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SciBooNE and MiniBooNE collaborations(Mahn, K. B. M. et al), Catala-Perez, J., Gomez-Cadenas, J. J., & Sorel, M. (2012). Dual baseline search for muon neutrino disappearance at 0.5 eV(2) < Delta m(2) < 40 eV(2). Phys. Rev. D, 85(3), 032007–10pp.
Abstract: The SciBooNE and MiniBooNE collaborations report the results of a nu(mu) disappearance search in the Delta m(2) region of 0.5-40 eV(2). The neutrino rate as measured by the SciBooNE tracking detectors is used to constrain the rate at the MiniBooNE Cherenkov detector in the first joint analysis of data from both collaborations. Two separate analyses of the combined data samples set 90% confidence level (CL) limits on nu(mu) disappearance in the 0.5-40 eV(2) Delta m(2) region, with an improvement over previous experimental constraints between 10 and 30 eV(2).
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Calle Cordon, A., Pavon Valderrama, M., & Ruiz Arriola, E. (2012). Charge independence, charge symmetry breaking in the S-wave nucleon-nucleon interaction, and renormalization. Phys. Rev. C, 85(2), 024002–13pp.
Abstract: We explore the interplay between renormalization, charge independence and charge symmetry breaking (CIB and CSB) in S-wave nucleon-nucleon scattering. The renormalizability requirement generates universality functions, that is, correlations between the low-energy scattering observables in the neutron-neutron, neutron-proton, and proton-proton systems. The universality functions only depend on the (known) form of the nucleon-nucleon potential at long distances and, in particular, they do not require any assumptions about short-range CIB and CSB effects. In addition, the inclusion of Coulomb effects is trivial for the particular case of proton-proton scattering, allowing us to relate strong and Coulomb scattering observables. Within this approach, and using a one-boson-exchange potential, the previous correlations are shown to be phenomenologically satisfied without the need to introduce further parameters.
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Garzon, E. J., & Oset, E. (2012). Effects of pseudoscalar-baryon channels in the dynamically generated vector-baryon resonances. Eur. Phys. J. A, 48(1), 5–20pp.
Abstract: We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach, including also the pseudoscalar-baryon channels which couple to the same quantum numbers. We examine the scattering amplitudes and their poles, which can be associated to the known J(P) = 1/2(-), 3/2(-) baryon resonances, and determine the role of the pseudoscalar-baryon channels, changing the width and eventually the mass of the resonances generated with only the basis of vector-baryon states.
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Sekihara, T., Martinez Torres, A., Jido, D., & Oset, E. (2012). Theoretical study of incoherent phi photoproduction on a deuteron target. Eur. Phys. J. A, 48(1), 10–17pp.
Abstract: We study the photoproduction of phi mesons in deuteron, paying attention to the modification of the cross-section from bound protons to the free ones. For this purpose we take into account Fermi motion in single scattering and rescattering of phi to account for phi absorption on a second nucleon as well as the rescattering of the proton on the neutron. We find that the contribution of the double scattering for phi is much smaller than the typical cross-section of gamma p -> phi p in free space, which implies a very small screening of the phi production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross-section of gamma p -> phi p in free space, and leads to a moderate reduction of the phi photoproduction cross-section on a deuteron at forward angles if the LEPS set-up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase-space in the free case. In particular, we find that for momentum transfer squared close to the maximum value, the Fermi motion changes drastically the shape of d sigma/dt, to the point that the ratio of this cross-section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem to be the most indicated to find effects of a possible phi absorption in the deuteron. This reaction is studied theoretically as a function of t and the results are contrasted with recent experiments at LEPS and Jefferson Lab. The effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction.
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Gomez-Cadenas, J. J., Hansen, C., Monfregola, L., et al. (2012). First muon-neutrino disappearance study with an off-axis beam. Phys. Rev. D, 85(3), 031103–8pp.
Abstract: We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neutrino beam from Tokai to Kamioka is the first implementation of the off-axis technique in a long-baseline neutrino oscillation experiment. With data corresponding to 1.43 x 10(20) protons on target, we observe 31 fully-contained single mu-like ring events in Super-Kamiokande, compared with an expectation of 104 +/- 14 (syst) events without neutrino oscillations. The best-fit point for two-flavor nu(mu) -> nu(tau) oscillations is sin(2)(2 theta(23)) = 0.98 and vertical bar Delta m(32)(2)vertical bar = 2.65 x 10(-3) eV(2). The boundary of the 90% confidence region includes the points sin(2)(2 theta(23)), vertical bar Delta m(32)(2)vertical bar = (1.0, 3.1 x 10(-3) eV(2)), (0.84, 2.65 x 10(-3) eV(2)) and (1.0, 2.2 x 10(-3) eV(2)).
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