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All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

International Design Study for the Neutrino Factory (The IDS-NF Collaboration) Interim Design Report

The starting point for the International Design Study for the Neutrino Factory (the IDS-NF) was the output of the earlier International Scoping Study for a future Neutrino Factory and super-beam facility (the ISS). The accelerator facility described in section 2 incorporates the improvements that have been derived from the substantial amount of work carried out within the Accelerator Working Group. Highlights of these improvements include: • Initial concepts for the implementation of the proton driver at each of the three example sites, CERN, FNAL, and RAL; • Detailed studies of the energy deposition in the target area; • A reduction in the length of the muon beam phase-rotation and bunching systems; • Detailed analyses of the impact of the risk that stray magnetic field in the accelerating cavities in the ionisation cooling channel will reduce the maximum operating gradient. Several alternative ionisation-cooling lattices have been developed as fallback options to mitigate this technical risk; • Studies of particle loss in the muon front-end and the development of strategies to mitigate the deleterious effects of such losses; • The development of more complete designs for the muon linac and re-circulating linacs; • The development of a design for the muon FFAG that incorporates insertions for injection and extraction; and • Detailed studies of diagnostics in the decay ring. Other sub-systems have undergone a more “incremental” evolution; an indication that the design of the Neutrino Factory has achieved a degree of maturity. The design of the neutrino detectors described in section 3 has been optimised and the Detector Working Group has made substantial improvements to the simulation and analysis of the Magnetised Iron Neutrino Detector (MIND) resulting in an improvement in the overall neutrino-detection efficiency and a reduction in the neutrino-energy threshold. In addition, initial consideration of the engineering of the MIND has generated a design that is feasible and a finite element analysis of the toroidal magnetic field to produce a realistic field map has been carried out. Section 3 also contains, for the first time, a specification for the near-detector systems and a demonstration that the neutrino flux can be determined with a precision of 1% through measurements of inverse muon decay at the near detector. The performance of the facility, the work of the Physics and Performance Evaluation Group, is described in section 1. The effect of the improved MIND performance is to deliver a discovery reach for CP-invariance violation in the lepton sector, the determination of the mass hierarchy, and of θ 13 that extends down to values of sin 2 2θ 13 ∼ 5 × 10 −5 and is robust against systematic uncertainties. In addition, the improved neutrino-energy threshold has allowed an indicative analysis of the kind of re-optimisation of the facility that could be carried out should θ 13 be found close to the current upper bound. The results presented in section 1 demonstrate that the discovery reach as well as the precision with which the oscillation parameters can be measured at the baseline Neutrino Factory is superior to that of other proposed facilities for all possible values of sin 2 2θ 13 .

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Coherent Elastic Neutrino Nucleus Scattering

Coherent Elastic Neutrino Nucleus Scattering (CENNS) has yet to be observed since its first prediction in 1974. The CENNS cross-section is precisely known in the Standard Model (SM). It is considerably larger than the other neutrino interaction channels at MeV energies. If measured at its predicted value, CENNS can be a very powerful tool for future neutrino oscillation experiments. Alternatively, any deviation from the very robust SM prediction could be a window to beyond-SM physics. The discovery of CENNS requires an intense source of low energy neutrinos, and a large-scale low energy threshold detector, both of which complement and build on existing programs at Fermilab. The Booster Neutrino Beamline (BNB) at Fermilab is a surprisingly powerful source of pion decay-at-rest ($\pi$DAR) neutrinos. The energy spectrum and flux of neutrinos in the backward direction (far-off-axis) of the BNB is excellent for a CENNS discovery measurement. At the closest practical location, the $\pi$DAR neutrino flux at BNB would be about a fifth of the neutrino flux of Spallation Neutron Source (SNS at Oak Ridge). The BNB site is preferable in almost every other aspect, however. First, the beam duty factor of BNB (2.5x10 -5 ) is about a factor of four better, which will help to reduce ambient backgrounds. Second, the potential experiment site, close to the BNB target, allows optimal placement of the detectors, with minimal sitting issues. The CENNS experiment would be completely parasitic to any running of the BNB. It would require no changes to the beamline, and place no additional requirements on the running mode or times. The $\pi$DAR neutrinos from the BNB are a by-product of running the beamline for MicroBooNE, and will be available for the foreseeable future. The CENNS detector would be a ton-scale single-phase Liquid Argon (LAr) detector, placed inside a water shield with an active cosmic ray veto. The low energy threshold and low background detector technology is already well developed thanks to work over the last decade in Dark Matter detector physics. Moreover, Fermilab is equipped with very strong technical and engineering resources in liquid argon detector development. One issue that must be addressed prior to the development of a full CENNS proposal is the question of whether the beam-related fast neutron background is low enough that it can be practically shielded.

