Measurement of the Branching Ratio of [pi][sup 0] [r arrow] e[sup +] e[sup [minus]] Using K[sub L] [r arrow] 3[pi][sup 0] Decays in Flight

Journal Article · Sun Aug 01 04:00:00 EDT 1999 · Physical Review Letters

OSTI ID:6272016

Cheu, E; Taegar, S A; Wang, J ^[1]; Arisaka, K; Jennings, J; Slater, W; Tripathi, A ^[2]; Kobrak, H G; Swanson, R A ^[3]; Blucher, E; Bown, C; Bright, S; Graham, G; Graham, J; Kessler, R; Monnier, E; Prasad, V; Qiao, C; Quinn, B; Roodman, A ; Shawhan, P S; Solomey, N; Swallow, E C; Wah, Y W; Winstein, B; Winston, R; Zimmerman, E D ^[4]; Barker, A R; LaDue, J; Mikelsons, P; Nauenberg, U; Toale, P A; Wu, J ^[5]; Swallow, E C ^[6]; Bellantoni, L; Ben-David, R; Bock, G J; Childress, S; Coleman, R; Crisler, M B; Ford, R; Hs,

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1. University of Arizona, Tucson, Arizona 85721 (United States)
2. University of California at Los Angeles, Los Angeles, California 90095 (United States)
3. University of California at San Diego, La Jolla, California 92093 (United States)
4. The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)
5. University of Colorado, Boulder, Colorado 80309 (United States)
6. Elmhurst College, Elmhurst, Illinois 60126 (United States)

The branching ratio of the rare decay [pi][sup 0][r arrow]e[sup +]e[sup [minus]] has been measured in E799-II, a rare kaon decay experiment using the KTeV detector at Fermilab. We observed 275 candidate [pi][sup 0][r arrow]e[sup +]e[sup [minus]] events, with an expected background of 21.4[plus minus]6.2 events which includes the contribution from Dalitz decays. We measured B[[pi][sup 0][r arrow]e[sup +]e[sup [minus]],thinsp (m[sub e[sup +]e[sup [minus]]]/m[sub [pi][sup 0]])[sup 2][gt]0.95]=(6.09[plus minus] 0.40[plus minus]0.24)[times]10[sup [minus]8] , where the first error is statistical and the second systematic. This result is the first significant observation of the excess rate for this decay above the unitarity lower bound. [copyright] [ital 1999] [ital The American Physical Society ]

• OSTI ID: 6272016
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Vol. 83:5; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

662350* -- Decays of Mesons-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
BOSONS
BRANCHING RATIO
CHIRAL SYMMETRY
DECAY
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
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MATTER
MESONS
PAIR PRODUCTION
PARTICLE DECAY
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PERTURBATION THEORY
PIONS
PIONS NEUTRAL
POSITRONS
PSEUDOSCALAR MESONS
SYMMETRY
WEAK INTERACTIONS
WEAK PARTICLE DECAY