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Nuclear Theory·nucl-th

Tuesday·June 20, 2017

17 papers—11 primary·6 cross-listed

All17Primary11Cross-lists6
  1. 01

    Solar neutrino physics on the beginning of 2017

    Francesco Vissani🇮🇹

    This writeup is a review of current hot topics on solar neutrinos. It is based on a talk at the conference "Neutrinos: the quest for a new physics scale", held at the CERN on March 2017, where the Organizers entrusted me with a discussion of the provocative question "whether solar neutrino physics is over". Rather than providing a straight (negative) answer, in view of an audience consisting mostly of colleagues working in theoretical particle physics, I deemed it more useful providing a description of what is the current activity of the physicists working in solar neutrinos, leaving the listener free of forming his/her own opinion apropos.

    nucl-thhep-phNucl.Phys.Atom.Energy(2017)·18 citations
  2. 02

    Numerical Simulation of the Hydrodynamical Combustion to Strange Quark Matter in the Trapped Neutrino Regime

    Amir Ouyed🇨🇦 · Rachid Ouyed🇨🇦 · Prashanth Jaikumar🇺🇸

    We simulate and study the microphysics of combustion (flame burning) of two flavored quark matter (u, d) to three flavoured quark matter (u,d,s) in a trapped neutrino regime applicable to conditions prevailing in a hot proto-neutron star. The reaction-diffusion-advection equations for (u,d) to (u,d,s) combustion are coupled with neutrino transport, which is modelled through a flux-limited diffusion scheme. The flame speed is proportional to initial lepton fraction because of the release of electron chemical potential as heat, and reaches a steady-state burning speed of (0.001-0.008)c. We find that the burning speed is ultimately driven by the neutrino pressure gradient, given that the pressure gradient induced by quarks is opposed by the pressure gradients induced by electrons. This suggests, somewhat counter-intuitively, that the pressure gradients that drive the interface are controlled primarily by leptonic weak decays rather than by the quark Equation of State (EOS). In other words, the effects of the leptonic weak interaction, including the corresponding weak decay rates and the EOS of electrons and neutrinos, are at least as important as the uncertainties related to the EOS of high density matter. We find that for baryon number densities nB <= 0.35 fm-3, strong pressure gradients induced by leptonic weak decays drastically slow down the burning speed, which is thereafter controlled by the much slower burning process driven by backflowing downstream matter. We discuss the implications of our findings to proto-neutron stars.

    nucl-thastro-ph.HEPLB(2018)·9 citations
  3. 03

    Formation and decay of resonance state in Be and B nuclei. Microscopic three-cluster model investigations

    V. S. Vasilevsky · K. Katō · N. Zh. Takibayev

    We study nature of the low-lying resonance states in mirror nuclei Be and B. Investigations are performed within a three-cluster model. The model makes use of the hyperspherical harmonics, which provides convenient description of three-cluster continuum. The dominant three-cluster configurations and in Be and B, respectively, are taken into account. Dominant decay channels for all resonance states in Be and B are explored. Much attention is paid to the controversial resonance states in both nuclei. We study effects of the Coulomb interaction on energy and width of three-cluster resonances in the mirror nuclei Be and B. We also search for the Hoyle-analogue state which is a key step for alternative way of Be and B syntheses in a triple collision of clusters in a stellar environment.

    nucl-thPhys.Sci.Tech.(2017)·16 citations
  5. 05

    Short-range interactions and narrow resonances in effective field theory

    Mohammad H. Alhakami

    We consider the effective field theory (EFT) treatment of two-body systems with narrow resonances. Within this approach, an -wave scattering amplitude can be expanded in powers of a typical momentum scale of a system , where represents a hard scale of a scattering system and an energy difference , where is a resonance peak energy. It is shown that at leading order in the double expansion a universal form of a two-body scattering amplitude is a sum of a Breit-Wigner term of order , a smooth background term of order , and an interference term of order . The techniques developed in this paper can be used to investigate the properties of narrow resonances that are produced by short-distance dynamics.

    nucl-thPRD(2017)·6 citations
  6. 06

    Central depression in nucleonic densities: Trend analysis in nuclear density-functional-theory approach