Brice, S. J.↗
DOE OSTI2016

A Search for Sterile Neutrinos at the NO$\nu$A Far Detector

NO$\nu$A is the current United States flagship long-baseline neutrino experiment designed to study the properties of neutrino oscillations. It consists of two functionally identical detectors each located $14.6$ mrad off the central axis from the Fermilab NuMI neutrino beam. The Near Detector is located $1\,\mbox{km}$ downstream from the beam source, and the Far Detector is located $810\,\mbox{km}$ away in Ash River, Minnesota. This long baseline, combined with the ability of the NuMI facility to switch between nearly pure neutrino and anti-neutrino beams, allows NO$\nu$A to make precision measurements of neutrino mixing angles, potentially determine the neutrino mass hierarchy, and begin searching for CP violating effects in the lepton sector. However, NO$\nu$A can also probe more exotic scenarios, such as oscillations between the known active neutrinos and new sterile species. This thesis showcases the first search for sterile neutrinos in a $3 + 1$ model at NO$\nu$A. The a nalysis presented searches for a deficit in the rate of neutral current events at the Far Detector using the Near Detector to constrain the predicted spectrum. The comparison between the observed and predicted spectra is translated into a measurement of the expanded PMNS mixing angles, $\theta_{34}$ and $\theta_{24}$ elements, and the matrix elements $\vert U_{\mu 4} \vert^2$ and $\vert U_{\tau 4} \vert^2$, assuming $0.05 < \Delta m^2_{41} < 0.5\,\mbox{eV}^2$. This analysis was performed using data taken between February $2014$ and May $2016$ corresponding to $6.69 \times 10^{20}$ protons on target. No deficit of events was observed, leading only to upper limits on the sterile mixing angles, $\theta_{34} < 32^\circ$ and $\theta_{24} < 20^\circ$, and on the matrix elements, $\vert U_{\mu 4} \vert^2 < 0.12$ and $\vert U_{\tau 4} \vert^2 < 0.27$, all at the $90\%$ confidence level. These measurements are consistent with the no sterile neutrino hypothesis. At the end of the diss ertation there is a short discussion of future sensitivity i! mprovements using a larger dataset

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Measurement of Muon Neutrino Disappearance with the NOvA Experiment

