Improved Evidence for Direct CP Violation in B{sup 0}{yields}{pi}{sup +}{pi}{sup -} Decays and Model-Independent Constraints on {phi}{sub 2}

Journal Article · Fri Sep 02 04:00:00 EDT 2005 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.95.101801· OSTI ID:20699384

Abe, K; Adachi, I; Gershon, T; Haba, J; Hara, K; Hazumi, M; Ishikawa, A; Itoh, R; Iwasaki, Y; Katayama, N; Kichimi, H; Nakamura, I; Nakao, M; Nakazawa, H; Nishida, S; Nozaki, T; Ozaki, H; Ronga, F J; Sagawa, H; Sakai, Y ^[1]

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1. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); and others

We present a new measurement of the time-dependent CP-violating parameters in B{sup 0}{yields}{pi}{sup +}{pi}{sup -} decays with 275x10{sup 6} BB pairs collected with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider operating at the {upsilon}(4S) resonance. We find 666{+-}43 B{sup 0}{yields}{pi}{sup +}{pi}{sup -} events and measure the CP-violating parameters: S{sub {pi}}{sub {pi}}=-0.67{+-}0.16(stat){+-}0.06(syst) and A{sub {pi}}{sub {pi}}=+0.56{+-}0.12(stat){+-}0.06(syst). We find evidence for large direct CP violation with a significance greater than 4 standard deviations for any S{sub {pi}}{sub {pi}} value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle {phi}{sub 2} of 0 deg. <{phi}{sub 2}<19 deg. and 71 deg. <{phi}{sub 2}<180 deg.

• OSTI ID: 20699384
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 10 Vol. 95; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMMETRY
B NEUTRAL MESONS
CP INVARIANCE
HADRONIC PARTICLE DECAY
ISOSPIN
PIONS MINUS
PIONS PLUS
QUARKS
TIME DEPENDENCE