Nuclear Theory·nucl-th

Tuesday·January 13, 2026

12 papers—6 primary·6 cross-listed

07
[Submitted on 9 Jan 2026] (cross-list from nucl-ex)
Direct transfer to $^{46, 48}$ K as a survey of the $π (s_{1/2})$ $- ν (s d p f)$ interaction
C. J. Paxman🇬🇧 · A. Matta🇫🇷 · W. N. Catford🇬🇧 · G. Lotay🇬🇧 · M. Assié🇫🇷 · E. Clément🇫🇷 · A. Lemasson🇫🇷 · D. Ramos🇫🇷 · N. A. Orr🇫🇷 · F. Galtarossa🇫🇷 · V. Girard-Alcindor🇫🇷 · J. Dudouet🇫🇷 and 67 other authors
The collapse of the canonical $N = 28$ magic number in nuclei with $Z < 20$ has drawn significant interest as it relates to the emergence of an island of inversion centered on $^{42}$ Si and $^{44}$ S. In particular, interactions between the $π s_{1/2}$ orbital -- empty in $^{42}$ Si and full in $^{44}$ S -- and the neutron orbitals just above and below the $N = 28$ gap are expected to be critical in this region, but remain relatively unexplored. In this paper, we expand upon the results of our previous study of the direct transfer reaction $^{47}$ K(d,p $γ$ ) $^{48}$ K [C.\,J.~Paxman \textit{et al.}, Phys. Rev. Lett. 134, 162504 (2025)] with the results of the complementary $^{47}$ K(d,t $γ$ ) $^{46}$ K reaction. Through this study, we present a comprehensive scan of the interaction between the critical $π s_{1/2}$ orbital and a broad range of neutron orbitals spanning nearly two full shells. We identify several discrepancies between the experimental results and state-of-the-art shell model calculations, which suggest a deficiency of the shell model to fully capture the complex proton configuration mixing in this region, highlighting a significant challenge for single-particle descriptions of the island of inversion.
Comments:
15 pages, 18 figures. To be submitted to Phys. Rev. C
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2601.06242 [pdf]
0 citations
08
[Submitted on 9 Jan 2026] (cross-list from hep-ph)
Hadronic Probes of Non-Standard Neutrino Interactions
Carlos Henrique de Lima🇨🇦 · David McKeen🇨🇦 · John Ng🇨🇦 · Douglas Tuckler🇨🇦
In this work, we study leptonic decays of hadrons as probes of light neutrinophilic scalars that mediate enhanced neutrino self-interactions. Such scalars can be emitted in processes involving neutrinos, turning two-body decays into three-body final states and producing characteristic spectral distortions. We compute these effects for charged pion decay and nuclear electron capture decay, including both on-shell and off-shell scalar emission, as well as the loop-induced renormalization required to cancel divergences. Using these results, we derive the projected sensitivity of PIONEER and assess the current and future reach of BeEST. The resulting low-energy spectral tails provide a characteristic signal for light neutrinophilic scalars, making upcoming hadron decay experiments powerful probes of light mediators of non-standard neutrino self-interactions.
Comments:
14 pages 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2601.06248 [pdf]
PRD(2026)·2 citations
09
[Submitted on 10 Jan 2026] (cross-list from hep-lat)
Lattice QCD determination of the $γ Z$ box contribution to the proton weak charge
Zhao-long Zhang🇨🇳 · Xu Feng🇨🇳 · Mikhail Gorchtein🇩🇪 · Lu-Chang Jin🇺🇸 · Chuan Liu🇨🇳 · Chien-Yeah Seng🇺🇸
We present the first lattice QCD determination of the $γ Z$ box contribution to parity-violating electron-proton scattering, $□_{γ Z}$ , a key ingredient for the precise tests of the Standard Model via the proton weak charge. Our calculation covers the electron beam energies up to $E = 155 M e V$ . For the axial-vector component, we achieve reduced uncertainties across the entire energy range compared with phenomenological estimates. For the vector component, the uncertainties remain slightly larger after continuum extrapolation. At $E = 0$ , where the vector part vanishes, we obtain $□_{γ Z} = 0.00412 (9)$ , reducing the uncertainty by a factor of $2$ relative to the most precise previous determination. Incorporating this result yields an updated weak charge of $Q_{W}^{p} = 0.06987 (50)$ . The calculated energy dependence of $□_{γ Z}$ further provides a first-principles input for the upcoming P2 experiment at Mainz, which will operate at the optimized beam energy of $155 M e V$ to extract $Q_{W}^{p}$ .
Comments:
15 pages, v1
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.06582 [pdf]
3 citations
10
[Submitted on 11 Jan 2026] (cross-list from hep-ph)
Probing the microscopic origin of prompt and non-prompt $D^{0}$ production through event-shape engineering in proton-proton collisions at the LHC
Aswathy Menon Kavumpadikkal Radhakrishnan · Suraj Prasad · Purnima Srivastava · Raghunath Sahoo
