In the last century, astronomy evolved from optical observation to the multi-wavelength study of celestial objects from radio waves up to x- and γ-rays, leading to a wealth of new discoveries and ...opening the way to high-energy astroparticle physics. In particular, the recent success of ground-based very-high-energy γ-ray telescopes has opened a new window on the most powerful and violent objects of the Universe, giving a new insight into the physical processes at work in such sources. In the context of high-energy astronomy, neutrinos constitute a unique probe since they escape from their sources, travel undisturbed on virtually cosmological distances and are produced in high-energy hadronic processes. In particular they would allow a direct detection and unambiguous identification of the sites of acceleration of high-energy baryonic cosmic rays, which remain unknown. This report discusses the physics potential of the domain and reviews the experimental techniques relevant for the detection of high-energy (⩾TeV) neutrinos. The results obtained by the first generation of such detectors are presented, along with the perspectives opened by new projects and prototypes being currently developed.
The calibration units of KM3NeT Le Breton, R.; Billault, M.; Boutonnet, C. ...
Journal of instrumentation,
09/2021, Letnik:
16, Številka:
9
Journal Article
Recenzirano
Odprti dostop
KM3NeT is a deep-sea infrastructure composed of two neutrino telescopes being deployed in the Mediterranean Sea: ARCA, near Sicily in Italy, designed for neutrino astronomy, and ORCA, near Toulon in ...France, designed for neutrino oscillation physics. To achieve the best performance, the exact location of the optical modules, affected by sea current, must be known at any time and the timing resolution between optical modules must reach the nanosecond. Moreover, the properties of the environment in which the telescopes are deployed must be continuously monitored because they affect the timing and positioning calibration. KM3NeT is going to deploy several dedicated Calibration Units to meet these calibration goals. Because of the difference in size between ARCA and ORCA, the design of the Calibration Unit is not the same for the two sites. This proceeding describes all the devices, features and purposes of the Calibration Units with a focus on the ORCA Calibration Unit.
A
bstract
Large mass ice/water Cherenkov experiments, optimized to detect low energy (1–20 GeV) atmospheric neutrinos, have the potential to discriminate between normal and inverted neutrino mass ...hierarchies. The sensitivity depends on several model and detector parameters, such as the neutrino flux profile and normalization, the Earth density profile, the oscillation parameter uncertainties, and the detector effective mass and resolution. A proper evaluation of the mass hierarchy discrimination power requires a robust statistical approach. In this work, the Toy Monte Carlo, based on an extended unbinned likelihood ratio test statistic, was used. The effect of each model and detector parameter, as well as the required detector exposure, was then studied. While uncertainties on the Earth density and atmospheric neutrino flux profiles were found to have a minor impact on the mass hierarchy discrimination, the flux normalization, as well as some of the oscillation parameter (
,
θ
13
,
θ
23
, and
δ
CP
) uncertainties and correlations resulted critical. Finally, the minimum required detector exposure, the optimization of the low energy threshold, and the detector resolutions were also investigated.
Abstract
The neutrino mass ordering (NMO) is one of the fundamental questions in neutrino physics. KM3NeT/ORCA and JUNO are two neutrino oscillation experiments both aiming at measuring the NMO with ...different approaches: ORCA with atmospheric neutrinos traversing the Earth and JUNO with reactor neutrinos. This contribution presents the potential of determining the NMO through a combined analysis of JUNO and ORCA data. In a joint fit, the NMO sensitivity is enhanced beyond the simple sum of the sensitivities of each experiment due to the tension between the respective Δ
m
31
2
best fit values obtained when the wrong ordering is assumed, together with good constraints on this parameter measurement by both experiments. From this analysis, we expect the true NMO to be determined with 5
σ
significance after 1–2 years of data taking by both experiments for the current global best-fit values of the oscillation parameters, while maximally 6 years will be needed for any other parameter set.
Sources of gravitational waves are often expected to be observable through several messengers, such as gamma-rays, X-rays, optical, radio, and/or neutrino emission. The simultaneous observation of ...electromagnetic or neutrino emission with a gravitational-wave signal could be a crucial aspect for the first direct detection of gravitational waves. Furthermore, combining gravitational waves with electromagnetic and neutrino observations will enable the extraction of scientific insight that was hidden from us before. We discuss the method that enables the joint search with the LIGO-Virgo-IceCube-ANTARES global network, as well as its methodology, science reach, and outlook for the next generation of gravitational-wave detectors.
