PaperPanorama

Nuclear Theory·nucl-th

Tuesday·September 1, 2015

19 papers11 primary·8 cross-listed

  1. 01

    [Submitted on 28 Aug 2015]

    The impact of individual nuclear properties on -process nucleosynthesis

    M. R. Mumpower🇺🇸 · R. Surman🇺🇸 · G. C. McLaughlin🇺🇸 · A. Aprahamian🇺🇸

    The astrophysical rapid neutron capture process or ` process' of nucleosynthesis is believed to be responsible for the production of approximately half the heavy element abundances found in nature. This multifaceted problem remains one of the greatest open challenges in all of physics. Knowledge of nuclear physics properties such as masses, -decay and neutron capture rates, as well as -delayed neutron emission probabilities are critical inputs that go into calculations of -process nucleosynthesis. While properties of nuclei near stability have been established, much still remains unknown regarding neutron-rich nuclei far from stability that may participate in the process. Sensitivity studies gauge the astrophysical response of a change in nuclear physics input(s) which allows for the isolation of the most important nuclear properties that shape the final abundances observed in nature. This review summarizes the extent of recent sensitivity studies and highlights how these studies play a key role in facilitating new insight into the process. The development of these tools promotes a focused effort for state-of-the-art measurements, motivates construction of new facilities and will ultimately move the community towards addressing the grand challenge of `How were the elements from iron to uranium made?'.

    Comments:
    60 pages, 20 figures, review article
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
    arXiv:
    1508.07352 [pdf]
    PPNP(2016)·478 citations
  2. 02

    [Submitted on 28 Aug 2015]

    Electromagnetic structure of light nuclei

    Saori Pastore🇺🇸

    The present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.

    Comments:
    Invited talk at the 21st International Conference on Few-body Problems in Physics, Chicago, IL, USA, May 18-22, 2015. 9 pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.07363 [pdf]
    EPJ Web Conf.(2016)·2 citations
  3. 03

    [Submitted on 29 Aug 2015]

    Universal noise and Efimov physics

    Amy N. Nicholson🇺🇸

    Probability distributions for correlation functions of particles interacting via random-valued fields are discussed as a novel tool for determining the spectrum of a theory. In particular, this method is used to determine the energies of universal N-body clusters tied to Efimov trimers, for even N, by investigating the distribution of a correlation function of two particles at unitarity. Using numerical evidence that this distribution is log-normal, an analytical prediction for the N-dependence of the N-body binding energies is made.

    Comments:
    6 pages, 3 figures. Invited contribution to the 21st International Conference on Few-Body Problems in Physics (FB21)
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Lattice (hep-lat)
    arXiv:
    1508.07493 [pdf]
    EPJ Web Conf.(2016)·1 citation
  4. 04

    [Submitted on 30 Aug 2015]

    The No-Core Gamow Shell Model: Including the continuum in the NCSM

    B. R. Barrett🇺🇸 · G. Papadimitriou · N. Michel🇫🇷 · M. Płoszajczak🇫🇷

    We are witnessing an era of intense experimental efforts that will provide information about the properties of nuclei far from the line of stability, regarding resonant and scattering states as well as (weakly) bound states. This talk describes our formalism for including these necessary ingredients into the No-Core Shell Model by using the Gamow Shell Model approach. Applications of this new approach, known as the No-Core Gamow Shell Model, both to benchmark cases as well as to unstable nuclei will be given.

    Comments:
    8 pages, 2 figures, 1 table. Proceedings of the "14th International Conference on Nuclear Reaction Mechanisms", Varenna (Italy), June 15-19, 2015
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.07529 [pdf]
    4 citations
  5. 05

    [Submitted on 30 Aug 2015]

    Asymptotic normalization coefficients of resonant and bound states from the phase shifts for and scattering

    Yu.V. Orlov · B.F. Irgaziev · L.I. Nikitina

    Recently we have published a paper [Irgaziev, Phys. Rev. C 91, 024002 (2015)] where the -matrix pole method (SMP) which is only valid for resonances has been developed to derive a new explicit expression for the asymptotic normalization coefficient (ANC), and is applied to the low-energy resonant states of nucleon and systems. The SMP results are compared with the effective-range expansion method (EFE) results. In the present paper the SMP and EFE plus the Padé-approximation are applied to study the excited 2 resonant states of . A contradiction is found between descriptions of the experimental phase shift data for scattering and of the resonant energy for 2 state. Using the EFE method, we also calculate the ANC for the ground 0 state with a very small width. This ANC agrees well with the value calculated using the known analytical expression for narrow resonances. In addition, for the states1 and 3 the SMP results are compared with the Padé-approximation results. We find that the Padé-approximation improves a resonance width description compared with the EFE results. The EFE method is also used to calculate the ANCs for the bound ground 0 state and for the excited 1 and 2 levels which are situated near the threshold of channel.

