Master of Science (MS), Ohio University, 2024, Physics and Astronomy (Arts and Sciences)

∆E-E detector systems measure both the stopping power and kinetic energy of each particle that passes through them and are especially useful in measuring reactions with multiple possible ejectiles. These system are able to produce two-dimensional data which may be filtered more easily than that from a single detector in order to identify and isolate specific particles in a reaction and obtain more accurate measurements. A ∆E-E detector system was designed and assembled for use in the Left 15 Scattering chamber at Edwards Accelerator Laboratory to measure differential cross sections and study angular distribution. The system was used to determine cross sections of 12C(6Li,p)17O, 12C(10B,p)21Ne, and 27Al(10B,p)36Ar reactions at 12, 16, and 19 MeV respectively at varying angles. These experimental cross sections were compared to theoretical values found using simulated data from the code PACE4. Experimental values were found to be in a rough agreement with simulated values. This system will be able to provide accurate measurements for reactions with multiple ejectiles in future experiments at EAL.

PhD, University of Cincinnati, 2024, Engineering and Applied Science: Mechanical Engineering

One of the largest sources of uncertainty in the calculation of stopping power ratios for use in proton radiotherapy is the measurement of Hounsfield Units (HU) for the determination of electron density. The primary source of this uncertainty is due to the relative difference in scatter between the patient and electron density calibration phantoms. In this dissertation, I will show how anatomy adaptive CT number to electron density calibration curves can improve the accuracy of stopping power ratio tabulations for proton radiation therapy dosimetry. We will generate new curves by measuring realistic (anthropomorphic) phantoms, fabricated using realistic tissue equivalent materials that accurately represent the internal structure and tissue types of the pelvis. The goal of this research is to use the new realistic anthropomorphic phantoms to evaluate how patient scatter affects measured electron density curves.

Doctor of Philosophy, The Ohio State University, 2024, Physics

In the seconds following their formation in core-collapse supernovae, `proto'-neutron stars (PNSs) drive neutrino-heated magneto-centrifugal winds. The neutrino-driven wind phase during the cooling of the PNS lasts $\sim 1-100$\,s. We construct unprecedentedly realistic models of the PNS cooling phase using two-dimensional axisymmetric magnetohydrodynamic simulations. We include the effects of neutrino heating and cooling, employ a general equation of state, consider strong magnetic fields along with a dynamic PNS magnetosphere, and include the effects of PNS rotation. We show that relatively slowly rotating magnetars (strongly magnetized PNSs) with initial spin periods $P_{\star0} \gtrsim 100$\,ms spin down rapidly during the cooling epoch. For polar magnetic field strengths $B_0\gtrsim10^{15}$\,G, we show that the spindown timescale is of the order seconds in early phases. We show that magnetars with mass $M$ born with $B_0$ greater than $\simeq1.3\times10^{15}\,{\rm\,G}\,(P_{\star0}/{400\,\rm\,ms})^{-1.4}(M/1.4\,{\rm M}_\odot)^{2.2}$ spin down to periods $> 1$\,s in just the first few seconds of evolution. We discuss the implications for observed magnetars, including the discrepancy between their characteristic ages and supernova remnant ages. On the other hand, we show that rapidly rotating magnetars with initial spin periods $P_{\star 0}\lesssim 4$\,ms and $B_0\gtrsim 10^{15}$\,G can release $10^{50}-5\times 10^{51}$\,ergs of energy during the first $\sim2$\,s of the cooling phase. Based on this result, it is plausible that sustained energy injection by magnetars through the relativistic wind phase can power gamma-ray bursts (GRBs). We also show that magnetars with moderate field strengths of $B_0\lesssim 5\times 10^{14}$\,G do not release a large fraction of their rotational kinetic energy during the cooling phase and hence, are not likely to power GRBs. We hypothesize that moderate field strength magnetars can be central engines of superluminous supern (open full item for complete abstract)

