Bulletin of the American Physical Society
Far West Section Fall 2021 Meeting
Volume 66, Number 12
Friday–Saturday, October 29–30, 2021; Virtual
Session M01: Nuclear/Applied Physics |
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Chair: Philip von Doetinchem, University of Hawaii at Manoa |
Saturday, October 30, 2021 11:00AM - 11:12AM |
M01.00001: Detecting and Sorting Alpha Accompanied Ternary Fission in the NIFFTE TPC Nicholas Androski The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) is a MICROMEGAS Time Projection Chamber (TPC) used to detect nuclear fission events induced by a pulsed beam from the Los Alamos Neutron Science Center (LANSCE). While most fission events are binary, involving a nucleus breaking into two charged fragments, there is a chance of ternary fission when three charged fragments are produced, typically including an alpha particle. To sort these rare alpha ternary events from NIFFTE experimental data on a U238/U235 target, a Hough Transform is applied for track reconstruction and a series of cuts are made on the tracks, such as a distance of closest approach (DCA) test. The candidate tracks are then sorted into populations based on their length and energy deposited within the TPC gas, and visually sorted. Current status on the effectiveness of the sorting algorithm and ternary to binary fission counts will be presented. [Preview Abstract] |
Saturday, October 30, 2021 11:12AM - 11:24AM |
M01.00002: Nucleon-level Effective Theory of Muon to Electron Conversion in the Nuclear Field Evan Rule The coming decade promises exceptional experimental progress in tests of charged lepton flavor violation (CLFV), with branching ratio sensitivities for $\mu \to e$ conversion searches expected to improve by more than four orders of magnitude due to efforts at Fermilab (Mu2E) and J-PARC (COMET). To support this progress, significant theoretical advances are required in order to connect low-energy tests of $\mu \to e$ conversion to candidate UV theories of CLFV. Here we describe an effective theory of $\mu \to e$ conversion formulated at the non-relativistic nucleon level which represents the most general constraint that this process can place on the underlying CLFV operators and provides the foundation to match onto effective theories at higher scales. This formulation provides a clear factorization of the CLFV physics from the nuclear physics (in analogy with standard-model processes like $\beta $ decay and $\mu $ capture), delineating what can and cannot be learned about CLFV operator coefficients from elastic $\mu \to e$ conversion. Using state-of-the-art shell model wave functions, we derive bounds on operator coefficients from existing $\mu \to e$ conversion and $\mu \to e\gamma $ results, and estimate the improvement in these bounds if Mu2e, COMET, and MEG II reach their design goals. [Preview Abstract] |
Saturday, October 30, 2021 11:24AM - 11:36AM |
M01.00003: A model to estimate the yields of uncorrelated double quarkonium production in PbPb collisions and pPb collisions Saeahram Yoo, Manuel Calderon de la Barca Sanchez We present a model to estimate the yields of uncorrelated double quarkonium production based on the multinomial distribution, the Glauber model, and single quarkonium production. The calculations focus on uncorrelated production of $\Upsilon$ and $J/\psi$ in PbPb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV and pPb collisions at $\sqrt{s_{NN}} =$ 8.16 TeV corresponding to $\mathcal{L}$$_{int}=$ 1.7 nb$^{-1}$ and $\mathcal{L}$$_{int}=$ 186 nb$^{-1}$, respectively. The number of nucleon-nucleon collisions in each nucleus collision was determined based on the Glauber model. Each nucleon-nucleon collision is treated as a possible source of double quarkonium production with a probability given by multinomial distribution. To obtain the probability of generating $\Upsilon$ and $J/\psi $ in a nucleon-nucleon collision, the cross-sections of $\Upsilon$ and $J/\psi$ were obtained from previously published calculations as well as Pythia 8.306 for comparison. We calculated the acceptance using the transverse momentum, while the pseudorapidity of the daughter muons was obtained via Pythia and the efficiency was directly found from the single muon CMS results. The model can be utilized to predict the yields of double quarkonium production in future experiments. [Preview Abstract] |
Saturday, October 30, 2021 11:36AM - 11:48AM |
M01.00004: X-ray fluorescence measurements of strontium concentration in a lamb bone sample Michelle Berrios, Mihai Gherase Strontium (Sr) is an essential element residing in bone in concentrations of 0.1 to 0.3 mg per gram of calcium. Low doses of dietary Sr were shown to reduce bone demineralization due to osteoporosis in animal studies. Bone Sr measurement was also demonstrated to improve the accuracy of human bone mineral content in dual x-ray absorptiometry (DXA) studies. \textit{In vivo} bone Sr measurements can be performed using x-ray fluorescence (XRF) methods. Human bone Sr detectability at low radiation doses was demonstrated in past XRF studies, but accurate Sr concentration determination from measurement remains elusive. The Sr content of superficial cortical bone from a lamb leg was probed using an optimal grazing-incidence XRF method developed in our lab. The lamb bone Sr concentration of 0.33 mg/g was determined using the XRF data from plaster-of-Paris samples doped with Sr. Further, the lamb bone and three overlying leather samples of 1.8-, 2.3-, and 2.5-mm thickness mimicked \textit{in vivo} human bone measurements. Analysis of XRF data indicated that Sr K$\beta $/K$\alpha $ ratio is a metric of soft tissue x-ray attenuation, a key ingredient in establishing a methodology for accurate bone Sr concentration measurements. [Preview Abstract] |
Saturday, October 30, 2021 11:48AM - 12:00PM |
M01.00005: The Problem of Time Nicholas Franco Classical Hamiltonian mechanics treats the time coordinate as a fixed background quantity. We can turn on gravity by introducing a dynamical metric, causing proper time to appear as an additional degree of freedom. But this additional degree of freedom ends up being a net of minus one degrees of freedom because it enforces two constraints. One of these, called the Hamiltonian constraint, ensures that the total energy of any gravitating system must remain precisely zero. If we canonically quantize gravity by imposing these constraints onto a wavefunction, the resulting wavefunction does not depend on time, since energy eigenstates do not evolve. We can conclude that quantum gravity does not approximate classical gravity, a serious problem given the experimental success of classical gravity. [Preview Abstract] |
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