“ Laser Cooling Exotic Atoms ”
Andy Schramka - OU
Mentor: Dr. Abraham
This 5-minute presentation provides an overview of the Abraham laboratory
summer project for the 2020 OU REU, which involves researching, designing,
and proposing an experiment to laser cool either carbon, nitrogen, or
oxygen. The presentation provides a brief overview of how lasers are used
to slow down atoms, lists some of the applications of laser cooling, and
details the problems encountered when trying to cool these atoms.
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“ Hot Carrier Solar Cells ”
Tanner Legvold - OU
Mentor: Dr. Sellers
Solar cells are a promising way to generate energy in a variety of
circumstances. For use in general energy production, solar cells must
become more cost efficient to compete with other commercial options. Hot
carrier solar cells are a technique to reduce thermalization, a major loss
of energy in current solar cells, with the potential to increase
efficiency to ~60%.
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“ Idealizing the Higgs Boson Control Regions ”
Katherine Sloan - OU
Mentor: Dr. Strauss
In particle physics, data is analyzed using certain cuts, or restrictions on variables. Signal regions are areas with cuts where a particle is expected to be found, and control regions are areas with
cuts that omit the target particle. Control regions typically include only one type of particle, but this is not the case for the 1 jet WW control region of the Higgs->WW-> eυμυ decay channel. Over the
summer, I will explore different cuts in this control region to reduce the amount of ttbar particles found there. I will do this by coding with the C++ language in the particle physics program ROOT,
analyzing different variables, and checking to see if any alterations to the cuts previously applied will improve the ratio of WW to ttbar particles in this region.
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“ Determining White Dwarf Variability ”
Shania Wolf - Missouri State Univ.
Mentor: Dr. Kilic
White dwarfs are late-evolution stars which evolve from main sequence stars of <10 solar
masses. This mass cutoff encapsulates 97% of the stars in the Milky Way, implying that the vast
majority of stars will eventually become a white dwarf. Therefore, it is important to understand
their different forms and processes, including their variability, as is the goal of this research.
Gentile-Fusillo et al. (2019) catalogued and confirmed white dwarf observations from GAIA’s
second data release. Cross-referencing this catalogue with data obtained from the ASASSN and
TESS surveys, we found a sample size of 8,504 white dwarf targets. Due to the sensitivity limit
of the ASASSN survey and the size of the TESS pixels, we restricted our targets to those brighter
than 17th magnitude. We aim to calculate the variability of each target by plotting a light curve
for each star. After determining which targets are variable stars, we will compare our results to
those of published papers. This will allow us to determine why the targets are variable and if any
of the targets are yet undocumented. In this way, we seek to discover white dwarf variable stars.
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“ Pulse-Field Ionization Spectrometer for Rydberg Atom Detection in Bose-Einstein Condensate ”
Chase Heinen - Univ. of Minn. Duluth
Mentor: Dr. Schwwettmann
As the next phase of experimental analysis of Bose-Einstein Condensate (BEC) at the University
of Oklahoma begins, a pulse-field ionization spectrometer is needed to ionize and detect Rydberg
atoms. Rydberg atoms are created in the BEC using the photoexcitation process, which involves
the single valence electron of sodium absorbing photons from tuned lasers. The design of the
pulse-field ionization spectrometer begins with the electric field magnitude needed to ionize
Rydberg atoms with excited electrons of principle quantum number n=60 to n=90. The electric
field magnitudes start at 24.798 V/cm for n=60 excitation states and decreases to 4.898 V/cm for
n=90. In addition, the electric field plates need to be small enough to slide into the 1.5 inch
diameter window of the vacuum chamber and be mounted in a geometric configuration that
prevents the cooling, excitation, and imaging lasers from being blocked. Finally, a parts list
containing the electric field plates, mounting system, and multi-channel plate detector is needed
to allow for the pulse-field ionization spectrometer to be assembled at the University of
Oklahoma.
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“ Z Boson Decay into the Hidden Sector (Z → HDγD) ”
Bailey Weakley - Oklahoma Baptist Univ.
Mentor: Dr. Stupak
Standard model (SM) particles can theoretically decay into the hidden sector. The hidden sector is a hypothetical model that relates SM particles to their ‘dark’ cousins. The dark Higgs boson is a postulated
long-lived particle whose existence could be used to test this model. The specific decay being analyzed is the Z boson decaying into the dark Higgs boson and dark photon (Z → HDγD). The purpose of this project is to
determine if the ATLAS detector at the LHC would be sensitive to this decay model. This will be found by using Monte Carlo event generators and will be analyzed using ROOT and python programs.
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“ Coding for WWgamma acceptance corrections ”
Katelynn Fleming- Drew Univ.
Mentor: Dr. Abbott
This talk presents an introduction to the research on the WWgamma decay mode currently being studied by Dr. Abbott's group working with the ATLAS detector at CERN. It then discusses what it means to apply
selection cuts to a high energy physics dataset, and why it is necessary to apply a correction to the final cross section. Finally, it explains the current endeavour, which is to use Monte Carlo probabilistic
simulations to create an acceptance correction for the work Dr. Abbott's group has done.
