Tue·Nov 25, 2025Tuesday·November 25, 2025

1. 01*

   Two-pion exchange contributions to the relativistic chiral nuclear force at N${}^3$LO

   Jun-Xu Lu🇨🇳 · Li-Sheng Geng🇨🇳

   We present the two-pion exchange contributions to the nucleon-nucleon interaction up to next-to-next-to-next-to leading order (N${}^3$LO) in covariant baryon chiral perturbation theory. Both one-loop and two-loop diagrams are calculated with the spectral functional regularization. We show that the phase shifts for partial waves with total angular momentum $3\le J\le 5$ are in better agreement with the partial wave analysis from the Nijmegen or the SAID group than their N${}^2$LO counterparts. In addition, the relativistic chiral force exhibits better convergence than its non-relativistic counterpart, suggesting the importance of relativistic corrections.

   ↳ nucl-thhep-phnucl-exPRC(2026)·2 citations
2. 02*

   Proton mass decompositions in the NNLO QCD

   Kazuhiro Tanaka (Juntendo Univ.)🇯🇵

   Proton matrix elements of the QCD energy-momentum tensor (EMT) are expressed by the gravitational form factors. The forward values of the gravitational form factors allow for a decomposition of the proton mass into contributions from quarks and gluons, and further subdivisions into contributions from quark masses and from the QCD trace anomaly may be considered. We present the most recent evaluations of these mass decompositions, using a recent quantitative evaluation of the forward values of relevant gravitational form factors at the next-to-next-to-leading order (NNLO) QCD. We also calculate the renormalization scale dependence of each component within these decompositions. Furthermore, similar calculations are performed with another decomposition of the proton mass, organized strictly according to the separation into the traceless part and trace part for each of the gauge-invariant quark/gluon parts of the EMT, such that the former (twist-two) quark/gluon contributions of the EMT embody the effects of the partonic motions inside the proton, while the latter (twist-four) contributions are induced as parton correlations by non-perturbative QCD interactions. We demonstrate the advantages of this new decomposition. We also present the results for the pion, which exhibit quite different parton-correlation behaviors from the proton.

   ↳ hep-phhep-exhep-latnucl-ex+14 citations
3. 03*

   Puzzling Isotonic Odd-Even Staggering of Charge Radii in Deformed Rare Earth Nuclei

   Endre Takacs🇺🇸 · Hunter Staiger🇺🇸 · Steven A. Blundell · Naoki Kimura · Hiroyuki A. Sakaue · Ronald F. Garcia Ruiz🇺🇸 · Witold Nazarewicz🇺🇸 · Paul-Gerhard Reinhard🇩🇪 · Chowdhury A. Faiyaz · Chihiro Suzuki · Dipti🇺🇸 · István Angeli🇭🇺 and 7 other authors

   The nuclear charge radius is a fundamental observable that encodes key aspects of nuclear structure, deformation, and pairing. Isotonic (constant neutron number) systematics in the deformed rare-earth region have long suggested that odd-$Z$ nuclei are more compact than their even-$Z$ neighbors - except for Lu, whose recommended radius appeared anomalously large relative to Yb and Hf. We report a high-precision determination of the natural-abundance-averaged Lu-Yb charge-radius difference using extreme-ultraviolet spectroscopy of highly charged Na-like and Mg-like ions, supported by high-accuracy relativistic atomic-structure calculations - a recently introduced method with the unique ability to measure inter-element charge radius differences. Combined with muonic-atom and optical isotope-shift data, our result resolves the longstanding Lu inversion anomaly and reestablishes a pronounced odd-even staggering along the $N=94$ isotonic chain. The magnitude of this staggering is unexpectedly large, far exceeding that observed in semi-magic nuclei and in deformed isotopic sequences. State-of-the-art nuclear density functional theory calculations, including quantified uncertainties, fail to reproduce this enhancement, possibly indicating missing structural effects in current models. Our work demonstrates the power of highly charged ions for precise, element-crossing charge-radius measurements and provides stringent new constraints for future theoretical and experimental studies of nuclear-size systematics.

   ↳ physics.atom-phnucl-ex4 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.