Events

Karl Warburton
Department of Physics and Astronomy
Iowa State University

Machine Learning in Long-Baseline Neutrino Oscillation Experiments

Neutrinos, the most abundant massive particle in the Universe have profoundly influenced its evolution, but are still the least understood fermion in the Standard Model (SM). The 2015 Nobel Prize in Physics was awarded to T. Kajita and A. McDonald following numerous experimental observations of neutrino oscillations, the process by which neutrinos created in one flavor state are observed interacting as different flavor states after traveling a given distance. This colloquium will cover two experiments focused on furthering our understanding of this phenomenon. NOνA is the current flagship long-baseline neutrino experiment in the USA and consists of two functionally identical, finely granulated detectors that are separated by 809 km. The NOνA three flavor neutrino oscillation results presented in June 2020 will be discussed with particular focus given to the impact that machine learning algorithms had increasing the sensitivity of the analysis. These algorithms use topological features for the reconstruction of neutrino interaction flavor and particle identification. The colloquium will conclude with an exploration of how machine learning tools will inform the physics reach of DUNE, a planned long-baseline neutrino experiment, which will begin data-taking in the mid-2020s.

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Meeting ID: 919 282 27187

Deep Medhi
Department of Computer Science & Electrical Engineering
University of Missouri — Kansas City

Interdisciplinary Science: Connecting Physics, Computer Science and Statistics with Computer Networking

The image of a black hole from April 2019 was widely seen by millions of people all over the world. To make this happen, it transcended traditional boundaries of a scientific discipline. In this talk, I will discuss examples such as black hole imaging and Large Hadron Collider for high energy physics, and connect them with computer science and statistics, and how computer networking plays a role.

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Meeting ID: 919 282 27187

Katelin Schutz
Department of Physics
Massachusetts Institute of Technology

Making Dark Matter out of Light

Dark matter could be a “thermal-ish” relic of freeze-in, where the dark matter is produced by extremely feeble interactions with Standard Model particles dominantly at low temperatures. In this talk, I will discuss how sub-MeV dark matter can be made through freeze-in, accounting for a dominant channel where the dark matter gets produced by the decay of plasmons (photons that have an in-medium mass in the primordial plasma of our Universe). I will also explain how the resulting non-thermal dark matter velocity distribution can impact cosmological observables.

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Meeting ID: 919 282 27187

Mike Wallbank
Physics Department
University of Cincinnati
Searching for Sterile Neutrinos using Antineutrino Oscillations with the NOνA Experiment

The NOνA experiment consists of two functionally identical liquid scintillator detectors to study neutrino oscillations over an 810 km baseline using Fermilab's NuMI neutrino beam. In additional to world- leading studies of oscillations between the three known neutrino flavors, NOνA is searching for evidence of oscillations involving an additional, sterile, neutrino. Despite observations of neutrino oscillations from the majority of experiments being consistent with a 3-neutrino mixing framework, results from LSND and MiniBooNE are incompatible with this model but could be explained by incorporating a sterile neutrino state. These intriguing results are not conclusive and are in tension with findings from other short-baseline and long-baseline experiments.
I will describe the NOνA experiment and show the latest oscillation results, including a novel sterile search using antineutrinos, and discuss the allowed limits on the mixing angles governing the oscillations. I will also talk about future improvements to the oscillation analyses, in particular highlighting an ongoing test beam program designed to improve our understanding of the detectors and allow more precise analyses through a reduction of the uncertainties.

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Meeting ID: 919 282 27187

Carl Herickhoff
Biomedical Engineering
University of Memphis

New Directions in Ultrasound Imaging Technology

Ultrasound has become an established clinical imaging tool in recent decades due to its speed, safety, affordability, and portability, yet biomedical ultrasound technology continues to rapidly advance in new and exciting ways. This talk will give an introduction to ultrasound imaging systems and devices, while also highlighting some current fundamental and applied ultrasound research efforts: intravascular elasticity imaging, dual-frequency superharmonic contrast imaging, large-scale body scanner arrays, low-cost freehand 3D imaging, and integration with augmented-reality displays for live ultrasound image guidance.

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https://olemiss.zoom.us/j/91928227187

Meeting ID: 919 282 27187

Umberto Tamponi
Particle Physics Group
INFN — Torino and the University of Mississippi

Bottomonium at the Super-B factories: QCD and new physics

In the last 15 years, several experiments contributed to an explosion of new results on heavy QCD bound states. Today, we potentially stand at the beginning of a new wave of discoveries, with the Belle II experiment starting its data taking, BESIII moving forward into its program and the LHC experiments moving into their next phase. These new experiments, collecting much larger statistics, will not only allow to constrain the low energy QCD models, but also to study rare decays sensitive to new physics scenarios.

