BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Study of the decay (B)over-bar(0) -> Lambda(+)(c) (p)over-bar pi(+) pi(-) and its intermediate states. Phys. Rev. D, 87(9), 092004–17pp.
Abstract: We study the decay (B) over bar (0) -> Lambda(+)(c) (p) over bar pi(+) pi(-), reconstructing the Lambda(+)(c) baryon in the pK(-) pi(+) mode, using a data sample of 467 X 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II storage rings at SLAC. We measure branching fractions for decays with intermediate Sigma(c) baryons to be B[(B) over bar (0) -> Sigma(c)(2455)(++) (p) over bar (-) pi(-)] = (21.3 +/- 1.0 +/- 1.0 +/- 5.5) X 10(-5), B[(B) over bar (0) -> Sigma(c)(2520)(++) (p) over bar (-) pi(-)] = (11.5 +/- 1.0 +/- 0.5 +/- 3.0) X 10(-5), B[(B) over bar (0) -> Sigma(c)(2455)(0) (p) over bar (-) pi(-)] – (9.1 +/- 0.7 +/- 0.4 +/- 2.4) X 10(-5), and B[(B) over bar (0) -> Sigma(c)(2520)(++) (p) over bar (-) pi(-)] – (2.2 +/- 0.7 +/- 0.1 +/- 0.6) X 10(-5), where the uncertainties are statistical, systematic, and due to the uncertainty on the Lambda(+)(c) -> pK(-) pi(+) branching fraction, respectively. For decays without Sigma(c)(2455) or Sigma(c)(2520) resonances, we measure B[(B) over bar (0) -> Lambda(+)(c) (p) over bar pi(+) pi(-)](non-Sigma c) =(79 +/- 4 +/- 4 +/- 20) X 10(-5). The total branching fraction is determined to be B[(B) over bar (0) -> Lambda(+)(c) (p) over bar pi(+) pi(-)](total) = (123 +/- 5 +/- 7 +/- 32) X 10(-5). We examine multibody mass combinations in the resonant three-particle Sigma(c) final states and in the four-particle Lambda(+)(c) (p) over bar pi(+) pi(-) final state, and observe different characteristics for the (p) over bar pi combination in neutral versus doubly charged Sigma(c) decays.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Study of e(+)e(-) -> p(p)over-bar via initial-state radiation at BABAR. Phys. Rev. D, 87(9), 092005–18pp.
Abstract: The process e(+)e(-) -> p (p) over bar gamma is studied using 469 fb(-1) of integrated luminosity collected with the BABAR detector at the SLAC National Accelerator Laboratory, at an e(+)e(-) center-of-mass energy of 10.6 GeV. From the analysis of the p (p) over bar invariant mass spectrum, the energy dependence of the cross section for e(+)e(-) -> p (p) over bar is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, vertical bar G(E)/G(M)vertical bar, and the asymmetry in the proton angular distribution are measured for p (p) over bar masses below 3 GeV. We also measure the branching fractions for the decays J/psi -> p (p) over bar and psi(2S) -> p (p) over bar are also determined.
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Garzon, E. J., Xie, J. J., & Oset, E. (2013). Case in favor of the N*(1700)(3/2(-)). Phys. Rev. C, 87(5), 055204–12pp.
Abstract: Using an interaction extracted from the local hidden-gauge Lagrangians, which brings together vector and pseudoscalar mesons, and the coupled channels rho N (s wave), pi N (d wave), pi Delta (s wave), and pi Delta (d wave), we look in the region ofv root s = 1400-1850 MeV and find two resonances dynamically generated by the interaction of these channels, which are naturally associated to N*(1520)(3/2(-)) and N*(1700)(3/2(-)). N*(1700)(3/2(-)) appears neatly as a pole in the complex plane. The free parameters of the theory are chosen to fit the pi N (d-wave) data. Both the real and imaginary parts of the pi N amplitude vanish in our approach in the vicinity of this resonance, which is similar to what happens in experimental determinations and which makes this signal very weak in this channel. This feature could explain why this resonance does not show up in some experimental analyses, but the situation is analogous to that of the f(0)(980) resonance, the second scalar meson after sigma[f(0)(500)] in the pi pi(d-wave) amplitude. The unitary coupled channel approach followed here, in connectionwith the experimental data, leads automatically to a pole in the 1700-MeV region and makes this second 3/2-resonance unavoidable.
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Stefanis, N. G., Bakulev, A. P., Mikhailov, S. V., & Pimikov, A. V. (2013). Can we understand an auxetic pion-photon transition form factor within QCD? Phys. Rev. D, 87(9), 094025–13pp.
