Abstract
The results of an amplitude analysis of the charmless three-body decay B+→π+π+π−, in which CP-violation effects are taken into account, are reported. The analysis is based on a data sample corresponding to an integrated luminosity of 3 fb−1 of pp collisions recorded with the LHCb detector. The most challenging aspect of the analysis is the description of the behavior of the π+π− S-wave contribution, which is achieved by using three complementary approaches based on the isobar model, the K-matrix formalism, and a quasi-model-independent procedure. Additional resonant contributions for all three methods are described using a common isobar model, and include the ρ(770)0, ω(782) and ρ(1450)0 resonances in the π+π− P-wave, the f2(1270) resonance in the π+π− D-wave, and the ρ3(1690)0 resonance in the π+π− F-wave. Significant CP-violation effects are observed in both S- and D-waves, as well as in the interference between the S- and P-waves. The results from all three approaches agree and provide new insight into the dynamics and the origin of CP-violation effects in B+→π+π+π− decays.22 MoreReceived 16 September 2019DOI:https://doi.org/10.1103/PhysRevD.101.012006Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.© 2020 CERN, for the LHCb CollaborationPhysics Subject Headings (PhySH)Research AreasHadronic decaysPhysical SystemsBottom mesonsPropertiesCP violationTechniquesHadron collidersParticles & Fields
Highlights
In the Standard Model (SM), CP violation originates from a single irreducible complex phase in the CabibboKobayashi-Maskawa (CKM) matrix [1,2]
Large CP asymmetries localized in regions of phase space of charmless three-body B-meson decays have been observed in model-independent analyses [10,11,12,13], but until recently there has been no description of these effects with an accurate model of the contributing resonances
Numerical results for the fit fractions and quasi-twobody CP asymmetries are given ; Appendixes A–C provide the correlation matrices for the CP-averaged fit fractions and CP asymmetries, while Appendix D presents the combined values for the three S-wave approaches
Summary
In the Standard Model (SM), CP violation originates from a single irreducible complex phase in the CabibboKobayashi-Maskawa (CKM) matrix [1,2]. Large CP asymmetries localized in regions of phase space of charmless three-body B-meson decays have been observed in model-independent analyses [10,11,12,13], but until recently there has been no description of these effects with an accurate model of the contributing resonances. Phenomenological studies [21,22,23,24,25,26] have focused on investigating the localized CP asymmetries seen in the model-independent analysis of Bþ → πþπþπ− decays [12], with some works indicating the potential importance of the ρ-ω mixing effect between the ρð770Þ0 and ωð782Þ resonances [27,28,29], and the interference between the ρð770Þ0 resonance and the broad S-wave contribution [30,31,32,33]. A shorter description of the analysis, more focused on the first observations of different sources of CP-violation effects, can be found in a companion article [37]
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