The NOvA experiment consists of two functionally identical tracking calorimeter detectors which measure the neutrino energy and flavour composition of the NuMI beam at baselines of 1~km and 810~km. Measurements of neutrino oscillation parameters are extracted by comparing the neutrino energy spectrum in the far detector with predictions of the oscillated neutrino energy spectra that are made using information extracted from the near detector. Observation of muon neutrino disappearance allows NOvA to make measurements of the mass squared splitting $\Delta m^2_{32}$ and the mixing angle $\theta_{23}$. The measurement of $\theta_{23}$ will provide insight into the make-up of the third mass eigenstate and probe the muon-tau symmetry hypothesis that requires $\theta_{23} = \pi/4$. This thesis introduces three methods to improve the sensitivity of NOvA's muon neutrino disappearance analysis. First, neutrino events are separated according to an estimate of their energy resolution to distinguish well resolved events from events that are not so well resolved. Second, an optimised neutrino energy binning is implemented that uses finer binning in the region of maximum muon neutrino disappearance. Third, a hybrid selection is introduced that selects muon neutrino events with greater efficiency and purity. The combination of these improvements produces an increase in the sensitivity of the analysis equivalent to collecting 40-100\% more data across the range of possible values of $\Delta m^2_{32}$ and $\sin^2\theta_{23}$. This thesis presents new results using a 14~ktonne detector equivalent exposure of $6.05\times 10^{20}$~protons~on~target. A fit to the far detector data, assuming normal hierarchy, produces $\Delta m^2_{32}=2.45^{+0.087}_{-0.079}\times10^{-3}~\text{eV}^2$ and $\sin^2\theta_{23}$ in the range 0.429~-~0.593 with two statistically degenerate best fit points at 0.481 and 0.547. This measurement is consistent with maximal mixing where $\theta_{ 23} = \pi/4$. The data used for this thesis is 1/6 of the to! tal data that NOvA expects to collect.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Measurement of the Kaon Production Normalization in the NuMI Target Using Uncontained Charged-Current Muon Neutrino Interactions in the NOvA Far Detector

aNOvA is a long-baseline neutrino oscillation experiment that uses the NuMI beam from Fermilab. Its physics goals include providing constraints to the neutrino mass hierarchy and the CP-violating phase $\delta$ by precision measurements of the electron (anti)neutrino appearance in a muon (anti)neutrino beam. Similarly, new limits on the values of $\sin^2{\theta_{23}}$ and $\Delta m^{2}_{32}$ will be achieved by measurements of the muon (anti)neutrino disappearance probabilities. A combined analysis measurement will allow a better resolution of the $\theta_{23}$ octant. The NuMI beam is produced by the collision of high energy protons into a target, giving rise to kaon and pion mesons that decay to neutrinos of a specific flavor. This thesis presents a measurement of the kaon production normalization scale using uncontained charged-current muon neutrinos at the Far Detector. Because the neutrino beam is not pure in flavor, it contains an admixture of other different n eutrino flavors that become a source of background. %in oscillation analysis. Therefore, it is of paramount importance for accelerator experiments, such as NOvA, to have a reliable flux prediction of the neutrino beam in order to achieve its physics goals. One method to constrain the flux is to constrain and measure each flux component independently. The kaon component contributes to the intrinsic $\nu_{e}$ contamination of the beam, a key background for the $\nu_{e}$-appearance analysis. We observed that the uncontained sample in the 10-20 GeV region corresponds to the kaon component of the NuMI beam at the Far Detector. We also found a 60-80\% correlation between the Near Detector $\nu_{e}$ background and the Far Detector $\nu_{\mu}$ uncontained signal. The data used for this analysis was collected from October 2014 to February 2017, corresponding to $7.99 \times 10^{20}$ protons-on-target (POT). The ratio between the Far Detector data and the simulation is fitted to a lin e in the 10-20 GeV energy region. Calibration, energy scale,! final state interactions and neutrino flux (e.g. beam transport and hadron production shape only) systematic uncertainties are considered. The kaon production normalization scale is measured to be $S_{K} = 1.07 \pm 0.16$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Search for a low-energy excess of electron neutrinos in MicroBooNE