Recent results from the ANTARES neutrino telescope Van Elewyck, Véronique
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2014, Letnik:
742
Journal Article
Recenzirano
Odprti dostop
The ANTARES neutrino telescope is currently the largest operating water Cherenkov detector and the largest neutrino detector in the Northern Hemisphere. Its main scientific target is the detection of ...high-energy (TeV and beyond) neutrinos from cosmic accelerators, as predicted by hadronic interaction models, and the measurement of the diffuse neutrino flux. Its location allows for surveying a large part of the Galactic Plane, including the Galactic Centre.
In addition to the standalone searches for point-like and diffuse high-energy neutrino signals, ANTARES has developed a range of multi-messenger strategies to exploit the close connection between neutrinos and other cosmic messengers such as gamma-rays, charged cosmic rays and gravitational waves. This contribution provides an overview of the recently conducted analyses, including a search for neutrinos from the Fermi bubbles region, searches for optical counterparts with the TAToO program, and searches for neutrinos in correlation with gamma-ray bursts, blazars, and microquasars. Further topics of investigation, covering e.g. the search for neutrinos from dark matter annihilation, searches for exotic particles and the measurement of neutrino oscillations, are also reviewed.
In the last 70 years, geophysics has established that the Earth’s outer core is an FeNi alloy containing a few percent of light elements, whose nature and amount remain controversial. Besides the ...classical combinations of silicon and oxygen, hydrogen has been advocated as the only light element that could account alone for both the core density and velocity profiles. Here we show how this question can be addressed from an independent viewpoint, by exploiting the tomographic information provided by atmospheric neutrinos, weakly-interacting particles produced in the atmosphere and constantly traversing the Earth. We evaluate the potential of the upcoming generation of atmospheric neutrino detectors for such a measurement, showing that they could efficiently detect the presence of 1 wt% hydrogen in the Earth’s core in 50 years of concomitant data taking. We then identify the main requirements for a next-generation detector to perform this measurement in a few years timescale, with the further capability to efficiently discriminate between FeNiH and FeNiSi
x
O
y
core composition models in less than 15 years.
► We estimate the gravitational-wave and high-energy neutrino emission window for GRBs. ► GRBs emit gravitational waves and high-energy neutrinos likely within 500
s. ► The derived time window allows ...for a 1000
s window in multimessenger searches. ► The analysis is largely based on model-motivated comparisons with observations.
We derive a conservative coincidence time window for joint searches of gravitational-wave (GW) transients and high-energy neutrinos (HENs, with energies ≳100
GeV), emitted by gamma-ray bursts (GRBs). The last are among the most interesting astrophysical sources for coincident detections with current and near-future detectors. We take into account a broad range of emission mechanisms. We take the upper limit of GRB durations as the 95% quantile of the
T
90’s of GRBs observed by BATSE, obtaining a GRB duration upper limit of ∼150
s. Using published results on high-energy (>100
MeV) photon light curves for 8 GRBs detected by Fermi LAT, we verify that most high-energy photons are expected to be observed within the first ∼150
s of the GRB. Taking into account the breakout-time of the relativistic jet produced by the central engine, we allow GW and HEN emission to begin up to 100
s before the onset of observable gamma photon production. Using published precursor time differences, we calculate a time upper bound for precursor activity, obtaining that 95% of precursors occur within ∼250
s prior to the onset of the GRB. Taking the above different processes into account, we arrive at a time window of
t
HEN
−
t
GW
∈
−500
s,
+500
s. Considering the above processes, an upper bound can also be determined for the expected time window of GW and/or HEN signals coincident with a detected GRB,
t
GW
−
t
GRB
≈
t
HEN
−
t
GRB
∈
−350
s,
+150
s. These upper bounds can be used to limit the coincidence time window in multimessenger searches, as well as aiding the interpretation of the times of arrival of measured signals.
We present a calculation of the damping of an ultra-energetic cosmic neutrino (UHEν) travelling through the thermal gas of relic neutrinos, using the formalism of finite-temperature field theory. ...From the self-energy diagram due to Z exchange, we obtain the annihilation cross-section for an UHEν interacting with an antineutrino from the background. This method allows us to derive the full expression for the UHEν transmission probability, taking into account the momentum of relic neutrinos. We discuss the effect of thermal motion on the shape of the absorption dips for different UHEν fluxes as well as in the context of relic neutrino clustering. We find that for ratios of the neutrino mass to the relic background temperature 10
2 or smaller, the thermal broadening of the absorption lines could significantly affect the determination of the neutrino mass and of the characteristics of the population of UHEν sources.
PDF