    Comments:
    9 pages, 3 figures, 1 table
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.07538 [pdf]
    PRC(2016)·24 citations
  6. 06

    [Submitted on 30 Aug 2015]

    Benchmark for a quasi-bound state of the system

    Roman Ya. Kezerashvili🇺🇸 · Shalva M. Tsiklauri🇺🇸 · Igor N. Filikhin🇺🇸 · Vladimir M. Suslov🇺🇸 · Branislav Vlahovic

    We present three-body nonrelativistic calculations within the framework of a potential model for the kaonic cluster using two completely different methods: the method of hyperspherical harmonics in the momentum representation and the method of Faddeev equations in configuration space. To perform a numerical benchmark, different and antikaon-nucleon interactions are applied. The results of the calculations for the ground state energy for the system obtained by both methods are in reasonable agreement. Although the ground state energy is not sensitive to the interaction, it shows very strong dependence on the potential. We show that the dominant clustering of the system in the configuration allows us to calculate the binding energy to good accuracy within a simple cluster approach for the differential Faddeev equations. The theoretical discrepancies in the binding energy and width for the system related to the different and interactions are addressed.

    Comments:
    14 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.07638 [pdf]
    2 citations
  7. 07

    [Submitted on 31 Aug 2015]

    A possible framework of the Lipkin model obeying the su(n)-algebra in arbitrary fermion number. I --- The su(2)-algebras extended from the conventional fermion-pair and determination of the minimum weight states ---

    Yasuhiko Tsue (Kochi Univ., Japan) · Constanca Providencia (Univ. de Coimbra, Portugal) · Joao da Providencia (Univ. de Coimbra, Portugal) · Masatoshi Yamamura (Kansai Univ., Japan)

    The minimum weight states of the Lipkin model consisting of n single-particle levels and obeying the su(n)-algebra are investigated systematically. The basic idea is to use the su(2)-algebra which is independent of the su(n)-algebra. This idea has been already presented by the present authors in the case of the conventional Lipkin model consisting of two single-particle levels and obeying the su(2)-algebra. If following this idea, the minimum weight states are determined for any fermion number occupying appropriately n single-particle levels. Naturally, the conventional minimum weight state is included: all fermions occupy energetically the lowest single-particle level in the absence of interaction. The cases n=2, 3, 4 and 5 are discussed in rather detail.

    Comments:
    28 pages, 6 figurs
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.07672 [pdf]
    PTEP(2016)·2 citations
  8. 08

    [Submitted on 31 Aug 2015]

    Construction of KbarN potential and structure of Lambda(1405) based on chiral unitary approach

    Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵

    Based on chiral unitary approach, we construct the realistic KbarN local potential, which is useful for the quantitative calculation of Kbar-nuclei. Since the resonance pole structure of the KbarN system seems important for the Kbar-nuclei and the spacial structure of Lambda(1405), we establish the construction procedure of the local potential paying attention to the scattering amplitude in the complex energy plane. Furthermore, for the quantitative study of the Kbar-nuclei, we consider the constraint from the recent experimental data measured by SIDDHARTA, which significantly reduces the uncertainty of the KbarN amplitude. With this new local potential, we estimate the spacial structure of Lambda(1405) and obtain the result indicating the meson-baryon molecular state of Lambda(1405).

    Comments:
    5 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1508.07707 [pdf]
    JPS Conf.Proc.(2016)·5 citations
  9. 09

    [Submitted on 31 Aug 2015]

    Possibility of DCC formation in pp collisions at LHC energy via reaction-diffusion equation

    Partha Bagchi🇮🇳 · Arpan Das🇮🇳 · Srikumar Sengupta🇮🇳 · Ajit M. Srivastava🇮🇳

    There are indications of formation of a thermalized medium in high multiplicity pp collisions at LHC energy. It is possible that such a medium may reach high enough energy density/temperature so that a transient stage of quark-gluon plasma, where chiral symmetry is restored, may be achieved. Due to rapid 3-dimensional expansion, the system will quickly cool undergoing spontaneous chiral symmetry breaking transition. We study the dynamics of chiral field, after the symmetry breaking transition, for such an event using reaction-diffusion equation approach which we have recently applied for studying QCD transitions in relativistic heavy-ion collisions. We show that the interior of such a rapidly expanding system is likely to lead to the formation of a single large domain of disoriented chiral condensate (DCC) which has been a subject of intensive search in earlier experiments. We argue that large multiplicity pp collisions naturally give rise to required boundary conditions for the existence of slowly propagating front solutions of reaction-diffusion equation with resulting dynamics of chiral field leading to the formation of a large DCC domain.

