| |
Bernabeu, J., & Espinoza, C. (2026). Flavor-Space Analog to the Aharonov-Bohm Effect for a Constant Scalar Matter Potential in Neutrino Flavor Interferometry. Phys. Rev. Lett., 136(13), 131802–7pp.
Abstract: The Aharonov-Bohm effect is one of the most surprising wonders of the quantum world. Its interpretation is debated between a physical significance of the potential versus nonlocality of quantum physics, ambiguity which cannot be resolved from all performed spatial interference experiments. We put forward the idea of replacing its study by flavor interferometry as observed in neutrino oscillations. The neutrino propagation through the crust of the Earth is affected by the constant scalar matter potential, with a phase shift between flavors and no force field anywhere. Here we show how to signal and experimentally disentangle this phase shift by its symmetry properties. The energy dependence of the neutrino-antineutrino asymmetry in the golden transition nu μ-> nu e allows for a clear separation of this matter component against the genuine asymmetry. Thus we find how to observe in a single experiment, like DUNE, the physical significance of the potential, the neutrino mass hierarchy, and the genuine matter-antimatter asymmetry in the lepton sector.
|
|
Xie, J. M., Liu, Z. W., Lu, J. X., Liang, H. Z., Molina, R., & Geng, L. S. (2026). Chiral evolution and femtoscopic signatures of the K1(1270) resonance. Phys. Rev. D, 113(7), 074002–11pp.
Abstract: We present a comprehensive study of the axial-vector resonance K1(1270) within the unitarized chiral perturbation theory, focusing on its two-pole structure and manifestation in femtoscopic observables. By considering the dominant pK and K*tr coupled channels, we reproduce the well-established double-pole structure and trace the chiral evolution of both poles as functions of the pion mass, using the vector-meson mass trajectories fitted to lattice-QCD data and experimental values. The lower pole, dominantly coupled to K*tr, evolves from an above-threshold resonance to a virtual or bound state with increasing pion mass. In comparison, the higher pole, dominantly coupled to pK, moves downward in energy, reflecting the strengthening of the chiral attraction. The influence of the finite vector-meson widths is systematically examined, showing that their inclusion smooths the pole trajectories without altering their qualitative behavior. Furthermore, femtoscopic correlation functions are calculated for all relevant vector-pseudoscalar channels in both charged sectors. The results exhibit distinct resonance and bound-state features consistent with the two-pole dynamics. The weak impact of higher channels, such as w K & strns;, K & strns;*rl, and % K & strns;, confirms that the simplified two-channel treatment captures the essential dynamics of the K1(1270) resonance. This study demonstrates that combining chiral extrapolation and femtoscopic correlation analyses provides a powerful and complementary framework for connecting lattice-QCD calculations, chiral effective theory, and experimental measurements, offering new insights into the molecular nature and chiral origin of the K1(1270) resonance.
|
|
Froustey, J., Foucart, F., Hall, C., Kneller, J. P., Kundu, D., Lin, Z. D., et al. (2026). Neutrino flavor instabilities in neutron star mergers with moment transport: Slow, fast, and collisional modes. Phys. Rev. D, 113(6), 063050–27pp.
Abstract: Determining where, when, and how neutrino flavor oscillations must be included in large-scale simulations of hot and dense astrophysical environments is an enduring challenge that must be tackled to obtain accurate predictions. Using an angular moment-based linear stability analysis framework, we examine the different kinds of flavor instabilities that can take place in the context of the postprocessing of a neutron star merger simulation, with a particular focus on the collisional flavor instability and a careful assessment of several commonly used approximations. First, neglecting anisotropies of the neutrino field, we investigate the extent to which commonly used monoenergetic growth rates reproduce the results obtained from a full multienergy treatment. Contrary to the large discrepancies found in core-collapse supernova environments, we propose a simple combination of energy-averaged estimates that reproduces the multienergy growth rates in our representative simulation snapshot. We then quantify the impact of additional physical effects, including nuclear many-body corrections, scattering opacities, and the inclusion of the vacuum term in the neutrino Hamiltonian. Finally, we include the neutrino distribution anisotropies, which allows us to explore, for the first time in a multienergy setting, the interplay between collisional, fast, and slow modes in a moment-based neutron star merger simulation. We find that, despite a dominance of the fast instability in most of the simulation volume, certain regions exhibit only a collisional instability, while others, especially at large distances, exhibit a slow instability that is largely underestimated if anisotropic effects are neglected.
|
|
Costantini, M. N., Mantani, L., Moore, J. M., & Ubiali, M. (2026). A linear PDF model for Bayesian inference. J. High Energy Phys., 04(4), 068–34pp.
Abstract: A robust uncertainty estimate in global analyses of Parton Distribution Functions (PDFs) is essential at the Large Hadron Collider (LHC), especially in view of the high-precision data anticipated by experimentalists in the High-Luminosity phase of the LHC. A Bayesian framework to determine PDFs provides a rigorous treatment of uncertainties and full control on the prior, though its practical implementation can be computationally demanding. To address these challenges, we introduce a novel approach to PDF determination tailored for Bayesian inference, based on the use of linear models. Unlike traditional parametrisations, our method represents PDFs as vectors in a functional space spanned by specially chosen bases, derived from the dimensional reduction of a neural network functional space, providing a compact yet versatile representation of PDFs. The low-dimensionality of the preferred models allows for particularly fast inference. The size of the bases can be systematically adjusted, allowing for transparent control over underfitting and overfitting, and facilitating principled model selection through Bayesian workflows. In this work, the methodology is applied to a fit of Deep Inelastic Scattering synthetic data, and thoroughly tested via multi-closure tests, thus paving the way to its application to global PDF fits.
|
|
de S. Silva, M. V., Crispim, T. M., Landim, R. R., Olmo, G. J., & Saez-Chillon Gomez, D. (2026). Tidal forces around the Letelier-Alencar cloud of strings black hole. Phys. Rev. D, 113(6), 064052–20pp.
Abstract: In this work, we investigate relativistic tidal forces around a black hole sourced by a cloud of strings, described by the generalized Letelier-Alencar solution. We first review the original Letelier spacetime and its recent generalization, computing the Kretschmann scalar and showing that the generalized model exhibits a stronger curvature divergence at r -> 0 than both Letelier and Schwarzschild cases. We then analyze geodesic motion in this background. For massless particles, we focus on circular photon orbits, while for massive particles, we consider both radial infall and circular motion. We find that the radii of the photon sphere and of the innermost stable circular orbit increase with the cloud of strings parameter gs and decrease with the length scale ls, and circular orbits cease to exist in certain regions of the parameter space. For radial motion, we compute the radial acceleration and the corresponding tidal forces. In this case, we show that an inversion between stretching and compression may occur, although this regime is typically hidden inside the event horizon. Once the tidal forces are known, we computed the behavior of the displacement vector in order to verify whether the usual stretching behavior induced by tidal forces is preserved. Finally, we study tidal forces for observers in circular motion, showing that the cloud of strings modifies the Keplerian frequency and the tidal force profile even at large distances, and that in this case there is no sign change of the tidal components.
|
|
|