Abstract: A state-of-the-art analysis of the pion-photon transition form factor is presented based on an improved theoretical calculation that includes the effect of a finite virtuality of the quasireal photon in the method of light-cone sum rules. We carry out a detailed statistical analysis of the existing experimental data using this method and by employing pion distribution amplitudes with up to three Gegenbauer coefficients a(2), a(4), a(6). Allowing for an error range in the coefficient a(6) approximate to 0, the theoretical predictions for gamma*gamma -> pi(0) obtained with nonlocal QCD sum rules are found to be in good agreement with all data that support a scaling behavior of the transition form factor at higher Q(2), like those of the Belle Collaboration. The data on gamma*gamma -> eta/eta' from CLEO and BABAR are also reproduced, while there is a strong conflict with the auxetic trend of the BABAR data above 10 GeV2. The broader implications of these findings are discussed.
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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). First observations of (B)over-bar(s)(0) -> D+D-, Ds+D- and D-0(D)over-bar(0) decays. Phys. Rev. D, 87(9), 092007–12pp.
Abstract: First observations and measurements of the branching fractions of the (B) over bar (0)(s) -> D+D-, (B) over bar (0)(s) -> Ds+D- and (B) over bar (0)(s) -> D-0(D) over bar (0) decays are presented using 1.0 fb(-1) of data collected by the LHCb experiment. These branching fractions are normalized to those of (B) over bar (0) -> D+D-, B-0 -> D-Ds+ and B- -> (DDs-)-D-0, respectively. An excess of events consistent with the decay (B) over bar (0) -> D-0(D) over bar (0) is also seen, and its branching fraction is measured relative to that of B- -> D0Ds-. Improved measurements of the branching fractions B((B) over bar (0)(s) -> Ds+Ds-) and B(B- -> (DDs-)-D-0) are reported, each relative to B(B-0 -> D-Ds+). The ratios of branching fractions are B((B) over bar (0)(s) -> D+D-)/B((B) over bar (0) -> D+D-) = 1.08 +/- 0.20 +/- 0.10, B((B) over bar (0)(s) -> Ds+D-)/B(B-0 -> D-Ds+) = 0.050 +/- 0.008 +/- 0.004, B((B) over bar (0)(s) -> D-0(D) over bar (0))/B((B) over bar (-) -> (DDs-)-D-0) = 0.019 +/- 0.003 +/- 0.003, B((B) over bar (0) -> D-0(D) over bar (0))/B(B- -> (DDs-)-D-0) < 0.0024 at 90% CL, B(<(B)over bar>(0)(s) -> D-s(+)(D) over bar (-)(s))/B(B-0 -> D-Ds+) = 0.56 +/- 0.03 +/- 0.04, B(B -> (DDs)-D-0)/B(B-0 -> D-Ds+) = 1.22 +/- 0.02 +/- 0.07, where the uncertainties are statistical and systematic, respectively.
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Szilner, S. et al, & Gadea, A. (2013). Structure of chlorine isotopes populated by heavy ion transfer reactions. Phys. Rev. C, 87(5), 054322–12pp.
Abstract: Neutron-rich chlorine isotopes were populated in the Ar-40 + Pb-208 multiple transfer reaction via the -1p channels in a fragment-gamma coincident measurement employing the Prisma-Clara setup. New gamma transitions have been identified and, together with already available data, level schemes have been revised and compared with the results of large-scale sd-pf shell-model calculations. The evolution of the energy splitting between the s(1/2) and d(3/2) orbitals and the increased mixing of different proton configurations in the populated Cl isotopic chain have been deduced by inspecting the shell-model wave functions.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Measurements of W gamma and Z gamma production in pp collisions at root s=7 TeV with the ATLAS detector at the LHC. Phys. Rev. D, 87(11), 112003–40pp.
Abstract: The integrated and differential fiducial cross sections for the production of a W or Z boson in association with a high-energy photon are measured using pp collisions at root s = 7 TeV. The analyses use a data sample with an integrated luminosity of 4.6 fb(-1) collected by the ATLAS detector during the 2011 LHC data-taking period. Events are selected using leptonic decays of the W and Z bosons [W(e nu, μnu) and Z(e(+)e(-), mu(+)mu(-), nu(nu) over bar)] with the requirement of an associated isolated photon. The data are used to test the electroweak sector of the Standard Model and search for evidence for new phenomena. The measurements are used to probe the anomalous WW gamma, ZZ gamma, and Z gamma gamma triple-gauge-boson couplings and to search for the production of vector resonances decaying to Z gamma and W gamma. No deviations from Standard Model predictions are observed and limits are placed on anomalous triple-gauge-boson couplings and on the production of new vector meson resonances.