    Comments:
    17 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1508.07752 [pdf]
    PRC(2016)·1 citation
  10. 10

    [Submitted on 31 Aug 2015]

    Single Freeze-Out, Statistics and Pion, Kaon and Proton Production in Central Pb-Pb Collisions at TeV

    Dariusz Prorok🇵🇱

    Many data in the high energy physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the acceptable fit to the whole spectra of pions, kaons and protons measured at midrapidity in central Pb-Pb collisions at TeV [Phys.Rev.Lett.109,252301(2012)] is obtained. The invariant distributions are predicted with the help of the single-freeze-out model in the chemical equilibrium framework. Low pions and protons are reproduced simultaneously as well as ratio. Additionally, correct predictions extend over lower parts of large data. Some more general, possible implications of this approach are pointed out.

    Comments:
    10 pages, 2 figures, matches published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1508.07922 [pdf]
    J.Phys.G(2016)·12 citations
  11. 11

    [Submitted on 31 Aug 2015]

    Evaluation of the forward Compton scattering off protons: I. Spin-independent amplitude

    Oleksii Gryniuk🇩🇪 · Franziska Hagelstein🇩🇪 · Vladimir Pascalutsa (JGU Mainz)🇩🇪

    We evaluate the forward Compton scattering off the proton, based on Kramers-Kronig kind of relations which express the Compton amplitudes in terms of integrals of total photoabsorption cross sections. We obtain two distinct fits to the world data on the unpolarized total photoabsorption cross section, and evaluate the various spin-independent sum rules using these fits. For the sum of proton electric and magnetic dipole polarizabilities, governed by the Baldin sum rule, we obtain the following average (between the two fits): . An analogous sum rule involving the quadrupole polarizabilities of the proton is evaluated too. The spin-independent forward amplitude of proton Compton scattering is evaluated in a broad energy range. The results are compared with previous evaluations and the only experimental data point for this amplitude (at 2.2 GeV). We remark on sum rules for the elastic component of polarizabilities.

    Comments:
    8 pages, 6 figures, 5 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1508.07952 [pdf]
    PRD(2015)·39 citations
  12. 12

    [Submitted on 28 Aug 2015] (cross-list from astro-ph.HE)

    The Sensitivity of Core-Collapse Supernovae to Nuclear Electron Capture

    Chris Sullivan · Evan O'Connor · Remco G. T. Zegers · Thomas Grubb · Sam M. Austin

    A weak-rate library aimed at investigating the sensitivity of astrophysical environments to variations of electron-capture rates on medium-heavy nuclei has been developed. With this library, the sensitivity of the core-collapse and early post-bounce phases of core-collapse supernovae to nuclear electron-capture is examined by systematically and statistically varying electron-capture rates of individual nuclei. The rates are adjusted by factors consistent with uncertainties indicated by comparing theoretical rates to those deduced from charge-exchange and -decay measurements. To ensure a model independent assessment, sensitivity studies across a comprehensive set of progenitors and equations of state are performed. In our systematic study, we find a +16/-4 % range in the mass of the inner-core at the time of shock formation and a 20% range of peak {\nu}e-luminosity during the deleptonization burst. These ranges are each five times as large as those seen from a separate progenitor study in which we evaluated the sensitivity of these parameters to 32 presupernova stellar models. It is also found that the simulations are more sensitive to a reduction in the electron-capture rates than an enhancement, and in particular to the reduction in the rates for neutron-rich nuclei near the N = 50 closed neutron-shell. As measurements for medium-heavy (A > 65) and neutron-rich nuclei are sparse, and because accurate theoretical models which account for nuclear structure considerations on the individual nucleus level are not readily available, rates for these nuclei may be overestimated. If more accurate estimates confirm this, results from this study indicate that significant changes to the core-collapse trajectory can be expected. For this reason, experimental and theoretical efforts should focus in this region of the nuclear chart.

