arXiv subjects

Mauricio Bustamante

Publications and source records attributed to Mauricio Bustamante.

At least 37 records · Page 2Linked to original sources

arXiv2025

Reconstruction of inclined cosmic-ray properties with GRAND data

Radio-detection is now an established technique for studying ultra-high-energy (UHE) cosmic rays with energies exceeding $\sim 10^{17}$ eV. The next generation of radio experiments, such as the Giant Radio Array for Neutrino Detection (GRAND), aims to expand this technique to the observation of Earth-skimming UHE neutrinos, which requires the detection of very inclined extensive air showers (EAS). Currently, GRAND is validating its detection principle -- autonomous radio detection -- in particular through the prototype array GRANDProto300, deployed in the Gobi Desert. In this phase, the array is limited to detecting inclined EAS from cosmic rays. Neutrinos cannot be observed because of the restricted detector size. We present a method to reconstruct the arrival direction and energy of EAS with zenith angles above $60^\circ$, applicable as well to upward-going trajectories. The approach combines a point-source-like description of the radio wavefront with the so-called Angular Distribution Function (ADF), a phenomenological model describing the angular pattern of radio signal amplitudes in the 50--200 MHz band. Applied directly to the voltage traces, this method enables efficient event selection with accurate direction reconstruction and a first-order energy estimate. We validate the approach with both simulations and experimental data, and reconstruct the first cosmic-ray candidates detected by GRANDProto300.

astro-ph.IM↗

arXiv2025

Probing Lorentz invariance with a high-energy neutrino flare

Time-of-flight measurements of high-energy astrophysical neutrinos can be used to probe Lorentz invariance, a pillar of modern physics. If Lorentz-invariance violation (LIV) occurs, it could cause neutrinos to slow down, with the delay scaling linearly or quadratically with their energy. We introduce non-parametric statistical methods designed to detect LIV-induced distortions in the temporal structure of a high-energy neutrino flare as it travels to Earth from a distant astrophysical source, independently of the intrinsic timing properties of the source. Our approach, illustrated using the 2014/2015 TeV-PeV neutrino flare from the blazar TXS 0506+056 detected by IceCube, finds that the LIV energy scale must exceed 10^{14} GeV (linear) or 10^9 GeV (quadratic). Our methods provide a robust means to investigate LIV by focusing solely on a neutrino flare, without relying on electromagnetic counterparts, and account for realistic energy and directional uncertainties. For completeness, we compare our limits inferred from TXS 0506+056 to the sensitivity inferred from multi-messenger detection of tentative coincidences between neutrinos and electromagnetic emission from active galactic nuclei and tidal disruption events.

astro-ph.HE↗

arXiv2025

A plethora of long-range neutrino interactions probed by DUNE and T2HK

The next-generation neutrino oscillation experiments would be sensitive to the new neutrino interactions that would strengthen the search for physics beyond the Standard Model. In this context, we explore the capabilities of the two leading future long-baseline neutrino oscillation experiments, DUNE and T2HK, to search for new flavor-dependent neutrino interactions with electrons, protons, and neutrons that could potentially modify neutrino flavor transitions. We forecast their sensitivities in the context of long-range neutrino interactions mediated by a neutral vector boson lighter than $10^{-10}$ eV and sourced by the vast amount of nearby and distant matter in the Earth, Moon, Sun, Milky Way, and local Universe. For the first time, we explore a plethora of $U(1)^\prime$ symmetries inducing the new interactions built from the combination of lepton and baryon numbers. We find that in all cases, DUNE and T2HK may constrain or discover the existence of new long-range neutrino interaction, and in some favorable cases, may identify the new $U(1)^\prime$ symmetry responsible for it. In this short proceeding, we only summarize the prospects of constraining the new interaction in case of all our candidate $U(1)^\prime$ symmetries, which have been discussed in JHEP 09 (2024) 055.

hep-ph↗

arXiv2025

Constraints on flavor-dependent long-range interactions of high-energy astrophysical neutrinos

Astrophysical neutrinos with energy in the TeV-PeV range traverse megaparsecs (Mpc) to gigaparsecs (Gpc) scale distances before they reach the Earth. Tiny physics effects that get accumulated over these large propagation paths during their journey may become observable at the detector. If there is some new interaction between neutrinos and the background matter, that can potentially affect the propagation of the astrophysical neutrinos. One such possible case is the flavor-dependent long-range interaction of neutrinos, which can affect the standard neutrino flavor transition, modifying the flavor composition of the astrophysical neutrinos at Earth. Using the present-day and future projection of the flavor-composition measurements of IceCube and IceCube-Gen2 along with the present and future measurement of the oscillation parameters, we explore the sensitivity of these experiments to probe long-range neutrino interaction with matter.

