Nuclear Theory·nucl-th

Monday·December 23, 2019

10 papers—6 primary·4 cross-listed

07
$π π$ scattering in a renormalized Hamiltonian matrix
María Gómez-Rocha🇪🇸 · Enrique Ruiz Arriola🇪🇸
A Wilsonian approach to $π π$ scattering based in the Glazek-Wilson Similarity Renormalization Group (SRG) for Hamiltonians is analyzed in momentum space up to a maximal CM energy of $s = 1.4$ GeV. To this end, we identify the corresponding relativistic Hamiltonian by means of the 3D reduction of the Bethe-Salpeter equation in the Kadyshevsky scheme, introduce a momentum grid and provide an isospectral definition of the phase-shift based on a spectral shift of a Chebyshev angle. We also propose a new method to integrate the SRG equations based on the Crank-Nicolson algorithm with a single step finite difference so that isospectrality is preserved at any step of the calculations. We discuss issues on the unnatural high momentum tails present in the fitted interactions and reaching far beyond the maximal CM energy of $s = 1.4$ GeV and how these tails can be integrated out explicitly by using Block-Diagonal generators of the SRG.
↳ hep-phnucl-thPoS(2020)·0 citations
08
Early signal of emerging nuclear collectivity in neutron-rich $^{129}$ Sb
T.J. Gray · J.M. Allmond · A.E. Stuchbery · C.-H. Yu · C. Baktash · A. Gargano · A. Galindo-Uribarri · D.C. Radford · J.C. Batchelder · J.R. Beene · C.R. Bingham · L. Coraggio and 11 other authors
Radioactive $^{129}$ Sb, which can be treated as a proton plus semi-magic $^{128}$ Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, $B (E 2)$ , for the $2^{+}$ $\times$ $π g_{7/2}$ multiplet members and candidate $π d_{5/2}$ state were measured. The results indicate that the total electric quadrupole strength of $^{129}$ Sb is a factor of 1.39(11) larger than the $^{128}$ Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wavefunctions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.
↳ nucl-exnucl-thPRL(2020)·22 citations
09
Isospin violating decay $D_{s}^{*} \to D_{s} π^{0}$ in chiral perturbation theory
Bin Yang🇨🇳 · Bo Wang🇨🇳 · Lu Meng🇨🇳 · Shi-Lin Zhu🇨🇳
We systematically calculate the isospin violating decay, $D_{s}^{*} \to D_{s} π^{0}$ , with the heavy meson chiral perturbation theory up to $O (p^{3})$ including the loop diagrams. The $O (p^{3})$ tree level amplitudes contain four undetermined LECs. We use two strategies to estimate them. With the nonanalytic dominance approximation, we get $Γ [D_{s}^{*} \to D_{s} π^{0}] = (3.38 \pm 0.12)$ eV. With the naturalness assumption, we give a possible range of the isospin violating decay width, $[1.11 - 6.88]$ eV. We find that the contribution of the $O (p^{3})$ corrections might be significant.
↳ hep-phhep-exhep-latnucl-thPRD(2020)·10 citations
10
Twin stars and the stiffness of the nuclear equation of state: ruling out strong phase transitions below $1.7 n_{0}$ with the new NICER radius measurements
Jan-Erik Christian · Jürgen Schaffner-Bielich
We explore the connection between the stiffness of an hadronic equation of state (EoS) with a sharp phase transition to quark matter to its tidal deformability. For this we employ a hadronic relativistic mean field model with a parameterized effective nucleon mass to vary the stiffness in conjunction with a constant speed of sound EoS for quark matter. We compute multiple scenarios with phase transitions according to the four possible cases of a hybrid star EoS with a stable second branch. We demonstrate at the example of GW170817 how the effective nucleon mass can be constrained by using gravitational wave data. We find, that certain values of the effective nucleon mass are incompatible with GW170817 and a phase transition simultaneously. By using the recent NICER measurements of J0030+0451 at the $1 σ$ level we constrain our results further and find that strong phase transitions with a visible jump in the mass-radius relation are ruled out at densities below 1.7 times saturation density.
↳ astro-ph.HEnucl-thApJL(2020)·78 citations

Affiliations

first authorsco-authorsvia INSPIRE

ππ scattering in a renormalized Hamiltonian matrix

Early signal of emerging nuclear collectivity in neutron-rich 129Sb

Isospin violating decay Ds∗​→Ds​π0 in chiral perturbation theory

Twin stars and the stiffness of the nuclear equation of state: ruling out strong phase transitions below 1.7n0​ with the new NICER radius measurements

Affiliations

$π π$ scattering in a renormalized Hamiltonian matrix

Early signal of emerging nuclear collectivity in neutron-rich $^{129}$ Sb

Isospin violating decay $D_{s}^{*} \to D_{s} π^{0}$ in chiral perturbation theory

Twin stars and the stiffness of the nuclear equation of state: ruling out strong phase transitions below $1.7 n_{0}$ with the new NICER radius measurements