Heavy-flavour hadrons are produced in the early stages of ultra-relativistic collisions at the LHC via hard partonic interactions and experience the whole system evolution. The study of prompt and non-prompt $D^{0}$ mesons provides an independent avenue to test the theories of quantum chromodynamics and to investigate beauty hadron production. Moreover, the production of both prompt and non-prompt $D^{0}$ is influenced by microscopic processes such as multi-partonic interactions (MPI) and hadronisation through fragmentation. In this study, an attempt is made to understand the production of prompt and non-prompt $D^{0}$ mesons in proton-proton collisions at $s = 13.6$ TeV using the PYTHIA8 event generator, which offers a qualitative description of charm production. The role of the transverse momentum transfer in the hardest partonic scattering ( $p^_{T}$ ), MPI, and color reconnection is systematically explored. In addition, the charged particle production in different topological regions with respect to the leading $D^{0}$ meson is studied to assess the influence of the $D^{0}$ meson on the event topology and to examine the selection biases arising from the use of charged particle multiplicity as an event classifier.
Comments:
14 pages and 11 captioned figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2601.06856 [pdf]
0 citations
11
[Submitted on 12 Jan 2026] (cross-list from hep-ph)
EPOS4 Model Predictions for Global Observables in Pb-Pb Collisions at $s_{N N}$ = 5.36 TeV
Hirak Kumar Koley🇮🇳 · Subikash Choudhury🇮🇳 · Mitali Mondal🇮🇳
The study of the Quark-Gluon Plasma (QGP), a deconfined state of nuclear matter, remains a central focus of high-energy heavy-ion collision experiments. The recent operation of the Large Hadron Collider (LHC) in Run 3 at the new center-of-mass energy of $s_{N N} = 5.36$ TeV necessitates theoretical predictions to characterize the energy dependence and bulk properties of the medium. In this study, we present comprehensive EPOS4 model predictions for key global observables in Pb-Pb collisions at $5.36$ TeV. We focus on the centrality dependence of the charged-particle pseudorapidity density ( $d N_{c h} / d η$ ), integrated yields ( $d N / d y$ ), mean transverse momentum ( $⟨ p_{T} ⟩$ ) for light-flavor hadrons ( $π^{\pm}, K^{\pm}, p (p ˉ)$ ), and the charged particle nuclear modification factor ( $R_{AA}$ ). The EPOS4 framework successfully captures the strong mass-dependent rise of $⟨ p_{T} ⟩$ with multiplicity, a definitive signature of collective radial flow. Furthermore, the predicted charged hadron $R_{AA}$ demonstrates a clear suppression, consistent with energy loss mechanisms incorporated into the model. By comparing these predictions to existing $5.02$ TeV data, we demonstrate that the EPOS4 model offers a consistent and robust description of heavy-ion dynamics, projecting minimal energy evolution for these bulk and hard-probe observables between the two energies.
Comments:
6 pages, 3 figures, European Physical Society Conference on High Energy Physics (EPS-HEP2025)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2601.07570 [pdf]
PoS(2026)·1 citation
12
[Submitted on 12 Jan 2026] (cross-list from hep-ph)
Dynamical gluon effects in twist-3 generalized parton distributions of the proton
Ziqi Zhang🇨🇳 · Chandan Mondal🇨🇳 · Siqi Xu🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸
Within the Basis Light-Front Quantization framework, we systematically investigate the subleading-twist (twist-3) generalized parton distributions (GPDs) of the proton's valence quarks beyond the Wandzura--Wilczek (WW) approximation. The twist-3 GPDs are not independent; through the equations of motion they decompose into a non-genuine contribution and a genuine twist-3 term. The latter encodes quark--quark--gluon correlations and involves interference between the light-front Fock sectors |qqq> and |qqqg>, which are typically neglected in the WW approximation. Using light-front wave functions obtained from diagonalizing the proton light-front Hamiltonian for its |qqq> and |qqqg> Fock components, we compute these GPDs via their overlap representations. To further explore their physical implications, we also evaluate several twist-3--related quantities, including the quark orbital angular momentum, the total quark spin contribution, and the quark spin--orbit correlation. Our results provide new nonperturbative input on higher-twist dynamics particularly multi-parton interference effects relevant for future measurements at the EicC and the EIC.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.07590 [pdf]
PRD(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Direct transfer to 46,48K as a survey of the π(s1/2​)−ν(sdpf) interaction

Hadronic Probes of Non-Standard Neutrino Interactions

Lattice QCD determination of the γZ box contribution to the proton weak charge

Probing the microscopic origin of prompt and non-prompt D0 production through event-shape engineering in proton-proton collisions at the LHC

EPOS4 Model Predictions for Global Observables in Pb-Pb Collisions at sNN​​ = 5.36 TeV

Dynamical gluon effects in twist-3 generalized parton distributions of the proton

Affiliations

Direct transfer to $^{46, 48}$ K as a survey of the $π (s_{1/2})$ $- ν (s d p f)$ interaction

Lattice QCD determination of the $γ Z$ box contribution to the proton weak charge

Probing the microscopic origin of prompt and non-prompt $D^{0}$ production through event-shape engineering in proton-proton collisions at the LHC

EPOS4 Model Predictions for Global Observables in Pb-Pb Collisions at $s_{N N}$ = 5.36 TeV