Nuclear Theory·nucl-th
12 papers—8 primary·4 cross-listed
In 1967 Akito Arima spent a year as a visiting professor in the physics department of Rutgers University. In this work we pay tribute to him by discussing topics that we worked on that were directly influenced by his works or were closely related to his interests. These include nuclear Symmetries, magnetic and other moments, analytic expressions in the single shell model and schematic interactions.
Tomoatsu Edagawa · Kazuki Yoshida · Yoshiki Chazono · Kazuyuki Ogata
The effective polarization of the residual nucleus in the proton-induced knockout reaction is investigated within the distorted wave impulse approximation framework. The strong absorption of the emitted particle results in strong selectivity on the reaction "position" depending on the third component of the single-particle orbital angular momentum of the particle inside a nucleus, hence on the spin direction of the reaction residue. This is caused by a mechanism that is similar to the Maris effect, the effective polarization in the proton-induced proton knockout reactions. However, as a distinct feature of the effective polarization in the knockout process, the spin degrees of freedom of the reacting particles play no role. The knockout process with complete kinematics can be a useful polarization technique for the residual nucleus, without actively controlling the spin of the proton.
Margaret E. Carrington🇨🇦 · Alina Czajka🇵🇱 · Stanislaw Mrowczynski🇵🇱
We calculate the transverse momentum broadening and collisional energy loss of hard probes traversing an evolving glasma during the earliest phase of a relativistic heavy-ion collision. We use a Fokker-Planck equation and apply a proper time expansion to describe the temporal evolution of the glasma. The correlators of the chromodynamic fields that determine the Fokker-Planck collision terms, which in turn provide and , are computed to fifth order. Both transport coefficients are strongly dependent on time. The maximum values they acquire before the proper time expansion breaks down are large: is of the order of a few and . Their precise values depend on the probe's velocity , the saturation momentum , and an IR regulator that is related to the confinement scale. We study the dependence of our results on these quantities. Different regularization procedures are analysed and shown to produce similar results. We also discuss the validity of the proper time expansion and the compatibility of the approximations that are inherent in the derivation of the Fokker-Planck equation. We show that hard probes lose a comparable amount of energy when they propagate through the short-lived glasma phase, and the long-lasting hydrodynamic phase. The conclusion is that the glasma plays an important role in jet quenching.
H. Ejiri🇯🇵 · L. Jokiniemi🇪🇸 · J. Suhonen🇫🇮
Nuclear matrix elements (NMEs) for neutrinoless double beta decays (DBDs) are required for studying neutrino physics beyond the standard model by DBD. The experimental spin-dipole (SD) giant resonance energy and the SD strength are shown for the first time to be closely related to the DBD-NME, and are used for studying the spin-isospin correlation and the quenching of the axial-vector coupling. So they are used to help the theoretical model calculation of the DBD-NME.
Bhoomika Maheshwari · Deepika Choudhury · Ashok Kumar Jain
The puzzle of finding consistent nuclear configurations for explaining both the decay probabilities and moments of the , and isomers in and around closed shell has been approached in the generalized seniority scheme. Though is the dominant orbital near Fermi energy, the role of configuration mixing from the surrounding and orbitals is found to be very important for the consistent explanation of all the isomeric properties such as the rates, moments and factors. The structural behavior of the closed shell isotonic isomers turns out to be very similar to the and isotonic isomers which have two neutron-holes and two neutron-particles, respectively. This is due to the pairing symmetries of nuclear many-body Hamiltonian. As a confirmation, the microscopic shell model occupancies are also calculated for these isomers in chain which support the generalized seniority results. Additional arguments using the systematics of odd-proton states in Tl (), Bi (), At () and Fr () isotopes are also presented.
Staring from the Lagrangian density that foots on the meson-propagated picture of nuclear force, the full Hamiltonian, that contains both mean field and pairing contributions, is derived by quantizing the Dirac spinor field in the Bogoliubov quasi-particle space, and the expectation with respect to the Bogoliubov ground state gives the full energy functional. As an extension of the D-RHF model, the degree of freedom associated with the -tensor (-T) coupling is implemented, and incorporating with the Bogoliubov scheme the finite-range Gogny force D1S is utilized as the pairing force. Moreover, qualitative analysis on the nature of the -PV and -T couplings are presented for better understanding their enhancements on the deformation effects. Space convergence related to the spherical DWS base is confirmed for the D-RHFB model by taking light nucleus Mg and mid-heavy one Sm as candidates. Compared to light nuclei, extraordinary more negative energy states are necessitated to keep the expansion completeness on the spherical DWS base for mid-heavy and heavy nuclei, due to the enhanced correlations between the expansion components with large -quantity as indicated by the nature of the -PV and -T couplings. Furthermore, because of the enhanced deformation effects by the -PV and -T couplings, the RHF Lagrangian PKA1 presents deeper bound ground state for Mg than the other selected Lagrangians, in addition to predicting a fairly deep bound local minimum with large oblate deformation.
