Nuclear Theory·nucl-th

Wednesday·September 8, 2021

6 papers—2 primary·4 cross-listed

01
Effective Range Expansion for Describing a Virtual State
C. Wibisono
I present numerical study of an elastic scattering by solving second order differential equations of Schroedinger Equation for some types of central potential (eg. square well, Yukawa, and Woods-Saxon) to find the wave function inside the potential, and extending the solution with the region outside the range of potential. The wave function outside the range of potential can be expanded in terms of spherical bessel and neumann function. At the boundary, logarithmic derivative is found which becomes a base to compute the phase shift. Once we have a phase shift, the scattering amplitude can then be expanded in terms of polynomial legendre, and the differential cross section can be deduced. Furthermore, the scattering at low energies is studied and the connection to the effective range expansion is discussed to determine the scattering length and effective radius. The signature of the virtual state from the scattering of $1$ neutron from $11$ nucleons are found for each potential and the energies are best described by the inclusion of the $O (k^{10})$ in the effective range expansion.
nucl-thquant-ph0 citations
02
Binding energy shifts from heavy-ion experiments in a nuclear statistical equilibrium model
S. Mallik🇮🇳 · H. Pais🇵🇹 · F. Gulminelli🇫🇷
Chemical constants extracted from $^{124}$ Xe+ $^{124}$ Sn collisions at 32 AMeV are compared to the predictions of an extended Nuclear Statistical Equilibrium model including mean-field interactions and in-medium binding energy shifts for the light ( $Z \leq 2$ ) clusters. The ion species and density dependence of the in-medium modification is directly extracted from the experimental data. We show that the shift increases with the mass of the cluster and the density of the medium, and we provide a simple linear fit for future use in astrophysical simulations in the framework of the CompOSE data base. The resulting mass fractions are computed in representative thermodynamic conditions relevant for supernova and neutron star mergers. A comparison to the results of a similar analysis of the same data performed in the framework of a relativistic mean-field model shows a good agreement at low density, but significant discrepancies close to the Mott dissolution of clusters in the dense medium.
nucl-thastro-ph.SRnucl-exEPJA(2021)·2 citations
03
Dissipative Magnetohydrodynamics for Non-Resistive Relativistic Plasmas
Elias R. Most🇺🇸 · Jorge Noronha🇺🇸
Based on a 14-moment closure for non-resistive (general-) relativistic viscous plasmas, we describe a new numerical scheme that is able to handle all first-order dissipative effects (heat conduction, bulk and shear viscosities), as well the anisotropies induced by the presence of magnetic fields. The latter is parameterized in terms of a thermal gyrofrequency or, equivalently, a thermal Larmor radius and allows to correctly capture the thermal Hall effect. By solving an extended Israel-Stewart-like system for the dissipative quantities that enforces algebraic constraints via stiff-relaxation, we are able to cast all first-order dissipative terms in flux-divergence form. This allows us to apply traditional high-resolution shock capturing methods to the equations, making the system suitable for the numerical study of highly turbulent flows. We present several numerical tests to assess the robustness of our numerical scheme in flat spacetime. The 14-moment closure can seamlessly interpolate between the highly collisional limit found in neutron star mergers, and the highly anisotropic limit of relativistic Braginskii magnetohydrodynamics appropriate for weakly collisional plasmas in black-hole accretion problems. We believe that this new formulation and numerical scheme will be useful for a broad class of relativistic magnetized flows.
↳ astro-ph.HEgr-qcnucl-thphysics.comp-ph+1PRD(2021)·42 citations
04
Holographic charm and bottom pentaquarks III: Excitations through photo-production of heavy mesons
Yizhuang Liu🇵🇱 · Kiminad A. Mamo🇺🇸 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸
