The CLAS detector was used to obtain the first ever measurement of the electromagnetic decay of the Sigma*(+)(1385) from the reaction gamma p -> K-0 Sigma*(+)(1385). A real photon beam with a maximum energy of 3.8 GeV was incident on a liquid-hydrogen target, resulting in the photoproduction of the kaon and Sigma* hyperon. Kinematic fitting was used to separate the reaction channel from the background processes. The fitting algorithm exploited a new method to kinematically fit neutrons in the CLAS detector, leading to the measured decay widths ratio Sigma(+)(1385)->Sigma(+)gamma/Sigma(+)(1385)->Sigma(+)pi(0)=11.95 +/-.2.21(stat)(-1.21)(+0.53)(sys)%and a deduced partial width of 250.0 +/- 56.9(stat)(-41.2)(+34.3)(sys) keV. AU-spin symmetry test using the SU(3) flavor-multiplet representation yields predictions for the Sigma*(+)(1385)->Sigma(+)gamma and Sigma*(0)(1385)->Lambda gamma partial widths that agree with the experimental measurements.
Keller, D., Hicks, K., Adhikari, K., Adikaram, D., Amaryan, M., Anghinolfi, M., et al. (2012). Branching ratio of the electromagnetic decay of the Sigma(+)(1385). PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY, 85(5), 052004-1-052004-20 [10.1103/PhysRevD.85.052004].
Branching ratio of the electromagnetic decay of the Sigma(+)(1385)
D'ANGELO, ANNALISA;PISANO, SILVIA;
2012-03-19
Abstract
The CLAS detector was used to obtain the first ever measurement of the electromagnetic decay of the Sigma*(+)(1385) from the reaction gamma p -> K-0 Sigma*(+)(1385). A real photon beam with a maximum energy of 3.8 GeV was incident on a liquid-hydrogen target, resulting in the photoproduction of the kaon and Sigma* hyperon. Kinematic fitting was used to separate the reaction channel from the background processes. The fitting algorithm exploited a new method to kinematically fit neutrons in the CLAS detector, leading to the measured decay widths ratio Sigma(+)(1385)->Sigma(+)gamma/Sigma(+)(1385)->Sigma(+)pi(0)=11.95 +/-.2.21(stat)(-1.21)(+0.53)(sys)%and a deduced partial width of 250.0 +/- 56.9(stat)(-41.2)(+34.3)(sys) keV. AU-spin symmetry test using the SU(3) flavor-multiplet representation yields predictions for the Sigma*(+)(1385)->Sigma(+)gamma and Sigma*(0)(1385)->Lambda gamma partial widths that agree with the experimental measurements.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.