The Micro Booster Neutrino Experiment (MicroBooNE) is a Liquid Argon Time Projection Chamber (LArTPC) designed for short-baseline neutrino physics at the Fermi National Accelerator Laboratory. The main physics goal of MicroBooNE is to address the low-energy excess of electron-like events observed by the MiniBooNE experiment and, if confirmed, clarify its nature. The MiniBooNE experiment is a Cherenkov detector and this technology does not allow to distinguish between electrons and single photons in the final state. LArTPC detectors, instead, offer excellent granularity and powerful separation between electrons and photons. For this reason, they represent an ideal technology for the detection of electron neutrino interactions. This thesis presents the first fully-automated electron neutrino selection in a LArTPC. The selection looks for charged-current electron neutrino interactions with no pions and at least one proton in the final state. It is applied on a sub-sample of the data acquired by the detector in the Booster Neutrino Beam, corresponding to $4.34\times10^{19}$~protons-on-target. A validation of the analysis is performed on two orthogonal side-bands, enriched with neutral-current and charged-current muon neutrino interactions, respectively. The uncertainties on the neutrino cross sections, flux, and detector simulation are evaluated. The MicroBooNE detector is placed off-axis with the Neutrinos at the Main Injector (NuMI) beam. An independent dataset of events acquired by triggering on the NuMI beam is employed to measure the significance of the detection of electron neutrinos in the beam using the selection presented here. The sensitivity of the MicroBooNE experiment to the MiniBooNE low-energy excess of electron-like events is evaluated. The efficiency and background-rejection power necessary to achieve $5\sigma$ sensitivity are also quantified.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Extraction of Neutrino Oscillation Parameters using a Simultaneous Fit of $\nu_{\mu}$ Disappearance and $\nu_{e}$ Appearance data with the NOvA Experiment

This thesis presents the analyses and results of the $\nu_{\mu} \rightarrow \nu_{\mu}$ disappearance and $\nu_{\mu} \rightarrow \nu_{e}$ appearance due to neutrino oscillations using 8.85 $\times$ 10$^{20}$ protons on target (POT) equivalent of data collected by the NOvA experiment. The data analyzed in this thesis was collected from February 06, 2014 to February 20, 2017. NOvA is an accelerator-based, long-baseline neutrino oscillation experiment and uses the two detector set-up to study the phenomenon of neutrino oscillation using a beam of muon neutrinos produced at Fermilab. One NOvA detector is placed within the Fermilab campus, 100 m underground, at a distance of 1 km from the neutrino source and is called the Near Detector (ND). The ND is 300 ton in mass and smaller in size than the Far Detector (FD) which is 14 kton in mass and is placed 810 km away from the neutrino source in Ash River, Minnesota (MN). Both ND and FD are made of the same material and are functionally identical. The ND being closer to the neutrino source, analyzes the neutrino beam before the neutrinos oscillate and the FD analyzes the neutrinos after oscillations. The ND is used to predict the signal and background expectations in the FD. The similarity in the ND and FD help to reduce the systematic uncertainties in the FD prediction. The combined oscillation fit to the $\nu_{\mu} \rightarrow \nu_{\mu}$ disappearance and $\nu_{\mu} \rightarrow \nu_{e}$ appearance gives the best fit values of the $\Delta m^{2}_{32}$, $\sin^{2}{\theta_{32}}$ and $\delta_{CP}$ oscillation parameters and are presented in this thesis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Searches for New Physics in Neutrino Oscillations at the MINOS+, NOvA, and DUNE Experiments

Neutrinos are some of the most mysterious fundamental particles in Standard Model: they are orders of magnitude lighter than the next lightest massive particle (the electron), and they rarely interact with other particles. In the last 20 years, we have firmly established that neutrinos change flavors as they travel by observing the disappearance of muon neutrinos produced by accelerators and interactions of cosmic rays with the atmosphere; the appearance of electron neutrinos in muon neutrino beams; and the disappearance of electron antineutrinos produced by nuclear reactors. Almost all experiments are consistent with the existence of only three neutrino flavor states which mix with three neutrino mass states. However, there are a few experiments which have seen evidence for oscillations at frequencies incompatible with the three known states, which would suggest the existence of a fourth state, the sterile neutrino. This project supported searches for physics beyond the Standard Model, especially sterile neutrinos, in neutrino oscillations at the MINOS/MINOS+ and NOvA experiments. These efforts were enabled through the use of Deep Learning approaches which have revolutionized selection and reconstruction methods in High Energy Physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Neutrino physics beyond the current paradigm

