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NOvA Experiment Announces First Results

NOvA Far Detector
NOvA Far Detector
Courtes Fermilab

University of Minnesota physicists Professor Greg Pawloski and Dr. Jianming Bian recently presented the first results from the NOvA experiment at a special seminar delivered to the School of Physics and Astronomy. The University of Minnesota is by far the largest university group in NOvA, which is the flagship experiment of the U.S. neutrino program. The 14 kiloton far detector is located near Ash River in Northern Minnesota.

University of Minnesota Professor Daniel Cronin-Hennessy was interviewed by WTIP's Dave TerSteeg from Minnesota North Shore Community Radio regarding NOvA's physics goals. The audio can be found at this link:

Construction of the Far Detector Laboratory in Ash River, MN was led by Professor Marvin Marshak and the assembly of the more than 11,000 far detector modules was led by Professor Ken Heller. In addition to our faculty and grad students, there were dozens of University staff members and more than 500 undergraduate students who contributed to the construction project.

The NOvA experiment is a multinational high-energy physics experiment that studies the nature of one of the most elusive particles in the universe, the neutrino. The neutrino is a subatomic particle that is one of the building blocks of the universe. Neutrinos come in three types or flavors and as they travel through space, they oscillate from one flavor to another. Pawloski explains, “It would be like having a tank full of oxygen and noticing that over time the atoms spontaneously convert from oxygen to a mixture of nitrogen and carbon and then back to oxygen again. Although this behavior is interesting in itself, the study of it can potentially answer questions that relate to the matter-antimatter asymmetry of the universe and fundamental ordering of the elementary particles.”

The neutrino beam generated at Fermilab passes through an underground near detector, which measures the beam’s neutrino composition before it leaves the Fermilab site. The particles then travel more than 500 miles straight through the earth, no tunnel required, oscillating (or changing types) along the way. About once per second, Fermilab’s accelerator sends trillions of neutrinos to the Far Detector. Neutrinos interact so rarely that only a few will register at the Far Detector.

Installation of the massive five-story far detector, one of the world’s largest plastic structures, was completed nearly eighteen months ago and since then the collaboration has been operating the experiment and collecting data. The analysis framework was created by a team of graduate students and research associates led by Professors Dan Cronin-Hennessy, Ken Heller, Greg Pawloski, and Ron Poling. The seminar by Pawloski and Bian included an introduction to the experiment, presentation of the first results from both the muon- and electron-appearance measurements, and description of plans and prospects for NOvA and future neutrino experiments.

“This is a great milestone for the School, The College of Science and Engineering and the U,” said Professor Ron Poling, Head of the School of Physics and Astronomy and member of the NOvA collaboration.

These initial results from the NOvA experiment represent only about 8% of the total data the experiment will collect over the next few years. Even with this small initial data set, Pawloski describes the results as possibly hinting at the ordering of neutrino masses and matter-antimatter asymmetry. NOvA is currently shut down for an upgrade to the beam accelerator, which recently set a record as the most powerful neutrino beam in the world. There will also be upgrades made to the detector during this period as well, allowing the experiment to take a much larger data set in 2016.

The NOvA collaboration comprises 210 scientists and engineers from 39 institutions in the United States, Brazil, the Czech Republic, Greece, India, Russia and the United Kingdom.

Professor Dan Cronin Hennessey talked with North Shore Community Radio on the topic of the NOVA first results.

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