BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2018). Study of the reactions e(+)e(-) -> pi(+)pi(-)pi(0)pi(0)pi(0) and pi(+)pi(-) pi(0)pi(0)eta at center-of-mass energies from threshold to 4.35 GeV using initial-state radiation. Phys. Rev. D, 98(11), 112015–23pp.
Abstract: We study the processes e(+)e--> pi(+)pi(-)pi(0)pi(0)pi(0)gamma and pi(+)pi(-)pi(0)pi(0)eta gamma in which an energetic photon is radiated from the initial state. The data are collected with the BABAR detector at SLAC. About 14 000 and 4700 events, respectively, are selected from a data sample corresponding to an integrated luminosity of 469 fb(-1). The invariant mass of the hadronic final state defines the effective e(+)e(-) center-of-mass energy. From the mass spectra, the first precise measurement of the e(+)e--> pi(+)pi(-)pi(0)pi(0)pi(0) cross section and the first measurement ever of the e(+)e--> pi(+)pi(-)pi(0)pi(0)pi(0)eta cross section are performed. The center-of-mass energies range from threshold to 4.35 GeV. The systematic uncertainty is typically between 10% and 13%. The contributions from omega pi(0)pi(0), eta pi(+)pi(-) and other intermediate states are presented. We observe the J/psi and psi(2S) in most of these final states and measure the corresponding branching fractions, many of them for the first time.
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BABAR and Belle Collaborations(Adachi, I. et al), Martinez-Vidal, F., & Oyanguren, A. (2018). First Evidence for cos 2 beta > 0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity. Phys. Rev. Lett., 121(26), 261801–11pp.
Abstract: We present first evidence that the cosine of the CP-violating weak phase 2 beta is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B-0 -> D-(*) h(0) with D -> K-S(0)pi(+)pi(-) decays, where h(0) is an element of {pi(0), eta, omega} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the (sic)(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471 +/- 3) x 10(6) B (B) over bar pairs recorded by the BABAR detector and (772 +/- 11) x 10(6) B (B) over bar pairs recorded by the Belle detector. The results of the measurement are sin 2 beta = 0.80 +/- 0.14 (stat) +/- 0.06 (syst) +/- 0.03 (model) and cos 2 beta = 0.91 +/- 0.22(stat) +/- 0.09 (syst) +/- 0.07(model). The result for the direct measurement of the angle beta of the CKM Unitarity Triangle is beta = [22.5 +/- 4.4 (stat) +/- 1.2 (syst) +/- 0.6(model)]degrees. The measurement assumes no direct CP violation in B-0 -> D-(*) h(0) decays. The quoted model uncertainties are due to the composition of the D-0 -> K-S(0)pi(+)pi(-) decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e(+)e(-) -> c (c) over bar data sample. CP violation is observed in B-0 -> D-(*) h(0) decays at the level of 5.1 standard deviations. The significance for cos 2 beta > 0 is 3.7 standard deviations. The trigonometric multifold solution pi/2 – beta = (68.1 +/- 0.7)degrees is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.
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BABAR and Belle Collaborations(Adachi, I. et al), Martinez-Vidal, F., & Oyanguren, A. (2018). Measurement of cos 2 beta in B-0 -> D((*))h(0) with D -> K-S(0)pi(+) pi(-) decays by a combined time-dependent Dalitz plot analysis of BABAR and Belle data. Phys. Rev. D, 98(11), 112012–29pp.
Abstract: We report measurements of sin 2 beta and cos 2 beta using a time-dependent Dalitz plot analysis of B-0 -> D((*))h(0) with D -> K-S(0)pi(+)pi(-) decays, where the light unflavored and neutral hadron h(0) is a pi(0),eta, or omega meson. The analysis uses a combination of the final data sets of the BABAR and Belle experiments containing 471 x 10(6) and 772 x 10(6) B (B) over bar pairs collected at the gamma(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. We measure sin 2 beta = 0.80 +/- 0.14(stat) +/- 0.06(syst) +/- 0.03(model) and cos 2 beta = 0.91 +/- 0.22(stat) +/- 0.09(syst) +/- 0.07(model). The result for the direct measurement of the angle is beta = (22.5 +/- 4.4(stat) +/- 1.2(syst) +/- 0.6(model))degrees. The last quoted uncertainties are due to the composition of the D-0 -> K-S(0)pi(+)pi(-) decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a high-statistics e(+) e(-) -> c (c) over bar data sample as part of this analysis. We find the first evidence for cos 2 beta > 0 at the level of 3.7 standard deviations. The measurement excludes the trigonometric multifold solution pi/2 – beta = (68.1 +/- 0.7)degrees at the level of 7.3 standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of beta = 0 degrees is ruled out at the level of 5.1 standard deviations, and thus CP violation is observed in B-0 -> D-(*) h(0) decays. The measurement assumes no direct CP violation in B-0 -> D-(*) h(0) decays.
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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). Evidence for an etac(1S)pi- resonance in B0 etac(1S)K+pi- decays. Eur. Phys. J. C, 78(12), 1019–23pp.