In this seminar, I will first outline the basic ideas and the status of the bottomonium physics, and then describe more in detail the potential of the measurement that will be performed at the Belle II experiment, ranging from the spectroscopy of the tetraquark-like states to the study of New-physics signatures in rare and forbidden decays.

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Meeting ID: 919 282 27187

Eugenio Bianchi
Institute for Gravitation and the Cosmos
Pennsylvania State University

Quantum Aspects of Black Hole Physics

I will discuss recent developments in black hole physics that are at the frontier of gravity, quantum field theory and quantum information. In particular I will discuss how thermal properties of black holes arise from energy eigenstates of the gravitational field in a manner similar to what happens in other isolated many-body quantum systems. I will also highlight how the observation of the statistical distribution of the spin of primordial black holes can provide the first observational test of black hole entropy.

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Meeting ID: 919 282 27187

Wanwei Wu
Neutrino Division
Fermi National Accelerator Laboratory

Liquid Argon Time Projection Chambers for Neutrino Physics

As the most abundant massive particles in our universe, neutrinos are elusive and provide a promising window to probe the fundamental physics. They are everywhere but almost never interact with matter. Questions about the nature of neutrinos and whether they are the reason that universe is made of matter rather than antimatter are still unanswered. One promising detector technology that can be used to study neutrinos in detail is the liquid argon time projection chamber (LArTPC), which has been adopted by many accelerator-based neutrino experiments including the Fermilab Short-Baseline Neutrino program and the Deep Underground Neutrino Experiment. LArTPCs promise to have millimeter-scale spatial resolution and excellent calorimetric capabilities in the detection of particles traversing the liquid argon and the measurement of their properties. In this talk, the landscape of LArTPCs for neutrino physics will be discussed, along with the prospects and status of the LArTPC neutrino experiments at Fermilab.

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Meeting ID: 919 282 27187

Lan Quynh Nguyen
Department of Physics
University of Notre Dame

Self Interacting Dark Matter and the Small-Scale Structure Problem

The core-cusp problem remains as a challenging discrepancy between observations and simulations in the standard CDM model for the formation of galaxies. The problem is that CDM simulations predict a steep power-law mass density profile at the center of galactic dark matter halos. However, observations of dwarf galaxies in the Local Group reveal a density profile consistent with a nearly flat distribution of dark matter near the center. A number of solutions to this dilemma have been proposed. Here, we summarize investigations into the possibility that the dark matter particles themselves self-interact and scatter. Such self-interacting dark matter (SIDM) particles can smooth out the dark-matter profile in high-density regions. We also review the theoretical proposal that self-interacting dark matter may arise as an additional Higgs scalar in the 3-3-1 extension of the standard model. We present new simulations of galaxy formation and evolution for this formulation of self-interacting dark matter. Current constraints on this self-interacting dark matter are then summarized.

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Meeting ID: 919 282 27187

Rachel Rosen
Department of Physics
Columbia University

Gravity Meets Particle Physics

Many of the most pressing open questions in fundamental physics today require a better understanding of the interplay between gravity and particle physics. In this talk, I will review what we learn by treating gravity as a theory of particle physics: what new theories emerge, what constraints they must obey, and what we might learn about gravitational phenomena such as black holes.

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Meeting ID: 919 282 27187

Christopher Berry
Center for Interdisciplinary Exploration and Research in Astrophysics
Northwestern University

The Secret Lives of Black Holes

Gravitational-wave astronomy provides a unique insight into the lives of black holes. Since the beginning of the advanced-detector era in September 2015, we have observed gravitational waves from over 40 binary black hole systems. From the measured gravitational-wave signal we can infer the properties of their source systems, and uncover new insights into their formation. There are currently many mysteries around how massive stars evolve and binaries form in order to create the population of binary black holes. I will explain how we can use the growing catalogue of gravitational-wave observations to unravel these mysteries and review our discoveries to date.