N. Hasegawa · K. Hagino · Y. Tanimura
We reply to the criticisms of our publication (N. Hasegawa, K. Hagino, and Y. Tanimura, Phys. Lett. B808, 135693 (2020)) made by A. Ono in his recent article, arXiv:2201.02966.
M. Shahrbaf🇵🇱 · D. Blaschke🇵🇱 · S. Typel🇩🇪 · G. R. Farrar🇺🇸 · D. E. Alvarez-Castillo🇷🇺
Following the idea that a stable sexaquark state with quark content (uuddss) would have gone unnoticed by experiment so far and that such a particle would be a good dark matter candidate, we investigate the possible role of a stable sexaquark in the physics of compact stars given the stringent constraints on the equation of state that stem from observations of high mass pulsars and GW170817 bounds on the compactness of intermediate mass stars. We find that there is a "sexaquark dilemma" (analogous to the hyperon dilemma) for which the dissociation of the sexaquark in quark matter is a viable solution fulfilling all present constraints from multi-messenger astronomy. The parameters needed to model the hybrid star including sexaquarks are in line with parameters of pre-existing quark- and hadronic-matter models. We find that current constraints -- tidal deformability in accordance with GW170817 and maximum mass above the lower limit from PSR J0740+6620 -- can be satisfied two ways: with early quark deconfinement such that neither sexaquarks nor hyperons are present in any NS interiors, or with later deconfinement such that a neutron-sexaquark shell surrounds the inner quark matter core.
Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸
This work is a continuation in our series of papers, that addresses quark models of hadronic structure on the light front. The chief focus of this paper is the quantum-mechanical solution of the three-quark model Hamiltonian, describing baryons. In Jacobi coordinates, we use a harmonic oscillator basis for the transverse directions. For the longitudinal momentum fractions , the pertinent basis follows from quantum mechanics in a "triangular cup" potential, which we solve exactly. We calculate the masses and light front wave functions for the flavor symmetric baryons .
Fangcheng He🇨🇳 · Chueng-Ryong Ji🇺🇸 · W. Melnitchouk🇺🇸 · A. W. Thomas🇦🇺 · P. Wang🇨🇳
We calculate the spin-averaged generalized parton distributions (GPDs) of sea quarks in the proton at zero skewness from nonlocal covariant chiral effective theory, including one-loop contributions from intermediate states with pseudoscalar mesons and octet and decuplet baryons. A relativistic regulator is generated from the nonlocal Lagrangian where a gauge link is introduced to guarantee local gauge invariance, with additional diagrams from the expansion of the gauge link ensuring conservation of electric charge and strangeness. Flavor asymmetries for sea quarks at zero and finite momentum transfer, as well as strange form factors, are obtained from the calculated GPDs, and results compared with phenomenological extractions and lattice QCD.
Thomas Vonk🇩🇪 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪
The process of pion axioproduction, , with an intermediate resonance is analyzed using baryon chiral parturbation theory. The resonance is included in two ways: First, deriving the -vertices, the axion is brought into contact with the resonance, and, second, taking the results of elastic scattering including the , it is implicitly included in the form of a pion rescattering diagram. As a result, the partial wave cross section of axion-nucleon scattering shows an enhancement in the energy region around the resonance. Because of the isospin breaking, the enhancement is not as pronounced as previously anticipated. However, since the isospin breaking here is much milder than that for usual hadronic processes, novel axion search experiments might still exploit this effect.
Yuji Koike🇯🇵 · Kazuki Takada🇯🇵 · Sumire Usui🇯🇵 · Kenta Yabe🇯🇵 · Shinsuke Yoshida🇨🇳
We study the transverse polarization of hyperons produced in semi-inclusive deep inelastic scattering, , in the framework of the collinear twist-3 factorization. The cross section from the twist-3 distribution functions and the twist-3 quark fragmentation functions is computed in the leading order with respect to the QCD coupling constant. The constraint relations among the twist-3 FFs are taken into account to simplify the formula. The formula is relevant to large- hyperon production in the future Electron-Ion-Collider experiment.
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