We consider the photo-excitation of charm and bottom pentaquarks with the holographic assignments $[\frac{1}{2} \frac{1}{2}^{-}]_{S = 0, 1}$ and $[\frac{1}{2} \frac{3}{2}^{-}]_{S = 1}$ , in the photo-production of heavy vector mesons such as charmonia and bottomonia near threshold. We use a Witten diagram to combine the s-channel photo-excitation of holographic pentaquarks with a massive t-channel graviton or tensor glueball exchange, to extract the scattering amplitude for heavy meson photo-production in the threshold region. The pentaquark signal is too weak to be detected at current electron facilities.
↳ hep-phhep-thnucl-exnucl-thPRD(2021)·10 citations
05
SU(3) flavor symmetry considerations for the $K ˉ N$ coupled channels system
P. C. Bruns🇨🇿 · A. Cieplý🇨🇿
We study the impact of SU(3) flavor symmetry breaking on the properties of dynamically generated $Λ^{*}$ states within an effective separable potential model describing the coupled channels $K ˉ N$ system. The model is based on the chiral meson-baryon Lagrangian at next-to-leading order, and constitutes an improvement over a previous model developed by our group, with its applicability being extended to higher energies covering the $Λ (1670)$ resonance region. It is demonstrated that the ratios of channel couplings to the resonant states can vary dramatically when the flavor breaking is gradually switched off, tracing a path to the restored SU(3) symmetry. We conclude that the couplings determined from physical observables cannot be used to reliably relate a given resonance to a specific flavor multiplet.
↳ hep-phnucl-thNPA(2022)·20 citations
06
Determination of $1 p$ and $2 p$ stripping excitation functions for $^{16}$ O+ $^{142}$ Ce using a Recoil Mass Spectrometer
Rohan Biswas · S. Nath · J. Gehlot · Gonika · Chandra Kumar · A. Parihari · N. Madhavan · A. Vinayak · Amritraj Mahato · Shoaib Noor · Phurba Sherpa · Kazuyuki Sekizawa
We report the first direct measurement of differential transfer cross sections using a Recoil Mass Spectrometer. Absolute differential $1 p$ and $2 p$ -stripping cross sections at $θ_{c.m.} = 18 0^{\circ}$ have been determined for the system $^{16}$ O+ $^{142}$ Ce by detecting the heavier target-like ions at the focal plane of the Heavy Ion Reaction Analyzer. Focal plane spectra have been compared with the results of a semi-microscopic Monte-Carlo simulation to unambiguously identify the transfer channels. Transmission efficiency of the target-like ions through the spectrometer has also been estimated using the simulation. The methodology adopted in this work can be applied to other recoil separators. The measured excitation functions for the reactions $^{142} Ce (^{16} O,^{15} N)^{143} Pr$ and $^{142} Ce (^{16} O,^{14} C)^{144} Nd$ have been compared with coupled reaction channel calculations. An excellent matching between measurement and theory has been obtained. For $1 p$ -stripping, major contribution to the cross section has been found to be the transfer of a proton from $^{16} O$ to the $2 d_{\frac{5}{2}}$ excited state of $^{143} Pr$ , leaving behind $^{15} N$ in the $1 p_{\frac{1}{2}}$ ground state. Transfer of a cluster of two protons from $^{16} O$ to the $2^{+}$ excited state of $^{144} Nd$ , resulting in $^{14} C$ in the $0^{+}$ ground state, appears to be the most probable cause for $2 p$ -stripping. Measured transfer probabilities for $1 p$ and $2 p$ channels have been compared with Time-Dependent Hartree-Fock calculations. Proton stripping channels are found to be more favourable compared to neutron pick-up channels. However, the theory overpredicts measurement hinting at the need for extended approaches with explicit treatment of pairing correlations in the calculations.
↳ nucl-exnucl-thEPJA(2023)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Effective Range Expansion for Describing a Virtual State

Binding energy shifts from heavy-ion experiments in a nuclear statistical equilibrium model

Dissipative Magnetohydrodynamics for Non-Resistive Relativistic Plasmas

Holographic charm and bottom pentaquarks III: Excitations through photo-production of heavy mesons

SU(3) flavor symmetry considerations for the KˉN coupled channels system

Determination of 1p and 2p stripping excitation functions for 16O+142Ce using a Recoil Mass Spectrometer

Affiliations

SU(3) flavor symmetry considerations for the $K ˉ N$ coupled channels system

Determination of $1 p$ and $2 p$ stripping excitation functions for $^{16}$ O+ $^{142}$ Ce using a Recoil Mass Spectrometer