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Xinyue Gong
Department of Physics and Astronomy
University of Mississippi
Hall Effect for Acoustic Waves Carrying Angular Momentum
Acoustic waves with a twisted wave front also carry
angular momentum in addition to linear momentum, in
analogy to optical and quantum fields. The law of
refraction states that the direction of refracted light
rays is normally in the plane of incidence as they
propagate across a sharp interface. Nevertheless, the
refraction law is not enough to describe the angular
momentum carried by refracted beams. Refracted light
beams carrying angular momentum have been observed to
undergo a shift in the direction that is transverse to
the plane of incidence, a phenomenon that was termed as
optical Hall effect. Here we pursue the first
experimental observation of Hall effects for acoustic
waves that carry angular momentum. Our experiment
exploits the more recently developed acoustic
metasurface to manipulate the wave refraction. A
theoretical calculation of the wave fields is also
conducted to compare with the experimental
measurements. The talk will present physics related to
the phenomenon, our experimental setup, and preliminary
results.
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Guoqin Liu
Department of Physics and Astronomy
University of Mississippi
Modeling and Simulations of Capillary-Gravity Wave Transmission Through a Surface Piercing Barrier
Capillary-gravity waves are waves traveling on a fluid
interface that are influenced by both the effects of
surface tension and gravity. Interactions of
capillary-gravity waves with boundaries in contact with
a solid and air play an essential role in both fluid
physics and fluid control techniques. Motion of the
contact line at the three phase boundary (solid,
liquid, and air) can influence the wave dynamics such
as the wave frequency, damping, refraction, and
transmission. Here we develop fluid dynamics modeling
and numerical simulations to investigate the
transmission of capillary-gravity wavesthrough a
surface piercing barrier under the effect of a pinned
contact line. Our modeling is validated via a
comparison with prior theory in ideal cases. We
numerically reveal how the surface tension and contact
lines affect the transmission in the realistic case for
waves of different frequencies and barriers of
different depths.
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M. Mahbub Alam
Daffodil International University, Dhaka, Bangladesh
Effects of Viscosity on Effective Dynamic Properties
Recent theoretical and experimental findings
demonstrate that as the particle concentration in a
suspension increases, the effect of viscosity of the
base fluid becomes more and more significant, thereby
requiring to be taken into account when calculating
effective properties of a suspension. Here, we employ a
core-shell, self-consistent, effective medium model to
derive analytical approximations for effective
bulk-modulus and effective mass density for a
suspension of solid elastic spheres. We incorporate the
viscosity of the suspending fluid into the model
through wave conversion phenomena, primarily between
compressional and shear wave modes. The analytical
approximations are explicit functions of particle
volume fraction, dimensionless compressional and shear
wavenumbers, and scattering coefficients of a single
sphere. The dependence of effective properties on
frequency, particle size, volume fraction, and
viscosity are also investigated numerically.
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Suravinda Kospalage
Department of Physics and Astronomy
University of Mississippi
Study of the Decay B± → Ks0π±π0 at the Belle Experiment
Belle is a particle physics experiment based at the KEK
laboratory in Tsukuba Japan which ran from 1999 to 2010
and collected 1ab-1 of data. The Belle
experiment is focused on studying the properties of
particles called B mesons which are produced
by accelerating and colliding electron and positron
beams. These B mesons show the biggest
differences between the properties of matter and
anti-matter of any known particles. One of the main
goals of the Belle experiments is to understand the
differences between matter and anti-matter,
specifically violations of charge-parity symmetry (CP
violation) and how anti-matter vanished and we come to
ive in a matter dominated universe.
This project explores the charmless B decay
B± → Ks0π±π0 with the Belle full
Monti Carlo (full MC) simulation and Belle data
corresponding to 571fb-1 of luminosity and
measure the decay's branching fraction (BF). Charmless
transitions can proceed by a b → u
transition via a tree level diagram or b → s or d transition via the so-called penguin diagram.
Both decay types are highly suppressed compared to the
b → c transition and we expect a small
branching fraction, smaller than 10-5. The
challenge in observing the B± → Ks0π±π0 decay is to suppress backgrounds from continuum events,
which do not contain b quarks, and background
from other B meson decays. Initial selections
plus multi-variate analysis (MVA) machine
learning/artificial intelligence technique called a
boosted decision tree (BDT) used to reduce the
backgrounds to the level to allow to clearly observe
the decay and measure the BF.
