Weak decays of {sub {lambda}}{sup 4}He

• Published in: Physical review. C, Nuclear physics Nuclear physics, 2007-09, Vol.76 (3)
• Main Authors: Parker, J. D., Athanas, M. J., Barnes, P. D., Diebold, G., Franklin, G. B., Quinn, B., Rozon, F., Schumacher, R. A., Sukaton, I., Zeps, V. J., Bart, S., Chrien, R., Pile, P., Sawafta, R., Sutter, R., Bassalleck, B., Johnston, K., Stearns, R., Szymanski, J. J.
• Format: Article
• Language: English
• Subjects: BRANCHING RATIO; FINAL-STATE INTERACTIONS; HELIUM 4; HELIUM 4 TARGET; HYPERNUCLEI; KAON MINUS REACTIONS; LAMBDA BARYONS; LIFETIME; MEV RANGE; NEUTRONS; NUCLEAR DECAY; NUCLEAR PHYSICS AND RADIATION PHYSICS; PARTICLE DECAY; PIONS MINUS; PROTONS; THREE-BODY PROBLEM
• ISSN: 0556-2813; 1089-490X
• DOI: 10.1103/PHYSREVC.76.035501

We measured the lifetime and the mesonic and nonmesonic decay rates of the {sub {lambda}}{sup 4}He hypernucleus. The hypernuclei were created using a 750 MeV/c momentum K{sup -} beam on a liquid {sup 4}He target by the reaction {sup 4}He (K{sup -},{pi}{sup -}){sub {lambda}}{sup 4}He. The {sub {lambda}}{sup 4}He lifetime was directly measured using protons from {lambda}p{yields}np nonmesonic decay (also referred to as proton-stimulated decay) and was found to have a value of {tau}=245{+-}24 ps. The mesonic decay rates were determined from the observed numbers of {pi}{sup -}'s and {pi}{sup circle}'s as {gamma}{sub {pi}{sup -}}/{gamma}{sub tot}=0.270{+-}0.024 and {gamma}{sub {pi}}/{gamma}{sub tot}=0.564{+-}0.036, respectively, and the values of the proton- and neutron-stimulated decay rates were extracted as {gamma}{sub p}/{gamma}{sub tot}=0.169{+-}0.019 and {gamma}{sub n}/{gamma}{sub tot}{