Neutrinos are elementary particles that carry no electric charge and have little mass. As they interact only weakly with other particles, they can penetrate enormous amounts of matter, and therefore have the potential to directly convey astrophysical information from the edge of the Universe and from deep inside the most cataclysmic high-energy regions. The neutrino's great penetrating power, however, also makes this particle difficult to detect. Underground detectors have observed low-energy neutrinos from the Sun and a nearby supernova, as well as neutrinos generated in the Earth's atmosphere. But the very low fluxes of high-energy neutrinos from cosmic sources can be observed only by much larger, expandable detectors in, for example, deep water or ice. Here we report the detection of upwardly propagating atmospheric neutrinos by the ice-based Antarctic muon and neutrino detector array (AMANDA). These results establish a technology with which to build a kilometre-scale neutrino observatory necessary for astrophysical observations.

We review the calculation of the prompt lepton flux, produced in the atmosphere by the semileptonic decay of charmed particles. We describe side by side the intermediary ingredients used by different authors, which include not only the charm production model, but also other atmospheric particle showering parameters. After evaluating separately the relevance of each single ingredient, we analyze the effect of different combinations over the final result. We highlight the impact of the prompt lepton flux calculation upon high-energy neutrino telescopes.Comment: 21 pages, 10 figures; revised version, accepted for publication in Astroparticle Physic

The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10 6 times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05 · 10 9 cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulations indicate that 90% of these events lie in the energy range 66 GeV to 3.4 TeV. The observation of atmospheric neutrinos consistent with expectations establishes AMANDA-B10 as a working neutrino telescope.PACS numbers: 95.55. Vj, 95.85.Ry, 96.40.Tv

The core collapse of a massive star in the Milky Way will produce a neutrino burst, intense enough to be detected by existing underground detectors. The AMANDA neutrino telescope located deep in the South Pole ice can detect MeV neutrinos by a collective rate increase in all photo-multipliers on top of dark noise. The main source of light comes from positrons produced in the CC-reaction of anti-electron neutrinos on free protonsν e + p → e + + n. This paper describes the first supernova search performed on the full sets of data taken during 1997 and 1998 (215 days of live time) with 302 of the detector's optical modules. No candidate events resulted from this search. The performance of the detector is calculated, yielding a 70% coverage of the Galaxy with one background fake per year with 90% efficiency for the detector configuration under study. An upper limit at the 90% c.l. on the rate of stellar collapses in the Milky Way is derived, yielding 4.3 events per year. A trigger algorithm is presented and its performance estimated. Possible improvements of the detector hardware are reviewed.

We discuss the possible existence of an observational window, in the TeVPeV energy range, for the detection of prompt neutrinos from the decay of charmed particles produced in cosmic ray interactions with the atmosphere. We calculate the event rates for muon and tau neutrinos of heavy quark, mostly charm, origin. We argue that their prompt fluxes are observable in a kilometer-scale neutrino telescope, even though the calculations are subjected to large uncertainties, which we quantify. We raise the possibility that a small component of prompt neutrinos may already be present in the observed samples of current experiments. We also discuss the interplay of the predicted fluxes with those produced by the flavor oscillation of conventional atmospheric neutrinos, and by anticipated cosmic sources. Typeset using REVT E X 1The quest to search for sources of cosmic neutrinos beyond the sun, to search for the particles that constitute the cold dark matter, and to exploit other science opportunities ranging from astronomy to particle physics, led to the commissioning of large volume highenergy neutrino telescopes. While AMANDA and Baikal are taking data [1,2], similar and much larger instruments are contemplated [3][4][5][6]. These detectors collect the Cherenkov radiation emitted by charged secondaries (electrons, muons and taus) produced in neutrino charged current interactions in the ice or water surrounding the optical sensors. In order to filter the background of atmospheric muons created by cosmic-ray interactions, only upwardgoing neutrinos which traverse the Earth are monitored. The first mission of a new neutrino telescope is to calibrate the detector on the known flux of atmospheric neutrinos [7]. Up to about 10 TeV, the main source of atmospheric neutrinos is the decay of pions and kaons in the atmosphere produced in the interactions of cosmic rays with the Earth's atmosphere; we will refer to them as constituting the "conventional" atmospheric neutrino flux. At higher energies, these mesons interact rather than decaying into a neutrino because of the increasing lifetime of the parent mesons. Therefore the semileptonic decay of very-short lived charmed particles becomes the dominant atmospheric source, giving rise to the "prompt" neutrino flux. The energy dependence of prompt neutrinos follows the cosmic ray spectrum whereas the spectrum of conventional neutrinos is steeper by one power in energy because of the competition of decay with interaction of the parent particles. The prompt neutrino flux is independent of zenith angle whereas conventional neutrinos are preferentially produced in the rarified atmosphere at large zenith.In this letter we discuss the possible existence of an observational window for prompt neutrinos in the TeV-PeV energy range. We calculate neutrino induced muon and tau event rates, recognizing that the fluxes are subject to large uncertainties arising from the combination of extreme atmospheric cascade parameters with different charm production models. We will argue that the pro...