PaperPanorama

Nuclear Theory·nucl-th

Tuesday·December 24, 2019

20 papers10 primary·10 cross-listed

  1. 01

    Neutron elastic scattering on calcium isotopes from chiral nuclear optical potentials

    T.R. Whitehead · Y. Lim · J.W. Holt

    We formulate microscopic neutron-nucleus optical potentials from many-body perturbation theory based on chiral two- and three-body forces. The neutron self energy is first calculated in homogeneous matter to second order in perturbation theory, which gives the central real and imaginary terms of the optical potential. The real spin-orbit term is calculated separately from the density matrix expansion using the same chiral interaction as in the self energy. Finally, the full neutron-nucleus optical potential is derived within the improved local density approximation utilizing mean field models consistent with the chiral nuclear force employed. We compare the results of the microscopic calculations to phenomenological models and experimental data up to projectile energies of MeV. Experimental elastic differential scattering cross sections and vector analyzing powers are generally well reproduced by the chiral optical potential, but we find that total cross sections are overestimated at high energies.

    nucl-thPRC(2020)·20 citations
  2. 02

    Rapidity dependence of global polarization in heavy ion collisions

    Zuo-Tang Liang🇨🇳 · Jun Song🇨🇳 · Isaac Upsal🇨🇳 · Qun Wang🇨🇳 · Zhang-Bu Xu🇨🇳

    We use a geometric model for the hadron polarization with an emphasis on the rapidity dependence. It is based on the model of Brodsky, Gunion, and Kuhn and that of the Bjorken scaling. We make predictions for the rapidity dependence of the hadron polarization in the collision energy range 7.7-200 GeV by taking a few assumed forms of the parameters. The predictions can be tested by future experiments.

    nucl-thCPC(2021)·27 citations
  3. 03

    High-momentum components in the He nucleus caused by inter-nucleon correlations

    Mengjiao Lyu · Takayuki Myo · Hiroshi Toki · Hisashi Horiuchi · Chang Xu · Niu Wan

    High-momentum components of nuclei are essential for understanding the underlying inter-nucleon correlations in nuclei. We perform the comprehensive analysis for the origin of the high-momentum components of He in the framework of Tensor-optimized High-momentum Antisymmetrized Molecular Dynamics (TO-HMAMD), which is a completely variational approach as an theory starting from the bare nucleon-nucleon () interaction. The analytical derivations are provided for the nucleon momentum distribution of the Antisymmetrized Momentum Dynamics (AMD) wave functions, with subtraction of center-of-mass motion. The nucleon momentum distribution for He is calculated by applying a new expansion technique to our wave function, and agrees with the values extracted from experimental data up to the high-momentum region. Fine-grained analysis is performed for the high-momentum components in He with respect to different nucleon correlations. Contributions from tensor, central with short-range, and many-body correlations are extracted from the nucleon momentum distributions. The manifestation of tensor correlation around 2 fm region is explicitly confirmed by comparing the momentum distributions predicted using different types of interactions with and without the tensor force.

    nucl-thPLB(2020)·24 citations
  4. 04

    Beyond mean-field boson-fermion description of odd nuclei

    Kosuke Nomura

    We develop a novel theoretical method for calculating spectroscopic properties of those nuclei with odd number of nucleons, that is based on the nuclear density functional theory and the particle-boson coupling scheme. Self-consistent mean-field calculation based on the DFT is performed to provide microscopic inputs to build the Hamiltonian of the interacting boson-fermion systems, which gives excitation spectra and transition rates of odd-mass nuclei. The method is successfully applied to identify the quantum shape phase transitions and the role of octupole correlations in odd-mass nuclei, and is extended further to odd-odd nuclear systems.

    nucl-thnucl-exActa Phys.Polon.Supp.(2020)·0 citations
  5. 05

    A Survey of Nuclear Pasta in the Intermediate Density Regime: Structure Functions for Neutrino Scattering

