Ishino, H;
Abe, K;
Abe, K;
Adachi, I;
Aihara, H;
Anipko, D;
Arinstein, K;
... Belle Collaboration; + view all
(2007)
Observation of direct CP violation in B-0 ->pi(+)pi(-) decays and model-independent constraints on the quark-mixing angle phi(2).
PHYS REV LETT
, 98
(21)
, Article 211801. 10.1103/PhysRevLett.98.211801.
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Abstract
We report a new measurement of the time-dependent CP-violating parameters in B-0 ->pi(+)pi(-) decays with 535x10(6) B (B) over bar pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Upsilon(4S) resonance. We find 1464 +/- 65 B-0 ->pi(+)pi(-) events and measure the CP-violating parameters S-pi pi=-0.61 +/- 0.10(stat)+/- 0.04(syst) and A(pi pi)=+0.55 +/- 0.08(stat)+/- 0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any S-pi pi value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2)=(97 +/- 11)degrees for the solution consistent with the standard model and exclude the range 11 degrees <phi(2)< 79 degrees at the 95% confidence level.
| Type: | Article |
|---|---|
| Title: | Observation of direct CP violation in B-0 ->pi(+)pi(-) decays and model-independent constraints on the quark-mixing angle phi(2) |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevLett.98.211801 |
| Publisher version: | http://dx.doi.org/10.1103/PhysRevLett.98.211801 |
| Language: | English |
| Additional information: | © 2007 The American Physical Society |
| Keywords: | B-DECAYS, BELLE, DETECTOR, MESONS |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1308550 |
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