154 research outputs found
Detecting neutrinos in IceCube with Cherenkov light in the South Pole ice
The IceCube Neutrino Observatory detects GeV-to-PeV+ neutrinos via the
Cherenkov light produced by secondary charged particles from neutrino
interactions with the South Pole ice. The detector consists of over 5000
spherical Digital Optical Modules (DOM), each deployed with a single
downward-facing photomultiplier tube (PMT) and arrayed across 86 strings over a
cubic-kilometer. IceCube has measured the astrophysical neutrino flux, searched
for their origins, and constrained neutrino oscillation parameters and cross
sections. These were made possible by an in-depth characterization of the
glacial ice, which has been refined over time, and novel approaches in
reconstructions that utilize fast approximations of Cherenkov yield
expectations.
After over a decade of nearly continuous IceCube operation, the next
generation of neutrino telescopes at the South Pole are taking shape. The
IceCube Upgrade will add seven additional strings in a dense infill
configuration. Multi-PMT OMs will be attached to each string, along with
improved calibration devices and new sensor prototypes. Its denser OM and
string spacing will extend sensitivity to lower neutrino energies and further
constrain neutrino oscillation parameters. The calibration goals of the Upgrade
will help guide the design and construction of IceCube Gen2, which will
increase the effective volume by nearly an order of magnitude.Comment: 5 pages, 5 figures, proceeding from the 11th International Workshop
on Ring Imaging Cherenkov Detectors (RICH2022
A binned likelihood for stochastic models
Metrics of model goodness-of-fit, model comparison, and model parameter
estimation are the main categories of statistical problems in science. Bayesian
and frequentist methods that address these questions often rely on a likelihood
function, which is the key ingredient in order to assess the plausibility of
model parameters given observed data. In some complex systems or experimental
setups, predicting the outcome of a model cannot be done analytically, and
Monte Carlo techniques are used. In this paper, we present a new analytic
likelihood that takes into account Monte Carlo uncertainties, appropriate for
use in the large and small sample size limits. Our formulation performs better
than semi-analytic methods, prevents strong claims on biased statements, and
provides improved coverage properties compared to available methods.Comment: 18 pages, 7 figures, 2 tables, code can be found at
https://github.com/austinschneider/MCLL
An improved infrastructure for the IceCube realtime system
The IceCube realtime alert system has been operating since 2016. It provides
prompt alerts on high-energy neutrino events to the astroparticle physics
community. The localization regions for the incoming direction of neutrinos are
published through NASA's Gamma-ray Coordinate Network (GCN). The IceCube
realtime system consists of infrastructure dedicated to the selection of alert
events, the reconstruction of their topology and arrival direction, the
calculation of directional uncertainty contours and the distribution of the
event information through public alert networks. Using a message-based workflow
management system, a dedicated software (SkyDriver) provides a representational
state transfer (REST) interface to parallelized reconstruction algorithms. In
this contribution, we outline the improvements of the internal infrastructure
of the IceCube realtime system that aims to streamline the internal handling of
neutrino events, their distribution to the SkyDriver interface, the collection
of the reconstruction results as well as their conversion into human- and
machine-readable alerts to be publicly distributed through different alert
networks. An approach for the long-term storage and cataloging of alert events
according to findability, accessibility, interoperability and reusability
(FAIR) principles is outlined.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC2023).
See arXiv:2307.13047 for all IceCube contributions. 8 pages, 3 figure
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
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