Moderadores
Neutrinos: The first ultra-high-energy neutrino & Neutrino production
- Mauricio Bustamante (Niels Bohr Institute, University of Copenhagen)
Neutrinos: Searches for extragalactic sources
- AYA ISHIHARA (ICEHAP, Chiba University)
Neutrinos: Galactic neutrinos
- Xavier Rodrigues (APC, Paris)
Neutrinos: Future detectors
- Claire Guépin Detrigne (CNRS, LUPM)
Neutrinos: Source modeling
- Denise Boncioli (University of L'Aquila and INFN-LNGS)
Neutrinos: Neutrino alerts & Standard neutrino physics
- Damiano Fiorillo ()
Neutrinos: Nonstandard neutrino physics & Primordial neutrinos
- Mauricio Bustamante (Niels Bohr Institute, University of Copenhagen)
The recent detection of a multi-PeV neutrino event by KM3NeT/ARCA opens a new window into the origin of high-energy neutrinos and ultra-high-energy cosmic rays. We revise the possibility of a cosmogenic origin of this neutrino by analysing the constraints induced by cascaded photons onto the isotropic gamma-ray background measured by the Fermi-LAT collaboration.
We consider two scenarios: the...
Primordial black holes (PBHs) may constitute part of all the Dark Matter, and as they evaporate they should emit an all particle spectrum, including neutrinos. The recently suggested theoretical framework of "memory burden" would allow the survival until today of PBHs with masses low enough to evaporate into particles of energy at the PeV and above.
In this talk we explore the scenario in...
On February 13 2023, at 01:16:46 UTC, the KM3NeT/ARCA neutrino telescope detected the $\sim 220$ PeV neutrino candidate KM3-230213A. Remarkably, the Yangbajing muon telescope in Tibet recorded a simultaneous burst of muons, showing a 5.7σ excess from a compatible direction. The burst exhibits a statistically significant exponential time profile, with a decay constant of τ = 7.0 ± 1.5 minutes,...
The detection of Ultra-High-Energy (UHE) neutrinos is key for the understanding of cosmic-ray acceleration mechanisms and the identification of their astrophysical sources. The Surface Detector of the Pierre Auger Observatory, comprising 1660 water-Cherenkov particle detectors deployed over an area of 3000 km$^2$, has operated continuously for over two decades, providing some of the most...
High-energy neutrino emission from black hole accretion flows is a promising probe of extreme plasma environments and cosmic-ray acceleration in active galactic nuclei (AGNs). While many previous studies have relied on simplified single-zone models, the influence of large-scale plasma inhomogeneity and turbulence remains poorly understood. In this study, we perform the first global simulations...
We develop a first-principles formalism, based on the transport equation in the line-of-sight approximation, to link the expected number of muons at neutrino telescopes to the flux of neutrinos at the Earth's surface. We compute the distribution of muons inside Earth, arising from the up-scattering of neutrinos close to the detector, as well as from the decay of taus produced farther away....
Accurately modeling neutrino flavor oscillations in global simulations of core-collapse supernovae or neutron star mergers remains a major challenge, albeit a potentially crucial one for making reliable predictions. Indeed, it is now widely recognized that flavor instabilities—in which classically computed neutrino distributions are dramatically altered when including quantum effects—are...
The IceCube Collaboration employs two primary detection channels: tracks and cascades. Point source searches with tracks, with their good angular resolution, are particularly sensitive to sources in the northern sky, while searches with cascades offer enhanced energy resolution and are more effective in the southern sky. Historically, high-energy neutrino point-source searches using IceCube...
IceCube has detected a diffuse flux of high energy neutrinos, with two significant observations of extragalactic sources identified to-date being the accreting supermassive black holes (SMBHs) TXS0506+056 and NGC1068. This suggests that other SMBHs may also contribute to the observed neutrino flux. It is possible that some fraction of the IceCube neutrinos originate in time-variable SMBH...
In 2017, the IceCube observatory associated (at a significance level of 3σ) a high-energy (HE, E ≥ 100 TeV) muon neutrino temporarily and spatially coinciding with an electromagnetic flare in blazar TXS 0506+056. Since then, no individual blazar-neutrino association at the same level of significance has been made. In November 2010, flat-spectrum radio quasar (FSRQ) 3C 454.3 had an...