An exciting program of international neutrino experiments aims to complete our understanding of three-neutrino mixing in the Standard Model (SM), which has had great success in describing world neutrino data. However, there exist a number of short-baseline neutrino anomalies that do not fit into this simple picture and could be pointing us instead to phenomena beyond the Standard Model (BSM). Neutrinos and neutrino experiments are excellent laboratories to search for BSM physics for a number a reasons. First, neutrinos mass itself is evidence of BSM physics as it implies the addition of new fields to the SM. In addition, neutrino properties are not well-constrained and allow sizable, new interactions. Finally, accelerator- and reactor-based short-baseline neutrino experiments bring high luminosity sources of photons, nuclear, and meson decays near large, sensitive detectors and can therefore probe a variety of dark sector models. In this talk, I will give an overview of worldwide accelerator- and reactor-based short-baseline neutrino experiments and their efforts to search for physics beyond the current paradigm.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Neutrino-Argon Cross-Section Measurements from the MicroBooNE Experiment

MicroBooNE is a liquid argon time projection chamber (LArTPC) neutrino detector located along the Fermilab Booster Neutrino Beam and 8 degrees off-axis to the Neutrinos at the Main Injector beam. MicroBooNE collected data from both beams accumulating a large neutrino-argon scattering dataset with a mean neutrino energy of approximately 0.8 GeV. Understanding neutrino-argon interactions is crucial for the next generation of neutrino oscillation experiments including DUNE. MicroBooNE has developed pioneering methodologies and novel reconstruction tools in order to benchmark models at very high sensitivity across the interaction phase space, including for ultra-rare channels. This talk will give an overview of the most recent MicroBooNE neutrino interaction results. These measurements provide invaluable datasets for constraining backgrounds and improving the modelling of neutrino scattering critical for the broader LArTPC neutrino physics program.

Liu, Liang [Fermilab]↗
DOE OSTI2026

Near Detector Selection for Neutral Current Disappearance Search at the Short-Baseline Neutrino Program

Various short baseline neutrino experiments observe anomalies that challenge the three-flavor neutrino oscillation model, consistent with a hypothetical “sterile” neutrino that does not interact via the weak force. This poster presents a near detector event selection at the Short-Baseline Near Detector (SBND), developed for the first search for neutral current (NC) disappearance at short-baseline experiments. NC disappearance provides ``smoking gun” insight into the sterile neutrino question because NC interactions are equally sensitive to all three active neutrinos, meaning any change in the NC interaction rate between near and far detectors cannot be explained by oscillations among known flavor states. This analysis focuses on the NC1p topology, the most common NC interaction type at the Short-Baseline Neutrino (SBN) Program. NC topologies are inherently challenging due to their low light yield and the absence of an outgoing charged lepton, which complicates identification and leads to poor energy reconstruction as the outgoing neutrino carries away a large portion of the neutrino’s initial energy. This work presents an NC1p event selection at the near detector, highlighting SBND’s impressive detector capabilities, including trigger efficiency studies. Combined with a novel kinematic energy reconstruction technique leveraging the detector’s outstanding hadronic detail, this analysis establishes a robust near detector foundation to target an NC disappearance measurement consistent with the 3$+$1 sterile neutrino model. This SBND selection will soon be combined with the far detector to conduct an NC disappearance search, providing unique insight and complementary information to traditional charged current searches and advancing the SBN Program’s goal to resolve the sterile neutrino question, including 3$+$1 searches and beyond.

Nicole Pallat, Nicole Pallat [Minnesota U.] (ORCID↗
DOE OSTI2019

Investigation of Two Fermi -LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube

After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria. We find one additional known gamma-ray source, the blazar GB6 J1040+0617, in spatial coincidence with a neutrino in this sample. The chance probability of this coincidence is 30% after trial correction. For the first time, we present a systematic study of the gamma-ray flux, spectral and optical variability, and multi-wavelength behavior of GB6 J1040+0617 and compare it to TXS 0506+056. We find that TXS 0506+056 shows strong flux variability in the Fermi-LAT gamma-ray band, being in an active state around the arrival of IceCube-170922A, but in a low state during the archival IceCube neutrino flare in 2014/15. In both cases the spectral shape is statistically compatible ($\leq 2\sigma$) with the average spectrum showing no indication of a significant relative increase of a high-energy component. While the association of GB6 J1040+0617 with the neutrino is consistent with background expectations, the source appears to be a plausible neutrino source candidate based on its energetics and multi-wavelength features, namely a bright optical flare and modestly increased gamma-ray activity. Finding one or two neutrinos originating from gamma-ray blazars in the given sample of high-energy neutrinos is consistent with previously derived limits of neutrino emission from gamma-ray blazars, indicating the sources of the majority of cosmic high-energy neutrinos remain unknown.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays

