TY - JOUR
T1 - Measurement of the Spin of the Xi(1530) Resonance
AU - Aubert, B.
AU - Playfer, Stephen
AU - The BaBar Collaboration
AU - Clark, Philip
N1 - 13 pages, 16 postscript figures
PY - 2008/3/12
Y1 - 2008/3/12
N2 - The properties of the Xi(1530) resonance are investigated in the Lambdac+ --> Xi- pi+ K+ decay process. The data sample was collected with the BaBar detector at the SLAC PEP-II asymmetric-energy e+ e- collider operating at center of mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately 230 inverse fb. The spin of the Xi(1530) is established to be 3/2. The existence of an S-wave amplitude in the Xi- pi+ system is inferred, and its interference with the Xi(1530)0 amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected for the Xi(1530). The P_1(cos[theta(Xi-)]) Legendre polynomial moment indicates the presence of a significant S-wave amplitude for Xi- pi+ mass values above 1.6 GeV/c^2, and a dip in the mass distribution at approximately 1.7 GeV/c^2 is interpreted as due to coherent addition of a Xi(1690)0 contribution to this amplitude. This would imply J^P=1/2^- for the Xi(1690). Attempts at fitting the Xi(1530)0 lineshape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K+ pi+ and/or Xi- K+ systems.
AB - The properties of the Xi(1530) resonance are investigated in the Lambdac+ --> Xi- pi+ K+ decay process. The data sample was collected with the BaBar detector at the SLAC PEP-II asymmetric-energy e+ e- collider operating at center of mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately 230 inverse fb. The spin of the Xi(1530) is established to be 3/2. The existence of an S-wave amplitude in the Xi- pi+ system is inferred, and its interference with the Xi(1530)0 amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected for the Xi(1530). The P_1(cos[theta(Xi-)]) Legendre polynomial moment indicates the presence of a significant S-wave amplitude for Xi- pi+ mass values above 1.6 GeV/c^2, and a dip in the mass distribution at approximately 1.7 GeV/c^2 is interpreted as due to coherent addition of a Xi(1690)0 contribution to this amplitude. This would imply J^P=1/2^- for the Xi(1690). Attempts at fitting the Xi(1530)0 lineshape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K+ pi+ and/or Xi- K+ systems.
KW - hep-ex
UR - http://www.scopus.com/inward/record.url?scp=49749131192&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.78.034008
DO - 10.1103/PhysRevD.78.034008
M3 - Article
JO - Physical Review D, particles, fields, gravitation, and cosmology
JF - Physical Review D, particles, fields, gravitation, and cosmology
ER -