dc.contributor |
Universitat de Barcelona |
dc.contributor.author |
Graugés Pous, Eugeni |
dc.contributor.author |
BABAR Collaboration |
dc.date |
2019-04-26T11:34:53Z |
dc.date |
2019-04-26T11:34:53Z |
dc.date |
2018-12-26 |
dc.date |
2019-04-26T11:34:53Z |
dc.identifier.citation |
0031-9007 |
dc.identifier.citation |
684821 |
dc.identifier.uri |
http://hdl.handle.net/2445/132435 |
dc.format |
11 p. |
dc.format |
application/pdf |
dc.language.iso |
eng |
dc.publisher |
American Physical Society |
dc.relation |
Reproducció del document publicat a: https://doi.org/10.1103/PhysRevLett.121.261801 |
dc.relation |
Physical Review Letters, 2018, vol. 121, num. 26, p. 261801 |
dc.relation |
https://doi.org/10.1103/PhysRevLett.121.261801 |
dc.rights |
(c) American Physical Society, 2018 |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Física de partícules |
dc.subject |
Experiments |
dc.subject |
Particle physics |
dc.subject |
Experiments |
dc.title |
First Evidence for cos2β>0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity |
dc.type |
info:eu-repo/semantics/article |
dc.type |
info:eu-repo/semantics/publishedVersion |
dc.description.abstract |
We present first evidence that the cosine of the C P -violating weak phase 2 β is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B 0 → D ( * ) h 0 with D → K 0 S π + π − decays, where h 0 ∈ { π 0 , η , ω } denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the Υ ( 4 S ) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain ( 471 ± 3 ) × 10 6 B ¯ B pairs recorded by the BABAR detector and ( 772 ± 11 ) × 10 6 B ¯ B pairs recorded by the Belle detector. The results of the measurement are sin 2 β = 0.80 ± 0.14 ( stat ) ± 0.06 ( syst ) ± 0.03 ( model ) and cos 2 β = 0.91 ± 0.22 ( stat ) ± 0.09 ( syst ) ± 0.07 ( model ) . The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β = [ 22.5 ± 4.4 ( stat ) ± 1.2 ( syst ) ± 0.6 ( model ) ] ° . The measurement assumes no direct C P violation in B 0 → D ( * ) h 0 decays. The quoted model uncertainties are due to the composition of the D 0 → K 0 S π + π − decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e + e − → c ¯ c data sample. C P violation is observed in B 0 → D ( * ) h 0 decays at the level of 5.1 standard deviations. The significance for cos 2 β > 0 is 3.7 standard deviations. The trigonometric multifold solution π / 2 − β = ( 68.1 ± 0.7 ) ° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. |