``Experimental Study of the Time Reversal Invariance in Polarized Epithermal Neutron Optics (J-PARC E99 : NOPTREX)''

The visibility of parity violating effects in nuclear interactions is extremely enhanced in the resonant neutron absorption via compound nuclear states for some of medium-heavy nuclei. The enhancement is explained as a result of the interference between parity-unfavored partial amplitudes of the compound nuclear process, which is referred to as "s-p mixing". The "s-p mixing" is expected to enhance the visibility of the effect of the breaking of both parity and time-reversal symmetry (P-odd T-odd).
Based on these consideration, an experimental approach to search for the P-odd T-odd effects to activate a novel type of new physics search beyond the standard model is in progress using the pulsed neutron beam from the pulsed spallation neutron source of Japan Proton Accelerator Research Complex (J-PARC) under the collaboration "Neutron Optical Parity and Time-Reversal EXperiment (NOPTREX)" as the program number J-PARC P99. P-odd T-odd effects will be studied in neutron optics in which fake T-violating effects can be controlled, with the enhanced sensitivity biased to chromo-EDM. We discuss the studies of the "s-p mixing" in 139La(n,gamma)140La and the plan of T-violation search with polarized lanthanum target.
(We also introduce other neutron fundamental physics on-going at the J-PARC.)

``Electroweak interactions of nuclei''

Abstract: Electroweak interactions provide us with wonderful opportunities and challenges in nuclear physics, and this colloquium focuses on three recent advances regarding the modeling, computation, and understanding of such processes. (i) The neutron distribution of atomic nuclei can be probed via elastic neutrino scattering and via parity-violating electron scattering. Such experiments test virtual Z-boson exchange at very low momentum transfers and the inferred size of the neutron distribution (when compared with easy-to-measure charge distribution) constrains the nuclear equation of state, linking nuclei to neutron stars. (ii) Beta decays of nuclei happen at slower rates than what is expected from the beta decay of the free neutron. Ab initio computations of such processes show that this “quenching” of beta-decay rates is due to two-body currents and correlations, i.e. interaction effects between the decaying neutron and nearby nucleons. (iii) Neutrino-less double beta decay is probed world wide in experiments that search for physics beyond the standard model. If observed, a nuclear matrix element connects the lifetime of this decay with the neutrino-mass scale. The colloquium presents the challenges and advances in computations of this matrix element. 

``The Electron-Ion Collider : The Next QCD Frontier''

The Electron-Ion Collider (EIC) is a pioneering new particle accelerator that will be built on the current site of the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. It will provide high energy collisions of polarized electrons with polarized protons and ions, allowing for experiments that probe the nature of strong interactions to unprecedented precision. The EIC Project has grown and evolved rapidly since the official launch by the U.S. Department of Energy in 2020. This talk will discuss the primary physics themes driving the EIC effort, the recent milestones achieved by the project and the efforts to establish two complementary detectors at adjacent interaction regions. 

Dr. Kyle Leach

Associate Professor

Department of Physics

Colorado School of Mines

Host: Korsch

Title: Hunting for Ghosts using Rare-Isotope Doped Superconducting and Optomechanical Sensors

Abstract: Nuclear beta and electron capture (EC) decay serve as sensitive probes of the structure and symmetries at the microscopic scale of our Universe. As such, precision measurements of the final-state products in these processes can be used as powerful laboratories to search for new physics from the meV to TeV scale. Significant advances in “rare isotope” availability and quality, coupled with decades of sensing technique development from the AMO community have led us into a new era of fundamental tests of nature using unstable nuclei. For the past few years, we have taken the approach of embedding radioisotopes in thin-film superconducting tunnel junctions (STJs) to precisely measure the recoiling atom that gets an eV-scale “kick” from the neutrino following EC decay. These recoils are encoded with the fundamental quantum information of the neutrino and decay process, as well as carrying unique signatures of weakly coupled beyond standard model (BSM) physics; including neutrino mass, exotic weak currents, and potential “dark” particles created within the energy-window of the decay. These measurements provide a complimentary and (crucially) model-independent portal to the dark sector with sensitivities that push towards synergy between laboratory and cosmological probes. In this talk, I will discuss the broad program we have developed to provide leading limits in these areas as well as the technological advances across several sub-disciplines of science required to enable this work, including subatomic physics, quantum engineering, atomic theory, and materials science. Finally, I will discuss future prospects of extending this work using macroscopic amounts of harvested exotic atoms from the Facility for Rare Isotope Beams (FRIB) in optically levitated nanospheres for direct momentum measurements of the decay recoils.

Dr. Jeyhan Kartaltepe

Associate Professor

Rochester Institute of Technology

School of Physics and Astronomy

Host: Sanders

Title: Pushing the Edge of the Cosmic Frontier with JWST

Abstract: The James Webb Space Telescope (JWST) launched in December 2021, first started collecting data in June 2022,  and is already revolutionizing our understanding of the distant Universe. With its large segmented mirror, and optimization for infrared wavelengths, JWST was designed to detect and characterize some of the first galaxies to form in our universe and investigate how galaxies then evolve over the age of the Universe to the present day. In this talk, I will present how JWST has pushed our cosmic frontier beyond what was possible with Hubble and share some early results from extragalactic deep surveys and their implications for our understanding of the early universe.

