Observation of the Decay {ital K}{sup +} {r_arrow} {pi}{sup +}{gamma}{gamma}
- Centre for Subatomic Research, University of Alberta, Edmonton, Alberta, T6G 2N5 (CANADA)
- Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Medium Energy Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Joseph Henry Laboratories, Princeton University, Princeton, New Jersey 08544 (United States)
- TRIUMF, Vancouver, British Columbia, V6T 2A3 (CANADA)
The first observation of the decay K{sup +}{r_arrow}{pi}{sup +}{gamma}{gamma} is reported. A total of 31 events was observed with an estimated background of 5.1{plus_minus}3.3 events in the {pi}{sup +} momentum range from 100 to 180 MeV/{ital c}. The corresponding partial branching ratio, B(K{sup +}{r_arrow}{pi}{sup +}{gamma}{gamma} ,100 MeV/c{lt}P{sub {pi}{sup +} }{lt}180 MeV/c) , is [6.0{plus_minus}1.5(stat){plus_minus}0.7 (syst)]{times}10{sup {minus}7} . No K{sup +}{r_arrow}{pi}{sup +}{gamma}{gamma} decay was observed in the {pi}{sup +} momentum region greater than 215 MeV/{ital c}. The observed {pi}{sup +} momentum spectrum is compared with the predictions of chiral perturbation theory. {copyright} {ital 1997} {ital The American Physical Society}
- Research Organization:
- Princeton University
- DOE Contract Number:
- FG02-91ER40671; W-7405-ENG-36
- OSTI ID:
- 564925
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 21 Vol. 79; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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