PHD, Kent State University, 2024, College of Arts and Sciences / Department of Physics

Numerous previous investigations of in-medium quarkonium suppression have tacitly relied on an adiabatic approximation, presuming that the potential governing heavy quark interactions evolves slowly with time. In this adiabatic scenario, one can decouple the calculation of the in-medium breakup rate and the temporal evolution of the medium, combining them only at the conclusion of the analysis. We relax this assumption by solving the 3d Schr¨odinger equation in real-time in order to compute quarkonium suppression dynamically. We introduce a method for reducing anisotropic heavy-quark potentials to isotropic potentials by using an effective screening mass that depends on the quantum numbers l and m of a given state. We demonstrate that using the resulting 1D effective potential model, one can solve a 1D Schr¨odinger equation and reproduce the full 3D results for the energies and binding energies of low-lying heavy-quarkonium bound states to relatively high accuracy. We introduce a framework called Heavy Quarkonium Quantum Dynamics (HQQD) which can be used to compute the dynamical suppression of heavy quarkonia propagating in the quark-gluon plasma using real-time in-medium quantum evolution. Using HQQD we compute large sets of real-time solutions to the Schr¨odinger equation using a realistic in-medium complex-valued potential. We sample 2 million quarkonia wave packet trajectories and evolve them through the QGP using HQQD to obtain their survival probabilities. Using the potential non-relativistic quantum chromodynamics (pNRQCD) effective field theory, we derive a Lindblad equation for the evolution of the heavy-quarkonium reduced density matrix that is accurate to next-to-leading order (NLO) in the ratio of the binding energy of the state to the temperature of the medium. The resulting NLO Lindblad equation can be used to more reliably describe heavy-quarkonium evolution in the quark-gluon plasma at low temperatures compared to the leading-order tr (open full item for complete abstract)

Bachelor of Sciences, Ohio University, 2024, Physics and Astronomy

Nuclear cross section is a tool used by physicists to characterize scattering interactions between particles. It relates the probability of a reaction occurring to an effective “size” of the target particle's cross sectional area. For electron-nucleon collisions, the elastic cross section values are well supported by experimental evidence for a wide range of Q^2 measurements. Because of this, comparing one's own experimental data to the known values can highlight possible issues with the data collection process. This makes elastic cross section an effective tool to safeguard against oversights when analyzing more complex interactions. This project analyzed elastic data from the Pion LT experiment run at Jefferson Lab in 2021-2022. Using the scattering analysis software ROOT and Jefferson Lab's Monte Carlo simulator SIMC, the measured elastic cross sections were able to be verified to the 10% level of their expected values.

PHD, Kent State University, 2024, College of Arts and Sciences / Department of Physics

The thermodynamics of N = 4 supersymmetric Yang-Mills theory in four dimensions (SYM4,4) is of great interest since, at finite-temperature, the weak-coupling limit of this theory has many similarities with quantum chromodynamics (QCD). Unlike QCD, however, in SYM4,4 it is possible to make use of the AdS/CFT correspondence between gravity in anti-de Sitter space (AdS) and the large-Nc limit of conformal field theories (CFT) on the boundary of AdS to obtain results for SYM4,4 thermodynamics in the strong coupling limit. The mathematical structure of SYM4,4 is similar to that of QCD, the difference is mostly in the number of degrees of freedom and the representations of fields. There are four Majorana fermions and six scalars and all the fields are in the adjoint representation. In the last decade or so the thermodynamics of SYM4,4 in a strong-coupling regime received a great deal of attention due to AdS/CFT where in SYM4,4 is mapped to its gravity dual. In this limit, the thermodynamics has been computed to the order λ−3/2, where λ = Nc g2 is the ‘t Hooft coupling. In the opposite sector of weak coupling, prior to our work, the free energy density of SYM4,4 was known to the order λ3/2. In this regime, calculations are performed using perturbative field theory methods. This weak-coupling expansion of SYM4,4 like QCD can pushed until λ5/2, after which non-perturbative effects come into play. In this SYM4,4 free energy density expansion interesting observations are made by constructing a generalized Pade which interpolates between strong and weak coupling expansion. The weak coupling expansion converges towards this Pade for λ ≲ 1 and the strong coupling for λ ≳ 10. The makes the weak and strong coupling expansion and their convergence in the intermediate region of 1 ≲ λ ≲ 10 of a great deal of interest. On the weak-coupling side the free energy density calculations in SYM4,4, like in QCD, are done and improved upon using various perturbative field t (open full item for complete abstract)

