Highlights
  • New evaluation and validation toward neutron reaction data on chromium isotopes at incident energies below 200 MeV
    Chromium (Cr) serves as an indispensable structural material in accelerator-driven systems (ADSs) and Generation IV reactors, where the precision of its neutron reaction data is important for ensuring reactor safety and operational reliability. However, significant discrepancies persist in both experimental data and evaluations for key reaction channels, such as $(n, p)$ and $(n, 2n)$, across the chromium isotopes ${}^{50,52,53,54}{\rm{Cr}}$. This paper presents a novel evaluation and validation of neutron reaction data for these isotopes at incident energies below 200 MeV, incorporating 571 experimental datasets from EXFOR covering cross sections, angular distributions, energy spectra, and double - differential cross sections. The newly evaluated data provide more reliable key cross sections: the ${}^{52}{\rm{Cr}}(n,2n)$ cross section resolves discrepancies and supports the data of Liskien et al.; the ${}^{52}{\rm{Cr}}(n, p)$ cross-section aligns well with natural chromium data across all energies and is validated by competition analysis. The results accurately replicate double differential cross sections and energy spectra, with neutron emission spectra matching experimental peaks and charged - particle spectra agreeing with measurements for ${}^{50,52}{\rm{Cr}}$. Moreover, the abundance - weighted sum of $(n, p)$ and $(n, 2n)$ cross sections for chromium isotopes agrees well with natural chromium data, confirming systematic consistency. All evaluations are validated using 62 ICSBEP 2014 benchmark facilities with $ k_{{\rm{eff}}}$ sensitivity to chromium neutron data > 1%. For the PMI002_01 experiment, the calculated $ k_{{\rm{eff}}}$ value decreased by $\sim 1000$ pcm relative to the CENDL - 3.2 results, improving agreement with the benchmark; in the OKTAVIAN shielding benchmark, the neutron leakage spectrum also reproduced experiments well.
  • Effective field theory description of light dilaton
    Dilatons, the CP-even pseudo-Nambu-Goldstone bosons arising from spontaneous scale symmetry breaking, offer a compelling alternative to axion-like particles (ALPs) yet lack a comprehensive low-energy framework. We address this by constructing a systematic effective field theory (EFT) for the dilaton based on a manifestly scale-invariant regularization scheme. This approach derives universal linear couplings to the trace anomaly while preserving consistent renormalization group evolution. We establish a hierarchical EFT tower connecting the ultraviolet conformal sector to the infrared, encompassing the dilaton-extended SMEFT, low-energy EFT up to dimension-7, and a chiral Lagrangian describing meson and baryon interactions. We perform a comprehensive phenomenological analysis across two distinct mass regimes, where the dilaton manifests as either a conventional particle or a wave-like particle. For MeV-scale dilatons behaving as conventional particles, we obtain constraints from LHC production, semi-invisible B- and K-meson decays, and supernova cooling. For ultralight dilatons acting as dark matter, we project sensitivities for atomic clocks and atom interferometers. This unified EFT framework would pave the way for extended phenomenological studies across the full mass spectrum of the light dilaton.
  • Analysis of molecular state ηcD* and J/ψD* in the effective Lagrangian approach
    In this work, we investigate the production and decay of molecular states with quark content $cc\bar c\bar q$ and $J^P=1^+$ using a phenomenological analysis and an effective Lagrangian approach. Based on an SU(3) flavor-symmetry analysis to identify golden channels, we further explore the dynamics of these processes under the molecular assumptions of ${\eta_c D^*}$ and ${J/\psi D^*}$. Our results indicate that the production branching ratio in $B_c$ decays is sizable: it can be of order $10^{-4}$ for the molecular configuration ${{\eta}_cD^*}$ and $10^{-5}$ for the molecule ${J/\psi D^*}$. In addition, we find that the decay widths of the two molecular configurations ${{\eta}_cD^*}$ and ${J/\psi D^*}$ are not significant, at the level of ${\cal{O}}$($\text{MeV}$).
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