    B. Schuetrumpf🇩🇪 · G. Martínez-Pinedo🇩🇪 · P.-G. Reinhard🇩🇪

    Background: Nuclear pasta matter, emerging due to the competition between the long-range Coulomb force and the short-range strong force, is believed to be present in astrophysical scenarios, such as neutron stars and core-collapse supernovae. Its structure can have a high impact e.g. on neutrino transport or the tidal deformability of neutron stars. Purpose: We investigate the impact of nuclear pasta on neutrino interactions and compare the results to uniform matter. Method: We calculate the elastic and inelastic static structure factors for nuclear pasta matter using density functional theory (DFT), which contain the main nuclear input for neutrino scattering. Results: Each pasta structure leaves a unique imprint in the elastic structure factor and it is largely enhanced. The inelastic structure factors are very similar for all configurations. Conclusion: Nuclear pasta has a noticeable impact on neutrino neutral-current scattering opacities. While for inelastic reactions the cross section is reduced, the elastic coherent scattering increases dramatically. The effect can be of importance for the cooling of neutron stars as well as for core-collapse supernova models.

    nucl-thastro-ph.HEPRC(2020)·18 citations
  6. 06

    Corrections to the Bethe formula for average ionization energy loss of relativistic charged particles in solids. I. Mott's corrections

    O. Voskresenskaya🇷🇺

    Based on the proposed representation of the Mott corrections to the Bethe stopping formula in the form of rapidly convergent series of quantities bilinear in the Mott partial amplitudes, the numerical calculations were performed for these corrections over a wide range of nuclear charge number of the incident particles at various values of their relative velocity.

    nucl-thhep-ph0 citations
  7. 07

    Dissipative type theories for Bjorken and Gubser flows

    Esteban Calzetta🇦🇷 · Lucas Cantarutti🇦🇷

    We use the dissipative type theory (DTT) framework to solve for the evolution of conformal fluids in Bjorken and Gubser flows from isotropic initial conditions. The results compare well with both exact and other hydrodynamic solutions in the literature. At the same time, DTTs enforce the Second Law of thermodynamics as an exact property of the formalism, at any order in deviations from equilibrium, and are easily generalizable to more complex situations.

    nucl-thhep-phInt.J.Mod.Phys.A(2020)·20 citations
  8. 08

    Electron- versus neutrino-nucleus scattering

    J.E. Amaro🇪🇸 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · R. González-Jiménez🇪🇸 · G.D. Megias🇯🇵 · I. Ruiz Simo🇪🇸

    We illustrate the connection between electron and neutrino scattering off nuclei and show how the former process can be used to constrain the description of the latter. After reviewing some of the nuclear models commonly used to study lepton-nucleus reactions, we describe in detail the SuSAv2 model and show how its predictions compare with the available electron- and neutrino-scattering data over the kinematical range going from the quasi-elastic peak to pion-production and highly inelastic scattering.

    nucl-thhep-exhep-phJ.Phys.G(2020)·70 citations
  9. 09

    Lepton kinematics in low energy neutrino-Argon interactions

    Nils Van Dessel🇧🇪 · Alexis Nikolakopoulos🇧🇪 · Natalie Jachowicz🇧🇪

    Background: Neutrinos in the low-energy regime provide a gateway to a wealth of interesting physics. While plenty of literature exists on detailing the calculation and measurement of total reaction strengths, relatively little attention is paid to the measurement and modeling of the final lepton through differential cross sections at low energies, despite the experimental importance. Purpose: We calculate differential cross sections for low-energy neutrino-nucleus scattering. We examine the role played by forbidden transitions in these distributions and how this differs across different energies and nuclear target masses. Attention is also paid to predictions for typical experimental neutrino spectra. Method: The differential cross sections are calculated within a Continuum Random Phase Approximation framework, which allows us to include collective excitations induced by long-range correlations. The Coulomb interaction of the final lepton in charged current events is treated in an effective way. Results: Kinematic distributions are calculated for O, Ar and Pb. Ar model results are compared for CC () reactions to events generated by the MARLEY event generator, with noticeable discrepancies. Conclusion: Forbidden transitions have a marked effect on the kinematic distributions of the final lepton at low-energy kinematics, such as for DAR neutrinos or for a Fermi-Dirac spectrum at low temperature. This could introduce biases in experimental analyses. Backwards scattering is noticeably more prominent than with MARLEY.