Additionally the Dalitz plot (DP) technique to study
the intermediate resonance contributions in this decay
using the Laura++ software to generate and fit toy Monte
Carlo (toy MC), full Monte Carlo simulated data, and,
based on the techniques developed on these simulations,
the experimental data to study the resonance sub-structure
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Dipangkar Dutta
Department of Physics and Astronomy
Mississippi State University
The Incredible Shrinking Proton and the Proton Radius Puzzle
For nearly half a century the charge radius of the
proton had been obtained from measurements of the
energy levels of the hydrogen atom or by scattering
electrons from hydrogen atoms. Until recently the
proton charge radius obtained from these two methods,
agreed with one another within experimental
uncertainties. In 2010 the proton charge radius was
obtained for the first time by precisely measuring the
energy levels of an exotic kind of hydrogen atom called
muonic hydrogen. The charge radius of the proton
obtained from muonic hydrogen was found to be
significantly smaller than those obtained from regular
hydrogen atoms. This was called the “proton
charge radius puzzle” and led to a rush of
experimental as well as theoretical efforts to
understand whythe size of the proton appears to be
different when measured in regular hydrogen vs. muonic
hydrogen. Many physicists were excited by the
possibility that the “puzzle” was an
indication of a possible new force that acted
differently on electrons and muons.
The Proton Charge Radius (PRad) experiment at the
Thomas Jefferson National Accelerator Facility
(Jefferson Lab) was one such major new effort which
used electron scattering from a regular hydrogen atom,
but with several innovations that made it the highest
precision electron scattering measurement. These
innovative methods have allowed us to measure the size
of the proton more precisely than it has been measured
before using electron scattering. I will provide a
brief review of the techniques used to measure the
proton's size and introduce the “ proton radius
puzzle”, and the world-wide effort to resolve
this puzzle. I will discuss the PRad experiment, the
new results from this experiment, the current status
of the “puzzle” and future prospects.
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Katerina Chatziioannou
Division of Physics, Mathematics and Astronomy
California Institute of Technology
Constraining the Neutron Star Equation of State with Gravitational Wave Signals
Detections of neutron stars in binaries through
gravitational waves offer a novel way to probe the
properties of extremely dense matter. In this talk I
will describe the properties of the signals we have
observed, what they have already taught us, and what
we expect to learn in the future. I will also discuss
how information from gravitational waves can be
combined and compared against other astrophysical and
terrestrial probes of neutron star matter to unveil to
the properties of the most dense material objects that
we know of.
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Stefano Tognini
Nuclear Energy and Fuel Cycle Division
Oak Ridge National Laboratory
Celeritas: Bringing Exascale Computing to HEP Detector Simulation
Within the next decade experimental High Energy Physics (HEP) will (mostly) finish building its next generation of particle detectors. This includes upgrades to the Large Hadron Collider and its main experiments, and completing the Deep Underground Neutrino Experiment (DUNE). This new Era brings a myriad of challenges, many being on the computational front. As DOE consolidates its network of Leadership Computing Facilities (LCFs) with supercomputers capable of reaching Exaflops of processing power, it is fundamental to better integrate these LCFs with HEP computing workflows. In this talk I will provide an overview of computing in HEP and its many challenges, and present Celeritas, a novel GPU Monte Carlo particle transport code developed by researchers from ORNL, Fermilab, ANL, and BNL, that aims to close the gap between DOE's LCFs and HEP experiments.
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Biswaranjan Behera
Department of Physics
Colorado State University
The Search for Sterile Neutrinos with the ICARUS Detector at Fermilab
The 476-ton active mass ICARUS T-600 liquid Argon Time Projection Chamber (LArTPC) was a pioneering development that became the template for neutrino and rare event detectors, including the massive next generation international Deep Underground Neutrino Experiment. It began operation in 2010 at the underground Gran Sasso National Laboratories and was transported to Fermilab in the US in 2017. To ameliorate the impact of shallow depth operation at Fermilab, the detector was enhanced with the addition of a new high granularity light detection system inside the LAr volume and an external cosmic ray tagging system. Currently in the final stages of commissioning, ICARUS is the largest LArTPC ever to operate in a neutrino beam. In this talk I will describe how ICARUS will resolve a long-standing neutrino anomaly that favors the existence of a new, non-interacting, "sterile" neutrino.
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Erika Hamden
Department of Astronomy and Steward Observatory
University of Arizona
Building Your Own Ultraviolet Telescope
Why do galaxies look the way they do? How do galaxies interact with their environments? How does a star form? How does the environment around a new star impact the planets that form around it? These questions can all be answered by observations in the ultraviolet, a seriously neglected wavelength range. In this talk, I will discuss several space and sub-orbital UV telescopes that I am developing to answer the questions above, including FIREBall-2 (a balloon-borne UV spectrograph), Aspera (a NASA funded extreme UV SmallSat), and Hyperion (a FUV mission in development). I will also describe the importance of technology development in enabling these missions and the science they can achieve. Finally, I will argue that the best way to answer difficult science questions is to stop waiting for someone else to build your telescope.