Master of Science (M.S.), University of Dayton, 2024, Aerospace Engineering

This research introduces an Origami-inspired dynamic spacecraft radiator, capable of adjusting heat rejection in response to orbital variations and extreme temperature fluctuations in lunar environments. The research centers around the square twist origami tessellation, an adaptable geometric structure with significant potential for revolutionizing radiative heat control in space. The investigative involves simulations of square twist origami tessellation panels using vector math and algebra. This study examines both a two-dimensional (2- D), infinitely thin tessellation, and a three-dimensional (3-D), rigidly-foldable tessellation, each characterized by an adjustable closure or actuation angle “φ”. Meticulously analyzed the heat loss characteristics of both the 2D and 3D radiators over a 180-degree range of actuation. Utilizing Monte Carlo Ray Tracing and the concept of “view factors”, the study quantifies radiative heat loss, exploring the interplay of emitted, interrupted, and escaped rays as the geometry adapts to various positions. This method allowed for an in-depth understanding of the changing radiative heat loss behavior as the tessellation actuates from fully closed to fully deployed. The findings reveal a significant divergence between the 2D and 3D square twist origami radiators. With an emissivity of 1, the 3D model demonstrated a slower decrease in the ratio of escaped to emitted rays (Ψ) as the closure/actuation angle increased, while the 2D model exhibited a more linear decline. This divergence underscores the superior radiative heat loss control capabilities of the 2D square twist origami geometry, offering a promising turndown ratio of 4.42, validating the model's efficiency and practicality for radiative heat loss control. Further exploration involved both non-rigidly and rigidly foldable radiator models. The non-rigidly foldable geometry, initially a theoretical concept, is realized through 3D modeling and physica (open full item for complete abstract)

Master of Science (MS), Ohio University, 0, Physics and Astronomy (Arts and Sciences)

The proton structure of 11B, which can be studied via proton induced reactions or transfer reactions on 10Be, has numerous applications in nuclear astrophysics. Reactions involving 10Be play a significant role in Core-Collapse Supernovae and in Big-Bang Nucleosynthesis. Additionally, the structure of 11B above neutron thresholds is important for neutron detection. Recently published work proposes a new excited state for 11B at Ex = 11.4 MeV. However this work finds no evidence for the existence of this resonance. An initial investigation into the proton structure of 11B was conducted at Edwards Accelerator Laboratory by studying the 10Be(d, n)11B reaction employing deuteron beam energies of seven, eight, and nine MeV. The resulting neutrons were measured at 0◦ by a detector located in a neutron time of flight tunnel. Through time of flight methods, populated states of 11B were studied via differential cross section measurements with particular interest at higher excitation energies.

PHD, Kent State University, 2023, College of Arts and Sciences / Department of Physics