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Archidiacono, M., Giusarma, E., Melchiorri, A., & Mena, O. (2013). Neutrino and dark radiation properties in light of recent CMB observations. Phys. Rev. D, 87(10), 103519–10pp.
Abstract: Recent cosmic microwave background measurements at high multipoles from the South Pole Telescope and from the Atacama Cosmology Telescope seem to disagree in their conclusions for the neutrino and dark radiation properties. In this paper we set new bounds on the dark radiation and neutrino properties in different cosmological scenarios combining the ACT and SPT data with the nine-year data release of the Wilkinson Microwave Anisotropy Probe (WMAP-9), baryon acoustic oscillation data, Hubble Telescope measurements of the Hubble constant, and supernovae Ia luminosity distance data. In the standard three massive neutrino case, the two high multipole probes give similar results if baryon acoustic oscillation data are removed from the analyses and Hubble Telescope measurements are also exploited. A similar result is obtained within a standard cosmology with N-eff massless neutrinos, although in this case the agreement between these two measurements is also improved when considering simultaneously baryon acoustic oscillation data and Hubble Space Telescope measurements. In the N-eff massive neutrino case the two high multipole probes give very different results regardless of the external data sets used in the combined analyses. When considering extended cosmological scenarios with a dark energy equation of state or with a running of the scalar spectral index, the evidence for neutrino masses found for the South Pole Telescope in the three neutrino scenario disappears for all the data combinations explored here. Again, adding Hubble Telescope data seems to improve the agreement between the two high multipole cosmic microwave background measurements considered here. In the case in which a dark radiation background with unknown clustering properties is also considered, SPT data seem to exclude the standard value for the dark radiation viscosity c(vis)(2) = 1/3 at the 2 sigma C.L., finding evidence for massive neutrinos only when combining SPT data with baryon acoustic oscillation measurements.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Measurement of W+W- production in pp collisions at root s=7 TeV with the ATLAS detector and limits on anomalous WWZ and WW gamma couplings. Phys. Rev. D, 87(11), 112001–29pp.
Abstract: This paper presents a measurement of the W+W- production cross section in pp collisions at root s = 7 TeV. The leptonic decay channels are analyzed using data corresponding to an integrated luminosity of 4: 6 fb(-1) collected with the ATLAS detector at the Large Hadron Collider. The W+W- production cross section sigma(pp -> W+W- + X) is measured to be 51.9 +/- 2.0(stat) +/- 3.9(syst) +/- 2.0(lumi) pb, compatible with the Standard Model prediction of 44.7(-1.9)(+2.1) pb. A measurement of the normalized fiducial cross section as a function of the leading lepton transverse momentum is also presented. The reconstructed transverse momentum distribution of the leading lepton is used to extract limits on anomalous WWZ and WW gamma couplings.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Search for B -> K-(*()) v(v)over-bar and invisible quarkonium decays. Phys. Rev. D, 87(11), 112005–13pp.
Abstract: We search for the flavor-changing neutral-current decays B -> K-(*()) v (v) over bar, and the invisible decays J/psi -> v (v) over bar and psi(2S) -> v (v) over bar via B -> K-(*())J/psi and B -> K-(*()) psi(2S), respectively, using a data sample of 471 x 10(6) B (B) over bar pairs collected by the BABAR experiment. We fully reconstruct the hadronBic decay of one of the B mesons in the Y(4S) -> B (B) over bar decay, and search for the B -> K-(*()) v (v) over bar decay in the rest of the event. We observe no significant excess of signal decays over background and report branching fraction upper limits of B(B+ -> K+ v (v) over bar) < 3.7 x 10(-5), B(B-0 -> K-0 v<(v)over bar>) < 8.1 x 10(-5), B(B+ -> K*(+) v<(v)over bar>) < 11.6 x 10(-5), B(B-0 -> K*(0) v<(v)over bar>), < 9.3 x 10(-5), and combined upper limits of B(B -> K v<(v)over bar>) < 3.2 x 10(-5) and B(B -> K* v<(v)over bar>) < 7.9 x 10(-5), all at the 90% confidence level. For the invisible quarkonium decays, we report branching fraction upper limits of B(J/psi -> v<(v)over bar>) < 3.9 x 10(-3) and B(psi(2S) -> v<(v)over bar> < 15.5 x 10(-3) at the 90% confidence level. Using the improved kinematic resolution achieved from hadronic reconstruction, we also provide partial branching fraction limits for the B -> K-(*()) v<(v)over bar> decays over the full kinematic spectrum.
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