    Comments:
    14 emulateapj pages, 10 figures, 1 table. Submitted to The Astrophysical Journal
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1508.07348 [pdf]
    ApJ(2016)·96 citations
  13. 13

    [Submitted on 30 Aug 2015] (cross-list from hep-ph)

    The Edge of Jets and Subleading Non-Global Logs

    Duff Neill🇺🇸

    A persistent and fascinating problem at the high energy colliders are jets. Often trying to observe physics underlying the hard interactions at colliders requires experimental cuts in phase space, defining several jet or beam regions. QCD being a gauge theory that readily decays into infra-red modes, correlations between jet regions is almost inevitable, spoiling the predictivity of fixed order QCD calculations. One is faced with the task of calculating the evolution of a reduced density matrix, where successively less energetic (jet) regions are integrated out, to gain control of the calculation. I relate the decay rates governing the flow into the IR to an effective field theory expansion in soft jets, allowing a systematic and resummed calculation of these rates, while further relating them to physically observable features of the QCD cascade. To demonstrate the utility of the soft jet expansion, I present a factorization theorem for a soft subjet collinearly splitting in and out of a parent fat jet. Using the resummation properties of this factorization theorem, I elucidate the structure of the subleading non-global logs (encoding the jet correlations) in the hemisphere jet mass distribution, as well as give a collinear improvement of the leading order resummation equation, the BMS equation. I compare to other approaches to subleading resummation of NGLs, and find the collinear improvement of the leading order equation removes the need for kinematic-dependent corrections in the IR averaging procedure of the reduced density matrix, so that no further large logs can be generated in the IR. Finally I end with speculation about connections with collinear improvements of the NLO B-JIMWLK hierarchy for small- resummation.

    Comments:
    3 figs. 37 pgs
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1508.07568 [pdf]
    35 citations
  14. 14

    [Submitted on 30 Aug 2015] (cross-list from hep-lat)

    Two Nucleon Systems at from Lattice QCD

    Kostas Orginos🇺🇸 · Assumpta Parreno🇪🇸 · Martin J. Savage🇺🇸 · Silas R. Beane🇺🇸 · Emmanuel Chang🇺🇸 · William Detmold🇺🇸

    Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a pion mass of in three spatial volumes using flavors of light quarks. At the quark masses employed in this work, the deuteron binding energy is calculated to be , while the dineutron is bound by . Over the range of energies that are studied, the S-wave scattering phase shifts calculated in the 1S0 and 3S1-3D1 channels are found to be similar to those in nature, and indicate repulsive short-range components of the interactions, consistent with phenomenological nucleon-nucleon interactions. In both channels, the phase shifts are determined at three energies that lie within the radius of convergence of the effective range expansion, allowing for constraints to be placed on the inverse scattering lengths and effective ranges. The extracted phase shifts allow for matching to nuclear effective field theories, from which low energy counterterms are extracted and issues of convergence are investigated. As part of the analysis, a detailed investigation of the single hadron sector is performed, enabling a precise determination of the violation of the Gell-Mann--Okubo mass relation. [An Erratum to the published version is included as an appendix. It details the impact of an error discovered in 2020 and corrects typographical errors.]

    Comments:
    29 pages, 31 figures, Erratum from 2020 included
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1508.07583 [pdf]
    PRD(2015)·167 citations
  15. 15

    [Submitted on 30 Aug 2015] (cross-list from hep-lat)

    Critical line of 2+1 flavor QCD: Toward the continuum limit

    Paolo Cea🇮🇹 · Leonardo Cosmai🇮🇹 · Alessandro Papa🇮🇹

    We determine the continuum limit of the curvature of the pseudocritical line of QCD with =2+1 staggered fermions at nonzero temperature and quark density. We perform Monte Carlo simulations at imaginary baryon chemical potentials, adopting the HISQ/tree action discretization, as implemented in the code by the MILC collaboration. Couplings are adjusted so as to move on a line of constant physics, as determined in Ref.~\cite{Bazavov:2011nk}, with the strange quark mass fixed at its physical value and a light-to-strange mass ratio . The chemical potential is set at the same value for the three quark species, . We attempt an extrapolation to the continuum using the results on lattices with temporal size up to . Our estimate for the continuum value of the curvature at zero baryon density, , is compared with recent lattice results and with experimental determinations of the freeze-out curve.

