Nuclear Theory·nucl-th

Monday·September 17, 2018

5 papers—3 primary·2 cross-listed

01
Masses of the doubly heavy tetraquarks in a constituent quark model
Woosung Park🇰🇷 · Sungsik Noh🇰🇷 · Su Houng Lee🇰🇷
We perform a constituent quark model analysis for the masses of the doubly heavy tetraquark states $T_{QQ}$ after we fix the parameters to fit the masses of the newly observed $Ξ_{cc}^{++}$ and hadrons involving heavy quarks relevant to the stability of these states. We investigate in detail how the relative distances between quark pairs vary as we change the quark content and how they affect the various contributions to the total tetraquark masses. We also find that our full calculations give in general less binding compared to simplified quark model calculations that treat quark dynamics inside the tetraquark the same as that inside a baryon. We trace the main origin to be the differences in the number of relative kinetic energies which increases as one goes from meson, baryon and tetraquarks. We also compare our new results with previous works using less constrained parameters and find that the tetraquark state $T_{bb} (u d b ˉ b ˉ)$ and $T_{bb} (u s b ˉ b ˉ)$ are bound by 120.56 MeV and 7.3 MeV respectively.
nucl-thhep-phNPA(2019)·83 citations
02
Correlations among symmetry energy elements in Skyrme models
C. Mondal · B. K. Agrawal · J. N. De · S. K. Samaddar
Motivated by the interrelationships found between the various symmetry energy elements of the energy density functionals (EDF) based on the Skyrme forces, possible correlations among them are explored. A total of 237 Skyrme EDFs are used for this purpose. As some of these EDFs yield values of a few nuclear observables far off from the present acceptable range, studies are done also with a subset of 162 EDFs that comply with a conservative set of constraints on the values of nuclear matter incompressibility coefficient, effective mass of the nucleon and the isovector splitting of effective nucleon masses to see the enhancement of the correlation strength, if any. The curvature parameter $K_{sy m}^{0}$ and the skewness parameter $Q_{sy m}^{0}$ of the symmetry energy are found to be very well correlated with the linear combination of the symmetry energy coefficient and its density derivative $L_{0}$ . The isovector splitting of the effective nucleon mass, however, displays a somewhat meaningful correlation with a linear combination of the symmetry energy, its slope and its curvature parameter.
nucl-thIJMPE(2018)·15 citations
03
Least action description of spontaneous fission in fermium and nobelium nuclei based on the Gogny energy density functional
R. Rodriguez-Guzman · L.M. Robledo
The systematic of the spontaneous fission half-lives for the nuclei $^{242 - 262}$ Fm and $^{250 - 260}$ No is analyzed, within a least action scheme, with the parametrization D1M of the Gogny energy density functional. The properties of the dynamic (least action) fission paths are analyzed and compared to those of the static (minimal energy) ones. The constrained Hartree-Fock-Bogoliubov approximation is used to compute deformed mean-field configurations, zero-point quantum corrections and collective inertias. It is shown that a cumbersome full variational search of the least action fission path, within the space of HFB states, might not be required if the relevant degrees of freedom are taken into account in the minimization of the Wentzel-Kramers-Brillouin action. The action is minimized in terms of pairing fluctuations that explore the pairing content of the HFB states along the fission paths of the considered nuclei. It is found that, for a given shape, the minimum of the action in fermium and nobelium nuclei corresponds to a value of the pairing fluctuations larger than the one associated with the minimal energy solution for the same shape. The reduction of the action, via larger pairing correlations, has a significant impact on the predicted spontaneous fission half-lives improving their comparison with the experiment by several orders of magnitude.
nucl-thPRC(2018)·24 citations

Affiliations

first authorsco-authorsvia INSPIRE

Masses of the doubly heavy tetraquarks in a constituent quark model

Correlations among symmetry energy elements in Skyrme models

Least action description of spontaneous fission in fermium and nobelium nuclei based on the Gogny energy density functional

Affiliations