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Zhenhua Tian
Department of Aerospace Engineering
Mississippi State University
Leveraging Acoustics for Structural Health Monitoring and Noncontact Manipulation of Micro/Nano Objects
Acoustic waves carry both information and energy that allow them to inspect material defects as well as create invisible robotic hands (i.e., acoustic tweezers) capable of manipulating matter. This talk will cover my previous studies on leveraging acoustics for structural health monitoring (SHM) and noncontact manipulation of micro/nanoparticles. The first part of the talk is about SHM systems based on laser ultrasonics and ultrasonic arrays for rapid inspection of defects in aerospace structures, such as delamination in composites, disbonding in honeycomb sandwich panels, and corrosion in metal plates. The second part of my talk focuses on dynamic acoustic tweezers based on 10's MHz surface acoustic waves (SAWs). These SAW-based acoustic tweezers use a programmable array of interdigital transducers (IDTs) for the translation, patterning, and concentration of micro/nano objects. Their functions will be discussed with experimental examples, including (i) constructing diverse lattice-like patterns of micro/nanoparticles, (ii) manufacturing composites with patterned carbon nanotubes, and (iii) printing anisotropic tissues with aligned cells.
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Prajwal Mohan Murthy
Department of Physics
University of Chicago
Search for the Neutron Electric Dipole Moment and "what next?"
Baryon asymmetry of the universe, i.e. the fact that much of the observed universe is made of matter as opposed to equal amounts of matter and anti-matter, demands violation of Charge-Parity (CP) symmetry. Yet,
the amount of CP violation from the Standard Model of particle physics is insufficient to explain the baryon asymmetry of the universe. Observation of a non-zero permanent electric dipole moment (EDM) coupled to the spin of any sub-atomic particle, such as the neutron, is an indication of CP violation. Therefore, measuring the neutron EDM, is a key technique of getting a handle on the amount of CP violation. The neutron EDM from the standard model sources is so small that no experiment has thus far achieved the sensitivity required. Nonetheless, searches for the neutron EDM is an important method by which to test and constrain physics beyond the standard model. The neutron EDM has been measured since
the 1940s and the sensitivity of the experiments has improved by over 8 orders of magnitude.
The most recent series of efforts were conducted at the Paul Scherrer Institute (PSI). This was a room temperature experiment employing the Ramsey technique of separated oscillating fields. These measurements used a 21 l storage chamber, in which ultracold neutrons were stored, and surrounded by 4 layers of mu-metal. Prior to 2006, the series of measurements at the Institut Laue-Langevin (ILL) culminated in the measurement of dn < 3 × 10-26 e.cm (90% C.L) [Phys. Rev. D 92, 092003 (2015)] over 5 years of data taking. The ILL apparatus was upgraded significantly with addition of: (i) 16 Cs-133 magnetometers to further characterize the magnetic field environment in the storage chamber, (ii) a new neutron detector system which could simultaneously count both the spin states of the neutron, and (iii) optimized coating inside the storage chamber to maximize the neutron density. The upgraded apparatus was moved to the Paul Scherrer Institute and independently achieved a measurement of dn < 1.8 × 10-26 e.cm (90% C.L) [Phys. Rev. Lett. 124, 081803 (2020)] in just 2 years of data taking. The PSI nEDM experiment has also been a source of rich physics program beyond the measurement of the nEDM. It has investigated neutron oscillation, provided input into neutron lifetime measurements, searched for axions, and tested Lorentz Invariance.
While the search for CPV EDM was first attempted in neutrons, searching for atomic EDM may be a more lucrative avenue, since multiple sources contribute to an atomic EDM, viz. nucleon EDM, nuclear
Schiff moment, CP violating interactions between the electrons and the nuclei, and the nuclear MQM also contributes to the atomic EDM. Nuclear Schiff moment and nuclear MQM are significantly enhanced in quadrupole and octupole deformed nuclei. We will also
discuss viable candidate isotopes which have maximally enhanced sensitivity to EDMs.
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Chu Ma
Department of Electrical and Computer Engineering
University of Wisconsin-Madison
Functional Materials/Devices and Signal Processing for Acoustic Sensing
Acoustic wave propagates through mechanical vibration, with frequencies ranging from below 20Hz to above 20MHz. Each frequency range corresponds to important areas of applications. Particularly, ultrasound is one of the most important diagnosis and therapy methods, allowing non-invasive, non-radiative imaging with resolutions in sub-millimeter range as well as tumor treatment, drug delivery, and excitation of neurons. Besides biomedical field, acoustic sensors and acoustic signal processing technologies support the development of non-contact and non-destructive sensing and communication capabilities both on land and in water.
In this talk, I will present our work on developing functional materials/devices and signal processing technologies for acoustic sensing applications. First, I will talk about utilizing combination of functional materials and computational imaging methods for acoustic super-resolution imaging that breaks the diffraction limit and achieves subwavelength resolution. Second, I will talk about the monitoring of microwave/ultrasound ablation enabled by thermoacoustic signals generated during pulsed heating. Third, I will talk about a new type of acoustic wearable sensor that is formed by piezoelectric fibers sewed into a fabric sheet. The sensor operates as a sensitive audible microphone while retaining the traditional qualities of fabrics, such as machine washability and draping.
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