Spring 2016

January 19 -

"Title: TBA"

Abstract:

January 26 -

"Title: TBA"

Abstract:

February 2 -

"Title: TBA"

Abstract:

February 9 - Nathan Harshman, American University

"Title: Five is Different: Symmetry, Solvability and Entanglement in Quantum Few-Body Systems"

Abstract: In quantum mechanics, one particle systems are "easy" to solve, and two particles are (technically) always solvable. Three and four particles are a lot harder, and five particles...fuhgettaboutit. But why? And why should we care? The second question is straightforward: phenomena in nuclear, atomic, molecular, and solid state systems can often be reduced to the properties of few-body systems. The increasingly precise measurement and control of ultracold atoms in optical traps allows predictions of few-body quantum theory to be tested as never before. Ultracold atoms could be the working material for new quantum technologies that exploit coherence and entanglement to perform efficient information processing. However, answering the first question "why is few body physics so hard" requires looking at how symmetry becomes less and less constraining as the number of particles increases, and finally completely fails (for most systems) at five particles.

Presentation: OCNPS 200 @ 3:00 pm

Refreshments: OCNPS Atrium @ 2:30 pm

All interested persons are cordially invited to attend.

February 16 - Doug Wells, South Dakota School of Mines and Technology

"Title: Uncertainties in Photonuclear Reaction Cross Sections and Why it Matters"

Abstract:Photonuclear reactions below the pion production threshold, with photons in either the entrance channel or the exit channel (or both), have been intensively studied since the late 1950s. The competitive advantage of real photons in exploring E1 excitation strength and decay channels and, to a lesser extent, E2 and M1 excitations, led to the systematic measurement and establishment of photonuclear sum rules for these low multipole excitations. Quantities such as integrated photo-absorption cross sections up to pion photo-production threshold, and the distribution of E1, E2 and M1 strength, are well established for many nuclei. However, there are large uncertainties in the cross sections and systematics of individual reaction channels, and the models that predict them, because of a dearth of measurements. Moreover, many stable isotope photo-nuclear cross sections are unmeasured or only measured over a small energy range. Yet, and perhaps most importantly, there are many proposed applications of photo-nuclear physics that require or would greatly benefit from well-measured cross sections of individual reaction channels. These range from radiation shielding and dosimetry, to radio-isotope production for medicine, to nuclear non-proliferation, homeland security and nuclear forensics, to photo-neutron sources for accelerator-driven subcritical systems (ADSS) The need for these photo-nuclear data can best be filled by a bright, CW photon source capable of high fluxes in the energy range from approximately 10 to 100 MeV. This presentation will focus on the photo-nuclear data gaps and how to fill them, the nuclear physics that such data would clarify, and the many nuclear applications that would benefit from these data.

Presentation: OCNPS 200 @ 3:00 pm

Refreshments: OCNPS Atrium @ 2:30 pm

All interested persons are cordially invited to attend.

February 23 - Sanjoy Mahajan, Olin College and MIT

"Title: The Art of Insight in Physics: Street-fighting tools for better teaching and thinking"

Abstract:With traditional science and mathematics teaching, students struggle with fundamental concepts. For example, they cannot reason with graphs and have no feel for physical magnitudes. Their instincts remain Aristotelian: In their gut, they believe that force is proportional to velocity. With such handicaps in intuition and reasoning, students can learn only by rote. I'll describe these difficulties using mathematical and physical examples, and illustrate how street-fighting mathematics and science---the art of insight and approximation---can improve our thinking and teaching, the better to handle the complexity of the world.

Presentation: OCNPS 200 @ 3:00 pm

Refreshments: OCNPS Atrium @ 2:30 pm

All interested persons are cordially invited to attend.

March 3 - Curtis Mobley, Sequoia Scientific, Inc., Joined colloquium with the Department of Ocean, Earth & Atmospheric Sciences

"Title: Improved Ocean Ecosystem Modelilng via Improved Optics"

Coupled hydrodynamical-biological-optical ocean ecosystem models are playing an increasingly important role understanding the oceans at regional to global spatial scales and daily to decadal temporal scales. Existing models often use very sophisticated treatments of the hydrodynamics and increasingly sophisticated biology, but still grossly oversimplify the optics. However, extremely fast radiative transfer codes now allow accurate light calculations within ecosystem models. Initial simulations for an idealized 3D upwelling-downwelling geometry show near-surface chlorophyll increases of tens of percent after only two weeks when accurate light calculations replace the approximate irradiance models currently used for photosynthesis and heating. Surface heating of the water is consequently greater, with less heating at depth, which increases thermal stratification. Model run times increase by less than 30% when accurate light calculations are used.

Presentation: OCNPS 200 @ 3:00 pm

All interested persons are cordially invited to attend.