In the field of high-energy nuclear physics, ultrarelativistic heavy-ion collisions serve as a one-of-a-kind laboratory for investigating the extreme properties of matter. These collisions involve massive nuclei, such as lead or gold, colliding with energies in the trillions of electron volts per nucleon range. These collisions produce an environment where the strong force, as described by quantum chromodynamics (QCD), is the dominant force. In particular, the collisions generate a state of matter known as the quark-gluon plasma (QGP), which is characterized by a state of quarks and gluons that is not confined inside hadrons such as protons and neutrons. The QGP is an intriguing state of matter that provides insights into the behavior of dense astrophysical objects and the early universe. It is produced when the energy density of the collision reaches a critical threshold, resulting in the transition from the confined to the unconfined state of quarks and gluons. The QGP is a hot and dense system, with temperatures on the order of trillions of Kelvin and densities several orders of magnitude greater than the density of atomic nuclei in ordinary matter. In the initial phases of a heavy-ion collision, the system is far from thermal equilibrium and possesses a highly anisotropic pressure. The pressure anisotropy results from the longitudinal expansion being more rapid than the transverse expansion. The dynamics of the system cannot be adequately described by ideal hydrodynamics, which assumes local isotropic thermal equilibrium at all times. To account for the pressure anisotropy and non-equilibrium nature of the QGP, a framework known as anisotropic hydrodynamics has been developed. Anisotropic hydrodynamics (aHydro) is a useful tool for describing the evolution of the QGP, especially during the early non-equilibrium evolution of the QGP. It goes beyond the ideal hydrodynamic limit by incorporating dissipative transport coefficients, such as shear viscosity, which (open full item for complete abstract)

Doctor of Philosophy (PhD), Ohio University, 0, Physics and Astronomy (Arts and Sciences)

The production mechanisms for boron, as well as for beryllium and lithium, are hypothesized to lie outside well established standard stellar nucleosynthesis processes. Boron is thought to have been formed via Core Collapse Supernovae as well as via cosmic ray nucleosynthesis. It is an element whose astrophysical origins facilitate a glimpse into some of the more extreme astrophysical processes in the Universe. Boron's stable isotopes, 10B and 11B, have therefore been studied for some time. The single proton structure of the 11B isotope, however, is understudied. For the purpose of studying the 11B single proton structure, we measured the 10Be(p,n)10B reaction at the Edwards Accelerator Laboratory by bombarding an 85-µg/cm2-thick 10BeO target with a proton beam. Two separate techniques were used: the time-of-fight method, and a neutron counting scheme via the use of proportional counters. The diferential and angle-integrated reaction cross sections were measured in the 0.5 ≤ Ep ≤ 7.0 MeV energy range using the Swinger beamline as well as the Helium Boron-Trifuoride Giant Barrel (HeBGB) neutron detector, respectively. Swinger beamline measurements measured a 0◦ excitation function in the 2.0 ≤ Ep ≤ 7.0 MeV energy range, and resonances were observed at Ep = 2.2-2.5, 3.5, 4.5-4.7, and 5.7 MeV. Angular distributions up to 150◦ and 105◦ were measured at 2.5 and 3.5 MeV, respectively. An angle-integrated excitation function was measured in the 0.5 ≤ Ep ≤ 2.4 MeV energy range using HeBGB. Resonances were observed at Ep = 1.09 - 1.55, 1.8, and 2.4 MeV. Gamma-ray spectra were also measured via the Swinger beamline, using a LaBr3 detector. Gamma-rays corresponding to the decay of the first two excited states of 10B, as well as the first excited state of 7Li, were observed. Lastly, a new target holder for HeBGB was designed and implemented to facilitate beam collimation when bombarding the 10BeO target

PHD, Kent State University, 2023, College of Arts and Sciences / Department of Physics

