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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2014). Measurement of the inclusive nu(mu) charged current cross section on iron and hydrocarbon in the T2K on-axis neutrino beam. Phys. Rev. D, 90(5), 052010–15pp.
Abstract: We report a measurement of the nu(mu) inclusive charged current cross sections on iron and hydrocarbon in the Tokai-to-Kamioka (T2K) on-axis neutrino beam. The measured inclusive charged current cross sections on iron and hydrocarbon averaged over the T2K on-axis flux with a mean neutrino energy of 1.51 GeVare (1.444 +/- 0.002(stat)(-0.157)(+0.189)- (syst)) x 10(-38) cm(2)/ nucleon and (1.379 +/- 0.009(stat)(-0.147)(+0.178) (syst)) x 10(-38) 38 cm(2)/ nucleon, respectively, and their cross-section ratio is 1.047 +/- 0.007(stat) +/- 0.035(syst). These results agree well with the predictions of the neutrino interaction model, and thus we checked the correct treatment of the nuclear effect for iron and hydrocarbon targets in the model within the measurement precisions.
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Lobo, F. S. N., Martinez-Asencio, J., Olmo, G. J., & Rubiera-Garcia, D. (2014). Dynamical generation of wormholes with charged fluids in quadratic Palatini gravity. Phys. Rev. D, 90(2), 024033–15pp.
Abstract: The dynamical generation of wormholes within an extension of General Relativity (GR) containing (Planck's scale-suppressed) Ricci-squared terms is considered. The theory is formulated assuming the metric and connection to be independent (Palatini formalism) and is probed using a charged null fluid as a matter source. This has the following effect: starting from Minkowski space, when the flux is active the metric becomes a charged Vaidya-type one, and once the flux is switched off the metric settles down into a static configuration such that far from the Planck scale the geometry is virtually indistinguishable from that of the standard Reissner-Nordstrom solution of GR. However, the innermost region undergoes significant changes, as the GR singularity is generically replaced by a wormhole structure. Such a structure becomes completely regular for a certain charge-to-mass ratio. Moreover, the nontrivial topology of the wormhole allows us to define a charge in terms of lines of force trapped in the topology such that the density of lines flowing across the wormhole throat becomes a universal constant. In light of our results, we comment on the physical significance of curvature divergences in this theory and the topology change issue, which support the view that space-time could have a foamlike microstructure pervaded by wormholes generated by quantum gravitational effects.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2014). Search for Scalar Diphoton Resonances in the Mass Range 65-600 GeV with the ATLAS Detector in pp Collision Data at root s=8 TeV. Phys. Rev. Lett., 113(17), 171801–18pp.
Abstract: A search for scalar particles decaying via narrow resonances into two photons in the mass range 65-600 GeV is performed using 20.3 fb(-1) of root s = 8 TeV pp collision data collected with the ATLAS detector at the Large Hadron Collider. The recently discovered Higgs boson is treated as a background. No significant evidence for an additional signal is observed. The results are presented as limits at the 95% confidence level on the production cross section of a scalar boson times branching ratio into two photons, in a fiducial volume where the reconstruction efficiency is approximately independent of the event topology. The upper limits set extend over a considerably wider mass range than previous searches.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the CKM angle gamma using B-+/- -> DK +/- with D -> K-S(0)pi(+)pi(-), (KSK+K-)-K-0 decays. J. High Energy Phys., 10(10), 097–52pp.
Abstract: A binned Dalitz plot analysis of B-+/- -> DK +/- decays, with D -> K-S(0) pi(+)pi(-) and D -> K0 S K + K -, is performed to measure the C P -violating observables x(+/-) and y(+/-), which are sensitive to the Cabibbo-Kobayashi-Maskawa angle gamma. The analysis exploits a sample of proton-proton collision data corresponding to 3.0 fb(-1) collected by the LHCb experiment. Measurements from CLEO-c of the variation of the strong-interaction phase of the D decay over the Dalitz plot are used as inputs. The values of the parameters are found to be x(+) = (-7.7 +/- 2.4 +/- 1.0 +/- 0.4) x 10(-2), x(-) = (2.5 +/- 2.5 +/- 1.0 +/- 0.5) x 10(-2), y(+) = (-2.2 +/- 2.5 +/- 0.4 +/- 1.0) x 10-2, and y(-) = (7.5 +/- 2.9 +/- 0.5 +/- 1.4) x 10(-2). The first, second, and third uncertainties are the statistical, the experimental systematic, and that associated with the precision of the strong-phase parameters. These are the most precise measurements of these observables and correspond to +/- = (62(-14)(+15))degrees, with a second solution at gamma -> gamma + 180 degrees, and r(B) = 0.080(-0.021)(+0.019), where r(B) is the ratio between the suppressed and favoured B decay amplitudes.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the chi(b) (3 P) mass and of the relative rate of chi(b1) (1 P) and chi(b2) (1 P) production. J. High Energy Phys., 10(10), 088–22pp.
Abstract: The production of chi(b) mesons in proton-proton collisions is studied using a data sample collected by the LHCb detector, at centre-of-mass energies of root s = 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb(-1). The chi(b) mesons are identified through their decays to Upsilon(1 S)gamma and Upsilon(2 S)gamma using photons that converted to e(+)e (-) pairs in the detector. The relative prompt production rate of chi(b1)(1 P) and chi(b2)(1 P) mesons is measured as a function of the Upsilon(1 S) transverse momentum in the chi(b) rapidity range 2.0 < y < 4.5. A precise measurement of the chi(b) (3 P) mass is also performed. Assuming a mass splitting between the chi(b1)(3 P) and the chi(b2)(3 P) states of 10.5 MeV/c(2), the measured mass of the chi(b1)(3 P) meson is m (chi(b1)(3 P)) = 10515.7(-3.9)(+2.2)(stat)(-2.1)(+1.5)(syst) MeV/c(2).
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