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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Observation of B-s(0) -> (D)over-bar(0)K(S)(0) and Evidence for B-s(0) -> (D)over-bar*K-0(S)0 Decays. Phys. Rev. Lett., 116(16), 161802–9pp.
Abstract: The first observation of the B-s(0) -> (D) over bar K-0(S)0 decay mode and evidence for the B-s(0) -> (D) over bar*K-0(S)0 decay mode are reported. The data sample corresponds to an integrated luminosity of 3.0 fb-1 collected in pp collisions by LHCb at center-of-mass energies of 7 and 8 TeV. The branching fractions are measured to be B(B-s(0) -> (D) over bar (0)(K) over bar (0)) = [4.3 +/- 0.5(stat) +/- 0.3 (syst) +/- 0.3(frag) +/- 0.6(norm)] x 10(-4), B(B-s(0) -> (D) over bar*(0)(K) over bar (0)) = [2.8 +/- 1.0(stat) +/- 0.3 (syst) +/- 0.2(frag) +/- 0.4(norm)] x 10(-4), where the uncertainties are due to contributions coming from statistical precision, systematic effects, and the precision of two external inputs, the ratio f(s)/f(d) and the branching fraction of B-0 (D) over bar K-0(S)0, which is used as a calibration channel.
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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. (2018). First Observation of the Doubly Charmed Baryon Decay Xi(++)(cc) -> Xi(+)(c)pi(+). Phys. Rev. Lett., 121(16), 162002–10pp.
Abstract: The doubly charmed baryon decay Xi(++)(cc) -> Xi(+)(c)pi(+) is observed for the first time, with a statistical significance of 5.9 sigma, confirming a recent observation of the baryon in the Lambda K-+(c)-pi(+)pi(+) final state. The data sample used corresponds to an integrated luminosity of 1.7 fb(-1), collected by the LHCb experiment in pp collisions at a center-of-mass energy of 13 TeV. The Xi(++)(cc) mass is measured to be 3620.6 +/- 1.5(stat) +/- 0.4(syst) +/- 0.3(Xi(+)(c)) MeV/c(2) and is consistent with the previous result. The ratio of branching fractions between the decay modes is measured to be [B(Xi(++)(cc) -> Xi(+)(c)pi(+)) x B(Xi(+)(c) -> pK(-)pi(+))]/[B(Xi(++)(cc) -> Lambda K-+(c)-pi(+)pi(+)) x B(Lambda(+)(c) -> pK(-)pi(+))] = 0.035 +/- 0.009 (stat) +/- 0.003 (syst).
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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). Angular Analysis of the B+ -> K*(+)mu(+) mu(-) Decay. Phys. Rev. Lett., 126(16), 161802–11pp.
Abstract: We present an angular analysis of the B+ -> K*(+)(-> K-S(0)pi(+))mu(+) mu(-) decay using 9 fb(-1) of pp collision data collected with the LHCb experiment. For the first time, the full set of CP-averaged angular observables is measured in intervals of the dimuon invariant mass squared. Local deviations from standard model predictions are observed, similar to those in previous LHCb analyses of the isospin-partner B-0 -> K*(0)mu(+)mu(-) decay. The global tension is dependent on which effective couplings are considered and on the choice of theory nuisance parameters.
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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 two new excited Ξ0b states decaying to Λ0bK−π+. Phys. Rev. Lett., 128(16), 162001–12pp.
Abstract: Two narrow resonant states are observed in the Λ0bK−π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb−1. The minimal quark content of the Λ0bK−π+ system indicates that these are excited Ξ0b baryons. The masses of the Ξb(6327)0 and Ξb(6333)0 states are m(Ξb(6327)0)=6327.28+0.23−0.21±0.12±0.24 MeV and m(Ξb(6333)0)=6332.69+0.17−0.18±0.03±0.22 MeV, respectively, with a mass splitting of Δm=5.41+0.26−0.27±0.12 MeV, where the uncertainties are statistical, systematic and due to the Λ0b mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ(Ξb(6327)0)<2.20 (2.56) MeV and Γ(Ξb(6333)0)<1.60 (1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξ0b resonances.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Search for f(J)(2220) in Radiative J/psi Decays. Phys. Rev. Lett., 105(17), 172001–7pp.
Abstract: We present a search for f(J)(2220) production in radiative J/psi --> gamma f(J)(2220) decays using 460 fb(-1) of data collected with the BABAR detector at the SLAC PEP-II e(+)e(-) collider. The f(J)(2220) is searched for in the decays to K+K- and (KSKS0)-K-0. No evidence of this resonance is observed, and 90% confidence level upper limits on the product of the branching fractions for J/psi --> gamma f(J)(2220) and f(J)(2220) --> K+K-((KSKS0)-K-0) as a function of spin and helicity are set at the level of 10(-5), below the central values reported by the Mark III experiment.
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