Diel, F., Fujita, Y., Fujita, H., Cappuzzello, F., Ganioglu, E., Grewe, E. W., et al. (2019). High-resolution study of the Gamow-Teller (GT_) strength in the Zn-64(He-3, t) Ga-64 reaction. Phys. Rev. C, 99(5), 054322–10pp.
Abstract: Gamow-Teller (GT) transitions starting from the T-z = +2 nucleus Zn-64 to the T-z = +1 nucleus Ga-64 were studied in a (p, n)-type (He-3,t) charge-exchange reaction at a beam energy of 140 MeV/nucleon and scattering angles close to 0 degrees. Here, T-z is the z component of the isospin T. The experiment was conducted at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan. An energy resolution of approximate to 34 keV was achieved by applying beam matching techniques to the Grand Raiden magnetic spectrometer system. With our good resolution, we could observe GT strength fragmented in many states up to an excitation energy of approximate to 11 MeV. By performing angular distribution analysis, we could identify states in Ga-64 excited by GT transitions. The reduced GT transition strengths [B(GT)values] were calculated assuming the proportionality between the cross sections and the B(GT)values. Shell-model calculations using the GXPF1J interaction reproduced the B(GT)strength distribution throughout the spectrum. States with isospin T = 3 were identified by comparing the Zn-64(He-3,t)Ga-64 spectrum with a Zn-64(d, He-2)Cu-64 spectrum. Relative excitation energies of the corresponding structures are in good agreement, supporting the robustness of isospin symmetry in the mass number A = 64 nuclei.
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Ding, G. J., Nath, N., Srivastava, R., & Valle, J. W. F. (2019). Status and prospects of 'bi-large' leptonic mixing. Phys. Lett. B, 796, 162–167.
Abstract: Bi-large patterns for the leptonic mixing matrix are confronted with current neutrino oscillation data. We analyse the status of these patterns and determine, through realistic simulations, the potential of the upcoming long-baseline experiment DUNE in testing bi-large ansatze and discriminating amongst them.
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Dombos, A. C., Spyrou, A., Naqvi, F., Quinn, S. J., Liddick, S. N., Algora, A., et al. (2019). beta-decay half-lives of neutron-rich nuclides in the A=100-110 mass region. Phys. Rev. C, 99(1), 015802–8pp.
Abstract: beta-decay half-lives of neutron-rich nuclides in the A = 100-110 mass region have been measured using an implantation station installed inside of the Summing NaI(T1) (SuN) detector at the National Superconducting Cyclotron Laboratory. Accurate half-lives for these nuclides are important for nuclear astrophysics, nuclear structure, and nuclear technology. The half-lives from the present work are compared with previous measurements, showing overall good agreement.
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Donini, A., Palomares-Ruiz, S., & Salvado, J. (2019). Neutrino tomography of Earth. Nat. Phys., 15(1), 37–40.
Abstract: Cosmic-ray interactions with the atmosphere produce a flux of neutrinos in all directions with energies extending above the TeV scale(1). The Earth is not a fully transparent medium for neutrinos with energies above a few TeV, as the neutrinonucleon cross-section is large enough to make the absorption probability non-negligible(2). Since absorption depends on energy and distance travelled, studying the distribution of the TeV atmospheric neutrinos passing through the Earth offers an opportunity to infer its density profiles(3-7). This has never been done, however, due to the lack of relevant data. Here we perform a neutrino-based tomography of the Earth using actual data-one-year of through-going muon atmospheric neutrino data collected by the IceCube telescope(8). Using only weak interactions, in a way that is completely independent of gravitational measurements, we are able to determine the mass of the Earth and its core, its moment of inertia, and to establish that the core is denser than the mantle. Our results demonstrate the feasibility of this approach to study the Earth's internal structure, which is complementary to traditional geophysics methods. Neutrino tomography could become more competitive as soon as more statistics is available, provided that the sources of systematic uncertainties are fully under control.
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Driencourt-Mangin, F., Rodrigo, G., Sborlini, G. F. R., & Torres Bobadilla, W. J. (2019). Universal four-dimensional representation of H -> gamma gamma at two loops through the Loop-Tree Duality. J. High Energy Phys., 02(2), 143–39pp.
Abstract: We extend useful properties of the H unintegrated dual amplitudes from one- to two-loop level, using the Loop-Tree Duality formalism. In particular, we show that the universality of the functional form regardless of the nature of the internal particle still holds at this order. We also present an algorithmic way to renormalise two-loop amplitudes, by locally cancelling the ultraviolet singularities at integrand level, thus allowing a full four-dimensional numerical implementation of the method. Our results are compared with analytic expressions already available in the literature, finding a perfect numerical agreement. The success of this computation plays a crucial role for the development of a fully local four-dimensional framework to compute physical observables at Next-to-Next-to Leading order and beyond.
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