Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session Y09: Astrophysical Neutrinos IRecordings Available
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Sponsoring Units: DPF Chair: Zoya Vallari, Caltech Room: Salon 3 |
Tuesday, April 12, 2022 1:30PM - 1:42PM |
Y09.00001: Reconstruction Methods for In-Situ Radio Neutrino Detectors Brian A Clark, Jorge Torres, Uzair Latif, Amy L Connolly Ultra-high energy (UHE) neutrinos are unique messengers to the distant universe, as gamma rays and cosmic rays do not arrive unattenuated or undeflected. A promising way to detect these UHE neutrinos is through the radio Cherenkov emission produced by neutrino-nucleon interactions in transparent media like ice. Several experiments are operating, under construction, or planning to observe neutrinos through this method, such as ARA, ARIANNA, RNO-G, and IceCube-Gen2. In this talk, we will discuss development of methods for reconstructing key properties of the neutrino interaction for in-situ neutrino detectors, including the vertex position and shower energy. These methods are based on simulations of a “deep” detector, with instrumentation deployed >100m. Reconstruction of the signal polarization, which is also a key measurement, is considered in a separate contribution. |
Tuesday, April 12, 2022 1:42PM - 1:54PM |
Y09.00002: Reconstructing the Direction Ultra-High Energy Neutrinos With the Askaryan Radio Array Justin C Flaherty The Askaryan Radio Array (ARA) is an experiment buried beneath the ice at the South Pole that aims to detect ultra-high energy (> 10 PeV) neutrinos. It consists of five stations of antennas that are designed to detect radiation emitted by relativistic particle showers that are byproducts of neutrino interactions within the ice, which generate a cone of Cherenkov radiation in the radio regime. This radiation is polarized normal to the surface of the cone, which we can use to identify our location on said cone. We can then use that to reconstruct the neutrino direction. In this talk, I will discuss applications of these reconstruction techniques as part of a comprehensive five-station analysis. I will also discuss how the crystal structure of the ice exhibits birefringence and how it affects our polarization measurements. |
Tuesday, April 12, 2022 1:54PM - 2:06PM |
Y09.00003: Search for tau neutrino double cascades with 6 years of IceCube cascade data. Zheyang Chen, Zelong Zhang, Joanna Kiryluk IceCube has discovered the flux of astrophysical high energy neutrinos of all flavors and characterized it. High energy (TeV-PeV) tau neutrinos contribute to the flux of astrophysical neutrino induced cascades, dominated by electron and tau neutrino interactions as measured with IceCube 6 years of cascade data. The identification of tau neutrinos is however challenging. This is due to IceCube strings and digital optical module spacing, where (low energy) tau neutrinos interacting via (charged) neutral current within detector volume are not distinguishable from electron neutrinos and both produce so-called single cascade signature. At high energies, in tau neutrino charged current interactions a high energy tau lepton is produced that decays predominantly into hadrons, as well as an electron-neutrino-electron pair. The event signature of such tau neutrinos is double cascade. We have developed an analysis which utilizes xgboost machine learning technique, utilizing single and double cascades reconstruction methods to detect tau neutrinos and have applied it to cosmic-ray background free 6 years of cascade data. This analysis is complementary to other tau neutrino searches with IceCube which identified a few tau neutrino candidates. In this talk we will present a method that improves double cascade tau neutrino identification. This method offers a high signal purity as well as maintains a good tau neutrino reconstruction quality. |
Tuesday, April 12, 2022 2:06PM - 2:18PM |
Y09.00004: First Results from NOvA's Magnetic Monopole Search Martin J Frank The existence of the magnetic monopole has eluded physicists for centuries. The NOvA far detector (FD), used for neutrino oscillation searches, also has the ability to identify slowly moving magnetic monopoles (v < c/100). With a surface area of 4,100 m2 and a location near the earth’s surface, the 14 kt FD provides us with the unique opportunity to be sensitive to potential low-mass monopoles unable to penetrate underground experiments. We have designed a novel data-driven triggering scheme that continuously searches the FD’s live data for monopole-like patterns. At the offline level, the largest challenge in reconstructing monopoles is to reduce the 148,000 Hz speed-of-light cosmic ray background. In this talk, I will present the first results of the NOvA monopole search for slow monopoles. |
Tuesday, April 12, 2022 2:18PM - 2:30PM |