    nucl-thPRC(2020)·19 citations
  10. 10

    Excitation of monopole pairing vibrations in two-neutron transfer reaction: a semiclassical approach

    V.I. Abrosimov · A.I. Levon

    For studying the collective pairing excitations of nuclei, the two-nucleon transfer reactions in superfluid nuclei (the pairing gap of the ground state is not zero), in particular, the (p,t) reaction, are of the greatest interest. A simple model of monopole pairing excitations in superfluid nuclei on the basis of the semiclassical time-dependent Hartree-Fock-Bogolyubov theory in the limit of small amplitudes is considered. Using the anomalous density response function, the monopole pairing mode in the energy region of double pairing gap and the variation of the pairing gap associated with this mode are found. The ratio of the spectroscopic factor for the excitation of monopole pairing vibrations in the (p,t) reaction in even superfluid nuclei to the spectroscopic factor for the transfer of two neutrons to the ground state of the daughter nucleus (the relative spectroscopic factor) is estimated. For this, it is assumed that the relative spectroscopic factor is proportional to the pairing gap variation associated with the monopole pairing vibrations in agreement with the corresponding quantum expression. Numerical estimate of the relative spectroscopic factors for superfluid nuclei of the rare-earth and actinide regions shows that the spectroscopic factor for the two-neutron transfer, leading to the excitation of the monopole pairing vibrations, does not exceed several percent of the spectroscopic factor for the transfer of two neutrons to the ground state. This semiclassical estimate is in agreement with the experimental rations of the cross sections for the excitation of 0+states in the energy region of double pairing gap to the cross sections for the excitation of the ground states for superfluid nuclei of the rare-earth and actinide regions.

    nucl-th0 citations
  11. 11

    Data-driven study of timelike Compton scattering

    O. Grocholski🇵🇱 · H. Moutarde🇫🇷 · B. Pire🇫🇷 · P. Sznajder🇵🇱 · J. Wagner🇵🇱

    In the framework of collinear QCD factorization, the leading twist scattering amplitudes for deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) are intimately related thanks to analytic properties of leading and next-to-leading order amplitudes. We exploit this welcome feature to make data-driven predictions for TCS observables to be measured in near future experiments. Using a recent extraction of DVCS Compton form factors from most of the existing experimental data for that process, we derive TCS amplitudes and calculate TCS observables only assuming leading-twist dominance. Artificial neural network techniques are used for an essential reduction of model dependency, while a careful propagation of experimental uncertainties is achieved with replica methods. Our analysis allows for stringent tests of the leading twist dominance of DVCS and TCS amplitudes. Moreover, this study helps to understand quantitatively the complementarity of DVCS and TCS measurements to test the universality of generalized parton distributions, which is crucial e.g. to perform the nucleon tomography.

    hep-phhep-exnucl-exnucl-thEPJC(2020)·29 citations
  12. 12

    New CTEQ global analysis of quantum chromodynamics with high-precision data from the LHC

    Tie-Jiun Hou🇨🇳 · Jun Gao🇨🇳 · T. J. Hobbs🇺🇸 · Keping Xie🇺🇸 · Sayipjamal Dulat🇨🇳 · Marco Guzzi🇺🇸 · Joey Huston🇺🇸 · Pavel Nadolsky🇺🇸 · Jon Pumplin🇺🇸 · Carl Schmidt🇺🇸 · Ibrahim Sitiwaldi🇨🇳 · Daniel Stump🇺🇸 · C.-P. Yuan🇺🇸