The IceCube Neutrino Observatory has detected TeV-scale neutrinos from NGC 1068, supporting the hypothesis that active galactic nuclei (AGN) may host high-energy neutrino production in obscured environments. Motivated by this, we investigate a catalog of intrinsically X-ray bright Seyfert galaxies in the Southern sky using a coronal model, which suggests cosmic-ray acceleration and hadronic...
Although the existence of a flux of high energy neutrinos emitted by extragalactic sources is well established, only two individual sources have been identified with high confidence: the blazar TXS 0506+056 and the Seyfert galaxy NGC 1068. We will review the results of observations of other Seyfert galaxies in the northern sky, and discuss the implications of both northern and southern...
Multimessenger follow-up observations triggered by high-energy neutrino signals offer a powerful method for identifying cosmic ray sources, particularly when the sources are transient. In the energy range of neutrinos above 100 TeV, X-ray transients are a plausible source candidate, especially if the cosmic neutrino background radiation above 100 TeV originates from the same class of objects...
Neutrino telescopes offer unique insights into some of the most extreme and energetic phenomena in the Universe. The ANTARES detector, which operated for 16 years off the coast of Toulon (France) until 2022, has played a pioneering role in deep-sea neutrino observations. The next-generation KM3NeT neutrino telescopes, ORCA and ARCA, designed to push the boundaries of atmospheric and...
The IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the South Pole instrumented within deep Antarctic ice. Recently, IceCube has reported evidence of TeV-scale neutrino emission from NGC 1068, a nearby Seyfert II galaxy, suggesting that active galactic nuclei could be potential sources of astrophysical neutrinos. Searches for time-dependent 10 GeV to 1 TeV...
The IceCube Neutrino Observatory has provided new insights into the high-energy universe, unveiling neutrinos from the galactic plane to extragalactic supermassive black holes. In this work, we present a 12.3-year, full-sky, all-flavor dataset, the IceCube Multi-Flavor Astrophysics Neutrino sample (ICEMAN). ICEMAN is the combination of three largely independent neutrino samples of different...
Gamma-ray emission from the plane of the Milky Way is understood as partly originating from the interaction of cosmic rays with the interstellar medium. The same interaction is expected to produce a corresponding flux of neutrinos. In 2023, IceCube reported the first observation of this galactic neutrino flux at 4.5𝜎 confidence level. The analysis relied on neutrino flux predictions — based on...
Galactic sources are key to understanding cosmic-ray acceleration and the extreme astrophysics environment in the Milky Way. Some of these sources are expected to emit both gamma rays and neutrinos: while gamma rays trace high-energy particle interactions, neutrinos provide a direct probe of hadronic acceleration processes. To study these phenomena, observatories with broad energy coverage and...
We present updated predictions for the very-high-energy neutrino and gamma-ray flux from the Galactic Plane. Our calculations account for both the diffuse emission generated by cosmic-ray interactions with interstellar gas and the cumulative flux from sources too faint to be resolved by current neutrino or gamma-ray telescopes. The diffuse flux estimates incorporate various assumptions...
The Milky Way hosts astrophysical accelerators capable of producing high-energy cosmic rays. These cosmic rays can interact with the interstellar medium across the Galaxy to produce neutrinos and gamma rays (propagation component), while their interactions with ambient material at their acceleration sites, such as supernova remnants, can give rise to source component of the gamma-ray and...
Young massive stellar clusters (YMSCs) have emerged as energetic non-thermal sources, after the recent observation of extended gamma-ray emission by a dozen YMSCs. The large size of their gamma-ray halos, of the order of the excavated bubble from the collective wind, makes the detection of individual YMSCs rather challenging because of the low surface brightness. As a result, the emission from...
The IceCube Neutrino Observatory at the geographic South Pole has achieved key milestones in neutrino astrophysics, including the discovery of a high-energy astrophysical neutrino flux and the correlation of neutrinos with flaring blazars and Seyfert galaxies. Building on this success, the IceCube Upgrade is scheduled for completion during the 2025/26 Antarctic summer season. It will add seven...
The Radio Neutrino Observatory in Greenland (RNO-G) will be, upon completion, the largest cosmic neutrino telescope that uses the in-ice radio detection mechanism. RNO-G is also the first radio detector of its kind, with each station having a combination of antennas deployed at different depths, the so-called shallow and deep components. With this approach, it is expected that RNO-G will be...