hep-ph↗

arXiv2025

Flavor-Dependent Long-Range Neutrino Interactions in DUNE and T2HK: Synergy Breeds Power

Discovering new neutrino interactions would provide evidence of physics beyond the Standard Model. We focus on flavor-dependent long-range neutrino interactions mediated by ultra-light mediators (masses below $10^{-10}$ eV) from lepton-number gauge symmetries $L_e-L_μ$, $L_e-L_τ$, and $L_μ-L_τ$. These interactions, sourced by electrons and neutrons in the Earth, Moon, Sun, Milky Way, and the local Universe, could modify neutrino oscillation probabilities. The upcoming long-baseline experiments, DUNE and T2HK, with their large statistics, reduced systematic uncertainties, and well-characterized neutrino beams, will probe these interactions. We forecast that, while individually DUNE and T2HK could constrain these long-range neutrino interactions, their combination lifts parameter degeneracies that weaken individual sensitivity and provides stronger constraints.

hep-ph↗

arXiv2025

Flavor Anisotropy in the High-Energy Astrophysical Neutrino Sky

High-energy astrophysical neutrinos, with TeV--PeV energies, offer unique insight into astrophysics and particle physics. Their incoming directions and flavor composition -- i.e., the proportion of electron, muon, and tau neutrinos in their flux -- are, individually, rewarding observables. Combined, they offer new opportunities, hitherto unexplored, that we expose for the first time. Anisotropy in the arrival directions of electron, muon, and tau neutrinos may reveal multiple populations of neutrino sources, differently distributed in the sky, and test whether neutrinos of different flavor propagate preferentially along certain directions, such as expected from breaking Lorentz invariance. Using 7.5 years of public IceCube High-Energy Starting Events, we make the first measurement of the directional flavor composition of high-energy astrophysical neutrinos, constrain the presence of flavor dipoles and quadrupoles, and improve constraints on "compass asymmetries" introduced by Lorentz invariance violation. In the near future, upcoming neutrino telescopes will improve these measurements across the board.

astro-ph.HE↗

arXiv2024

Two-detector flavor sensitivity to ultra-high-energy cosmic neutrinos

Ultra-high-energy (UHE) cosmic neutrinos, with energies above 100 PeV, could be finally discovered in the near future. Measuring their flavor composition would reveal information about their production and propagation, but new techniques are needed for UHE neutrino telescopes to have the capabilities to do it. We address this by proposing a new way to measure the UHE neutrino flavor composition that does not rely on individual telescopes having flavor-identification capabilities. We manufacture flavor sensitivity from the joint detection by one telescope sensitive to all flavors -- the radio array of IceCube-Gen2 -- and one mostly sensitive to $ν_τ$ -- GRAND. From this limited flavor sensitivity, predominantly to $ν_τ$, and even under conservative choices of neutrino flux and detector size, we extract important insight. For astrophysics, we forecast meaningful constraints on the neutrino production mechanism; for fundamental physics, vastly improved constraints on Lorentz-invariance violation. These are the first measurement forecasts of the UHE $ν_τ$ content.

astro-ph.HE↗

arXiv2024

A plethora of long-range neutrino interactions probed by DUNE and T2HK

Upcoming neutrino experiments will soon search for new neutrino interactions more thoroughly than ever before, boosting the prospects of extending the Standard Model. In anticipation of this, we forecast the capability of two of the leading long-baseline neutrino oscillation experiments, DUNE and T2HK, to look for new flavor-dependent neutrino interactions with electrons, protons, and neutrons that could affect the transitions between different flavors. We interpret their sensitivity in the context of long-range neutrino interactions, mediated by a new neutral boson lighter than $10^{-10}$ eV, and sourced by the vast amount of nearby and distant matter in the Earth, Moon, Sun, Milky Way, and beyond. For the first time, we explore the sensitivity of DUNE and T2HK to a wide variety of $U(1)^\prime$ symmetries, built from combinations of lepton and baryon numbers, each of which induces new interactions that affect oscillations differently. We find ample sensitivity: in all cases, DUNE and T2HK may constrain the existence of the new interaction even if it is supremely feeble, may discover it, and, in some cases, may identify the symmetry responsible for it.