    Comments:
    10 pages, 4 figures, 16 tables; modified title and abstract, added two tables and a few comments in the text, added appendix with 13 tables; version to appear on Phys. Rev. D
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1508.07599 [pdf]
    PRD(2016)·112 citations
  16. 16

    [Submitted on 31 Aug 2015] (cross-list from nucl-ex)

    Elastic proton scattering at intermediate energies as a probe of the He nuclear matter densities

    Le Xuan Chung · Oleg A. Kiselev · Dao T. Khoa · Peter Egelhof

    The Glauber model analysis of the elastic He+ scattering data at energies around 700 MeV/nucleon, measured in two separate experiments at GSI-Darmstadt, has been done using several phenomenological parametrizations of the nuclear matter density. By taking into account the new data points measured at the high momentum transfer, the nuclear matter radii of He were accurately determined from the Glauber model analysis of the data, with the spin-orbital interaction explicitly taken into account. The well-known geometry for the core and dineutron halo has been used with the new parametrizations of the He density to extract the detailed information on the structure of He in terms of the core and dineutron halo radii. An enhanced sensitivity of the data measured at the high momentum transfer to the core part of the He densities has been found.

    Comments:
    Accepted for publication in Physical Review C
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1508.07679 [pdf]
    PRC(2015)·20 citations
  17. 17

    [Submitted on 31 Aug 2015] (cross-list from hep-ph)

    Charge-conjugation symmetric complete impulse approximation for the pion electromagnetic form factor in the Covariant Spectator Theory

    Elmar P. Biernat🇵🇹 · Franz Gross🇺🇸 · M. T. Peña🇵🇹 · Alfred Stadler🇵🇹

    The pion form factor is calculated in the framework of the charge-conjugation invariant Covariant Spectator Theory. This formalism is established in Minkowski space and the calculation is set up in momentum space. In a previous calculation we included only the leading pole coming from the spectator quark (referred to as the relativistic impulse approximation). In this paper we also include the contributions from the poles of the quark which interacts with the photon and average over all poles in both the upper and lower half planes in order to preserve charge conjugation invariance (referred to as the -symmetric complete impulse approximation). We find that for small pion mass these contributions are significant at all values of the four-momentum transfer but, surprisingly, do not alter the shape obtained from the spectator poles alone.

    Comments:
    14 pages, 6 figures; some typos corrected; version published in Phys. Rev. D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1508.07809 [pdf]
    PRD(2015)·18 citations
  18. 18

    [Submitted on 31 Aug 2015] (cross-list from hep-ph)

    Initial state and thermalization in the Color Glass Condensate framework

    F. Gelis🇫🇷

    In this review, I present the description of the early stages of heavy ion collisions at high energy in the Color Glass Condensate framework, from the pre-collision high energy nuclear wavefunction to the point where hydrodynamics may start becoming applicable.

    Comments:
    Review to appear in QGP5, 64 pages, 67 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1508.07974 [pdf]
    IJMPE(2015)·40 citations
  19. 19

    [Submitted on 31 Aug 2015] (cross-list from hep-ph)

    Sensitivity to Z-prime and non-standard neutrino interactions from ultra-low threshold neutrino-nucleus coherent scattering

    Bhaskar Dutta🇺🇸 · Rupak Mahapatra🇺🇸 · Louis E. Strigari🇺🇸 · Joel W. Walker🇺🇸

    We discuss prospects for probing Z-prime and non-standard neutrino interactions using neutrino-nucleus coherent scattering with ultra-low energy (~ 10 eV) threshold Si and Ge detectors. The analysis is performed in the context of a specific and contemporary reactor-based experimental proposal, developed in cooperation with the Nuclear Science Center at Texas A&M University, and referencing available technology based upon economical and scalable detector arrays. For expected exposures, we show that sensitivity to the Z-prime mass is on the order of several TeV, and is complementary to the LHC search with low mass detectors in the near term. This technology is also shown to provide sensitivity to the neutrino magnetic moment, at a level that surpasses terrestrial limits, and is competitive with more stringent astrophysical bounds. We demonstrate the benefits of combining silicon and germanium detectors for distinguishing between classes of models of new physics, and for suppressing correlated systematic uncertainties.

    Comments:
    As published in PRD; 13 pages, 7 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1508.07981 [pdf]
    PRD(2016)·76 citations

Affiliations

first authorsco-authorsvia INSPIRE