A Search for Ultra-High Energy Neutrinos and Cosmic-Rays with ANITA-2


Book Description

The winner of UCL's annual HEP thesis prize, this work describes an analysis of the data from the second flight of the Antarctica Impulsive Transient Antenna (ANITA). ANITA is a balloon-borne experiment that searches for radio signals originating from ultra-high energy neutrinos and cosmic rays interacting with the Antarctic ice or air. The search for ultrahigh energy neutrinos of astrophysical origin is one of the outstanding experimental challenges of the 21st century. The ANITA experiment was designed to be the most sensitive instrument to ultra-high energy neutrinos that originate from the interactions of cosmic rays with the cosmic microwave background. The methodology and results of the neutrino and cosmic ray searches are presented in the thesis.




A Search for Astrophysical Ultra High Energy Neutrinos with the ANITA-IV Experiment


Book Description

The Antarctic Impulsive Transient Antenna (ANITA) is a balloon-based experiment designed to search for ultra-high energy(UHE) neutrinos and cosmic rays in Antarctica. A successful detection would be an important step in understanding the most energetic cosmic accelerators in the universe. The fourth flight of ANITA (ANITA-IV) funded by NASA took place in December 2016. It uses a radio antenna array designed to detect Askaryan radiation from UHE neutrino-induced showers in ice and geomagnetic radiation from Extensive Air Showers (EAS) induced by cosmic rays.




High Energy Neutrinos from Gamma Ray Bursts: Theoretical Predictions, Experimental Searches, and Prospects for Detection


Book Description

Abstract Gamma-ray bursts (GRBs) are the most luminous transient events in the observed Universe. However, there is no direct observational evidence for what exactly drives a GRB. The most widely accepted model for these cosmic events is the fireball model where it is thought that a substantial fraction of the kinetic energy of the source is converted to gamma-radiation by shock accelerated electrons emitting synchrotron and inverse-Compton radiation. The acceleration of protons in the gamma-ray emitting region of the GRB has been hypothesized as well. In this hadronic acceleration model, it is predicted that protons may interact with gamma-ray photons to produce a burst of neutrinos at energy ∼10^14 eV during prompt emission and energy ∼10^18 eV during afterglow emission. Several experimental searches for these high energy neutrinos have been conducted and no GRB neutrinos have yet been found. The analytical prediction for neutrino flux has been replaced with a more thorough numerical prediction for neutrino flux. The neutron model of GRBs, where only neutrons can escape the GRB and reach Earth as cosmic rays, has been ruled out by the experimental work of IceCube and ANTARES. Upgraded versions of current experiments such as IceCube, ANTARES, ANITA and ARA, as well as new experiments such as KM3NeT, are preparing to probe and further constrain the fireball paradigm of GRB neutrino production. This review includes: Introduction Early theoretical predictions for neutrino fluences due to GRBs Overview of high energy neutrino experiments and related physics Experimental searches for high energy neutrinos from GRBs Prospects for detection of high energy neutrinos from GRBs High Energy Neutrinos from Gamma Ray Bursts: Theoretical Predictions, Experimental Searches, and Prospects for Detection was originally written as a review submitted for my Ph.D. candidacy paper on Nov 23, 2015. It has been edited for a "Short Read" on Amazon Kindle Direct Publishing in Oct 2020. It is a public domain work. Special thanks to the Connolly group at Ohio State University (OSU) and the physics and astronomy departments at OSU. Moreover, I am grateful for the contribution of each and every scientist and author listed in the "References" section of this review. This review would not be possible without their published science and hard work. Please let me know if you find any mistakes or problems, I will fix it. My email is [email protected]. I am happy for this to be a living document. I am anxious to improve it but feel that it needs to be out at this point before that can happen.




