2,690 research outputs found

    Directions for model building from asymptotic safety

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    Building on recent advances in the understanding of gauge-Yukawa theories we explore possibilities to UV-complete the Standard Model in an asymptotically safe manner. Minimal extensions are based on a large avor sector of additional fermions coupled to a scalar singlet matrix field. We find that asymptotic safety requires fermions in higher representations of SU(3)C SU(2)L. Possible signatures at colliders are worked out and include R-hadron searches, diboson signatures and the evolution of the strong and weak coupling constants

    Precision Measurement of 11Li moments: Influence of Halo Neutrons on the 9Li Core

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    The electric quadrupole moment and the magnetic moment of the 11Li halo nucleus have been measured with more than an order of magnitude higher precision than before, |Q| = 33.3(5)mb and mu=3.6712(3)mu_N, revealing a 8.8(1.5)% increase of the quadrupole moment relative to that of 9Li. This result is compared to various models that aim at describing the halo properties. In the shell model an increased quadrupole moment points to a significant occupation of the 1d orbits, whereas in a simple halo picture this can be explained by relating the quadrupole moments of the proton distribution to the charge radii. Advanced models so far fail to reproduce simultaneously the trends observed in the radii and quadrupole moments of the lithium isotopes.Comment: 4 pages, 4 figures, 1 tabl

    Q-Value and Half-Lives for the Double-Beta-Decay Nuclide 110Pd

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    The 110Pd double-beta decay Q-value was measured with the Penning-trap mass spectrometer ISOLTRAP to be Q = 2017.85(64) keV. This value shifted by 14 keV compared to the literature value and is 17 times more precise, resulting in new phase-space factors for the two-neutrino and neutrinoless decay modes. In addition a new set of the relevant matrix elements has been calculated. The expected half-life of the two-neutrino mode was reevaluated as 1.5(6) E20 yr. With its high natural abundance, the new results reveal 110Pd to be an excellent candidate for double-beta decay studies

    A Data-informed Public Health Policy-Makers Platform

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    Hearing loss is a disease exhibiting a growing trend due to the number of factors, including but not limited to the mundane exposure to the noise and ever-increasing amount of older population. In the framework of a public health policymaking process, modeling of the hearing loss disease based on data is a key factor in alleviating the issues related to the disease issuing effective public health policies. First, the paper describes the steps of the data-driven policymaking process. Afterward, a scenario along with the part of the proposed platform, responsible for supporting policymaking are presented. With the aim of demonstrating the capabilities and usability of the platform for the policy-makers, some initial results of preliminary analytics are presented in a framework of a policy-making process. Ultimately, the utility of the approach is validated throughout the results of the survey which was presented to the health system policy-makers professionals involved in the policy development process in Croatia

    Probing the N = 32 shell closure below the magic proton number Z = 20: Mass measurements of the exotic isotopes 52,53K

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    The recently confirmed neutron-shell closure at N = 32 has been investigated for the first time below the magic proton number Z = 20 with mass measurements of the exotic isotopes 52,53K, the latter being the shortest-lived nuclide investigated at the online mass spectrometer ISOLTRAP. The resulting two-neutron separation energies reveal a 3 MeV shell gap at N = 32, slightly lower than for 52Ca, highlighting the doubly-magic nature of this nuclide. Skyrme-Hartree-Fock-Boguliubov and ab initio Gorkov-Green function calculations are challenged by the new measurements but reproduce qualitatively the observed shell effect.Comment: 5 pages, 5 figure

    Ground-State Electromagnetic Moments of Calcium Isotopes

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    High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the 4351^{43-51}Ca isotopes. The ground state magnetic moments of 49,51^{49,51}Ca and quadrupole moments of 47,49,51^{47,49,51}Ca were measured for the first time, and the 51^{51}Ca ground state spin I=3/2I=3/2 was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the 40^{40}Ca core in their ground state.Comment: Accepted as a Rapid Communication in Physical Review

    Spins, Electromagnetic Moments, and Isomers of 107-129Cd

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    The neutron-rich isotopes of cadmium up to the N=82 shell closure have been investigated by high-resolution laser spectroscopy. Deep-UV excitation at 214.5 nm and radioactive-beam bunching provided the required experimental sensitivity. Long-lived isomers are observed in 127Cd and 129Cd for the first time. One essential feature of the spherical shell model is unambiguously confirmed by a linear increase of the 11/2- quadrupole moments. Remarkably, this mechanism is found to act well beyond the h11/2 shell

    Precision Mass Measurements of 129-131Cd and Their Impact on Stellar Nucleosynthesis via the Rapid Neutron Capture Process

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    Masses adjacent to the classical waiting-point nuclide 130Cd have been measured by using the Penning- trap spectrometer ISOLTRAP at ISOLDE/CERN. We find a significant deviation of over 400 keV from earlier values evaluated by using nuclear beta-decay data. The new measurements show the reduction of the N = 82 shell gap below the doubly magic 132Sn. The nucleosynthesis associated with the ejected wind from type-II supernovae as well as from compact object binary mergers is studied, by using state-of-the-art hydrodynamic simulations. We find a consistent and direct impact of the newly measured masses on the calculated abundances in the A = 128 - 132 region and a reduction of the uncertainties from the precision mass input data

    A new beamline for laser spin-polarization at ISOLDE

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    A beamline dedicated to the production of laser-polarized radioactive beams has been constructed at ISOLDE, CERN. We present here different simulations leading to the design and construction of the setup, as well as technical details of the full setup and examples of the achieved polarizations for several radioisotopes. Beamline simulations show a good transmission through the entire line, in agreement with observations. Simulations of the induced nuclear spin-polarization as a function of atom-laser interaction length are presented for 26,28^{26,28}Na, [1] and for 35^{35}Ar, which is studied in this work. Adiabatic spin rotation of the spin-polarized ensemble of atoms, and how this influences the observed nuclear ensemble polarization, are also performed for the same nuclei. For 35^{35}Ar, we show that multiple-frequency pumping enhances the ensemble polarization by a factor 1.85, in agreement with predictions from a rate equations model. [1] J. Phys. G: Nucl. Part. Phys./174408400

    The eccentricity distribution of compact binaries

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    The current gravitational wave detectors have reached their operational sensitivity and are nearing detection of compact object binaries. In the coming years, we expect that the Advanced LIGO/VIRGO will start taking data. At the same time, there are plans for third generation ground-based detectors such as the Einstein Telescope, and space detectors such as DECIGO. We discuss the eccentricity distribution of inspiral compact object binaries during they inspiral phase. We analyze the expected distributions of eccentricities at three frequencies that are characteristic of three future detectors: Advanced LIGO/VIRGO (30 Hz), Einstein Telescope (3 Hz), and DECIGO (0.3 Hz). We use the StarTrack binary population code to investigate the properties of the population of compact binaries in formation. We evolve their orbits until the point that they enter a given detector sensitivity window and analyze the eccentricity distribution at that time. We find that the eccentricities of BH-BH and BH-NS binaries are quite small when entering the Advanced LIGO/VIRGO detector window for all considered models of binary evolution. Even in the case of the DECIGO detector, the typical eccentricities of BH-BH binaries are below 10^{-4}, and the BH-NS eccentricities are smaller than 10^{-3}. Some fraction of NS-NS binaries may have significant eccentricities. Within the range of considered models, we found that a fraction of between 0.2% and 2% NS-NS binaries will have an eccentricity above 0.01 for the Advanced LIGO/VIRGO detectors. For the ET detector, this fraction is between 0.4% and 4%, and for the DECIGO detector it lies between 2% and 27%.Comment: 8 pages, 5 figures, accepted by A&
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