CLEO measurement of B-->π+π- and determination of weak phase α
Abstract
The CLEO Collaboration has recently reported a (first) measurement of BR(B-->π+π-)=(4.7+1.8-1.5+/-0.6)×10-6. We study, using recent results on QCD improved factorization, the implications of this measurement for the determination of the Cabibbo-Kobayashi-Maskawa (CKM) phase α and also for the rate for B-->π0π0. If the B-->π- form factor is large (>~0.3), then we find that the CLEO measurement favors small \|Vub/Vcb\| so that the expected error (due to neglecting the QCD penguin amplitude) in the measurement of α using only the time-dependent analysis of the decay B-->π+π- is large ~15°. However, if \|Vub/Vcb\| is known, then it is possible to determine the correct value of sin2α.
- Publication:
-
Physical Review D
- Pub Date:
- April 2000
- DOI:
- 10.1103/PhysRevD.61.071301
- arXiv:
- arXiv:hep-ph/9909298
- Bibcode:
- 2000PhRvD..61g1301A
- Keywords:
-
- 13.25.Hw;
- 12.15.Hh;
- Decays of bottom mesons;
- Determination of Kobayashi-Maskawa matrix elements;
- High Energy Physics - Phenomenology
- E-Print:
- LaTeX file, 14 pages including 5 eps figures. Revised version with a slightly modified title. In the new version, we use QCD improved factorization. For the value of form factor used earlier, the conclusion that small Vub/Vcb is preferred leading to large error in alpha is unchanged. We have added results for a smaller value of the form factor. We also show that if Vub/Vcb is known, then it is possible to determine the correct value of sin 2 alpha. Typos corrected