hep-ph↗

arXiv2024

Mapping class groups of exotic tori and actions by ${\rm SL}_d(\mathbb Z)$

We determine for which exotic tori $\mathcal{T}$ of dimension $d\neq4$ the homomorphism from the group of isotopy classes of orientation-preserving diffeomorphisms of $\mathcal{T}$ to ${\rm SL}_d(\mathbb Z)$ given by the action on the first homology group is split surjective. As part of the proof we compute the mapping class group of all exotic tori $\mathcal{T}$ that are obtained from the standard torus by a connected sum with an exotic sphere. Moreover, we show that any nontrivial ${\rm SL}_d(\mathbb Z)$-action on $\mathcal{T}$ agrees on homology with the standard action, up to an automorphism of ${\rm SL}_d(\mathbb Z)$. When combined, these results in particular show that many exotic tori do not admit any nontrivial differentiable action by ${\rm SL}_d(\mathbb Z)$.

math.GT↗

arXiv2024

The Giant Radio Array for Neutrino Detection (GRAND) Collaboration -- Contributions to the 38th International Cosmic Ray Conference (ICRC 2023)

The Giant Radio Array for Neutrino Detection (GRAND) is an envisioned observatory of ultra-high-energy particles of cosmic origin, with energies in excess of 100 PeV. GRAND uses large surface arrays of autonomous radio-detection units to look for the radio emission from extensive air showers that are triggered by the interaction of ultra-high-energy cosmic rays, gamma rays, and neutrinos in the atmosphere or underground. In particular, for ultra-high-energy neutrinos, the future final phase of GRAND aims to be sensitive enough to discover them in spite of their plausibly tiny flux. Presently, three prototype GRAND radio arrays are in operation: GRANDProto300, in China, GRAND@Auger, in Argentina, and GRAND@Nancay, in France. Their goals are to field-test the design of the radio-detection units, understand the radio background to which they are exposed, and develop tools for diagnostic, data gathering, and data analysis. This list of contributions to the 38th International Cosmic Ray Conference (ICRC 2023) presents an overview of GRAND, in its present and future incarnations, and a look at the first data collected by GRANDProto13, the first phase of GRANDProto300.

hep-ex↗

arXiv2024

The Giant Radio Array for Neutrino Detection (GRAND) Collaboration -- Contributions to the 10th International Workshop on Acoustic and Radio EeV Neutrino Detection Activities (ARENA 2024)

This is an index of the contributions by the Giant Radio Array for Neutrino Detection (GRAND) Collaboration to the 10th International Workshop on Acoustic and Radio EeV Neutrino Detection Activities (ARENA 2024, University of Chicago, June 11-14, 2024). The contributions include an overview of GRAND in its present and future incarnations, methods of radio-detection that are being developed for them, and ongoing joint work between the GRAND and BEACON experiments.

astro-ph.IM↗

arXiv2024

Targeting 100-PeV tau neutrino detection with an array of phased and high-gain reconstruction antennas

Neutrinos at ultrahigh energies can originate both from interactions of cosmic rays at their acceleration sites and through cosmic-ray interactions as they propagate through the universe. These neutrinos are expected to have a low flux which drives the need for instruments with large effective areas. Radio observations of the inclined air showers induced by tau neutrino interactions in rock can achieve this, because radio waves can propagate essentially unattenuated through the hundreds of kilometers of atmosphere. Proposed arrays for radio detection of tau neutrinos focus on either arrays of inexpensive receivers distributed over a large area, the GRAND concept, or compact phased arrays on elevated mountains, the BEACON concept, to build up a large detector area with a low trigger threshold. We present a concept that combines the advantages of these two approaches with a trigger driven by phased arrays at a moderate altitude (1 km) and sparse, high-gain outrigger receivers for reconstruction and background rejection. We show that this design has enhanced sensitivity at 100 PeV over the two prior designs with fewer required antennas and discuss the need for optimized antenna designs.

astro-ph.IM↗

arXiv2024

The next galactic supernova can uncover mass and couplings of particles decaying to neutrinos

Many particles predicted by extensions of the Standard Model feature interactions with neutrinos, e.g., Majoron-like bosons $ϕ$. If the mass of $ϕ$ is larger than about 10 keV, they can be produced abundantly in the core of the next galactic core-collapse supernova through neutrino coalescence, and leave it with energies of around 100 MeV. Their subsequent decay to high-energy neutrinos and anti-neutrinos provides a distinctive signature at Earth. Ongoing and planned neutrino and dark matter experiments allow us to reconstruct the energy, flavor, and time of arrival of these high-energy neutrinos. For the first time, we show that these measurements can help pinpointing the mass of $ϕ$ and its couplings to neutrinos of different flavor. Our results can be generalized in a straightforward manner to other hypothetical feebly interacting particles, like novel gauge bosons or heavy neutral leptons, that decay into neutrinos.

hep-ph↗

arXiv2024

The flavor composition of ultra-high-energy cosmic neutrinos: measurement forecasts for in-ice radio-based EeV neutrino telescopes

