Session C2: Intersection of Atomic, Particle and Nuclear Physics

Present status of the proton radius puzzle

Measurements of the Lamb shift in muonic hydrogen imply a proton size significantly smaller than previously indicated by hydrogen spectroscopy and electron scattering from protons. The present status of efforts to explain this situation will be reviewed with emphasis on the role of vacuum polarization.   

Numerical split-shift potential method for relativistic quantum systems with radial symmetry

We show how the spectrum of a radially symmetric Dirac-Hamiltonian can be computed rather accurately on a spatial grid based using a split-shift potential method. This method is sufficiently accurate such that the fine structure splittings of hydrogen-like relativistic ions with nuclear charge Z can be reproduced for a relatively small number of spatial radial grid points. We use this analytically known spectrum to examine the error scaling of this method. The method is then applied to examine the impact of a spatial confinement on the fine structure splittings and the bound states for hydrogen.   

Towards Entangled Atom Interferometry

Atom interferometry is an indispensable tool for ultra-precise metrology of electric, magnetic, and gravitational fields. The resolution available in the standard atom interferometric schemes is dictated by the standard quantum limit and it scales as $1/\sqrt{N}$, where $N$ is the total number of atoms passing through the interferometer. One can, in principle, increase this resolution by a factor of $\sqrt{N}$ if one is able to employ entangled atoms as opposed to uncorrelated atoms to achieve resolution that scales as $1/N$. It is, however, extremely difficult to obtain entangled states of atoms suitable for atom interferometry. In this presentation I intend to discuss the challenges and possible routes to developing entangled atom interferometry using tools of quantum optics that allow us precise control over atom-light interaction and possible applications of such schemes.   

The Sanford Underground Research Facility at Homestake

The Sanford Underground Research Facility, on the site of the former Homestake gold mine in Lead, South Dakota, is a dedicated research facility designed for the pursuit of rare-process physics research as well as research on topics in biology, geology, and other fields. The major laboratories for physics are located at the 4850-foot level (4300 m.w.e.). These include the LUX dark matter experiment and the MAJORANNA DEMONSTRATOR neutrinoless double-beta decay experiment at the Davis Campus and the CASPAR nuclear astrophysics accelerator facility and the Black Hills State University Underground Campus for low-background counting at the Ross Campus. Work is being done to prepare for future experiments at this level, most notably DUNE, the Fermilab-led international long-baseline neutrino program, and LUX-ZEPLIN, a next generation direct-detection dark matter experiment. SURF is a dedicated research facility with significant expansion capability.   

J/$\psi $ photo-production at RHIC using $\surd $s$_{\mathrm{NN}} \quad =$ 200 GeV Au$+$Au collisions

The exclusive coherent photo-production of J/$\psi $ mesons, $\gamma $A $\to $ J/$\psi $A, has been studied in $\surd $s$_{\mathrm{NN}} \quad =$ 200 GeV Au$+$Au collisions with the STAR detector at RHIC, with a photon-nucleus center of mass of energy range of [15 -- 35] GeV. The J/$\psi $ is identified via its electron and muon decay channels in the mid-rapidity region of the STAR detector. The analysis is based on an event sample corresponding to an integrated luminosity of about 1075 $\mu $b$^{\mathrm{-1}}$. The differential cross section d$\sigma $/dy is presented in the rapidity range, -1 \textless y \textless 1. Finally, the measurements are compared with theoretical predictions   

Relativistic Coupling between the Center of Mass and Internal Dynamics of a System

Einstein's well-known equation $E=mc^2$ suggests that the internal energy of a system should be included in the mass of the system. Pursuing this idea yields the coupling between the center of mass motion and the internal dynamics of the system, and its effects are examined through two examples, a spring-mass oscillator in a rocket and a two-level atom bound in an infinite potential well. As a result, it is revealed that the coupling causes time dilation of the internal dynamics and, in the quantum case, a loss of interference due to entanglement.   

Relativistic quantum mechanics of the real roots of the mass-energy-momentum relationship

The real roots of the Einstein mass-energy-momentum relationship are derived and explored for applicability to relativistic quantum mechanics. A formula for hydrogen-like atomic spectra is developed and the calculated energy levels are compared to the Dirac equation solution results.