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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). Observation of Several Sources of CP Violation in B+ -> pi(+)pi(+)pi(-) Decays. Phys. Rev. Lett., 124(3), 031801–11pp.
Abstract: Observations are reported of different sources of CP violation from an amplitude analysis of B+ -> pi(+)pi(+)pi(-) decays, based on a data sample corresponding to an integrated luminosity of 3 fb(-1) of pp collisions recorded with the LHCb detector. A large CP asymmetry is observed in the decay amplitude involving the tensor f(2)(1270) resonance, and in addition significant CP violation is found in the pi(+)pi S- wave at low invariant mass. The presence of CP violation related to interference between the pi(+)pi S- wave and the P wave B+ -> rho(770)(0)pi(+) amplitude is also established; this causes large local asymmetries but cancels when integrated over the phase space of the decay. The results provide both qualitative and quantitative new insights into CP -violation effects in hadronic B decays.
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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). Observation of sizeable w contribution to chi c1(3872) -> pi+ pi- J/Psi decays. Phys. Rev. D, 108(1), L011103–12pp.
Abstract: Resonant structures in the dipion mass spectrum from & chi;c1(3872) & RARR; & pi;+& pi;-J=& psi; decays, produced via B+ & RARR; K+& chi;c1(3872) decays, are analyzed using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1. A sizeable contribution from the isospin conserving & chi;c1(3872) & RARR; & omega;J=& psi; decay is established for the first time, (21.4 & PLUSMN; 2.3 & PLUSMN; 2.0)%, with a significance of more than 7.1 & sigma;. The amplitude of isospin violating decay, & chi;c1(3872) & RARR; & rho;0J=& psi;, relative to isospin conserving decay, & chi;c1(3872) & RARR; & omega;J=& psi;, is properly determined, and it is a factor of 6 larger than expected for a pure charmonium state.
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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). Observation of structure in the J/psi-pair mass spectrum. Sci. Bull., 65(23), 1983–1993.
Abstract: Using proton-proton collision data at centre-of-mass energies of root s = 7, 8 and 13 TeV recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9 fb(-1), the invariant mass spectrum of J/psi pairs is studied. A narrow structure around 6.9 GeV/c(2) matching the line-shape of a resonance and a broad structure just above twice the J/psi mass are observed. The deviation of the data from nonresonant J/psi-pair production is above five standard deviations in the mass region between 6.2 and 7.4 GeV/c(2), covering predicted masses of states composed of four charm quarks. The mass and natural width of the narrow X(6900) structure are measured assuming a Breit-Wigner lineshape.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2017). Observation of the Annihilation Decay Mode B-0 -> K+K-. Phys. Rev. Lett., 118(8), 081801–9pp.
Abstract: A search for the B-0 -> K+K- decay is performed using pp-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0 and 2.0 fb(-1) at center-of-mass energies of 7 and 8 TeV, respectively. This decay is observed for the first time, with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the B-s(0) -> pi(+)pi(-) decay. The measured branching fractions are B(B-0 -> K+K-) = (7.80 +/- 1.27 +/- 0.81 +/- 0.21) x 10(-8) and B(B-s(0) -> pi(+)p(-)) = (6.91 +/- 0.54 +/- 0.63 +/- 0.19 +/- 0.40) x 10(-7). The first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the B-0 -> K+pi(-) branching fraction used as a normalization. For the B-s(0) mode, the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into B-s(0) and B-0 mesons.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2017). Observation of the B+ -> D*K-(+) pi(+) decay. Phys. Rev. D, 96(1), 011101–10pp.
Abstract: The B+ -> D*K--(+)pi(+) decay potentially provides an excellent way to investigate charm meson spectroscopy. The decay is searched for in a sample of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). A clear signal is observed, and the ratio of its branching fraction to that of the B+ -> D*(-)pi(+)pi(+) normalization channel is measured to be beta(B+ -> D*K--(+)pi(+))/beta(B+ -> D*(-)pi(+)pi(+)) = (6.39 +/- 0.27 +/- 0.48) x 10(-2); where the first uncertainty is statistical and the second is systematic. This is the first observation of the B+ -> D*K--(+)pi(+) decay.
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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 of the B+ → Jψη'K+ decay. J. High Energy Phys., 08(8), 174–27pp.