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Meeting ID: 919 282 27187

Paul Elmore
Applied Physics Laboratory (APL)
Johns Hopkins University

The Johns Hopkins University — Applied Physics Laboratory and the KTY Group & The Physics Career from the Mid-Career Perspective

This talk, intended for both undergraduate and graduate students, is dual purpose. The first part is a short recruitment talk on Johns Hopkins University — Applied Physics Laboratory and the Acoustics and Electromagnetics Group. The laboratory and group employ physics graduates at the Bachelor's, Master's and Ph.D. levels. The second part of this talk is centered on general advice for a career in physics. I will use my personal career path as an illustration of what, in my opinion (which is admittedly biased), are the biggest advantages of being a physicist vs an engineer or specialized physical scientist. These advantages are

A. Being a “generalist” in the physical sciences, which can provide flexibility in job opportunities and specialization choices in your early career

B. Formal training and general capability to solve hard analytic problems

There are trade-offs, of course (e.g., lack of specialization for jobs that require it, lack of training in engineering approaches, etc.), but the advantages can outweigh the trade-offs. In addition, this talk will provide some discussion for the following topics and time for Q&A:

• Whether or not to get your Ph.D. or perhaps enter the workforce at the Bachelor's or Master's degree level.
• The importance of publications and in structuring your publication for readability and information flow in order to enhance potential citation count.
• The importance of public speaking and going to conferences.
• A few bits of career “self-care” advice.

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Meeting ID: 919 282 27187

Meghna Bhattacharya
Department of Physics and Astronomy
University of Mississippi

First Results from the Muon g-2 Experiment at Fermilab — Muons Leading the Way

The first results from the Muon g-2 experiment at Fermilab will be presented in this talk. The latest result from the Fermilab confirms the discrepancy between the theoretical prediction and the experimental measurement earlier reported by the Brookhaven experiment. The aim of the Fermilab experiment is to measure the anomalous magnetic moment of the muon, a_μ = (g-2)/2, to a groundbreaking precision of 140 ppb, obtaining a near four-fold increase in precision over BNL. This is an incredibly challenging experiment with a unique opportunity to provide new insight into nature. An overview of this ultra-high precision measurement will be discussed in this talk.

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Meeting ID: 919 282 27187

Department of Physics and Astronomy
University of Mississippi

Research Poster Session

Despite the pandemic, student researchers in the Department of Physics and Astronomy have continued to do some excellent work. In the spirit of scientific discourse, we will be holding a research poster session tomorrow, Thursday April 22 at 4 pm in front of Lewis Hall. Please join us to hear about ongoing research in the department, and maybe get some ideas for a new project!

The web page can be found here.

Jake Bennett, etc.
Department of Physics and Astronomy
University of Mississippi

What can you do with a Physics degree?

Undeclared, interested in exploring other majors, or just curious about the Department of Physics and Astronomy? Want to prepare for professional school or just develop the tools and qualities employers value most? Join us to discover what a degree in Physics can do for you. You will also get the chance to observe some fun and interesting demonstrations.

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Meeting ID: 919 282 27187

Martin Frank
Department of Physics
University of South Alabama

First Results from NOνA's Magnetic Monopole Search

The existence of the magnetic monopole has eluded physicists for centuries. The NOνA 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 NOνA monopole search for slow monopoles.

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Meeting ID: 919 282 27187

Shawn Pollard
Department of Physics and Materials Science
University of Memphis

Designing Chiral Magnetism Through Interface Engineering – From Skyrmions to Magnetic Memory

Chirality is a fundamental concept in condensed matter physics. The ability to control magnetic chirality through broken symmetry at interfaces has led to the development of new devices governed by control of the local spin structure. One such structure, the skyrmion, a result of the Dzyaloshinskii-Moriya interaction (DMI), has been proposed as both a building block of new spintronic devices and as a tool to probe a variety of novel electrical transport phenomena. In this talk, I will describe our efforts to design chiral structures including skyrmions with tunable stability and dynamics by modifying the interface properties in both heavy metal/ferromagnet bi- and multilayers. We find that by tuning the heavy metal and ferromagnetic layer thicknesses and repetition numbers, we can control the skyrmion boundary structure, which has profound effects on its dynamics. This includes the first observation of an interlayer DMI in which a breaking of domain wall degeneracy can be used to prevent off-axial current driven skyrmion motion known as the skyrmion Hall effect. I also discuss our work developing new techniques in which to quantify magnetic phenomena in these materials.