For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1985

Three dimensional calculation of flux of low energy atmospheric neutrinos

Results of three-dimensional Monte Carlo calculation of low energy flux of atmospheric neutrinos are presented and compared with earlier one-dimensional calculations 1,2 valid at higher neutrino energies. These low energy neutrinos are the atmospheric background in searching for neutrinos from astrophysical sources. Primary cosmic rays produce the neutrino flux peaking at near E sub=40 MeV and neutrino intensity peaking near E sub v=100 MeV. Because such neutrinos typically deviate by 20 approximately 30 from the primary cosmic ray direction, three-dimensional effects are important for the search of atmospheric neutrinos. Nevertheless, the background of these atmospheric neutrinos is negligible for the detection of solar and supernova neutrinos.

Lee, H.↗
NASA NTRS2019

POEMMA's Target of Opportunity Sensitivity to Cosmic Neutrino Transient Sources

We calculate the sensitivity of space-based cosmic neutrino detection from transient sources in the context of the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission using Target- of-Opportunity (ToO) observations. POEMMA uses two spacecraft each with a large Schmidt telescope to simultaneously view the optical signals generated by extensive air showers (EASs). POEMMA is designed for both ultrahigh-energy cosmic ray and very-high-energy neutrino measurements. POEMMA has significant neutrino sensitivity starting in the 10 PeV decade via measurements of Cherenkov signals from upward-moving EASs initiated by tau neutrinos interacting in the Earth. For ToO observations, POEMMA uses the ability to quickly repoint (90° in 500 seconds) each of the two spacecraft to the direction of the transient source. POEMMA EAS measurements are performed during astronomical night, leading to different observational constraints for short- and long-duration bursts. For short-bursts of order 10(exp 3) s, POEMMA will increase the sensitivity of existing experiments (e.g., IceCube and the Pierre Auger Observatory) by up to two orders of magnitude. For long-duration bursts on the scale of 10(exp 5−6) s, the full celestial sky is available and the average neutrino sensitivity will be increased by up to a factor of 50, reaching the desired level to probe model predictions of transient neutrino sources (e.g., of blazer flares as well as both black hole-black hole and neutron star-neutron star mergers). POEMMA’s neutrino sensitivity to various models of transient neutrino sources are detailed. Altogether, our results demonstrate better sensitivity to ToO neutrino sources from the space-based POEMMA experiment compared to current ground-based experiments, and more importantly, demonstrate unique full-sky coverage for ToO neutrino sources.