    We present the new parton distribution functions (PDFs) from the CTEQ-TEA collaboration, obtained using a wide variety of high-precision Large Hadron Collider (LHC) data, in addition to the combined HERA I+II deep-inelastic scattering data set, along with the data sets present in the CT14 global QCD analysis. New LHC measurements in single-inclusive jet production with the full rapidity coverage, as well as production of Drell-Yan pairs, top-quark pairs, and high- bosons, are included to achieve the greatest sensitivity to the PDFs. The parton distributions are determined at NLO and NNLO, with each of these PDFs accompanied by error sets determined using the Hessian method. Fast PDF survey techniques, based on the Hessian representation and the Lagrange Multiplier method, are used to quantify the preference of each data set to quantities such as , and the gluon and strange quark distributions. We designate the main resulting PDF set as CT18. The ATLAS 7 TeV precision data are not included in CT18, due to their tension with other data sets in the global fit. Alternate PDF sets are generated including the ATLAS precision 7 TeV data (CT18A), a new scale choice for low- DIS data (CT18X), or all of the above with a slightly higher choice for the charm mass (CT18Z). Theoretical calculations of standard candle cross sections at the LHC (such as the fusion Higgs boson cross section) are presented.

    hep-phhep-exnucl-thPRD(2021)·1013 citations
  13. 13

    Hadron multiplicity calculation: a configurational entropy approach to the saturation scale in QCD

    Gayane Karapetyan🇧🇷

    This paper investigates the configurational entropic content of hadron-nucleus collisions. Hadron multiplicities and Au nuclei are employed to compute the critical points of the configurational entropy as a function of the saturation scale in deep inelastic scatterings, in QCD. The results match phenomenological data to the precision of 0.39%.

    hep-phnucl-thEPL(2020)·22 citations
  14. 14

    The Gor'kov and Melik-Barkhudarov correction to the mean-field critical field transition to Fulde-Ferrell-Larkin-Ovchinnikov states

    Heron Caldas · Qijin Chen

    The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states, characterized by Cooper pairs condensed at finite-momentum are, at the same time, exotic and elusive. It is partially due to the fact that the FFLO states allow superconductivity to survive even in strong magnetic fields at the mean-field level. The effects of induced interactions at zero temperature are calculated in both clean and dirty cases, and it is found that the critical field at which the quantum phase transition to an FFLO state occurs at the mean-field level is strongly suppressed in imbalanced Fermi gases. This strongly shrinks the phase space region where the FFLO state is unstable and more exotic ground state is to be found. In the presence of high level impurities, this shrinkage may destroy the FFLO state completely.

    cond-mat.quant-gascond-mat.str-elcond-mat.supr-connucl-thAnnalen Phys.(2020)·0 citations
  15. 15

    Diffractive deeply virtual Compton scattering

    Bernard Pire🇫🇷 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷

    Diffractive deeply virtual Compton scattering (DiDVCS) is the process , where N is a nucleon or light nucleus, in the kinematical regime of large rapidity gap between the and the final photon-nucleus system, and in the generalized Bjorken regime where both photon virtualities and are large. We show that this process has the unique virtue of combining the large diffractive cross sections at high energy with the tomographic ability of deeply virtual Compton scattering to scrutinize the quark and gluon content of nucleons and light nuclei. Its study at an electron-ion collider would enlighten the internal structure of hadrons.

    hep-phhep-exnucl-exnucl-thPRD(2020)·21 citations
  16. 16

    Time- and parity-violating effects of nuclear Schiff moment in molecules and solids

    V. V. Flambaum🇦🇺 · V. A. Dzuba🇦🇺 · H. B. Tran Tan🇦🇺

    We show that existing calculations of the interaction between nuclear Schiff moments and electrons in molecules use an inaccurate operator which gives rise to significant errors. By comparing the matrix elements of the accurate and imprecise Schiff moment operators, we calculated the correction factor as a function of the nuclear charge Z and presented corrected results for the T,P-violating interaction of the nuclear spin with the molecular axis in the TlF, RaO, PbO, TlCN, ThO, AcF molecules and in the ferroelectric solid PbTiO.

    physics.atom-phhep-phnucl-thphysics.chem-phPRA(2020)·12 citations
  17. 17

    Radiative processes and jet modification at the EIC

    Ivan Vitev🇺🇸

    A U.S.-based Electron-Ion Collider will provide the ultimate capability to determine both the structure and properties of nucleons and nuclei, as well as how matter and energy can be transported through a strongly interacting quantum mechanical environment. The production and propagation of long-lived heavy subatomic particles is a unique and critical part of this planned decade-long research program. In these proceedings we report the derivation of all branching processes in nuclei that lead to a modification of semi-inclusive hadron production, jet cross sections, and jet substructure when compared to the vacuum. This work allows for their evaluation to any desired order in opacity. As an example, we show an application to the modification of light hadron and open heavy flavor fragmentation functions at the EIC. We discuss how this observable can shed light on the physics of hadronization and parton energy loss in large nuclei.

