Differential cross sections for the exclusive reaction pp-->ppeta observed via the eta-->pi(+)pi(-)pi(0) decay channel have been measured at T-beam=2.15 GeV, 2.50 GeV, and 2.85 GeV (excess energies 324 MeV, 412 MeV, and 554 MeV). The influence of the N(1535)S-11 resonance is clearly seen in the invariant mass and momentum dependent differential cross sections. The extracted resonance parameters are compatible with existing data. No significant evidence for further resonance contributions has been found. In addition, angular distributions of the ppeta final state have been measured. The polar angle distribution of the eta shows an anisotropy with respect to the beam axis for the lowest beam energy, which vanishes for the higher energies. The sign of this anisotropy is negative and expected to be sensitive to the dominant production mechanism. In contrast, the proton polar angle in the pp rest frame tends to be more strongly aligned along the beam axis with increasing beam energy. The analyzing power A(y) is compatible with zero for all beam energies.

Exclusive eta production in proton-proton reactions

BALESTRA, Ferruccio;BERTINI, Raimondo Pietro;BUSSA, Maria Pia;FERRERO, Andrea;FERRERO, Livio;FROLOV, VLADIMIR;GARFAGNINI, Raffaello;GRASSO, Antonino;MAGGIORA, MARCO;PANZIERI, Daniele;PIRAGINO, Guido;ZOSI, Gianfranco
2004-01-01

Abstract

Differential cross sections for the exclusive reaction pp-->ppeta observed via the eta-->pi(+)pi(-)pi(0) decay channel have been measured at T-beam=2.15 GeV, 2.50 GeV, and 2.85 GeV (excess energies 324 MeV, 412 MeV, and 554 MeV). The influence of the N(1535)S-11 resonance is clearly seen in the invariant mass and momentum dependent differential cross sections. The extracted resonance parameters are compatible with existing data. No significant evidence for further resonance contributions has been found. In addition, angular distributions of the ppeta final state have been measured. The polar angle distribution of the eta shows an anisotropy with respect to the beam axis for the lowest beam energy, which vanishes for the higher energies. The sign of this anisotropy is negative and expected to be sensitive to the dominant production mechanism. In contrast, the proton polar angle in the pp rest frame tends to be more strongly aligned along the beam axis with increasing beam energy. The analyzing power A(y) is compatible with zero for all beam energies.
2004
69
064003-1
064003-9
http://journals.aps.org/prc/
F. BALESTRA; Y. BEDFER; R. BERTINI; L. C. BLAND; A. BRENSCHEDE; F. BROCHARD; M. P. BUSSA; SEONHO CHOI; M. L. COLANTONI; R. DRESSLER; M. DZEMIDZIC; J.-CL. FAIVRE; A. FERRERO; L. FERRERO; J. FORYCIARZ; I. FRHLICH; V. FROLOV; R. GARFAGNINI; A. GRASSO; S. HEINZ; W. W. JACOBS; W. KHN; A. MAGGIORA; M. MAGGIORA; A. MANARA; D. PANZIERI; H.-W. PFAFF; G. PIRAGINO; A. POPOV; J. RITMAN; P. SALABURA; V. TCHALYSHEV; F. TOSELLO; S. E. VIGDOR; G. ZOSI
File in questo prodotto:
File Dimensione Formato  
2004_PR_C69_064003-1-9.pdf

Accesso riservato

Tipo di file: POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione 551.84 kB
Formato Adobe PDF
551.84 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1262
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 35
  • ???jsp.display-item.citation.isi??? 29
social impact