Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Measurement of the. Sigma. sup 0 yields. Sigma. sup 0. gamma. branching ratio

Thesis/Dissertation ·
OSTI ID:6902636
The data on hyperon weak radiative decays is scarce. The branching ratios for most of these rare decays have been measured but no events of the {Sigma}{sup 0} {yields} {Sigma}{sup 0} {gamma} type have yet been observed. A search was made for {Sigma}{sup 0} {yields} {Sigma}{sup 0}{gamma} decays in experiment 751 at Brookhaven National Laboratory, at 6.0 GeV/c momentum K{sup {minus}} beam, using the Multiparticle Spectrometer (MPS) and a lead glass calorimeter. The produced {Sigma}{sup 0} decayed into a {Lambda} and a {gamma} and the {Lambda} was detected via its {Lambda} {yields} p{pi}{sup {minus}} decay mode. The p and {pi}{sup {minus}} trajectories were reconstructed in the MPS and both photons were detected in the lead glass. A sample of 452 events containing a {Lambda} and at lest two photons satisfied all the selection criteria. Of these events, 145 had a {Lambda}{gamma} mass in the {Sigma}{sup 0} mass range. The expected background and signal curves were generated by Monte Carlo calculation. A background and signal fit to the data yielded 0{sub {minus}14}{sup +7.3} signal events which corresponds to an upper limit of 8.0 {times} 10{sup {minus}3} for the {Sigma}{sup 0} {yields} {Sigma}{sup 0}{gamma} branching ratio at the 90% confidence level. This result is in agreement with the measured branching ratios for similar hyperon radiative decays.
Research Organization:
Brandeis Univ., Waltham, MA (USA)
OSTI ID:
6902636
Country of Publication:
United States
Language:
English