    hep-phnucl-exnucl-th4 citations
  18. 18

    Dense 2-color QCD towards continuum and chiral limits

    Tamer Boz🇮🇪 · Pietro Giudice🇮🇹 · Simon Hands🇬🇧 · Jon-Ivar Skullerud🇮🇪

    We study two-color QCD with two flavors of Wilson fermion as a function of quark chemical potential mu and temperature T, for two different lattice spacings and two different quark masses. We find that the quarkyonic region, where the behaviour of the quark number density and the diquark condensate are described by a Fermi sphere of almost free quarks distorted by a BCS gap, extends to larger chemical potentials with decreasing lattice spacing or quark mass. In both cases, the quark number density also approaches its non-interacting value. The pressure at low temperature is found to approach the Stefan-Boltzmann limit from below.

    hep-lathep-phnucl-thPRD(2020)·60 citations
  19. 19

    Constraining the dense matter equation of state with joint analysis of NICER and LIGO/Virgo measurements

    G. Raaijmakers🇳🇱 · S. K. Greif🇩🇪 · T. E. Riley🇳🇱 · T. Hinderer🇳🇱 · K. Hebeler🇩🇪 · A. Schwenk🇩🇪 · A. L. Watts🇳🇱 · S. Nissanke🇳🇱 · S. Guillot🇫🇷 · J. M. Lattimer🇺🇸 · R. M. Ludlam🇺🇸

    The NICER collaboration recently published a joint estimate of the mass and the radius of PSR J0030+0451, derived via X-ray pulse-profile modeling. Raaijmakers et al. (2019) explored the implications of this measurement for the dense matter equation of state (EOS) using two parameterizations of the high-density EOS: a piecewise-polytropic model, and a model based on the speed of sound in neutron stars. In this work we obtain further constraints on the EOS following this approach, but we also include information about the tidal deformability of neutron stars from the gravitational wave signal of the compact binary merger GW170817. We compare the constraints on the EOS to those set by the recent measurement of a 2.14 solar mass pulsar, included as a likelihood function approximated by a Gaussian, and find a small increase in information gain. To show the flexibility of our method, we also explore the possibility that GW170817 was a neutron star-black hole merger, which yields weaker constraints on the EOS.

    astro-ph.HEnucl-thApJL(2020)·279 citations
  20. 20

    Vortical effects in Dirac fluids with vector, chiral and helical charges

    Victor E. Ambrus🇷🇴 · M. N. Chernodub🇫🇷

    Helicity of free massless Dirac fermions is a conserved, Lorentz-invariant quantity at the level of the classical equations of motion. For a generic ensemble consisting of particles and antiparticles, the helical and chiral charges are different conserved quantities. The flow of helicity can be modelled by the helicity current, which is again conserved in the absence of interactions. Similar to the axial vortical effect which generates an axial (chiral) current, the helicity current is induced by vorticity in a finite temperature medium with vector (electrical) charge imbalance via the helical vortical effects, leading to new nondissipative transport phenomena. These phenomena lead to the appearance of a new hydrodynamic excitation, the helical vortical wave. Our results suggest the existence of a new type of triangle anomalies in QED which involve the helicity currents in addition to the standard vector and axial currents. Further exploiting the conservation of the helical current, we show that a finite helical chemical potential may be used to characterise thermodynamic ensembles of fermions similarly to, but independently of, the vector charge and chirality. We derive the pressure for fermions at finite vector, axial and helical chemical potentials and show that the quantities arising in anomalous transport, including various vortical and circular conductivities and the shear-stress coefficients, can be obtained by differentiation of with respect to the appropriate chemical potentials. Finally, we calculate the helicity relaxation time in the quark-gluon plasma above the crossover and show that it is similar to that for the axial charge.

    hep-thcond-mat.mes-hallnucl-thEPJC(2023)·40 citations

Affiliations

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