Constraining the nuclear equation of state with muonic x-ray spectroscopy

This repository contains the pre-publication manuscript and the complete source code for RASTAMAN (Relativistic All-order Self-consistent Tool for Axial Multicomponent Analysis of Nuclei). The RASTAMAN framework introduces a novel terrestrial anchor for the nuclear equation of state (EoS) by dynamically modeling the $2p \to 1s$ isotopic shift in muonic lead ($^{208}\mathrm{Pb} - ^{206}\mathrm{Pb}$). By integrating this purely electromagnetic probe with pure neutron matter Chiral Effective Field Theory ($\chi$EFT), NICER mass-radius profiles, and the tidal deformability limits of LIGO GW170817, this joint multi-messenger Bayesian analysis successfully resolves the persistent symmetry energy degeneracy ($L$-$K_{sym}$) and bridges the tension between terrestrial hadronic probes (PREX-II, CREX). Key Results: Symmetry Energy Slope: $L = 52.90^{+6.01}_{-6.49}$ MeV Symmetry Energy Curvature: $K_{sym} = -70.05^{+21.30}_{-21.40}$ MeV Repository Contents muon_EoS_manuscript.pdf: The full text of the preliminary manuscript detailing the theoretical framework, systematic uncertainties, and astrophysical synthesis. rastaman_mrsa.py: The primary Python orchestrator. Handles the coupled Dirac-Hartree-Bogoliubov (DIRHB) spatial relaxation, explicit QED potentials, parity-violating weak interactions, and the Macroscopic Sum Rule Approximation (MSRA) for Dynamic Nuclear Polarization (DNP). analyzeRASTAMAN.py: The Gaussian Process emulator and affine-invariant ensemble sampler (emcee) used to generate the joint posterior distributions. rastaman_msra_production.csv: The raw data outputs from the systematic functional sweep (DD-ME-L parameterizations). ModifiedDIRHB/: The modified FORTRAN mathematical engine based on DIRHBspeedup. Citation This repository establishes the muonic EoS constraint methodology and the resulting $L$ and $K_{sym}$ values prior to formal journal and arXiv publication. If you utilize the RASTAMAN codebase or the preliminary data contained in this repository for your own research, you are required to cite this Zenodo record: Rampair, A. (2026). RASTAMAN Framework & Preprint: Constraining the Nuclear Equation of State with Muonic X-ray Spectroscopy [Software & Preprint]. Zenodo. https://doi.org/10.5281/zenodo.20126662 System Requirements & Usage RASTAMAN requires a Unix-like environment (Linux, macOS, or Windows Subsystem for Linux) to compile the underlying FORTRAN core. Navigate to the ModifiedDIRHB/dirhbz directory. Compile the core using a standard FORTRAN compiler (e.g., make). Execute the Python orchestrator: python3 rastaman_mrsa.py. The script will automatically resolve the portable directory structure and execute the self-consistent loop. License and Third-Party Components Software: The RASTAMAN Python architecture is released under the GNU General Public License v3.0 or later (GPL-3.0-or-later). Preprint: The manuscript PDF is released under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Third-Party Code: This package includes modifications of the DIRHB nuclear structure package (T. Nikšić et al., Comput. Phys. Commun. 185, 1808, 2014) and the DIRHBspeedup optimization (A. Bjelčić et al., 2021). These specific FORTRAN components are redistributed under the CPC Program Library License for non-commercial research use.