Measurement of Branching Fraction and First Evidence of CP Violation in B0 --> a1+-(1260) pi-+ Decays

Abstract

We present a measurement of the branching fraction and time-dependent CP violation parameters in B0 --> a_1^+-(1260) pi^-+ decays. The results are obtained from the final data sample containing 772x10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We also measure an upper limit on the product branching fraction for a possible decay with the same final state B0 --> a_2^+-(1320) pi^-+. In a time-dependent measurement to extract CP asymmetries, we find evidence of mixing-induced CP violation in B0 --> a_1^+-(1260) pi^-+ decays with a 3.1 sigma significance and the rate where the a_1^+-(1260) does not contain the spectator quark is found to dominate the rate where it does at the 4.1 sigma level. However, there is no evidence for either time and flavor integrated direct CP violation or flavor-dependent direct CP violation.

arXiv comment24 pages, 6 figures, Submitted to PRD

References in corpus (16)

• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• Impact of tag-side interference on time-dependent CP asymmetry measurements using coherent B0 B0bar pairs
• Neutral B Flavor Tagging for the Measurement of Mixing-induced CP Violation at Belle
• Precise measurement of the CP violation parameter sin2phi_1 in B0-->(c\bar c)K0 decays
• A Study of B0 to rho+rho- Decays and Constraints on the CKM Angle alpha
• Hadronic charmless B decays B-> AP
• Observation of Direct CP-Violation in B0 --> pi+pi- Decays and Model-Independent Constraints on phi2
• Proper-time Resolution Function for Measurement of Time Evolution of B Mesons at the KEK B-Factory
• Measurement of CP Asymmetry in a Time-Dependent Dalitz Analysis of B^0 \to (ρπ)^0 and a Constraint on the Quark Mixing Matrix Angle ϕ_2
• Measurement of CP-Violating Asymmetries in B0-->(rhopi)0 Using a Time-Dependent Dalitz Plot Analysis
• Measurements of CP-Violating Asymmetries in B0 to a1(1260)^{+-} pi^{-+} Decays
• Nonleptonic two-body B-decays including axial-vector mesons in the final state
• Improved measurement of CP-violating parameters in rho+rho- decays
• Weak phase alpha from B^0-> a_1^{+-}(1260) pi^{-+}
• Measurement of branching fractions of B decays to K1(1270)pi and K1(1400)pi and determination of the CKM angle alpha from B0 --> a1(1260)+/- pi-/+
• Non leptonic B decays to axial-vector mesons and factorization

Cited by in corpus (15)

• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2018
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Measurement of the CP Violation Parameters in B0 -> pi+ pi- Decays
• Amplitude Analyses of $D^0\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ and $D^0\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ Decays
• CP violation in the B system
• Probing New Physics with $\bar{B}\to \rho (770){\ell }^{-}{\bar{\nu }}_{\ell }$ and $\bar{B}\to a_1(1260){\ell }^{-}{\bar{\nu }}_{\ell }$
• Observation of the $B^0\to {\rho }^0{\rho }^0$ decay from an amplitude analysis of $B^0\to ({\pi }^{+}{\pi }^{-})({\pi }^{+}{\pi }^{-})$ decays
• Study of B^0 -> rho^0 rho^0 decays, implications for the CKM angle phi_2 and search for other B^0 decay modes with a four-pion final state
• Study of ${\mathbf{B}}^0\to {\rho }^{+}{\rho }^{-}$ decays and implications for the CKM angle ${\varphi }_2$
• $a_1(1260),a_1(1420)$ and the production in heavy meson decays
• Experimental Status of the CKM Matrix
• Measurements of $CP$ asymmetries in charmless four-body ${\Lambda }_b$ and ${\Xi }_b^0$ decays
• Rescaling the isospin triangle argument for constraining ${\varphi }_2$ ($\alpha$): consolidating Belle II and a potential path forward for LHCb
• What We've Learned from Heavy Flavour Experiments Since CKM2010