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Nuclear Theory·nucl-th

Thursday·November 3, 2016

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    Uncertainty propagation within the UNEDF models

    T. Haverinen · M. Kortelainen

    The parameters of the nuclear energy density have to be adjusted to experimental data. As a result they carry certain uncertainty which then propagates to calculated values of observables. In the present work we quantify the statistical uncertainties of binding energies, proton quadrupole moments, and proton matter radius for three UNEDF Skyrme energy density functionals by taking advantage of the knowledge of the model parameter uncertainties. We find that the uncertainty of UNEDF models increases rapidly when going towards proton or neutron rich nuclei. We also investigate the impact of each model parameter on the total error budget.

    nucl-thJ.Phys.G(2017)·14 citations
  2. 02

    Three-body model for the two-neutron decay of Be

    A.E. Lovell · F.M. Nunes · I.J. Thompson

    While diproton decay was first theorized in 1960 and first measured in 2002, it was first observed only in 2012. The measurement of Be in coincidence with two neutrons suggests that Be does decay through the simultaneous emission of two strongly correlated neutrons. In this work, we construct a full three-body model of Be (as Be + n + n) in order to investigate its configuration in the continuum and in particular the structure of its ground state. In order to describe the three-body system, effective n-Be potentials were constructed, constrained by the experimental information on Be. The hyperspherical R-matrix method was used to solve the three-body scattering problem, and the resonance energy of Be was extracted from a phase shift analysis. In order to reproduce the experimental resonance energy of Be within this three-body model, a three-body interaction was needed. For extracting the width of the ground state of Be, we use the full width at half maximum of the derivative of the three-body phase shifts and the width of the three-body elastic scattering cross section. Our results confirm a dineutron structure for Be, dependent on the internal structure of the subsystem Be.

    nucl-thPRC(2017)·26 citations
  3. 03

    Determination of the number of participating nucleons in p+p interactions at SPS energies

    H. Stroebele🇩🇪

    In the past the analyses of inelastic p+p collision for example in terms of the hadron gas model have assumed that always both protons participate in the interaction. In this article we show that (at sqrt(s) = 17.3 GeV ) on average only 1,89 protons are interacting. Measurements of the mean multiplicities of protons, neutrons, charged pions, charged kaons and {\Lambda} hyperons allow to compute the number of initial state nucleons using conservation of baryon number, strangeness, and isospin. We further argue that once the number of initial state nucleons is given and the mean multiplicities of protons and charged pions are known in p+p interactions at center-of-mass energies below a few tens of GeV, the yields of net neutrons, kaons, and hyperons can be estimated with a precision of a few percent using again baryon and isospin conservation.

    nucl-thhep-ph1 citation
  4. 04

    Dissipationless Hall Current in Dense Quark Matter in a Magnetic Field

    E. J. Ferrer🇺🇸 · V. de la Incera🇺🇸

    We show the realization of axion electrodynamics within the Dual Chiral Density Wave phase of dense quark matter in the presence of a magnetic field. The system exhibits an anomalous dissipantionless Hall current perpendicular to the magnetic field and an anomalous electric charge density. Connection to topological insulators and 3D optical lattices, as well as possible implications for heavy-ion collisions and neutron stars are outlined.

    nucl-thhep-phPLB(2017)·35 citations
  5. 05

    Ab Initio Excited States from the In-Medium Similarity Renormalization Group

    N. M. Parzuchowski · T. D. Morris · S. K. Bogner

    We present two new methods for performing ab initio calculations of excited states for closed-shell systems within the in-medium similarity renormalization group (IMSRG) framework. Both are based on combining the IMSRG with simple many-body methods commonly used to target excited states, such as the Tamm-Dancoff approximation (TDA) and equations-of-motion (EOM) techniques. In the first approach, a two-step sequential IMSRG transformation is used to drive the Hamiltonian to a form where a simple TDA calculation (i.e., diagonalization in the space of ph excitations) becomes exact for a subset of eigenvalues. In the second approach, equations-of-motion (EOM) techniques are applied to the ground-state-decoupled IMSRG Hamiltonian to access excited states. We perform proof-of-principle calculations for parabolic quantum dots in two-dimensions and the closed shell nuclei O and O. We find that the TDA-IMSRG approach gives better accuracy than the EOM-IMSRG when calculations converge, but is otherwise lacking the versatility and numerical stability of the latter. Our calculated spectra are in reasonable agreement with analogous EOM-coupled-cluster (EOM-CC) calculations, which paves the way for more interesting applications of the EOM-IMSRG to calculations of consistently evolved observables such as electromagnetic strength functions and nuclear matrix elements, and extensions to nuclei within 1-2 nucleons of a closed shell by generalizing the EOM ladder operator to include particle-number nonconserving terms.

    nucl-thPRC(2017)·35 citations

Affiliations

first authorsco-authorsvia INSPIRE