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Meeting ID: 919 282 27187

Samrat Choudhury
Department of Mechanical Engineering
University of Mississippi

Machine Learning Enabled Multi-Scale Modeling of Materials

Traditional computational investigation of processing-chemistry-structure-property linkage in materials science involves the usage of specialized computational tools at discrete length scales ranging from electronic to atomic to mesoscale. Alternatively, over the past two decades, a multi-length scale approach combining simulation tools at different length scales has been adopted where electronic/atomic information from lower length scale is passed to higher length scale. However, such traditional computational approaches can provide only limited insights into a highly complex set of interactions spanning over multiple length and time scales each of which are linked to the property and performance of the materials, thus requiring an out-of-the box approach. In this presentation, I will focus on the application of machine learning tools to guide simulations at multiple length scales to augment the capabilities of traditional computational tools. Further, it will be shown that machine learning enabled computational approach provides a fast and efficient pathway to navigate the vast processing, microstructure and chemical search space for a targeted property, a departure from the traditional time consuming and expensive Edisonian trial-and-error approach based on synthesis-testing experimental cycles.

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Meeting ID: 919 282 27187

Jake Bennett, Gavin Davies, Anuradha Gupta, and John Waite
Department of Physics and Astronomy
University of Mississippi

Preparing for Job Interviews (including mock interview examples)

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Meeting ID: 919 282 27187

Sudeep Adhikari
Department of Physics and Astronomy
University of Mississippi

Universality in Activated Barrier Crossing

The thermal activation process by which a system passes from one local energy minimum to another by crossing an energy barrier is a recurring motif in physics, chemistry, and biology. For instance, biopolymer chains are typically modeled in terms of energy landscapes, with folded and unfolded configurations represented by two distinct wells separated by a barrier. The rate of transfer from the unfolded to folded state depends most importantly on the height of the barrier with respect to the temperature of the heat bath—but also in seemingly idiosyncratic ways on the details of the shape of the barrier. We consider the case of bias due to an external force, analogous to the pulling force applied in optical tweezer experiments on biopolymers. We identify the universal behavior of the barrier crossing process and demonstrate that data collapse onto a universal curve can be achieved for simulated data over a wide variety of energy landscapes having barriers of different heights and shapes.

John Waite
Department of Physics and Astronomy
University of Mississippi

Flavor SU(3) in Cabibbo-favored D-meson Decays

Model-independent description of nonleptonic decays of charmed mesons is a challenging task due to the large nonperturbative effects of strong interactions on the transition amplitudes. We discuss the equivalence of two different flavor-SU(3)-based descriptions of Cabibbo-favored non-leptonic decays of charmed mesons to two-pseudoscalars final states including the η and η′ mesons.

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Meeting ID: 919 282 27187

Zara Bagdasarian
Department of Physics
University of California — Berkeley

Reaching for the Stars with CNO Solar Neutrinos and Other Adventures of Novel Neutrino Detectors

The latest breakthrough in neutrino physics is the first experimental evidence of the carbon-nitrogen-oxygen (CNO) fusion cycle in the Sun. The discovery was possible due to the unprecedented radiopurity of the Borexino liquid-scintillator detector (Italy), employing innovative hardware and software developments. In the future, new technologies can further facilitate access to a broad physics agenda and applications in neutrino physics. Of particular interest are the cutting-edge detection techniques and novel target materials that aim to fully utilize both scintillation and Cherenkov signals from low- and high-energy neutrino interactions. The first deployment of Large Area Picosecond Photodetectors (LAPPDs) and water-based liquid scintillator (WbLS) in the ANNIE experiment at Fermi National Accelerator Laboratory (USA) will be exciting milestones in the evolution of neutrino detection. Neutrino Experiment One (NEO) will be the first ktonne-scale detector built by the Watchman collaboration at Boulby Underground Laboratory (UK). Its goal is to demonstrate, for the first time, nuclear non-proliferation capabilities using antineutrino detection. Finally, the multi-ktonne detector, Theia, aims to detect solar neutrinos, determine neutrino mass ordering and the CP-violating phase, observe diffuse supernova neutrinos and neutrinos from a supernova burst, search for nucleon decay, and, ultimately, neutrinoless double beta decay.

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Meeting ID: 919 282 27187

Zara Bagdasarian
Department of Physics
University of California — Berkeley

Reaching for the Stars with CNO Solar Neutrinos and Other Adventures of Novel Neutrino Detectors