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“ Probing Axions Through Astrophysics Magnetic Phenomena ”
Elijah Sheridan -Vanderbilt
Mentor: Dr. Sinha
Since their conception in the 1970s, axions and axion-like particles (ALPs)—electrically
neutral, weakly-coupled, pseudoscalar elementary particles, denoted A—have acted as theoretical solutions to a variety of modern problems in physics. In particular, axions were
originally proposed as a resolution to the strong CP problem, they are cosmological dark
matter particle candidates, and they appear in string theory, thereby providing a means for
experimentally probing string theoretic parameters and predictions. One of the fundamental axion/ALP interactions, the Aγγ primitive vertex, results in an axion-photon mixing
effect in the presence of a magnetic field (wherein axions can convert to photons and vice
versa), enabling us to study the difficult-to-detect axions through photons, which are much
better understood. Astrophysical phenomena, such as magnetars, generate magnetic fields
with strengths of up to eight orders of magnitude higher than those artificially produced
by humans, implying that perhaps astroparticle physics presents the most appropriate and
powerful domain for studying axions and constraining its parameter space through axionphoton mixing. As previously alluded to, such investigations have important ramifications
for some of the biggest questions in high energy theory and cosmology.
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“ Studying a Comparison Sample for a Selection of Low-Redshift FeLoBALs ”
Julianna Voelker - OU
Mentor: Dr. Leighly
Quasars are particularly luminous active galactic nuclei, powered by the accretion of
material into the active black holes that lie at their centers. We studied a sample of 88
quasars with the intent to compare them to a preexisting sample of 30 low ionization,
broad absorption line quasars with iron absorption lines (FeLoBAL quasars) to study the
presence of both strong FeII and strong OIII emission lines in the spectra. Our sample
was chosen by isolating 18 intermediate quasars from the original sample and using a 3-
micron flux density cutoff and a signal-to-noise cutoff to select approximately 5
equivalent quasars for each original quasar. Our comparison sample is similar to the
original in all ways except for the absence of absorption lines in our sample. We seek to
determine if the absorption lines in the original sample account for the presence of both
strong FeII and strong OIII. We discuss in detail the process of spectral fitting, focusing
on the spectrum we’ve already fit and those we will be fitting in the near future. We used
our sample of quasars to confirm previous findings in Boroson and Green (1992), to
compare the equivalent widths of FeII, OIII, and Hbeta (discussed in Cora DeFrancesco’s
talk), and to analyze the presence of both strong FeII and strong OIII in our spectra. For
the rest of the summer, we will be using SimBAL, a novel spectral-synthesis code used to
model broad absorption line quasars (BALQs), to analyze higher redshift FeLoBALs.
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“ Optical Properties in Low Redshift FeLoBAL Quasars ”
Cora DeFrancesco - OU
Mentor: Dr. Leighly
We analyzed a subset of a sample of high redshift (z>2), high
luminosity FeLoBAL quasars. We describe the location of the
outflows with respect to the size scale of a host galaxy. We find a
large difference in outflow radius R spanning 4 dex. We confirm
the inverse proportionality of R with the ionization parameter and
gas density. Furthermore, we calculate the outflow strength and
find that more objects show outflows greater than 0.5% of quasar
luminosity than in previous samples. This is most likely due to a
luminosity selection effect. Further analysis of the complete
sample will provide more information on outflow strength and the
possibility of high redshift, high luminosity quasars supporting
feedback.
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“ Using Machine Learning to Increase Significance of our measurement of WWgamma ”
Caroline Doctor - Univ. of Georgia
Mentor: Dr. Abbott
With the impending release of the discovery of WW𝞬 production using data collected from the
ATLAS detector, it is imperative that we start thinking about the next steps. In order to analyze
trends in WW𝞬 production, one must first raise the value of significance (σ) in order to minimize
error. To do so, I will be employing machine learning techniques using the TMVA package
included in ROOT as well as other programs if necessary. Once σ has been raised, we will be
able to determine the differential cross-sections of various subsets of data and determine
cross-section as a function of the various resulting characteristics of the final state particles with
a low degree of error.
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“ Analyzing Photon Statistics ”
Cordelia Meixsel - Stetson Univ.
Mentor: Dr. Marino
Dr. Marino, Dr. Tekuru, Mr. Nirala, and I will be analyzing photon statistics gathered by their
apparatus on campus which will be described shortly. There are three important elements to photon
statistics that are the basis of our project, the first being photon counters. Similar to Geiger counters,
photon counters detect impacting photons and relay the results in a binary fashion of either no photon
or one photon. The other two elements of photon statistics are the mean value 𝑛-bar which, in this
context, is the average number of photons in a beam segment and the variance (Delta n)^2 of the data used
to obtain the mean. By using these three elements of photons statistics, you can classify light into three
categories: Super-Poissonian, Poissonian, and Sub-Poissonian. For our project, we have a low intensity
laser that travels through 85Rb vapor which separates the beam into two correlated beams that get
detected by two photon counters. Since these two beams are correlated, for every photon in one beam
the other also has a photon in the same location, therefore both photon counters should always register
a photon at the same time. Individually these two correlated beams are Super-Poissonian, but together,
via subtracting one’s photon counter’s results by the other, you are left with Sub-Poissonian data. Our
project is to make a MATLAB program to take the Super-Poissonian data, interpret it, and receive SubPoissonian data.
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“ Casimir Friction ”
Bill McNulty - OU
Mentor: Dr. Milton
The Casimir friction on an electric dipole in vacuum moving at constant velocity parallel to a dielectric slab is investigated. The expression for the force is derived classically and modified to obtain a
quantum formulation. Contributions to the self-force on the dipole from both dipole fluctuations and field fluctuations are included.
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“ Visualization of Electron Densities of Gold Atoms Using XCrySDen Program ”
Grace Ward - Michigan State Univ.
Mentor: Dr. Bumm
To visualize the gold crystalline structures, I am going to use the program XCrySDen with WAVECAR file data and potentially, the program VESTA. The plots of these structures will contain electron density
isosurfaces and contours from the analysis tools of the programs. Although there is not a clear plan and problem stated, we will first retrieve the WAVECAR file, observe the plots and try various combinations
of the data.
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