Theory and Phenomenology

Our group explores fundamental physics with neutrino data. We study how new particles and interactions beyond the Standard Model could shape astrophysical, cosmological, and laboratory neutrino observations, with a focus on dark matter, theories of neutrino mass, and quantum gravity.

A major theme of our research is the theoretical modeling of dark sectors and their associated phenomenology in neutrino experiments. We investigate how dark matter may interact with ordinary matter through new mediators in our galaxy, on extragalactic scales, or in cosmic-ray accelerators such as Active Galactic Nuclei (AGN), and how these processes manifest in multi-messenger emissions detectable on Earth. Using both analytical tools and numerical simulations, we predict observable signatures that can be tested with experiments such as IceCube, KM3NeT, and other multi-messenger observatories.

We also explore phenomenology associated with neutrino masses and flavor structure, connecting theory with oscillation data and neutrino fluxes across vastly different energy and distance scales. These studies span terrestrial experiments such as beam dumps and colliders, as well as astrophysical neutrinos traversing cosmological distances. This program allows us to probe scenarios related to the nature of neutrinos, including heavy neutral leptons, the cosmic neutrino background, quasi-Dirac neutrinos, and nonstandard flavor mixing effects. By linking neutrino astrophysics and cosmology with laboratory searches, we aim to uncover the mechanism behind neutrino mass generation and its role in the early Universe.

Another important focus of our group is the connection between neutrino signatures and theories of low-scale quantum gravity, including models with extra dimensions, many particle species, or string-theoretic constructions. We pursue this both through effective, model-agnostic searches for flavor-dependent effects using high-energy neutrino data, and through studies of thermal high-energy neutrino signatures arising from black hole and graviton production in specific theoretical frameworks.

By bridging theory with experiment, our goal is to translate deep questions about the nature of space, time, and matter into concrete predictions for current and upcoming neutrino and multi-messenger observatories.

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References

  1. C. A. Argüelles, A. Kheirandish, and A. C. Vincent, Imaging Galactic Dark Matter with High-Energy Cosmic Neutrinos, Physical Review Letters 119 (2017) 201801.
  2. C. A. Argüelles et al., Dark Matter Annihilation to Neutrinos, Reviews of Modern Physics 93 (2021) 035007.
  3. C. A. Argüelles et al., Dark Matter Decay to Neutrinos, Physical Review D 108 (2023) 123021.
  4. T. Bertólez-Martínez et al., The Highest-Energy Neutrino Event Constrains Dark Matter–Neutrino Interactions, arXiv:2506.08993.
  5. F. Ferrer, G. Herrera, and A. Ibarra, New Constraints on Dark Matter–Neutrino and Dark Matter–Photon Scattering from TXS 0506+056, JCAP 05 (2023) 057.
  6. G. Herrera and K. Murase, Probing Light Dark Matter through Cosmic-Ray Cooling in AGN, Physical Review D 110 (2024) L011701.
  7. G. Herrera, Plausible Indication of Gamma-Ray Absorption by Dark Matter in NGC 1068, arXiv:2504.21560.
  8. A. Hussein and G. Herrera, Dark Matter–Electron Interactions Alter the Luminosity and Spectral Index of M87, arXiv:2510.12877.
  9. S. Vergani et al., Explaining the MiniBooNE Excess through a Mixed Model of Neutrino Oscillation and Decay, Physical Review D 104 (2021) 095005.
  10. M.-S. Liu, N. Kamp, and C. A. Argüelles, Constraints and Sensitivities for Dipole-Portal Heavy Neutral Leptons, Physical Review D 112 (2025) 035012.
  11. M. Císcar-Monsalvatje, G. Herrera, and I. M. Shoemaker, Upper Limits on the Cosmic Neutrino Background from Cosmic Rays, Physical Review D 110 (2024) 063036.
  12. G. Herrera, S. Horiuchi, and X. Qi, Diffuse Boosted Cosmic Neutrino Background, arXiv:2405.14946.
  13. K. Carloni et al., Probing Pseudo-Dirac Neutrinos with Astrophysical Sources at IceCube, Physical Review D 109(2024) L051702.
  14. K. Carloni et al., Signatures of Quasi-Dirac Neutrinos in Diffuse High-Energy Astrophysical Neutrino Data, arXiv:2503.19960.
  15. C. A. Argüelles, T. Katori, and J. Salvado, New Physics in Astrophysical Neutrino Flavor, Physical Review Letters 115 (2015) 161303.
  16. IceCube Collaboration, Search for Quantum Gravity using Astrophysical Neutrino Flavor, Nature Physics 18(2022) 1287–1292.
  17. M. Ettengruber and G. Herrera, New Tests of Low-Scale Quantum Gravity with Cosmic-Ray Collisions, arXiv:2510.11879.

 

Laboratory for Particle Physics and Cosmology (LPPC), Harvard University.       18 Hammond Street, Cambridge, MA 02138, USA