Heavy ion collisions at Relativistic Heavy Ion Collider (RHIC) provide a unique environment to probe nuclear matter under extremely high temperature and density conditions. Among the many insights that can be provided are studying the Quark Gluon Plasma (QGP) created in these collisions, the interaction of color-charged probes with the QGP, the mechanism of hadronization as well as the nature of phase transition to the deconfined phase. Production of heavy quarks in high-energy nuclear collisions occurs mainly through initial hard scattering, via gluon fusion and quark anti-quark annihilation, since the thermal production in the hot QCD medium is significantly suppressed due to the heavy quark masses. This makes heavy quarks ideal probes of the QGP as they experience the whole medium evolution. The diffusion of a heavy particle through a heat bath of the hot-QCD medium can be quantified by the spatial diffusion coefficient Ds, in analogy to the Brownian motion in molecular physics. Early calculations based on perturbative methods for the diffusion coefficient for the charm and bottom quarks in a QGP produced values of Ds(2ϖ T) ∼ 30 ∼ O(1/αs2) for a strong coupling constant of αs ∼ 0.3-0.4 and with a value varying only weakly with temperature. We now know that these values for Dss are too large to account for the open heavy-flavor (HF) observables, including the elliptic flow (v2) of D0 mesons, in heavy-ion collisions at RHIC and the LHC. New measurements, including of higher order flow, with better precision and studying their dependence on collision geometry and size and shape of the produced medium allow us to better constrain the value of Ds and the heavy quark interaction with the QGP. The Solenoidal Tracker At RHIC (STAR) experiment is one of the two remaining large detector systems at the RHIC. The Time Projection Chamber (TPC) is the main detector at STAR measuring 4.2 m in length and 4 m in diameter, it provides full azimuthal coverage out to ± 1.0 unit (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2023, Physics

One of the key aspects in developing advanced nuclear reactor technology is the stability of the materials, which directly impacts the reactor's lifespan. These materials are subject to coupled extreme environmental stresses such as high radiation, corrosive media, and large temperature gradients, which synergistically contribute to the buildup of defects and eventual material failure. To build a comprehensive understanding of defect evolution, it is important to study the early stages of defect evolution, beginning with the formation of vacancies, voids, dislocations, and non-equilibrium defects. On the experimental front, it is challenging to quantify these vacancy-type defects with standard characterization techniques, as it requires sub-nanometer resolution. Positron Annihilation Spectroscopy (PAS) bridges this gap, comprising a set of non-destructive techniques capable of directly detecting atomic-scale defects, at concentrations as low as 1 vacancy per ten million atoms. This thesis will detail the work done for the ongoing development of two positron beamlines, with an emphasis on the beamline used for in-situ investigations of ion-induced damage in nuclear materials. The first measurements using the newly developed beamline are presented for low-dose radiation-induced self-ion damage in Fe. Later, refinements to the apparatus and experimental design are also discussed with regards to revisiting the experiment. Additionally, two studies on a class of high-performance multi-principal element/high-entropy alloys are discussed. Using positron annihilation lifetime Spectroscopy (PALS) and Doppler broadening spectroscopy (DBS), the phase structure and chemical complexity effects on MoNbTi-based alloys are explored with evidence of radiation resistance in MoNbTiZr and MoNbTi as well as defect recovery observed in MoNbTiVZr. Finally, exploratory measurements using DBS on a ternary mutli-principal element alloys (MPEA), CoCrNi, have recently been performed (open full item for complete abstract)

Bachelor of Science (BS), Ohio University, 2023, Physics

The field of subatomic particles has existed for over a hundred years now. From the discovery of the electron that sparked the field, to the discovery of the Higgs Boson, physicists have always wanted to uncover the subatomic structure of the atoms, nuclei, and their constituents at smaller and smaller levels. By the 1930s, the proton, neutron, and electron had been discovered. These protons and neutrons are types of hadrons, and many different types of hadrons had been discovered by the 1960s. In 1964, Murray Gell-man and George Zweig independently proposed the quark model to explain the different hadrons. A quark is a particle that makes up a hadron, accounting for the many different types of hadrons that had been discovered; the other hadrons were composed of 2 or 3 of the 6 quarks. These include the up, down, top, bottom, charm, and strange quarks. The proton is made of 2 up quarks and 1 down quark, while the π0 particle is made of an up and an anti-up, or a down and an anti-down quark, for example. Advancements in technology allowed physicists to be able to accelerate particles and smash them together in particle accelerators and colliders. These new machines were how physicists were able to split open atoms, and the hadrons inside, to uncover these quarks. In the search for these different quarks, other particles were being discovered as well. This included the 6 leptons, the electron, the tau, and the muon, and their neutrino counterparts. The leptons are grouped separately from quarks because they participate only in electroweak interactions, while quarks also participate in strong interactions. Electroweak interactions describe the interactions caused by the electromagnetic force and the weak nuclear force. The strong interactions describe those caused by the strong nuclear force. These 3 forces, along with gravity, are the four fundamental forces of the universe, with the strong force being the strongest force and responsible for most of the energy in (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2022, Physics

