The properties of the Xi(1530) resonance are investigated in the Lambda(+)(c)->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 fb(-1). 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 the 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) line shape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K(+)pi(+) and/or Xi(-)K(+) systems.
Measurement of the spin of the Xi(1530) resonance
CALDERINI, GIOVANNI;ANGELINI, CARLO;BATIGNANI, GIOVANNI;BETTARINI, STEFANO;FORTI, FRANCESCO;GIORGI, MARCELLO;PAOLONI, EUGENIO;RIZZO, GIULIANA;
2008-01-01
Abstract
The properties of the Xi(1530) resonance are investigated in the Lambda(+)(c)->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 fb(-1). 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 the 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) line shape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K(+)pi(+) and/or Xi(-)K(+) systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