March 15 - Michael Kong, Old Dominion University (CANCELLED)

"Title: TBA"

Abstract:

March 22 - Swapan Chattopadhyay, Northern Illinois University and Fermilab

Title: "Accelerator R&D at Fermilab: Towards Precision Neutrino and Muon Experiments"

Abstract: I will present the current plans for high intensity proton accelerator development at Fermilab - both PIP-II accelerator complex as a driver in the near term towards the long-baseline neutrino experiment DUNE (Deep Underground Neutrino Experiment) as well as research and development on IOTA ( Integrable Optics Test Accelerator) as a test storage ring to enable future "smart booster" developments to go beyond PIP-II for multi-Megawatt proton beams for even higher intensity long baseline neutrinos. At the foundation are the basic understanding of various intensity limitations e.g. particle loss and beam instabilities as well as fundamentals of accelerators based upon integrable and near-integrable nonlinear dynamics and advanced phase-space control techniques. We will also touch upon two major precision experiments on the horizon in near future using muons: the "g-2" experiment to explore the anomalous magnetic moment of muons and the "Mu-2-e" experiment for exotic decays of muons, both experiments having implications beyond the Standard Model of particle physics

March 29 - Ani Aprahamian, University of Notre Dame

Title: "The origin(s) of the heavy elements and what can nuclear physics say about it?"

Abstract: The NRC report ``Connecting Quarks to the Cosmos'' identified eleven of the most challenging open questions for all of physics in the 21st century. One of these eleven questions includes the identification of the site(s) for the production of the heaviest elements found in nature. Most of the elements above Fe are thought to have been produced by either the slow (s-process) or rapid (r-process) capture of neutrons in astrophysical environments. The s-process proceeds close to stability and astrophysical sites have been identified, while the r-process allows the production of nuclei much further from stability and potential sites remain unresolved.
Nuclear masses, beta-decay rates, and neutron-capture cross-sections play an important role in identifying the astrophysical constraints for a possible site for the r-process. Many of the nuclei that may be involved in an r-process lie far from stability and themselves present a challenge and impetus to experimental nuclear physics. The challenge is predominantly in the development of new facilities that can reach ever more exotic nuclei and the associated detection developments and techniques to detect ever fewer events in difficult measurements. Nuclear mass models and mass measurements have a pivotal role in both the impetus side of experiments and the simulation/constraint side of astrophysical site calculations. We have recently reported1 on the sensitivities of the r-process to nuclear masses, n-capture rates, beta-decay rates, and beta delayed neutron emission probabilities under various astrophysical trajectories. These sensitivity studies have now for the first time have been carried out with the propagation of an individual mass uncertainty in a correlated way. We identify key nuclei in the study whose mass has a substantial impact on final r-process abundances and thereby set strict constraints on the astrophysical trajectories that have been considered while highlighting the nuclei that could be measured at existing and future radioactive beam facilities.

April 5 - Stepan Stepanyan, JLab/ODU

Title: "J/Ψ production at JLAB"

Abstract: Since its discovery in 1974, ground state charmonium, J/Ψ-meson, has been subject of detail studies in fixed target and collider experiments. The mass and the width have been measured with high precision. Many decay modes have been examined and branching ratios measured. However, there are still unanswered questions that are waiting resolution from experiments. Upgraded facilities at Jefferson lab will provide beams of electrons and photons with enough energy and luminosity to allow for firm answers to some these questions. Particular interest for these experiments is the study of J/Ψ production near threshold region, the exact mechanism of which is yet unknown. Since there are no charm quarks in the nucleon, the photoproduction of J/Ψ probes gluonic field of the target, important quantity that is difficult to access in any other way.

In this talk, after a brief summary of discovery and experimental studies of J/Ψ, planned experiments at Jefferson lab will be discussed. Experiment E12-12-001 with CLAS12 in experimental Hall-B will measure J/Ψ in e+e- decay mode and will study production mechanism from the threshold, 8.2 GeV, to 11 GeV. This experiment is also in a good position to search for and study hidden charm pentaquarks recently discovered by LHCb at CERN.

Presentation: OCNPS 200 @ 3:00 pm

Refreshments: OCNPS Atrium @ 2:30 pm

All interested persons are cordially invited to attend.

April 12 -

Title: "TBA"

April 21 - Senior Thesis Presentations

Old Dominion University Department of Physics

Physics Undergraduate Seniors' Day

Senior Thesis Presentations
Scale-Up Room OCNPS 142-144

Senior Thesis Presenters

Caleb Fogler
"Setup of the BoNuS RTPC Drift Time Experiment"

Alan Anderson
"Investigation of Multi-Cell Superconducting Crabbing Cavity for Jefferson Lab Electron-Ion Collider"

Joshua Monroe

"Forward Tracking with the JLab EIC Detector Concept"

Ian Reed
"Investigation of Soluble and Insoluble Salts on Moore Drive Bridge, Rochester, NY"

Robert Conn
"Ion Beam Polarization Monitoring in the Electron Ion Collider at Jefferson Lab"

Presentation: OCNPS 142-144 @ 2:50 - 4:15 pm.

Refreshments: OCNPS First floor Atrium @ 2:30 - 2:45 pm.

All interested persons are cordially invited to attend.