Improved Measurement of CP Asymmetry in the Neutral B Meson System

2002/05/10 by T. Higuchi, Higuchi, T.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.hep-ex/0205020

openalex publication_date 2002/05/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We present an improved measurement of the standard model CP violation parameter sin2phi1 (also known as sin2beta) based on a sample of 45x10⁶ BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. One neutral B meson is reconstructed in the J/psiKS, Psi(2S)KS, chi_c1KS, eta_cKS, J/psiK^*0, or J/psiKL CP-eigenstate decay channel and the flavor of accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we obtain sin2phi1 = 0.82 +/- 0.12(stat) +/- 0.05(syst). The result is preliminary.

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