torayev M. Ungaro B. Vernarsky A.V. Vlassov H. Voskanyan E. Voutier 3 N.K. Walford D.P. Watts D.P. Weygand M. Williams N. Zachariou L. Zana J. Zhang Z.W. Zhao I. Zonta
Abstract : The reaction gamma + p -> K+ + Sigma + pi was used to determine the invariant mass distributions or "line shapes" of the Sigma+ pi-, Sigma- pi+ and Sigma0 pi0 final states, from threshold at 1328 MeV/c^2 through the mass range of the Lambda(1405) and the Lambda(1520). The measurements were made with the CLAS system at Jefferson Lab using tagged real photons, for center-of-mass energies 1.95 < W < 2.85 GeV. The three mass distributions differ strongly in the vicinity of the I=0 \Lambda(1405), indicating the presence of substantial I=1 strength in the reaction. Background contributions to the data from the Sigma0(1385) and from K^* Sigma production were studied and shown to have negligible influence. To separate the isospin amplitudes, Breit-Wigner model fits were made that included channel-coupling distortions due to the NKbar threshold. A best fit to all the data was obtained after including a phenomenological I=1, J^P = 1/2^- amplitude with a centroid at 1394\pm20 MeV/c^2 and a second I=1 amplitude at 1413\pm10 MeV/c^2. The centroid of the I=0 Lambda(1405) strength was found at the Sigma pi threshold, with the observed shape determined largely by channel-coupling, leading to an apparent overall peak near 1405 MeV/c^2.
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Submitted on : Wednesday, January 23, 2013 - 8:33:09 AM
Last modification on : Tuesday, January 5, 2021 - 1:38:05 PM

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K. Moriya, R.A. Schumacher, K.P. Adhikari, D. Adikaram, M. Aghasyan, et al.. Measurement of the Sigma pi photoproduction line shapes near the Lambda(1405). Physical Review C, American Physical Society, 2013, 87, pp.035206. ⟨10.1103/PhysRevC.87.035206⟩. ⟨in2p3-00780047⟩



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