arXiv subjects

Nicolás Viaux M

Publications and source records attributed to Nicolás Viaux M.

3 recordsLinked to original sources

arXiv2026

Neutrino Spectral Pinching in 3D Core-Collapse Supernovae: Late-Time Convergence, Failed-Explosion Signatures, and Viewing-Angle Dispersion

We present a systematic survey of the neutrino spectral pinching parameter alpha_p(t, M, n-hat) across the Princeton Fornax ensemble of 3D core-collapse supernova simulations. We analyze 25 simulations spanning progenitor masses 8.1-100 M_sun with durations up to 8.47 s post-bounce, computed with the Fornax code and the SFHo equation of state. The pinching parameter alpha_p = (2^2 - E_rms^2)/(E_rms^2 - ^2) is derived from 12-bin spectral moments on a 128x256 sky grid for three neutrino species, enabling time- and angle-resolved spectral characterization. Four results emerge. (1) The nu-bar_e pinching floor is alpha_p = 1.92 +/- 0.10 (N=13 long-running models), lying 0.2-0.4 below 1D predictions due to 3D PNS convection. (2) Both BH-forming models (12.25, 14 M_sun) show anti-pinching (alpha_p < 0.9) before collapse, with deficit Delta alpha_p ~ 0.65 visible from t = 0.5 s. (3) Two of six long-running models exhibit a hierarchy reversal ( > ) after t = 5 s; leptonic flavors carry (40 +/- 3)% of radiated energy. (4) The LESA dipole is suppressed by >3x in BH-forming models; viewing-angle spread Delta alpha_p(68%) ~ 0.8-1.5 dominates spectral-inversion uncertainty. Mollweide sky maps reveal coherent angular structures with alpha_p anticorrelated with luminosity and correlated with mean energy. Detection rates at Hyper-Kamiokande, DUNE, JUNO, and IceCube yield 8-12% NMO/IMO discrimination during Kelvin-Helmholtz cooling. The late-time nu-bar_e pinching floor represents the first 3D characterization of spectral convergence during Kelvin-Helmholtz cooling.

astro-ph.HE↗

arXiv2026

Operator Identification in Charged Lepton-Flavor Violation: Global EFT Analysis with RG Evolution, Polarization Observables, and Bayesian Model Discrimination at Future Colliders

Charged lepton-flavor violation is a null-test frontier of the Standard Model and a direct probe of physics beyond it. We present a global effective field theory (EFT) analysis across FCC-ee, ILC, CLIC, HL-LHC, HE-LHC, and muon colliders at 3 and 10 TeV, with operator identification as the primary target rather than exclusion reach alone. The analysis combines low-energy constraints, collider differential observables, and Dalitz-level $μ\to 3e$ information in a common profile-likelihood framework. Key hadron-collider and muon-collider signal/background samples are generated at event level and propagated through Delphes detector simulation, while clean $e^+e^-$ benchmark channels are modeled with CDR-calibrated parametric response. We include one-loop renormalization-group (RG) running and operator mixing between UV matching and measurement scales, finding 10--30\% shifts in selected operator-correlation entries when comparing tree-level and RG-evolved coefficient mappings at multi-TeV matching scales. Polarization asymmetries are used to separate $c_{H\ell}$ and $c_{He}$ directions, and UV discrimination is quantified with Bayes factors for benchmark leptoquark and heavy-neutral-lepton hypotheses. The full code chain for event generation, detector response, inference, and figure reproduction is provided.

hep-ph↗

arXiv2025

Refining the Greisen Profile for Low-Energy Cosmic Gamma-Rays: Quantifying Deviations Across Altitudes and Zenith Angles

This study refines the Greisen formalism by comparing the classical Greisen profile and a modified Greisen profile, which incorporates an empirical correction to the shower age parameter with zenith-angle dependence, aiming to better describe low-energy cascades against CORSIKA simulations of cosmic gamma-ray showers (20-800 GeV). Fittings across altitudes of 5000-5900 m and zenith angles from 0 to 40 degrees quantify deviations in particle numbers, showing that the modified profile yields deviations below 4.7%, compared to up to 12.5% for the classical profile. These improvements address low-energy ionization losses, atmospheric density variations, and zenith-angle effects, enhancing accuracy for high-altitude observatories like HAWC and the proposed CONDOR array. The modified profile offers a computationally efficient alternative, providing precise particle number predictions to advance gamma-ray astrophysics and cosmic-ray research.

astro-ph.HE↗