High Energy Astrophysical Neutrinos


Book Description

This book provides a pedagogical introduction to the likely sources of these neutrinos, their propagation and detection mechanisms. Detection of high energy neutrinos of extragalactic origin has led to an interdisciplinary field of research, involving astronomy, astrophysics and particle physics. An extensive review of various detectors and the observations is provided that consolidates the latest findings. Above a few tens of TeVs, neutrinos are conceived as more reliable messengers for astronomy than photons as these photons get absorbed in the background photon field. Determining the neutrino spectrum not only helps in exploring astrophysical objects like AGN, GRB, etc. but also allows us to study particle physics at unprecedented energies. This introductory book is intended to help advanced undergraduate and graduate students to get into the subject with ease, and it simultaneously caters to practicing theoretical or experimental physicists as a reference book.







A Search for Ultra-high Energy Cosmic Neutrinos


Book Description

Ultra-high Energy (UHE) neutrinos represent an increasingly important messenger in astronomy and astrophysics. The Antarctic Impulsive Transient Antenna (ANITA) experiment campaign utilizes a balloon-borne phased antenna array to detect coherent Cherenkov radio-frequency pulses induced by UHE neutrinos interacting with the Antarctic ice. We analyzed the data from the third ANITA flight (ANITA-III) for evidence of Ultra-high energy neutrinos by augmenting interferometric methods used in analyses of previous ANITA flights. Continuous wave (CW) radio content from ground-based Antarctic habitations and orbiting geostationary communications satellites interferes with the detection and analysis of neutrino-induced radio signals; we developed circular polarization analysis methods to facilitate improved rejection of false positives induced by satellite CW. We also developed new methods of calculating signal-to-noise ratio (SNR) of event waveforms, and enhanced event localization by applying a probability distribution function (PDF) based on the measured resolution of our interferometry. We developed a final linear discriminant cut for rejecting thermal and anthropogenic signals by dividing the continent into equal-area bins and optimizing the cut to each individual bin, so as to obtain the strongest possible the upper limit on cosmic neutrino flux.




A Binned Search for Ultra High Energy Neutrinos with Data from the Third Flight of the Antarctic Impulsive Transient Antenna


Book Description

Ultra-high energy (UHE) neutrinos are an important and under-explored component of multi-messenger astronomy. The Antarctic Impulsive Transient Antenna (ANITA) is a balloon-borne discovery experiment, searching for the ¿rst neutrinos in an energy region above IceCube’s energy band. ANITA ¿ies over Antarctica, one of the most radio-quiet areas on the planet. Anthropogenic noise, however, is still an enormous problem for ANITA. We discuss here the addition of the Tunable Universal Front-end Filter (TUFF) as a method of ¿ltering continuous wave (CW) noise for ANITA-IV, as well as the reintroduction of the hybrid, a signal polarization converter, added to o¿er a means of avoiding false triggers on satellite CW noise. We also discuss the analysis of ANITA-III data, using a binned analysis method which splits the ice of Antarctica into smaller regions, with the end goal of discovering UHE neutrino candidates or setting a limit on neutrino production models.




Studies in Particle Astrophysics with the ANITA Experiment


Book Description

The Antarctic Impulsive Transient Antenna (ANITA) is a NASA long-duration balloon experiment with the primary goal of detecting ultra-high-energy ($>10^{18}\,\mbox{eV}$) neutrinos via the Askaryan Effect. In the fourth ANITA mission, the Tunable Universal Filter Frontend (TUFF) boards were deployed for mitigation of narrow-band, anthropogenic noise with tunable, switchable notch filters. They contributed to a factor of 2.8 higher total instrument livetime in ANITA-4 compared to ANITA-3. A search for a diffuse flux of ultra-high-energy neutrinos was conducted using the data collected during the ANITA-3 flight with a new approach where the Antarctic ice area is sectioned off into bins and a search is performed with different thresholds in different bins. The binned analysis methods were extended to the development of a search for neutrinos from Gamma Ray Bursts, implementing constraints in time, and for the first time, in direction. Lower analysis thresholds were achieved in a feasibility search even when extending the search to include longer afterglow periods.