The latest breakthrough in neutrino physics is the first experimental evidence of the carbon-nitrogen-oxygen (CNO) fusion cycle in the Sun. The discovery was possible due to the unprecedented radiopurity of the Borexino liquid-scintillator detector (Italy), employing innovative hardware and software developments. In the future, new technologies can further facilitate access to a broad physics agenda and applications in neutrino physics. Of particular interest are the cutting-edge detection techniques and novel target materials that aim to fully utilize both scintillation and Cherenkov signals from low- and high-energy neutrino interactions. The first deployment of Large Area Picosecond Photodetectors (LAPPDs) and water-based liquid scintillator (WbLS) in the ANNIE experiment at Fermi National Accelerator Laboratory (USA) will be exciting milestones in the evolution of neutrino detection. Neutrino Experiment One (NEO) will be the first ktonne-scale detector built by the Watchman collaboration at Boulby Underground Laboratory (UK). Its goal is to demonstrate, for the first time, nuclear non-proliferation capabilities using antineutrino detection. Finally, the multi-ktonne detector, Theia, aims to detect solar neutrinos, determine neutrino mass ordering and the CP-violating phase, observe diffuse supernova neutrinos and neutrinos from a supernova burst, search for nucleon decay, and, ultimately, neutrinoless double beta decay.

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Meeting ID: 919 282 27187

Alexandru Lupsasca
Department of Physics
Princeton

The Black Hole Photon Ring

The photon ring is a narrow ring-shaped feature, predicted by General Relativity but not yet observed, that appears on images of sources near a black hole. It is caused by extreme bending of light within a few Schwarzschild radii of the event horizon and provides a direct probe of the unstable bound photon orbits of the Kerr geometry. I will review the origin and structure of the photon ring, before discussing the prospects for its future detection. I will argue that the precise shape of the observable photon ring is remarkably insensitive to the astronomical source profile and can therefore be used as a stringent test of strong-field General Relativity. A space-based interferometry experiment targeting the photon ring of M87* could test the Kerr nature of the source to the sub-sub-percent level.

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Meeting ID: 919 282 27187

Kathy Gunn
Department of Oceanography
Commonwealth Scientific and Industrial Research Organisation (Australia)

Vertical Mixing and Heat Fluxes Conditioned by a Seismically Imaged Oceanic Front

The southwest Atlantic gyre connects several distinct water masses, which means that this oceanic region is characterized by a complex frontal system and enhanced water mass modification. Despite its significance, the distribution and variability of vertical mixing rates have yet to be determined for this system. Specifically, potential conditioning of mixing rates by frontal structures, in this location and elsewhere, is poorly understood. Here, we analyze vertical seismic (i.e., acoustic) sections from a three-dimensional survey that straddles a major front along the northern portion of the Brazil-Falkland Confluence. Hydrographic analyses constrain the structure and properties of water masses. By spectrally analyzing seismic reflectivity, we calculate spatial and temporal distributions of the dissipation rate of turbulent kinetic energy, ε, of diapycnal mixing rate, K, and of vertical diffusive heat flux, FH. We show that estimates of ε, K, and FH are elevated compared to regional and global mean values. Notably, cross-sectional mean estimates vary little over a 6 week period whilst smaller scale thermohaline structures appear to have a spatially localized effect upon ε, K, and FH. In contrast, a mesoscale front modifies ε and K to a depth of 1 km, across a region of O(100) km. This front clearly enhances mixing rates, both adjacent to its surface outcrop and beneath the mixed layer, whilst also locally suppressing ε and K to a depth of 1 km. As a result, estimates of FH increase by a factor of two in the vicinity of the surface outcrop of the front. Our results yield estimates of ε, K and FH that can be attributed to identifiable thermohaline structures and they show that fronts can play a significant role in water mass modification to depths of 1 km.

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Meeting ID: 919 282 27187

Saptaparna Bhattacharya
Department of Physics and Astronomy
Northwestern University

An Experimental Overview of Effective Field Theory Exploration at the LHC

The effective field theory (EFT) approach posits that in a scenario where new particles cannot be observed directly at low energy, the source of new physics are heavy fields beyond our current reach. The Standard Model (SM) Lagrangian contains fields of dimension-4 and the EFT frame-work extends the SM Lagrangian in an expansion in inverse powers of the scale of new physics. Within this framework, the potential impact of higher dimensional operators can be explored. The most common example of an EFT appears in the Fermi theory of weak interactions where the appearance of the four Fermi vertex features an operator of dimension-6. In this talk, I will provide an overview of EFT explorations at the LHC. With the collection of more than 150 fb^-1 of data at the LHC, rare processes predicted in the Standard Model have become accessible. These rare processes can be used as probes of new physics using the EFT framework. The large dataset also enables precision measurements of certain processes allowing the ability to study deviations from SM expectations and characterizing the nature of potential excesses within the EFT formalism. I will focus on the exploration of dimension-6 and dimension-8 operators at the LHC in final states arising out of the decay of multiple gauge bosons. I will provide a snapshot of LHC Run II analyses as we embark on Run III.

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Meeting ID: 919 282 27187