The proton spin puzzle is a longstanding problem in high-energy nuclear physics: how the proton spin distributes among the spin and orbital angular momenta of the quarks and gluons inside. Two unknown pieces of the puzzle are the contributions from quark and gluon spins at small Bjorken $x$. This dissertation fills the gap by constructing the evolution of these quantities into the small-$x$ region, through their relations with the polarized dipole amplitudes. The dominant contributions to the evolution equations resum powers of $\alpha_s\ln^2(1/x)$, where $\alpha_s$ is the strong coupling constant. In general, these evolution equations do not close. However, once the large-$N_c$ or large-$N_c\& N_f$ limit is taken, they turn into a system of linear integral equations that can be solved iteratively. (Here, $N_c$ and $N_f$ represents the number of quark colors and flavors, respectively.) At large $N_c$, the evolution equations are shown to be consistent with the gluon sector of the polarized DGLAP evolution in the small-$x$ limit. We numerically solve the equations in the large-$N_c$ and large-$N_c\& N_f$ limits and obtain the following small-$x$ asymptotics for $N_f \leq 5$: $$g_1(x,Q^2)\sim \Delta\Sigma(x,Q^2) &\sim \Delta G(x,Q^2) \sim \left(\frac{1}{x}\right)^{\alpha_h\sqrt{\frac{\alpha_sN_c}{2\pi}}}\,.$$ with the intercept, $\alpha_h$, decreasing with $N_f$. In particular, in the large-$N_c$ limit, we have $\alpha_h = 3.66$, which agrees with the earlier work by Bartels, Ermolaev and Ryskin. Furthermore, at $N_f=6$, the asymptotic form becomes $$g_1(x,Q^2)\sim \Delta\Sigma(x,Q^2) &\sim \Delta G(x,Q^2) \sim \left(\frac{1}{x}\right)^{\alpha_h\sqrt{\frac{\alpha_sN_c}{2\pi}}} \cos\left(\omega_h\sqrt{\frac{\alpha_sN_c}{2\pi}}\,\ln\frac{1}{x} + \varphi_h\right),$$ where the parameters, $\alpha_h$, $\omega_h$ and $\varphi_h$, are calculated and listed in the text. The emerging oscillation has a period spanning several units of rapidity. Finally, parts of the (open full item for complete abstract)

Master of Science, The Ohio State University, 2022, Nuclear Engineering

In this thesis, an algorithm addresses a simple method to help the fusion of different radiation imaging modalities into one image. A computational program was utilized to achieve this goal by retaining the structural and compositional information in the final fused image. It appears to be a promising method to gather as many details as possible from different imaging modalities, such as neutron and X-ray images. The essential information on each imaging modality can be comprehensive and vital for the final assessment. This thesis focuses on the algorithm used to achieve the primary goal of complete data from each involved imaging modality. Fusing two images can have significant benefits in industrial and medical imaging, such as non-destructive testing applications and helping to diagnose certain diseases. A similar procedure was performed by another research group earlier to achieve similar kinds of objectives [1][2][3][4]. It is vital to have this tool available to be helpful for the correct assessment of images in several image fusion applications. It will solve the issue of incomplete information in an image by merely one imaging method. This algorithm is based on discrete wavelet transform, which shows superiority over other fusion methods as it does not lose quality during the process and keeps the spatial resolution of the images [5]. Various materials have similar atomic numbers and differing thermal cross-sections, or vice versa. This could cause confusion in the image understanding; therefore, this will be solved by the fusion of neutron and X-ray, which will provide a more convenient and comprehensive image to be analyzed by limiting the shortcomings of both imaging methods. This algorithm can also be applied to other radiation imaging modules. After obtaining the fused image, quality assessment techniques were performed and compared to previous work results to validate our algorithm.

