EeV Neutrinos
We discuss the recent developments in the study of alternative detection possibilites offered by the radio technique and air shower arrays.
astro-ph↗
arXiv subjects
E. Zas
Publications and source records attributed to E. Zas.
Characterization of neutrino signals with radiopulses in dense media through the LPM effect
We discuss the possibilities of detecting radio pulses from high energy showers in ice, such as those produced by PeV and EeV neutrino interactions. It is shown that the rich radiation pattern structure in the 100 MHz to few GHz allows the separation of electromagnetic showers induced by photons or electrons above 100 PeV from those induced by hadrons. This opens up the possibility of measuring the energy fraction transmitted to the electron in a charged current electron neutrino interaction with adequate sampling of the angular distribution of the signal. The radio technique has the potential to complement conventional high energy neutrino detectors with flavor information.
astro-ph↗
The LPM effect for EeV hadronic showers in ice: implications for radio detection of neutrinos
We study the longitudinal development of hadronic showers in ice for energies up to 100 EeV and its implications for radio and optical Cherenkov emission. A small fraction of showers induced by primaries of energy above 1 EeV is shown to display the characteristic elongation associated to the Landau Pomeranchuck Migdal (LPM) effect. The rest look like ordinary showers because the highest energy $π^0$'s interact instead of decaying in two photons. The LPM effect observed in this fraction of the showers is mainly due to $η$ and $η'$ production and decay. We give parameterizations for the total and excess charge tracklengths and for the amplitude and angular spread of the electric field spectrum in the Cherenkov direction. Implications for neutrino detection are briefly addressed.
astro-ph↗
On the detection of Ultra High Energy Neutrinos with the Auger Observatory
We show that the Auger Air Shower Array has the potential to detect neutrinos of energies in the $10^{19}~$eV range through horizontal air showers. Assuming some simple conservative trigger requirements we obtain the acceptance for horizontal air showers as induced by high energy neutrinos by two alternative methods and we then give the expected event rates for a variety of neutrino fluxes as predicted in different models which are used for reference.
astro-ph↗
Cherenkov radio pulses from EeV neutrino interactions: the LPM effect
We study the implications of the LPM effect for the Cherenkov radiation of EeV electromagnetic showers in the coherent radiowave regime for ice. We show that for showers above 100~PeV the electric field scales with shower energy but has a markedly narrower angular distribution than for lower energy showers. We give an electric field frequency and angular spectrum parameterization valid for showers having energy up to the EeV regime and discuss the implications for neutrino detectors based on arrays of radio antennas. Implications of the LPM effect for under water neutrino detectors in project are also briefly addressed.
astro-ph↗
Neutrino Fluxes from Active Galaxies: a Model-Independent Analysis
There are tantalizing hints that jets, powered by supermassive black holes at the center of active galaxies, are true cosmic proton accelerators. They produce photons of TeV energy, possible higher, and may be the enigmatic source of the highest energy cosmic rays. Photoproduction of neutral pions by accelerated protons on UV light is the source of the highest energy photons, in which most of the bolometric luminosity of the galaxy may be emitted. The case that proton beams power active galaxies is, however, far from conclusive. Neutrinos from the decay of charged pions represent an uncontrovertible signature for the proton induced cascades. We show that their flux can be estimated by model-independent methods, based on dimensional analysis and textbook particle physics. Our calculations also demonstrate why different models for the proton blazar yield very similar results for the neutrino flux, consistent with the ones obtained here.
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Limits on Topological Defect Neutrino fluxes from Horizontal Air Shower measurements
We obtain the horizontal air shower rate from the (EeV) high energy neutrino flux predicted in some topological defect scenarios as the source for the highest energy cosmic rays. Emphasis is made on the different character of the events depending on the neutrino flavor an type of interaction. We show that the bound for muon poor showers in the $10^5-10^7$ GeV energy range is violated by maximal predictions for superconducting cosmic string neutrino fluxes, we compare it to other neutrino flux limits and we discuss the future of such measurements to further constrain these models.
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Ultra-Transparent Antarctic Ice as a Supernova Detector
We have simulated the response of a high energy neutrino telescope in deep Antarctic ice to the stream of low energy neutrinos produced by a supernova. The passage of a large flux of MeV-energy neutrinos during a period of seconds will be detected as an excess of single counting rates in all individual optical modules. We update here a previous estimate of the performance of such an instrument taking into account the recent discovery of absorption lengths of several hundred meters for near-UV photons in natural deep ice. The existing AMANDA detector can, even by the most conservative estimates, act as a galactic supernova watch.
astro-ph↗
High Energy Neutrino Telescopes Detect Supernovae
We have simulated the response of a high energy neutrino telescope to the stream of low energy neutrinos produced by a supernova. The nominal threshold of such detectors is in the GeV energy range. The passage of a large flux of MeV neutrinos during a period of seconds will nevertheless be detected as an excess of single counting rates in all individual optical modules. Detectors under construction, which consist of roughly 200 modules, will be able to detect a galactic supernova at or above the 5 $σ$ level. The rate of fake signals is, however, too large for the telescope to serve as a neutrino watch. Such capability requires detectors with roughly 3 times the number of optical modules, thus within easy reach of the next generation detectors.
hep-ph↗