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Interpretation of experimental J{sub PC} exotic signals

Description: The authors investigate theoretical interpretations of the 1.4 GeV J{sup PC} exotic resonance reported by the E852 collaboration. It is argued that interpretation in terms of a hybrid meson is untenable. A K-matrix analysis shows that the 1.4 GeV enhancement in the E852 {eta}{pi} data can be understood as an interference of a non-resonant Deck-type background and a resonance at 1.6 GeV. A final state rescattering calculation shows that the 1.6 GeV hybrid has a {eta}{pi} width which is bounded above by 57 {+-} 14 MeV.
Date: August 1, 1998
Creator: Donnachie, Alexander & Page, Philip R.
Partner: UNT Libraries Government Documents Department

Studies of neutron dissociation at FermiLab energies

Description: The characteristics of diffraction dissociation of neutrons into p$pi$$sup -$ systems at high energies were examined. A substantial correlation is observed between the mass and the t of the produced system. The spin structure of the p$pi$$sup -$ amplitudes at low mass is very complex, but is described surprisingly well by the simple Deck Mechanism. Both $pi$-exchange and proton-exchange contributions are evident in diffractive production. The t- channel and s-channel helicity amplitudes contain comparable contributions from flip and nonflip terms and the produced states are not restricted to those expected on the basis of the Morrison rule. (auth)
Date: August 21, 1975
Creator: Ferbel, T.
Partner: UNT Libraries Government Documents Department

Deck model calculation of $pi$$sup -$p $Yields$ $pi$$sup -$$pi$$sup +$$pi$$sup -$p

Description: A Deck-like model for the reaction pi /sup -/p yields pi /sup -/ pi / sup +/ pi /sup -/p is formulated and studied. The model differs from previous Deck calculations in two respects: i) experimental data are used for both pi pi and pi N scattering, and ii) the amplitude has proper Bose symmetry. Feature i) allows one to examine any desired region of 3 pi mass (the A/sub 3/ is treated on the same footing as the A/sub 1/); features i) and ii) allow one to examine all the angular dependence in the final state and to compare with partinl wave analyses of experimental data. The results of a study are presented in which events generated from the model by a Monte Carlo method are plotted and fit in the same way as experimental events. Many of the features of the data are qualitatively reproduced including certain important properties obtained from the partial wave analysis in the A/sub 1/ region. The A/sub 3/ region is not accurately representcd by the model. (auth)
Date: August 1, 1973
Creator: Ascoli, G.; Cutler, R.; Jones, L.M.; Kruse, U.; Roberts, T.; Weinstein, B. et al.
Partner: UNT Libraries Government Documents Department

Unitary coupled channel deck model

Description: A unitary Deck model with coupled K*..pi.. and Krho channels, including only one resonance in the Q region is constructed. Adjusting the resonance parameters, one achieves a satisfactory description of the experimental phase variations and structure in the mass spectra. The resonance is determined to belong to the J/sup PC/ = 1/sup + -/ SU(3) octet, and is thus the Q/sub B/. The relative coupling strength K*..pi../Krho is approximately 2/3.
Date: May 1, 1976
Creator: Basdevant, J. L. & Berger, E. L.
Partner: UNT Libraries Government Documents Department

Diffractive dissociation process. pi. /sup -/p. -->. pi. /sup -/ (. pi. /sup -/. pi. /sup +/p) at 14 GeV/c. [Cross sections, Deck effect, t- and s-channel helicity conservation]

Description: An experiment in which a 14 GeV/c ..pi../sup -/ beam was incident on a hydrogen bubble chamber is described. Fast forward scattered pions traversed a wire spark chamber spectrometer downstream of the bubble chamber. Events identified as inelastic by the spectrometer induced a trigger of the bubble chamber camera. The film produced contained a heavy enrichment of events of proton diffractive dissociation. A sample from this exposure of 4400 events of the reaction ..pi../sup -/p ..-->.. ..pi../sup -/N* ..-->.. ..pi../sup -/..pi../sup -/..pi../sup +/p was studied. In the two body mass spectra the only noteworthy feature is the ..delta../sup + +/(1230). In the N* mass spectrum one observes enhancements at 1.49 GeV, 1.72 GeV, and 2.0 GeV. For the prominent 1.72 GeV feature estimates are given of the width and cross section as well as evidence favoring a substantial branching fraction to ..pi delta..(1230). We looked for production of N*(1470) followed by decay to ..pi delta..(1230) with negative result. An examination of the ..delta../sup + +/(1230) decay distribution suggests that the Deck mechanism is the major contributor to the ..pi delta.. subchannel. The s-channel and t-channel helicity conservation rules were tested. One observed violent conflict with sCHC and mild conflict with tCHC. One also tested for simultaneous validity of tCHC and the Gribov--Morrison rule and found no significant contradiction with this dual hypothesis.
Date: May 1, 1977
Creator: Rosenfeld, C.
Partner: UNT Libraries Government Documents Department