arXiv subjects

Dan-Yang Pang

Publications and source records attributed to Dan-Yang Pang.

5 recordsLinked to original sources

arXiv2026

Perturbative calculations of nucleon-deuteron elastic scattering in chiral effective field theory

We develop a framework for calculating nucleon-deuteron scattering using strict perturbation theory for treating subleading interactions in chiral effective field theory (ChEFT). Rather than using direct evaluations in the distorted-wave expansion, our approach solves a hierarchy of integral equations to obtain subleading scattering amplitudes. A benchmark with the wave packet continuum-discretization is performed. This framework benefits from the fact that the renormalization-group invariance chiral forces involves only a limited number of two-body partial waves at leading order. We use it to calculate nucleon-deuteron elastic scattering differential cross sections and analyzing powers up to next-to-leading order.

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arXiv2025

Neutron-deuteron scattering revisited with the EKM chiral nuclear force and the WPCD method

We revisit the neutron-deuteron scattering using the Wave-Packet Continuum Discretization (WPCD) method with the EKM chiral nuclear force at various chiral orders. We rederive the permutation operator and solve the Faddeev-AGS equations directly, without rewriting the initial Faddeev kernel $tG_0$ and introducing pseudo-states, thereby rendering the approach easily extendable to a relativistic framework. We find that up to the next-to-next-to-next-to-leading order (N$^3$LO), although one can well describe the differential cross sections, one cannot resolve the long-standing $A_y$ puzzle, consistent with previous studies. The fact that the N$^3$LO chiral forces can well describe the $NN$ phase shifts and the results obtained with the EKM and Idaho N$^3$LO chiral forces agree with each other underscores the need for further investigations to resolve the $A_y$ puzzle, e.g., considering three-body forces or relativistic effects.

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arXiv2025

Constraining Neutron Capture Cross Sections for $^{88}\mathrm{Y}$ with Gamma-ray Strength Function in $(p,p^\prime\gamma)$ Surrogate Reaction

We demonstrate to extract $^{88}\mathrm{Y}(n,\gamma)$ cross sections using the $(p,p'\gamma)$ surrogate reaction with proper treatment of the spin-parity distribution of the compound nucleus $^{89}\mathrm{Y}$. Experimental data of both $\gamma$-decay probability and $\gamma$-ray strength function are used to constrain the nuclear model parameters within a computational framework combining the Bayesian optimization and Markov chain Monte Carlo method, which helps to significantly reduce the $(n,\gamma)$ data uncertainty. The $^{88}\mathrm{Y}(n,\gamma)$ cross sections are then extracted with a narrow uncertainty of 7.6\%-23.1\% within neutron energy range of 0.01 to 3.0 MeV for the first time, where no experimental data are available. Moreover, our method is verified with the $^{88}\mathrm{Sr}(p,\gamma)$ reaction, of which the measured data are available for comparison. This work opens interesting perspectives on the matter of extracting ($n,\gamma$) reaction cross sections on unstable nuclei as surrogate reaction experiments are becoming widely available.

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arXiv2024

Single-proton removal reaction in the IQMD+GEMINI model benchmarked by elemental fragmentation cross sections of $^{29-33}\mathrm{Si}$ on carbon at $\sim$230~MeV/nucleon

We report on the first measurement of the elemental fragmentation cross sections (EFCSs) of $^{29-33}\mathrm{Si}$ on a carbon target at $\sim$230~MeV/nucleon. The experimental data covering charge changes of $\Delta Z$ = 1-4 are reproduced well by the isospin-dependent quantum molecular dynamics (IQMD) coupled with the evaporation GEMINI (IQMD+GEMINI) model. We further explore the mechanisms underlying the single-proton removal reaction in this model framework. We conclude that the cross sections from direct proton knockout exhibit a overall weak dependence on the mass number of $\mathrm{Si}$ projectiles. The proton evaporation induced after the projectile excitation significantly affects the cross sections for neutron-deficient $\mathrm{Si}$ isotopes, while neutron evaporation plays a crucial role in the reactions of neutron-rich $\mathrm{Si}$ isotopes. It is presented that the relative magnitude of one-proton and one-neutron separation energies is an essential factor that influences evaporation processes.

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arXiv2021

Experimental study of intruder components in light neutron-rich nuclei via single-nucleon transfer reaction

With the development of radioactive beam facilities, studies concerning the shell evolution of unstable nuclei have recently gained prominence. Intruder components, particularly s-wave intrusion, in the low-lying states of light neutron-rich nuclei near N=8 are of importance in the study of shell evolution. The use of single-nucleon transfer reactions in inverse kinematics has been a sensitive tool that can be used to quantitatively investigate the single-particle orbital component of selectively populated states. The spin-parity, spectroscopic factor (or single-particle strength), and effective single-particle energy can all be extracted from such reactions. These observables are often useful to explain the nature of shell evolution, and to constrain, check, and test the parameters used in nuclear structure models. In this article, the experimental studies of the intruder components in low-lying states of neutron-rich nuclei of He, Li, Be, B, and C isotopes using various single-nucleon transfer reactions are reviewed. The focus is laid on the precise determination of the intruder s-wave strength in low-lying states.

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