Situated near Summit Station, Greenland in 2023 and 2024, the Radar Echo Telescope for Cosmic Rays (RET-CR) experiment searched for radar echoes produced by reflections from in-ice cosmic-ray (CR) cascades. These secondary cascades are generated by energetic CR air showers impacting a high altitude ice sheet and depositing a portion of their energy into the ice. They can be detected with radar...
The Payload for Ultrahigh Energy Observations (PUEO) is a balloon-borne radio detector for neutrinos at energies above 1EeV, scheduled to fly over Antarctica in the austral summer of 2025/2026. Through the observation of radio signals from neutrino interactions in the Antarctic ice sheet, PUEO can achieve an effective detection volume that is unparalleled by other experiments.
Charged leptons...
The IceCube Neutrino Observatory has discovered an extragalactic neutrino flux and observed neutrinos from the Milky Way. Even though two active galaxies, NGC 1068 and TXS 0506+056, are candidate neutrino sources, the classes of objects responsible for the extragalactic flux are not known. And the Milky Way flux should be a combination of yet to be identified individual sources as well as a...
The detection of high-energy astrophysical neutrinos by IceCube has opened a new window on our Universe. While IceCube has measured the flux of these neutrinos at energies up to several PeV, much remains to be discovered regarding their origin and nature. Currently, the discovery of point sources of neutrinos is hindered by atmospheric neutrino backgrounds; likewise, astrophysical neutrino...
Core-collapse Supernovae (SN) release nearly all their binding energy as a burst of neutrinos of all three flavours. RES-NOVA addresses a major challenge in astroparticle physics by introducing a novel detection technique based on low-temperature calorimeters operated at the milliKelvin scale, exploiting Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) as detection channel.
CE$\nu$NS...
Blazars are strong neutrino source candidates owing to their high intrinsic power and Doppler boost. However, in the sub-PeV range, where IceCube is most sensitive, blazars are inefficient neutrino emitters, and models seem to require extreme proton luminosities. In this talk, I present a new leptohadronic blazar model that captures the energetics and the extended nature of the relativistic...
Multimessenger observations, combining electromagnetic radiation and neutrinos, offer critical insights into the high-energy processes occurring in astrophysical sources. Recent coincident detections of high-energy neutrinos from the direction of blazars highlight them as ideal candidates for multimessenger modeling, and at the same time underscore the necessity of accurate modeling frameworks...
The recent detection of high-energy neutrinos from NGC 1068 supports the idea that AGN coronae—magnetized, compact regions around supermassive black holes—can accelerate protons and produce neutrinos via photohadronic interactions with X-ray photons. I present a plasma-informed framework for this coronal scenario, grounded in particle-in-cell simulations of magnetic reconnection and...
Observation of high-energy neutrinos from the direction of the nearby active galaxy, NGC 1068, was a major step in identifying the origin of high-energy neutrinos. This observation revealed that high-energy neutrinos originated at the heart of active galaxies, which are opaque to very-high-energy gamma-ray emission. This realization is further reinforced by the multimessenger picture for the...
The interactions of high-energy cosmic rays produce neutrinos and gamma rays. However, while neutrinos travel unimpeded, the accompanying gamma rays can trigger electromagnetic cascades via pair production on ambient photons, reprocessing their energy to lower frequencies. For intergalactic cascades produced in the propagation through extragalactic radiation, the resulting photons have a...
Gamma-ray observations have established that pulsar magnetospheres are efficient accelerators of electrons and positrons. Analytical models and numerical simulations further suggest that a fraction of a pulsar’s rotational energy can be converted into the acceleration of cosmic rays, positioning pulsars as potential contributors to the Galactic cosmic-ray population. However, direct...
Despite growing statistics, the sources of most high energy neutrinos remain unknown. Here we present a tomographic approach that makes use of the angular, harmonic cross-correlation between IceCube data and galaxy surveys. If neutrino sources follow the Large Scale Structure (LSS), this cross-correlation will be non-zero and, if detected, it will determine how neutrino sources correlate with...
The moment a neutrino event, likely of astrophysical origin, triggers a light emission in the glacial ice at the South Pole, the IceCube Neutrino Observatory issues a real-time alert to potential observers worldwide. The same filters that select alerts with track-like signatures were applied to the entire IceCube data sample from 2011 to 2023, leading to the public release of the IceCat-1...