Abstract: The B+ -> J psi eta'K+ decay is observed for the first time using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13TeV, corresponding to a total integrated luminosity of 9 fb(-1). The branching fraction of this decay is measured relative to the known branching fraction of the B+ -> psi(2S)K+ decay and found to be B(B+ -> J psi eta'K+)/B(B+ -> psi(2S)K+) = (4.91 +/- 0.47 +/- 0.29 +/- 0.07) x 10(-2), where the first uncertainty is statistical, the second is systematic and the third is related to external branching fractions. A first look at the J/psi eta' mass distribution is performed and no signal of intermediate resonances is observed.
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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). Observation of the B-0 -> (D)over-bar*K-0(+) pi(-) and B-s(0) -> (D)over-bar*K-0(-)pi(+) decays. Phys. Rev. D, 105(7), 072005–22pp.
Abstract: The first observations of B-0 -> (D) over bar*(2007)K-0(+)pi(-) and B-s(0) -> (D) over bar*(2007)K-0(-)pi(+) decays are presented, and their branching fractions relative to that of the B ->( D) over bar* (2007)(0)pi(+)pi(-) decay are reported. These modes can potentially be used to investigate the spectroscopy of charm and charm-strange resonances and to determine the angle gamma of the Cabibbo-Kobayashi-Maskawa unitarity triangle. It is also important to understand them as a source of potential background in determinations of gamma from B+ -> DK+ and B-0 -> DK+pi(-) decays. The analysis is based on a sample corresponding to an integrated luminosity of 5.4 fb(-1 )of proton-proton collision data at 13 TeV center-of-mass energy recorded with the LHCb detector. The (D) over bar*(2007)(0) mesons are fully reconstructed in the (D) over bar (0)pi(0) and (D) over bar (0)gamma channels with the (D) over bar (0) -> K+pi(-) decay. A novel weighting method is used to subtract background while simultaneously applying an event-by-event efficiency correction to account for resonant structures in the decays.
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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 of the B0s → D*+ D*- decay. J. High Energy Phys., 07(7), 119–19pp.
Abstract: The first observation of the B-s(0) -> D*+ D*- decay and the measurement of its branching ratio relative to the B-0 -> D*+ D*(-) decay are presented. The data sample used corresponds to an integrated luminosity of 9 fb(-1) of proton-proton collisions recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018. The decay is observed with more than 10 standard deviations and the time-integrated ratio of branching fractions is determined to be [GRAPHICS] . where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the fragmentation fraction ratio f(s)/f(d). The B-s(0) -> D*(+) D*(-) branching fraction is calculated to be [GRAPHICS] . where the fourth uncertainty is due to the B-0 -> D*(+) D*(-) branching fraction. These results are calculated using the average B-s(0) meson lifetime in simulation. Correction factors are reported for scenarios where either a purely heavy or a purely light B-s(0) eigenstate is considered.
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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 of the B0s → χc1(3872)π+π- decay. J. High Energy Phys., 07(7), 084–25pp.
Abstract: The first observation of the B-s(0) -> (chi(c1)(3872) -> J/Psi pi(broken vertical bar) pi(-)) pi(broken vertical bar) pi(-) decay is reported using proton-proton collision data, corresponding to integrated luminosities of 1, 2 and 6 fb(-1), collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV, respectively. The ratio of branching fractions relative to the B-s(0) -> (Psi(2S) -> J/Psi pi(+) pi(-)) pi(+) pi(-) decay is measured to be [GRAPHICS] where the first uncertainty is statistical and the second systematic. The mass spectrum of the pi(+) pi(-) system recoiling against the chi(c1)(3872) meson exhibits a large contribution from B-s(0) -> chi(c1)(3872) (integral(0)(980) -> pi(+) pi(-)) decays.
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LHCb Collaboration(Aaij, R. et al), Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2021). Observation of the Bs0 -> (DD -/+)-D-*+/- decay. J. High Energy Phys., 03(3), 099–19pp.
Abstract: A search for the B-s(0) -> D*(+/-) D--/+ decay is performed using proton-proton collision data at centre-of-mass energies of 7, 8 and 13TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). The decay is observed with a high significance and its branching fraction relative to the B-0 -> D*(+/-) D--/+ decay is measured to be B(B-s(0) -> D*D-+/-(-/+))/B(B-0 -> D*D-+/-(-/+)) = 0.137 +/- 0.017 +/- 0.002 +/- 0.006, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the ratio of the B-s(0) and B-0 hadronisation fractions.
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