Abstract: A Dalitz plot analysis of /30 ric(1S)K+7decays is performed using data samples of pp collisions collected with the LHCb detector at centre -of -mass energies of./7 = 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 4.7 fb-1. A satisfactory description of the data is obtained when including a contribution representing an exotic qc (1 S).7-- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096 20 is MeV and 152 +58 -P6 MeV, respectively. The spin -parity assignments JP = 0+ and JP = 1- are both consistent with the data. In addition, the first measurement of the B -> ric(1S)K+71-branching fraction is performed and gives B(B -> = (5.73 0.24 0.13 0.66) x 10-4, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.
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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). Study of Gamma production in pPb collisions at root s(NN) = 8.16 TeV. Journal of High Energy Physics, 11(11), 194–36pp.
Abstract: The production of (nS) mesons (n = 1; 2; 3) in p Pb and Pb p collisions at a centre-of-mass energy per nucleon pair p sNN = 8 : 16TeV is measured by the LHCb experiment, using a data sample corresponding to an integrated luminosity of 31.8 nb. The (nS) mesons are reconstructed through their decays into two opposite-sign muons. The measurements comprise the di ff erential production cross-sections of the (1 S) and (2 S) states, their forward-to-backward ratios and nuclear modi fi cation factors. The measurements are performed as a function of the transverse momentum pT and rapidity in the nucleon-nucleon centre-of-mass frame y of the (nS) states, in the kinematic range pT < 25 GeV/ c and 1 : 5 < y < 4 : 0 (5 : 0 < y < 2 : 5) for p Pb (Pb p) collisions. In addition, production cross-sections for (3 S) are measured integrated over phase space and the production ratios between all three (nS) states are determined. Suppression for bottomonium in proton-lead collisions is observed, which is particularly visible in the ratios. The results are compared to theoretical models.
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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). Search for lepton-flavour-violating decays of Higgs-like bosons. Eur. Phys. J. C, 78(12), 1008–12pp.
Abstract: A search is presented for a Higgs-like boson with mass in the range 45 to 195 GeV/c(2) decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass energy of 8 TeV, collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb -1. The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-sectionmultiplied by the branching fraction at 95% confidence level is set and ranges from 22 pb for a boson mass of 45 GeV/c(2) to 4 pb for a mass of 195 GeV/c(2).
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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). Measurement of Antiproton Production in p-He Collisions at root S-NN=110 GeV. Phys. Rev. Lett., 121(22), 222001–10pp.
Abstract: The cross section for prompt antiproton production in collisions of protons with an energy of 6.5 TeV incident on helium nuclei at rest is measured with the LHCb experiment from a data set corresponding to an integrated luminosity of 0.5 nb(-1). The target is provided by injecting helium gas into the LHC beam line at the LHCb interaction point. The reported results, covering antiproton momenta between 12 and 110 GeV/c, represent the first direct determination of the antiproton production cross section in p-He collisions, and impact the interpretation of recent results on antiproton cosmic rays from space-borne experiments.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2018). Measurement of the gamma*gamma* -> eta ' transition form factor. Phys. Rev. D, 98(11), 112002–11pp.
Abstract: We study the process e(+)e(-) -> e(+)e(-)eta' in the double-tag mode and measure for the first time the gamma*gamma* -> eta' transition form factor F-eta'(Q(1)(2), Q(2)(2)) in the momentum-transfer range 2 < Q(1)(2), Q(2)(2) < 60 GeV2. The analysis is based on a data sample corresponding to an integrated luminosity of around 469 fb(-1) collected at the PEP-II e(+)e(-) collider with the BABAR detector at center-of-mass energies near 10.6 GeV.
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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). Search for CP violation in Lambda(0)(b)-> pK(- )and Lambda(0)(b) -> p pi(-) decays. Phys. Lett. B, 787, 124–133.
Abstract: A search for CP violation in Lambda(0)(b)-> pK(- )and Lambda(0)(b) -> p pi(-) decays is presented using a sample of pp collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0fb(-1). The CP-violating asymmetries are measured to be A(CP)(pK- )( = -0.020 +/- 0.013 +/- 0.019 and A(CP)(p pi-) = -0.035 +/- 0.017 +/- 0.020, and their difference A(CP)(pK-) – A(CP)(p pi-) = 0.014 +/- 0.022 +/- 0.010, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date.
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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). Measurement of the time-integrated CP asymmetry in D (0) -> K (S) (0) K (S) (0) decays. J. High Energy Phys., 11(11), 048–19pp.
Abstract: A measurement of the time-integrated CP asymmetry in D (0) -> K (S) (0) K (S) (0) decays is reported. The data correspond to an integrated luminosity of about 2 fb(-1) collected in 2015-2016 by the LHCb collaboration in pp collisions at a centre-of-mass energy of 13 TeV. The D (0) candidate is required to originate from a D (*+) -> D (0) pi (+) decay, allowing the determination of the flavour of the D (0) meson using the pion charge. The D (0) -> K (+) K (-) decay, which has a well measured CP asymmetry, is used as a calibration channel. The CP asymmetryfor D (0) -> K (S) (0) K (S) (0) is measured to be where the first uncertainty is statistical and the second is systematic. This result is combined with the previous LHCb measurement at lower centre-of-mass energies to obtain A(CP) (D-0 -> K-S(0) K-S(0)) = (2.3 +/- 2.8 +/- 0.9)%.
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