In-ice radio-detection is a promising technique to discover and characterize ultra-high-energy (UHE) neutrinos, with energies above 100 PeV, adopted by present - ARA, ARIANNA, and RNO-G - and planned - IceCube-Gen2. So far, their ability to measure neutrino flavor has remained unexplored. We show and quantify how the neutrino flavor can be measured with in-ice radio detectors using two complementary detection channels. The first channel, sensitive to $ν_e$, identifies them via their charged-current interactions, whose radio emission is elongated in time due to the Landau-Pomeranchuk-Migdal effect. The second channel, sensitive to $ν_μ$ and $ν_τ$, identifies events made up of multiple showers generated by the muons and taus they generate. We show this in state-of-the-art forecasts geared at IceCube-Gen2, for representative choices of the UHE neutrino flux. This newfound sensitivity could allow us to infer the UHE neutrino flavor composition at their sources - and thus the neutrino production mechanism - and to probe UHE neutrino physics.

astro-ph.HE↗

arXiv2024

New limits on neutrino decay from high-energy astrophysical neutrinos

Since neutrinos have mass differences, they could decay into one another. But their lifetimes are likely long, even when shortened by new physics, so decay likely impacts neutrinos only during long trips. This makes high-energy astrophysical neutrinos, traveling for up to billions of light-years, sensitive probes of decay. However, their sensitivity must be tempered by reality. We derive from them thorough bounds on the neutrino lifetimes accounting for critical astrophysical unknowns and the nuances of neutrino detection. Using the diffuse neutrino flux, we disfavor lifetimes $τ\lesssim 20$-450 s $(m/{\rm eV})$, based on present IceCube data, and forecast factor-of-10 improvements by upcoming detectors. Using, for the first time, neutrinos from the active galaxy NGC 1068, extant unknowns preclude placing lifetime bounds today, but upcoming detectors could disfavor $τ\sim 100$-5000 s $(m/{\rm eV})$.

astro-ph.HE↗

arXiv2023

The Milky Way shines in high-energy neutrinos

The most energetic astrophysical sources in the Milky Way, cosmic accelerators capable of producing high-energy cosmic rays, have resisted discovery for over a century. Up to now, astrophysicists sought these sources mainly by scouring the Galaxy for the gamma rays they are expected to emit. In 2023, the IceCube Neutrino Observatory discovered high-energy neutrinos from the Milky Way, inaugurating a telltale stream of evidence of cosmic-ray production and interaction in the Galaxy.

astro-ph.HE↗

arXiv2023

Searches for dark matter decay with ultra-high-energy neutrinos endure backgrounds

Next-generation ultra-high-energy (UHE) neutrino telescopes, presently under planning, will have the potential to probe the decay of heavy dark matter (DM) into UHE neutrinos, with energies in excess of $10^7$~GeV. Yet, this potential may be deteriorated by the presence of an unknown background of UHE neutrinos, cosmogenic or from astrophysical sources, not of DM origin and seemingly large enough to obscure the DM signature. We show that leveraging the angular and energy distributions of detected events safeguards future searches for DM decay against such backgrounds. We focus on the radio-detection of UHE neutrinos in the planned IceCube-Gen2 neutrino telescope, which we model in state-of-the-art detail. We report promising prospects for the discovery potential of DM decay into UHE neutrinos, the measurement of DM mass and lifetime, and limits on the DM lifetime, despite the presence of a large background, without prior knowledge of its size and shape.

astro-ph.HE↗

arXiv2023

Identifying Energy-Dependent Flavor Transitions in High-Energy Astrophysical Neutrino Measurements

The flavor composition of TeV--PeV astrophysical neutrinos, i.e., the proportion of neutrinos of different flavors in their flux, is a versatile probe of high-energy astrophysics and fundamental physics. Because flavor identification is challenging and the number of detected high-energy astrophysical neutrinos is limited, so far measurements of the flavor composition have represented an average over the range of observed neutrino energies. Yet, this washes out the potential existence of changes in the flavor composition with energy and weakens our sensitivity to the many models that posit them. For the first time, we measure the energy dependence of the flavor composition, looking for a transition from low to high energies. Our present-day measurements, based on the 7.5-year public sample of IceCube High-Energy Starting Events (HESE), find no evidence of a flavor transition. The observation of HESE and through-going muons jointly by next-generation neutrino telescopes Baikal-GVD, IceCube-Gen2, KM3NeT, P-ONE, TAMBO, and TRIDENT may identify a flavor transition around 200TeV by 2030. By 2040, we could infer the flavor composition with which neutrinos are produced with enough precision to establish the transition from neutrino production via the full pion decay chain at low energies to muon-damped pion decay at high energies.

astro-ph.HE↗