Venters, Tonia M.↗
NASA NTRS2020

POEMMA’s Target-of-Opportunity Sensitivity to Cosmic Neutrino Transient Sources

We investigate the capability of the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA)in performing Target-of-Opportunity (ToO) neutrino observations. POEMMA is a proposed space-based probe-class mission for ultra high-energy cosmic ray and very-high-energy neutrino detection using two spacecraft, each equipped with a large Schmidt telescope to detect optical and near-ultraviolet signals generated by extensive air showers (EASs). POEMMA will be sensitive to Cherenkov radiation from upward-moving EASs initiated by tau neutrinos interacting in the Earth. POEMMA will be able to quickly re-point (90◦in 500 s) each of the two spacecraft to the direction of an astrophysical source, which in combination with its orbital speed will provide it with unparalleled capability to follow up transient alerts. We calculate POEMMA’s transient sensitivity for two observational configurations for the satellites (ToO-stereo and ToO-dual for smaller and larger satellite separations, respectively) and investigate the impact of variations arising due to POEMMA’s orbital characteristics on its sensitivity to tau neutrinos in various regions of the sky. We explore separate scenarios for long (∼105−6s) and short (∼103s) duration events, accounting for intrusion from the Sun and the Moon in the long-duration scenario. We compare the sensitivity and sky coverage of POEMMA for ToO observations with those for existing experiments (e.g., IceCube, ANTARES, and the Pierre Auger Observatory) and other proposed future experiments (e.g., GRAND200k).For long bursts, we find that POEMMA will provide a factor of&7 improvement in average neutrino sensitivity above 300 PeV with respect to existing experiments, reaching the level of model predictions for neutrino fluences at these energies and above from several types of long-duration astrophysical transients (e.g., binary neutron star mergers and tidal disruption events). For short bursts, POEMMA will improve the sensitivity over existing experiments by at least an order of magnitude forEν∼>100 PeV in the “best-case” scenario. POEMMA’s orbital characteristics and rapid re-pointing capability will provide it access to the full celestial sky, including regions that will not be accessible to ground-based neutrino experiments. Finally, we discuss the prospects for POEMMA to detect neutrinos from candidate astrophysical neutrino sources in the nearby universe. Our results demonstrate that with its improved neutrino sensitivity at ultra-high energies and unique full-sky coverage, POEMMA will be an essential, complementary component in a rapidly expanding multi-messenger network.

Tonia M Venters↗
NASA NTRSDate not supplied

Monte Carlo simulations of neutrino and charged lepton propagation in the Earth with nuPyProp

An accurate modeling of neutrino flux attenuation and the distribution of leptons they produce in transit through the Earth is an essential component to determine neutrino flux sensitivities of underground, sub-orbital and space-based detectors. Through neutrino oscillations over cosmic distances, astrophysical neutrino sources are expected to produce nearly equal fluxes of electron, muon and tau neutrinos. Of particular interest are tau neutrinos that interact in the Earth at modest slant depths to produce leptons. Some leptons emerge from the Earth and decay in the atmosphere to produce extensive air showers. Future balloon-borne and satellite-based opticalCherenkov neutrino telescopes will be sensitive to upward air showers from tau neutrino induced lepton decays. We present nuPyProp, a python code that is part of the nuSpaceSim package. nuPyProp generates look-up tables for exit probabilities and energy distributions for (see paper for proper equation) propagation in the Earth. This flexible code runs with either stochastic or continuous electromagnetic energy losses for the lepton transit through the Earth. Current neutrino cross section models and energy loss models are included along with templates for user input of other models. Results from nuPyProp are compared with other recent simulation packages for neutrino and charged lepton propagation. Sources of modeling uncertainties are described and quantified.

Yosui Akaike↗
DOE OSTI2013

Scientific Opportunities with the Long-Baseline Neutrino Experiment

In this document, we describe the wealth of science opportunities and capabilities of LBNE, the Long-Baseline Neutrino Experiment. LBNE has been developed to provide a unique and compelling program for the exploration of key questions at the forefront of particle physics. Chief among the discovery opportunities are observation of CP symmetry violation in neutrino mixing, resolution of the neutrino mass hierarchy, determination of maximal or near-maximal mixing in neutrinos, searches for nucleon decay signatures, and detailed studies of neutrino bursts from galactic supernovae. To fulfill these and other goals as a world-class facility, LBNE is conceived around four central components: (1) a new, intense wide-band neutrino source at Fermilab, (2) a fine-grained `near' neutrino detector just downstream of the source, (3) the Sanford Underground Research Facility (SURF) in Lead, South Dakota at an optimal distance (~1300 km) from the neutrino source, and (4) a massive liquid argon time-projection chamber (LArTPC) deployed there as a 'far' detector. The facilities envisioned are expected to enable many other science opportunities due to the high event rates and excellent detector resolution from beam neutrinos in the near detector and atmospheric neutrinos in the far detector. This is a mature, well developed, world class experiment whose relevance, importance, and probability of unearthing critical and exciting physics has increased with time.

Adams, C.↗