    Bastian Schuetrumpf · Witold Nazarewicz · Paul-Gerhard Reinhard

    Central depression of nucleonic density, i.e., a reduction of density in the nuclear interior, has been attributed to many factors. E.g., bubble structures in superheavy (SH) nuclei are believed to be due to the electrostatic repulsion. In light nuclei, the mechanism has been discussed in terms of shell effects associated with occupations of s-orbits. The objective of this work is to reveal mechanisms behind the formation of central depression in nucleonic densities in light and heavy nuclei. We introduce several measures of the internal nucleonic density. Through the statistical analysis, we study the information content of these measures with respect to nuclear matter properties. We apply nuclear density functional theory with Skyrme functionals. Using the statistical tools of linear least square regression, we inspect correlations between various measures of central depression and model parameters, including nuclear matter properties. We study bivariate correlations with selected quantities as well as multiple correlations with groups of parameters. Detailed correlation analysis is carried out for Si for which a bubble structure has been reported recently, Ca, and N=82, 126, and 184 isotonic chains. We show that the central depression in medium-mass nuclei is very sensitive to shell effects, whereas for SH systems it is firmly driven by the electrostatic repulsion. An appreciable semi-bubble structure in proton density is predicted for Og, which is currently the heaviest nucleus known experimentally. Our correlation analysis reveals that the central density indicators in nuclei below Pb carry little information on parameters of nuclear matter; they are predominantly driven by shell structure. On the other hand, in the SH nuclei there exists a clear relationship between the central nucleonic density and symmetry energy.

    nucl-thPRC(2017)·51 citations
  7. 07

    A symmetry for heavy nuclei: Proxy-SU(3)

    Dennis Bonatsos🇬🇷 · I. E. Assimakis🇬🇷 · N. Minkov🇧🇬 · Andriana Martinou🇬🇷 · R. B. Cakirli🇹🇷 · R. F. Casten🇺🇸 · K. Blaum🇩🇪

    The SU(3) symmetry realized by J. P. Elliott in the sd nuclear shell is destroyed in heavier shells by the strong spin-orbit interaction. However, the SU(3) symmetry has been used for the description of heavy nuclei in terms of bosons in the framework of the Interacting Boson Approximation, as well as in terms of fermions using the pseudo-SU(3) approximation. We introduce a new fermionic approximation, called the proxy-SU(3), and we comment on its similarities and differences with the other approaches.

    nucl-th1 citation
  8. 08

    Proxy-SU(3) symmetry in heavy nuclei: Foundations

    Dennis Bonatsos🇬🇷 · I. E. Assimakis🇬🇷 · N. Minkov🇧🇬 · Andriana Martinou🇬🇷 · R. B. Cakirli🇹🇷 · R. F. Casten🇺🇸 · K. Blaum🇩🇪

    An approximate SU(3) symmetry appears in heavy deformed even-even nuclei, by omitting the intruder Nilsson orbital of highest total angular momentum and replacing the rest of the intruder orbitals by the orbitals which have escaped to the next lower major shell. The approximation is based on the fact that there is a one-to-one correspondence between the orbitals of the two sets, based on pairs of orbitals having identical quantum numbers of orbital angular momentum, spin, and total angular momentum. The accuracy of the approximation is tested through calculations in the framework of the Nilsson model in the asymptotic limit of large deformations, focusing attention on the changes in selection rules and in avoided crossings caused by the opposite parity of the proxies with respect to the substituted orbitals.

    nucl-th1 citation
  9. 09

    Parameter-independent predictions for shape variables of heavy deformed nuclei in the proxy-SU(3) model

    Dennis Bonatsos🇬🇷 · I. E. Assimakis🇬🇷 · N. Minkov🇧🇬 · Andriana Martinou🇬🇷 · S. Sarantopoulou🇬🇷 · R. B. Cakirli🇹🇷 · R. F. Casten🇺🇸 · K. Blaum🇩🇪

    Using a new approximate analytic parameter-free proxy-SU(3) scheme, we make predictions of shape observables for deformed nuclei, namely beta and gamma deformation variables, and compare these with empirical data and with predictions by relativistic and non-relativistic mean-field theories.

    nucl-th6 citations
  10. 10

    Prolate dominance and prolate-oblate shape transition in the proxy-SU(3) model

    Dennis Bonatsos🇬🇷 · I. E. Assimakis🇬🇷 · N. Minkov🇧🇬 · Andriana Martinou🇬🇷 · S. Sarantopoulou🇬🇷 · R. B. Cakirli🇹🇷 · R. F. Casten🇺🇸 · K. Blaum🇩🇪

    Using a new approximate analytic parameter-free proxy-SU(3) scheme, we make simple predictions for the global feature of prolate dominance in deformed nuclei and the locus of the prolate-oblate shape transition and compare these with empirical data.

    nucl-th1 citation
  11. 11

    Proton structure fluctuations: from HERA to the LHC

    Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Prithwish Tribedy🇺🇸

    We constrain the amount of event-by-event fluctuations of the proton by comparing with the HERA coherent and incoherent diffractive production data. We find that the HERA measurements prefer large geometric fluctuations. We then include the constrained fluctuating proton shapes in viscous hydrodynamical simulations of the proton-nucleus collisions at TeV, and find a good description of the mean transverse momentum and flow harmonics measured at the LHC.

    nucl-thhep-phPoS(2018)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE