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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Amplitude analysis of the B+ -> pi(+)pi(+)pi(-) decay. Phys. Rev. D, 101(1), 012006–46pp.
Abstract: The results of an amplitude analysis of the charmless three-body decay B+ -> pi(+)pi(+)pi(-) , 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 pi(+)pi(-) 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 rho(770)(0), omega(782)(0) and rho(1450)(0) resonances in the pi(+)pi(-) P-wave, the f(2) (1270) resonance in the pi(+)pi D- -wave, and the rho(3) (1690)(0) resonance in the pi(+)pi(-) 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+ -> pi(+)pi(+)pi(-) decays.
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., Remon Alepuz, C., et al. (2023). Search for the rare hadronic decay Bs0 → p(p)over-bar. Phys. Rev. D, 108(1), 012007–12pp.
Abstract: A search for the rare hadronic decay B-s(0) -> p (p) over bar is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb(-1). No evidence of the decay is found and an upper limit on its branching fraction is set at B(B-s(0) -> p (p) over bar) < 4.4(5.1)x 10(-9) at 90% (95%) confidence level; this is currently the world's best upper limit. The decay mode B-0 -> p<(p)over bar> is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be B(B-0 -> p (p) over bar) = (1.27 +/- 0.15 +/- 0.05 +/- 0.04) 10(-8), where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel B-0 -> K+pi(-). The combination of the two LHCb measurements of the B-0 -> p (p) over bar branching fraction yields B(B-0 -> p (p) over bar) (1.27 +/- 0.13 +/- 0.05 +/- 0.03) x 10(-8).
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2023). Direct CP violation in charmless three-body decays of B± mesons. Phys. Rev. D, 108(1), 012008–17pp.
Abstract: Measurements of CP asymmetries in charmless three-body decays of B-+/- mesons are reported using proton-proton collision data collected by the LHCb detector, corresponding to an integrated luminosity of 5.9 fb(-1). The previously observed CP asymmetry in B-+/- -> pi(K+K-)-K-+/- decays is confirmed, and CP asymmetries are observed with a significance of more than five standard deviations in the B-+/- -> pi(+/-)pi(+)pi and B-+/- -> (KK+K-)-K-+/- decays, while the CP asymmetry of B-+/- -> K-+/-pi(+)pi(-) decays is confirmed to be compatible with zero. The distributions of these asymmetries are also studied as a function of the three-body phase space and suggest contributions from rescattering and resonance interference processes. An indication of the presence of the decays B+ -> pi(+) chi(c0) (1P) in both B+ ->pi(+)pi(+)pi and B+ ->pi+K+K- decays is observed, as is CP violation involving these amplitudes.
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2022). Measurement of the B-s(0) -> mu(+)mu(-) decay properties and search for the B-0 -> mu(+)mu(-) and B-s(0) -> mu(+)mu(-) gamma decays. Phys. Rev. D, 105(1), 012010–34pp.
Abstract: An improved measurement of the decay B-s(0) -> mu(+)mu(-) and searches for the decays B-0 -> mu(+)mu(-) and B-s(0) -> mu(+)mu(-)gamma are performed at the LHCb experiment using data collected in proton-proton collisions at root s = 7, 8 and 13 TeV, corresponding to integrated luminosities of 1, 2 and 6 fb(-1), respectively. The B-s(0) -> mu(+)mu(-) branching fraction and effective lifetime are measured to be B(B-s(0) -> mu(+)mu(-)) = (3.09(-0.43-0.11)(+0.46+0.15)) x 10(-9) and tau(B-s(0) -> mu(+)mu(-)) = (2.07 +/- 0.29 +/- 0.03) ps, respectively, where the uncertain-ties include both statistical and systematic contributions. No significant signal for B-0 -> mu(+)mu(-) and B-s(0) -> mu(+)mu(-) gamma decays is found and the upper limits B(B-0 -> mu(+)mu(-)) < 2.6 x 10(-10) and B(B-s(0) -> mu(+)mu(-)gamma) 2.0 x 10(-9) at 95% confidence level are determined, where the latter is limited to the range m(mu mu) > 4.9 GeV/c(2). Additionally, the ratio between the B-0 -> mu(+)mu(-) and B-s(0) -> mu(+)mu(-) branching fractions is measured to be R mu+mu- < 0.095 at 95% confidence level. The results are in agreement with the Standard Model predictions.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Measurement of the branching fraction of the decay B-s(0) -> (KSKS0)-K-0. Phys. Rev. D, 102(1), 012011–15pp.
Abstract: A measurement of the branching fraction of the decay B-s(0) -> (KSKS0)-K-0 is performed using proton- proton – collision data corresponding to an integrated luminosity of 5 fb(-1) collected by the LHCb experiment between 2011 and 2016. The branching fraction is determined to be B(B-s(0) -> (KSKS0)-K-0) = [8.3 +/- 1.6(stat) +/- 0.9(syst) +/- 0.8(norm) +/- 0.3(f(s)/f(d))] x 10(-6), where the first uncertainty is statistical, the second is systematic, and the third and fourth are due to uncertainties on the branching fraction of the normalization mode B-0 -> phi K(S)(0 )and the ratio of hadronization fractions f(s)/f(d). This is the most precise measurement of this branching fraction to date. Furthermore, a measurement of the branching fraction of the decay B-s(0) -> (KSKS0)-K-0 is performed relative to that of the B-s(0) -> (KSKS0)-K-0 channel, and is found to be B(B-s(0) -> (KSKS0)-K-0)/B(B-s(0) -> (KSKS0)-K-0) = [7.5 +/- 3.1(stat) 0.5(syst) +/- 0.3(f(s)/f(d))1 x 10(-2).
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