Doctor of Philosophy (PhD), Ohio University, 2022, Physics and Astronomy (Arts and Sciences)

We extend an Effective Field Theory (EFT) developed to describe rotational bands in even-even nuclei to the odd-mass case. This organizes Bohr & Mottelson's treatment of a particle coupled to a rotor as a model-independent expansion in powers of the angular velocity of the overall system. We carry out this expansion up to fourth order in the angular velocity and present results for 99Tc, 159Dy, 167,169Er, 167,169Tm, 183W, 235U and 239Pu. In each case, we get clear systematic improvement, as we go to higher orders in our EFT, starting form simple low energy degrees of freedom. We clearly show the main benefit of this EFT by using a Bayesian analysis framework to properly and rigorously account for theoretical uncertainty. We make use of the EFT expansion to perform a Bayesian analysis of data on the rotational energy levels of the nuclei above and in 155Gd and 157Gd. The error model in our Bayesian analysis includes both experimental and EFT truncation uncertainties. It also accounts for the fact that low-energy constants (LECs) at even and odd orders are expected to have different sizes. We use Markov Chain Monte Carlo (MCMC) sampling to explore the joint posterior of the EFT and error-model parameters and show both the LECs and the breakdown scale can be reliably determined. We extract the LECs up to fourth order in the EFT and find that, provided we correctly account for EFT truncation errors in our likelihood, results for lower-order LECs are stable as we go to higher orders. LEC results are also stable with respect to the addition of higher-energy data. We extract the expansion parameter for all the nuclei listed above and find a clear correlation between the extracted and the expected value of the inverse breakdown scale, W, based on the single-particle and vibrational energy scales. However, the W that actually determines the convergence of the EFT expansion is markedly smaller than would be naively expected based on those scales.

Doctor of Philosophy, The Ohio State University, 2022, Physics

In this thesis we study the dynamics of quark and gluon distributions inside a proton, allowing for the proton and its constituent quarks to be polarized transversely with respect to the momentum of the proton (or the beam axis in a scattering experiment). We call such a polarization transverse spin, and the interactions between the orbital motion of quarks within a proton and this transverse spin of both the proton and the quarks themselves lead to a variety of fascinating effects in nuclear physics, including the existence of time-reversal odd observables and the violation of traditional wisdom that transverse spin-dependent effects should diminish rapidly at high energy. We consider the dynamics of transverse spin in the context of high energy collisions, which probe the quarks and gluons carrying the smallest fraction x (called Bjorken x) of the proton's momentum. As the collision energy is increased and consequently lower values of x are probed, the population of quarks and gluons grows and turns the proton into an extremely dense cloud of gluons. Tightly packing the proton or a nucleus as in this dense regime yields effects like nuclear shadowing and saturation as non-linear gluon recombination effects slow the growth of the gluon distributions toward very small values of x. In this work we study some features of transverse spin dynamics at small values of x, beginning with an investigation of the transverse spin asymmetry in collisions of transversely polarized protons off unpolarized proton or nucleus targets AN. Here we use a model calculation to see how a final state interaction between the constituents of the polarized proton (after scattering off the unpolarized target) can give a qualitative explanation of several puzzling features of this asymmetry. Next, we study the small-x asymptotics of the time reversal (T)-odd, leading-twist quark TMDs, the quark Sivers function f1T⊥ and the Boer-Mulders function h1⊥ . In order to derive these (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2022, EECS - Electrical Engineering