KM3NeT, a Cherenkov-based neutrino telescope sensitive to energies ranging from MeV to PeV, is currently under construction in the depths of the Mediterranean Sea. It comprises two detectors, KM3NeT/ARCA and KM3NeT/ORCA, already partially deployed and data taking; full completion is anticipated by the end of the decade. Its design provides a large field of view and high duty cycle, enabling it...
The IceCube Neutrino Observatory, situated at the South Pole, plays a pivotal role in multi-messenger astronomy by continuously monitoring the entire sky for high-energy neutrinos. This presentation highlights recent advancements in IceCube's real-time alert system, particularly focusing on the Gamma-ray Follow-Up (GFU) program and the innovative Neutrino FlareWatch platform. These...
High center-of-mass electromagnetic (EM) interactions could produce decaying heavy leptons and hadrons, leading to neutrino generation. These processes might occur in the most extreme astrophysical and cosmological scenarios, potentially altering the expected gamma-ray and neutrino fluxes in both the hadronic and the leptonic pictures. For instance, neutrinos could arise from high-redshift EM...
The IceCube Neutrino Observatory has selected a sample of very pure, primarily atmospheric, predominantly muon neutrino events over 11 years from all directions below the horizon, spanning the energy range 500 GeV to 100 TeV. These neutrinos traverse the earth and are attenuated in varying amounts depending on their energy and traversed column density. By parameterizing the earth as multiple...
The all-sky very-high energy ($10^4$ - $10^6$ GeV) atmospheric muon flux, most recently measured by IceCube, shows a spectral hardening in the higher energy range, indicating a prompt component. Since the atmospheric muon neutrino flux at high energy, also measured by IceCube, is dominated by the astrophysical flux, only upper bounds on the prompt atmospheric muon neutrino flux contribution...
Tau neutrinos, being most likely of astrophysical origin, plays a crucial role in solving cosmic‐ray–related puzzles. In IceCube, iterations of searches for tau neutrinos via their characteristic “double-cascade” / "double pulse” morphology have been conducted. However, this signature is not unique to tau neutrinos: the much less studied charmed production can lead to a similar signature due...
Over the past decade, high-energy neutrino events have been piling up, resulting in a large statistical dataset covering a broad range of energies and directions. As neutrinos traverse the Earth, they undergo energy- and angle-dependent attenuation, which encodes information about the neutrino–nucleon cross section. In this work, we extract the neutrino–nucleon cross section using a large...
In the framework of open quantum systems, neutrino may interact with their surrounding environment, introducing stochastic fluctuations to their quantum phase. This perturbation causes a gradual loss of coherence during neutrino propagation, a phenomenon known as decoherence, which alters the neutrino oscillation probabilities.
KM3NeT/ARCA is a water Cherenkov detector currently under...
Charm-induced di-muons observed in neutrino experiments have played a pivotal role in advancing our understanding of quantum chromodynamics. IceCube is positioned to observe di-muon events at energies beyond those available to previous neutrino beam experiments, thereby probing novel regions of light quark dynamics within the proton. In this presentation, I will discuss the current status of...
We present new constraints on neutrino secret interactions (νSI) using high-energy and ultra high-energy astrophysical neutrinos as probes of new physics beyond the Standard Model. By studying neutrinos from established sources, such as SN1987A, NGC 1068, TXS 0506+056, PKS 0735+178, and the extreme-energy KM3-230213A event, we explore the potential interactions of Dirac neutrinos with a...
Although the sources of astrophysical neutrinos are still unknown, they are believed to be produced by a diffuse population of sources in the distant universe. Measurements of the astrophysical flux can thus be sensitive to energy-dependent propagation effects, such as the very long baseline oscillations that would occur if neutrinos are quasi-Dirac. Assuming simple models of the source flux,...
Among the few ways that allow or could allow us to probe the early Universe from the observation of a flux of primordial particles, there is one possibility which has been little studied: the observation today of high energy neutrinos which could have been emitted short after the Big Bang, from the decay or annihilation of early universe relics.
We perform a general study of such a...
Cosmological observations, such as Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB), provide vital insights into the early Universe, allowing us to trace its evolution to times as short as t∼0.01 s and to test extensions of the Standard Model. Accurately modeling the non-trivial dynamics of neutrinos in the decoupling era typically requires solving a system of Boltzmann...