Y09.00005: Tau depolarization from electromagnetic interactions at very high energies Diksha Garg, Carlos A Arguelles, Sameer Patel, Mary H Reno, Ibrahim Safa The neutrino interaction length scales with energy, and becomes comparable to Earth's diameter above PeV energies. At such high energies, the tau's short lifetime leads to energetic regenerated tau neutrino flux, $\nu_\tau\to\tau\to \nu_\tau$, within the Earth. The next generation of neutrino experiments aim to detect ultra-high energy neutrinos, and many of them rely on detecting either the regenerated tau neutrino, or a tau decay shower. Both of these signatures are affected by polarization of the tau through the energy distribution of the secondary particles produced from the tau's decay. While $\tau$'s produced in weak interactions at such high energies are nearly 100\% polarized, it is expected that $\tau$'s experience some depolarization due to electromagnetic energy loss in the Earth. In this talk, we quantify the depolarization of $\tau$'s in electromagnetic interactions and its impact on the energy of the regenerated tau-neutrino. Taus with higher energy have more electromagnetic interactions than lower energy tau leptons, which causes more depolarization. The regenerated tau-neutrinos produced from depolarized taus have lower energies. We also show the effect of tau depolarization on the tau survival probability using Monte Carlo simulations such as nuPyProp and TauRunner. |
Tuesday, April 12, 2022 2:30PM - 2:42PM |
Y09.00006: Hunting for the Neutrino Oscillation Parameters with One Million Neutrinos in SK and IceCube Miaochen Jin, Carlos A Arguelles, Ivan Martinez Soler, Pablo Fernandez Menendez IceCube and Super-Kamiokande are two of the largest atmospheric neutrino detectors. Both experiments are sensitive to neutrino oscillation of the atmospheric neutrino parameters by measuring the same naturally-occurring neutrino flux at different complementary energies. With Super-K with Gadoliunum (Super-K-Gd) online and IceCube expecting an upgrade within a few years, we will be looking at more and finer data for atmospheric neutrinos. We provide a combined sensitivity analysis of atmospheric neutrinos across these two experiments using Monte-Carlo simulations for Super-K-Gd and IceCube Upgrade. Under the light of Super-K-Gd and IceCube Upgrade, we will be able to confine the mixing angles and mass squared differences more strictly, potentially resulting in new findings. |
Tuesday, April 12, 2022 2:42PM - 2:54PM |
Y09.00007: Measurement of the 8B Solar Neutrino Flux in the Partial Fill Phase of the SNO+ Detector Max Smiley SNO+ is a kiloton-scale, multipurpose neutrino experiment located in Sudbury, Ontario, Canada. Initially filled with an ultrapure water target, SNO+ is now filled with the liquid scintillator linear alkyl benzene (LAB) loaded with the wavelength shifter 2,5-Diphenyloxazole (PPO), and will soon be loaded with 130Te to study neutrinoless double beta decay. Due to interruptions from the COVID-19 pandemic, filling of the detector with liquid scintillator was paused from April to October of 2020, allowing an extended period of stable data-taking with the detector about half-filled with scintillator. This work will discuss the measurement of the 8B solar neutrino flux during this phase of the experiment. Preliminary results for a similar measurement in the now fully-filled detector will also be shown and the outlook for future solar neutrino studies with SNO+ will be discussed. |
Tuesday, April 12, 2022 2:54PM - 3:06PM |
Y09.00008: The transverse drift electromagnetic filter for PTOLEMY Andi Tan PTOLEMY is an experiment for detecting neutrinos, produced in the early moments of the Big Bang, captured on tritium targets. A new concept of the transverse drift filter is developed to enable a precision analysis of the energy spectrum of electrons near the tritium β-decay endpoint. This talk will present the first realization of the required magnetic field with an iron magnet and the low field optimization on the endpoint electron transport. The PTOLEMY transverse drift filter run "in reverse" is a new particle accelerator for injection charged particles into a high magnetic field region with potential use for plasma heating. |
Tuesday, April 12, 2022 3:06PM - 3:18PM |
Y09.00009: Astrophysical neutrino flux measurement with 11 years of IceCube cascade data Zelong Zhang, Joanna Kiryluk The IceCube Neutrino Observatory at the geographical South Pole in Antarctica has discovered a diffuse flux of neutrino signals. Since its discovery, astrophysical neutrino flux has been measured in various detection channels and analyses over a wide 10TeV-10PeV energy range. The most precise measurement and characterization of this flux so far was performed with 6 years (2010-2015) of neutrino induced cascades data, with astrophysical neutrino interactions being dominated by electron and tau neutrino flavors. The - unexpectedly large - flux is consistent with the single unbroken energy power-law function with a soft spectral index of γ = 2.53 ± 0.07 . IceCube continues collecting more data. Recently the collaboration re-processed historical data, the so-called data "pass2”, to update and unify across years different analyses data stream filters and calibration. The knowledge of ice (detector medium) continues being improved, resulting in a reduction of the dominant systematic uncertainties in diffuse neutrino analyses. |
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