This thesis shows that permanent magnets and electromechanical control systems can enable power-efficient, high-sensitivity, low-noise modalities for spectroscopy and wireless communication. Specifically I present two examples. The first is a radio frequency (RF) spectrometer which uses a detector cooled to 77 K to maximize measurement sensitivity, coupled with a minimally-intrusive network of active duplexers and mechanical contact switches to realize a reconfigurable series/parallel resonant network. I present a receiver which combines the highly sensitive analog frontend instrumentation with a mixed signal embedded system to monitor and control secondary processes. The cryogenic system increases the measurement signal to noise ratio (SNR) by a factor of 10×. The second example is an extremely low frequency (ELF) communication system which uses a mechanically-rotated dipole instead of an electrical antenna to generate the oscillating field of the transmitter. I show how a synchronous digital controller can maintain stable control over the dynamic process while a complementary embedded system modulates the set-point and monitors the channel. My transmitter achieves a power efficiency 7.6× greater than an equivalent electrical antenna in a device small enough to be moved by one person. I carry the transmitter into a cave and demonstrate cave-to-surface message transmission through 15 m of rock and frozen soil in a real-world field test. I present each solution in the context of scientific and human motivation, and explore tradeoffs required to achieve design goals. Emphasis is also placed on whether there exists a position of harmony and balance, where one may reasonably proclaim the optimum implementation has been achieved. The receiver is relatively more complex than the transmitter in the case of RF spectroscopy. In the case of ELF communication it is the reverse.

Doctor of Philosophy (PhD), Ohio University, 2022, Physics and Astronomy (Arts and Sciences)

A number of recent experiments have been able to successfully measure the parity violating asymmetry of electron-nucleus scattering and use its value to constrain the nuclear structure. The most recent of these, the Calcium Radius Experiment (CREX), finished taking data in Hall A of Jefferson Lab in 2021, and successfully extracted a neutron radius for 48Ca. While the main measurements of these experiments are parity violating, there is an increasing amount of interest in the parity conserving Beam Normal Single Spin Asymmetry (BNSSA) systematic. If not properly suppressed, the BNSSA can compete with or exceed the parity violating measurement. Recent attempts to model the contributions from standard model suppressed higher order diagrams have struggled to predict behavior of BNSSA for all nuclei. This document reports new measurements of the BNSSA at a beam energy of 2.18 GeV for 12C, 40Ca, 48Ca, and 208Pb from the CREX running period. The values for 12C, 40Ca, and 48Ca are found to agree with model predictions. The two values of calcium agree with each other, indicating no strong isotopic scaling. The value for 208Pb is consistent with zero, in stark disagreement with model predictions. This thesis contains a discussion of how these values were measured, as well as a proposed method to phenomenologically scale models to bring them into closer agreement with world data at lower energies.

Bachelor of Sciences, Ohio University, 2022, Physics and Astronomy

The study of nuclear reactions is critical to understanding nuclear structure. For all nuclear reactions, the cross section is the probability of a particular nuclear reaction occurring. Cross sections can be simulated with two nuclear coding and analysis software packages known as Empire and TALYS, both based on the Hauser-Feshbach formalism. Empire can simulate multiple types of nuclear reactions given any number of parameters. It can simulate fission, fusion, and scattering, with both subatomic and heavier nuclei as incident particles. TALYS is a similar nuclear reaction simulation software, but is less flexible than Empire, as it can only utilize incident subatomic particles. Due to the similarity between the two software packages, generating graphs that match between them and are consistent with literature provide confidence in the reliability of both Empire and TALYS. In this study, Empire and TALYS were first compared using reactions involving the target nuclei 54Fe, 93Nb, and 209Bi. Next, existing data from Edwards Accelerator Laboratory from an experiment involving a 12C beam incident on a 27Al target has been collected and will be analyzed soon. Cross sections for various reactions of 12C + 27Al were simulated with Empire, and results are discussed