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BABAR Collaboration(Aubert, B. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Measurement of branching fractions of B decays to K-1(1270)pi and K-1(1400)pi and determination of the CKM angle alpha from B-0 -> a(1)(1260)(+/-)pi(-/+). Phys. Rev. D, 81(5), 052009–16pp.
Abstract: We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K-1(1270) or K-1(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454 x 10(6) B (B) over bar pairs produced in e(+)e(-) annihilation. We measure the branching fractions B(B-0 -> K-1(1270)(+)pi(-) + K-1(1400)(+)pi(-)) = 3.1(-0.7)(+0.8) x 10(-5) and B(B+ -> K-1(1270)(0)pi(+) + K1(1400)(0)pi(+)) = 2.9(-1.7)(+2.9) x 10(-5) (< 8.2 x 10(-5) at 90% confidence level), where the errors are statistical and systematic combined. The B-0 decay mode is observed with a significance of 7.5 sigma, while a significance of 3.2 sigma is obtained for the B+ decay mode. Based on these results, we estimate the weak phase alpha = (79 +/- 7 +/- 11)degrees from the time-dependent CP asymmetries in B-0 -> a(1)(1260)(+/-)pi(-/+) decays.
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BABAR Collaboration(Aubert, B. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Observation of the decay (B)over-bar(0) -> Lambda(+)(c)(p)over-bar pi(0). Phys. Rev. D, 82(3), 031102–8pp.
Abstract: In a sample of 467 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP- II collider at SLAC we have observed the decay (B) over bar (0) -> Lambda(+)(c)(p) over bar pi(0) and measured the branching fraction to be (1.94 +/- 0.17 +/- 0.14 +/- 0.50 x 10(-4), where the uncertainties are statistical, systematic, and the uncertainty on the Lambda(+)(c) -> pK(-)pi(+) branching fraction, respectively. We determine an upper limit of 1.5 x 10(-6) at 90% C.L. for the product branching fraction B((B) over bar (0) -> Sigma(+)(c) (2455)(p) over bar) x B(Lambda(+)(c) -> pK(-) pi(+)). Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon- antibaryon pair.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2024). Improved Measurement of CP Violation Parameters in B0s → J/ψ K+ K- Decays in the Vicinity of the φ(1020) Resonance. Phys. Rev. Lett., 132(5), 051802–12pp.
Abstract: The decay-time-dependent CP asymmetry in B0s -> J=psi(-> mu+mu-)K+K- decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb-1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 B0s signal decays with an invariant K+K- mass in the vicinity of the phi(1020) resonance, the CP-violating phase phi s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B0s-B over bar 0s system, Delta Gamma s, and the difference of the average B0s and B0 meson decay widths, Gamma s – Gamma d. The values obtained are phi s = -0.039 +/- 0.022 +/- 0.006 rad, Delta Gamma s = 0.0845 +/- 0.0044 +/- 0.0024 ps-1, and -0.0015 +/- 0.0014 ps-1, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase phi s is also measured independently for each polarization state of the K+K- system and shows no evidence for polarization dependence.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2024). Measurement of the CKM angle γ in the B0 → D K*0 channel using self-conjugate D → KS0 h+ h- decays. Eur. Phys. J. C, 84(2), 206–18pp.
Abstract: A model-independent study of CP violation in B-0 -> DK (*0) decays is presented using data corresponding to an integrated luminosity of 9 fb(-1) collected by the LHCb experiment at centre-of-mass energies of v s = 7, 8 and 13TeV. The CKM angle. is determined by examining the distributions of signal decays in phase-space bins of the self-conjugate D. K(S)(0)h(+) h(-) decays, where h = p, K. Observables related to CP violation are measured and the angle. is determined to be = (49+22 -19). Measurements of the amplitude ratio and strong-phase difference between the favoured and suppressed B-0 decays are also presented.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Observation and branching fraction measurement of the decay Ξb- → Λ0 bπ-. Phys. Rev. D, 108(7), 072002–16pp.
Abstract: The decay E-b -> A0bx-- is observed using a proton-proton collision data sample collected at center-of-ffiffimass energy p s 1/4 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 5.5 fb-1. This process is mediated by the s -> uu over bar d quark-level transition, where the b quark in the E-b baryon is a spectator in the decay. Averaging the results obtained using the two A0b decay modes, A0b -> A thorn c x-- and A0b -> A thorn c x--x- thorn x--, the relative production ratio is measured to be ofE-b =fA0b thorn BoE-b -> A0bx-- thorn 1/4 o7.3 ⠂ 0.8 ⠂ 0.6 thorn x 10-4. Here the uncertainties are statistical and systematic, respectively, and fE-bofA0b thorn is the fragmentation fraction for a b quark into a E-b (A0b) baryon. Using an independent measurement of fE-b =fA0b, the branching fraction BoE-b -> A0bx-- thorn 1/4 o0.89 ⠂ 0.10 ⠂ 0.07 ⠂ 0.29 thorn % is obtained, where the last uncertainty is due to the assumed SU(3) flavor symmetry in the determination of fE-b =fA0b.
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