Montanari, D. et al, & Gadea, A. (2011). Elastic, inelastic, and one-nucleon transfer processes in (48)Ca+(64)Ni. Phys. Rev. C, 84(5), 9pp.
Abstract: Elastic, inelastic, and one-nucleon transfer channels in the (48)Ca+(64)Ni reaction have been measured at approximate to 6 MeV/nucleon with the PRISMA-CLARA setup, at Legnaro National Laboratory, consisting of the coupling of a large solid angle magnetic spectrometer with a germanium array. By trajectory reconstruction the reaction products have been fully identified in mass, nuclear charge, and kinetic energy, while coincident gamma spectra of binary partners have been constructed after Doppler correction. Absolute differential cross sections have been extracted for the inelastic excitation and one-nucleon transfer, also for specific excited states. The data are in good agreement with semiclassical calculations and distorted wave Born approximation predictions. The work outlines an experimental method which can become valuable to extract structural information from heavy-ion reaction studies.
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n_TOF Collaboration(Sarmento, R. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Measurement of the (236)U(n, f) cross section from 170 meV to 2 MeV at the CERN n_TOF facility. Phys. Rev. C, 84(4), 044618–10pp.
Abstract: The neutron-induced fission cross section of (236)U was measured at the neutron Time-of-Flight (nTOF) facility at CERN relative to the standard (235)U(n, f) cross section for neutron energies ranging from above thermal to several MeV. The measurement, covering the full range simultaneously, was performed with a fast ionization chamber, taking advantage of the high resolution of the nTOF spectrometer. The n_TOF results confirm that the first resonance at 5.45 eV is largely overestimated in some nuclear data libraries. The resonance triplet around 1.2 keV was measured with high resolution and resonance parameters were determined with good accuracy. Resonances at high energy have also been observed and characterized and different values for the cross section are provided for the region between 10 keV and the fission threshold. The present work indicates various shortcomings of the current nuclear data libraries in the subthreshold region and provides the basis for an accurate re-evaluation of the (236)U(n, f) cross section, which is of great relevance for the development of emerging or innovative nuclear reactor technologies.
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Olmo, G. J. (2011). Palatini actions and quantum gravity phenomenology. J. Cosmol. Astropart. Phys., 10(10), 018–15pp.
Abstract: We show that an invariant an universal length scale can be consistently introduced in a generally covariant theory through the gravitational sector using the Palatini approach. The resulting theory is able to capture different aspects of quantum gravity phenomenology in a single framework. In particular, it is found that in this theory field excitations propagating with different energy-densities perceive different background metrics, which is a fundamental characteristic of the DSR and Rainbow Gravity approaches. We illustrate these properties with a particular gravitational model and explicitly show how the soccer ball problem is avoided in this framework. The isotropic and anisotropic cosmologies of this model also avoid the big bang singularity by means of a big bounce.
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Forero, D. V., Morisi, S., Tortola, M., & Valle, J. W. F. (2011). Lepton flavor violation and non-unitary lepton mixing in low-scale type-I seesaw. J. High Energy Phys., 09(9), 142–18pp.
Abstract: Within low-scale seesaw mechanisms, such as the inverse and linear seesaw, one expects (i) potentially large lepton flavor violation (LFV) and (ii) sizeable non-standard neutrino interactions (NSI). We consider the interplay between the magnitude of non-unitarity effects in the lepton mixing matrix, and the constraints that follow from LFV searches in the laboratory. We find that NSI parameters can be sizeable, up to percent level in some cases, while LFV rates, such as that for μ-> e gamma, lie within current limits, including the recent one set by the MEG collaboration. As a result the upcoming long baseline neutrino experiments offer a window of opportunity for complementary LFV and weak universality tests.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2011). Study of Y(3S, 2S) -> eta Y(1S) and Y(3S, 2S) -> pi(+) pi(-) Y(1S) hadronic transitions. Phys. Rev. D, 84(9), 092003–8pp.
Abstract: We study the Y(3S, 2S) -> eta Y(1S) and Y (3S,2S) -> pi(+)pi(-) transitions with 122 x 10(6) x Y(3S) and 100 x 10(6) Y (2S) mesons collected by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider. We measure B[Y(2S) -> eta Y(1S)] = (2.39 +/- 0.31 (stat) +/- 0.14(syst)) x 10(-4) and Gamma[Y(2S) -> eta Y(1S)]/Gamma[Y(2S) ->pi(+)pi(-)(1S)] – (2.39 +/- 0.31(stat) +/- 0.14(syst)) x 10(-3). We find no evidence for Y(3S) -> eta Y (1S) and obtain B[Y(3S) -> eta Y(1S)] < 1.0 x 10(-4) and Gamma[Y (3S) -> eta Y(1S)/Gamma[Y(3S) -> pi(+)pi(-) Y(1S)] < 2.3 x 10(-3) as upper limits at the 90% confidence level. We also provide improved measurements of the Y(S) – Y(1S) and Y(3S) – Y (1S) mass differences, 562.170 +/- 0.007(stat) +/- 0.088(syst). MeV/c(2) and 893.813 +/- 0: 015(stat) +/- 0.107(syst.) MeV/c(2), respectively.
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