Miguel Arratia

Assistant Professor

Department of Physics and Astronomy

University of California-Riverside

Host: Renee Fatemi

Title: Jet Tomography of the Proton and Its Enabling Technologies

Recent theoretical advances have elevated jet studies in electron-proton scattering as a powerful new method for investigating the proton's quantum phase-space density, a core focus of the upcoming Electron-Ion Collider (EIC). As construction of the EIC progresses, reexamining data from its precursor, HERA, becomes invaluable, especially in light of new theoretical frameworks. In this colloquium, I will present our latest measurements of jets and their substructure at HERA, which have pioneered the use of a key AI/ML technique enabling much higher dimensional measurements. I'll also discuss ongoing R&D efforts in high-granularity calorimetry, enabled by advances in silicon-photomultiplier technology, essential for future jet analyses at the EIC.Abstract: 

Rosi Reed

Associate Professor

Lehigh University

Department of Physics

Host: Renee Fatemi

Title: Golden Age of Jet Tomography in Heavy Ion Collisions: The Evolution of Jets as Probes of the Quark Gluon Plasma

Abstract: The strong nuclear force, or quantum chromodynamics (QCD), remains one of the most enigmatic of the four fundamental forces of nature due to its rich structure and many emergent properties. The collision of heavy ions at ultra-relativistic speeds gives rise to a remarkable medium known as the quark gluon plasma (QGP). In this extreme state of QCD matter, protons and neutrons dissolve into partons - quarks and gluons - creating a nearly perfect liquid.  A fundamental question is whether quasi-particles exist in this medium, given the incredibly low viscosity over entropy ratio.  Answering questions regarding the evolution of the QGP structure, and the connection to QCD, requires probes with extremely small spatial resolution. Enter the particle jets created in high momentum transfer parton-parton collisions. These jets, produced early in the heavy-ion collision evolution, traverse the newly formed QGP and lose energy in a process called jet quenching, which modifies the final state properties of the resultant jets.  Understanding the mechanisms of jet quenching will allow the determination of QGP transport coefficients and thus lead to a better understanding of QCD.  The path-length dependence of the jet energy loss is one way to better understand the underlying mechanisms, though it has proven challenging to derive explicit values for the path-length dependence from experimental data.  We can gain critical insights into the nature of the QGP at both the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), to determine the temperature dependence, and system-size dependence of many jet observables.  In this presentation, I will discuss the latest Solenoidal Tracker at RHIC (STAR) experimental jet results, including a new measurement of the azimuthal asymmetry of jets in Ruthenium and Zirconium collisions, and compare these results with similar results from the LHC experiments, as well as the potential outlook for measurements with the newly built sPHENIX detector.  I will compare these results to recent advances in theory and connect them to other heavy ion jet measurements such as photon jet correlations and measurements of the structure of the jets themselves.

Prof. Robert Stamps

Department of Physics and Astronomy

University of Manitoba

Host: Lance DeLong and Todd Hastings

Title: Spin Vision: Using Artificial Spin Ice to Study Complex Systems

Abstract: Artificial Spin Ice is the name given to a class of metamaterials that are used as models for frustrated systems. In these models, frustration is introduced through competing interactions in a mesoscopic-scale array of interacting particles. Their experimental realization using nanomagnets as the interacting particles was first demonstrated in 2006 and opened a new field of study for frustrated systems. [1] As models in experiment, Artificial Spin Ice facilitate detailed observation in real time with high spatial resolution of complex out of equilibrium dynamics and thermodynamic processes. This flexibility underwrites their use in fundamental studies of a variety of nonlinear dynamics and ordering phenomena in low dimensions. 

Recent advances in fabrication now enable creation of complex two- and three-dimensional structures that have opened new possibilities for structural design and exciting new potentials for application in practical devices. [2] In this talk, a new cross-discipline direction for research that can benefit from Artificial Spin Ice models is explored. Motivated by studies of neural network models used in the analysis of experiments on primate vision, [3,4] a new type of three-dimensional Artificial Spin Ice geometry is proposed for implementation of a biologically plausible neuroscientific model called ‘active inference’. [5] Cast in the form of nanomagnetic spin geometries that can be studied experimentally, the approach can be used to facilitate a physics-based understanding of how complex systems might spontaneously generate a type of Bayesian filtering.

To achieve this, novel mechanisms for the control of magnetic states and ordering processes using three-dimensional geometries are required and different strategies are discussed. [6,7] A rudimentary ‘smart ASI’ is described whose design is based on state optimization principles assumed in some models used to describe general neurological processes.

1. RF Wang et al., Nature 439, 303 (2006).
2. SH Skjærvø, CH Marrows, RL Stamps, LJ Heyderman, Nature Reviews Physics 2, 13 (2020).
3. M Falconbridge, RL Stamps, DR Badcock, Neural Computation 18, 415 (2006).
4. M Falconbridge, RL Stamps, M Edwards, DR Badcock, i-Perception (in press).
5. RA Adams, E Aponte, L Marshall, KJ Friston, J. Neuroscience Methods 242, 1 (2015).
6. VM Parakkat, GM Macauley, RL Stamps, KM Krishnan, Physical Review Letters 126, 017203 (2021).
7. RB Popy, J Frank, RL Stamps, Journal of Applied Physics 132, 133902 (2022).

Tracy Webb

Associate Professor

Department of Physics

McGill University

Host: Yuanyuan Su

Title: Witnessing the evolution of the most massive galaxies in the densest regions of the universe

Abstract: An understanding of the formation and evolution of massive galaxies is a forefront goal of astrophysics today, observationally and theoretically. While we generally understand structure growth in the context of CDM hierarchical structure formation, and indeed this idea has been highly successful, new observations have shown that baryonic physics plays a key role. Indeed, the complex physics of galaxy-galaxy mergers, large scale gas cooling, and AGN feeding and feedback drive the evolution of massive galaxies. Given that at any given cosmic epoch the most massive galaxies tend to be found in over dense regions of the universe, one way to observationally find and study these systems is through a search for such peaks. In this talk I will describe, after introducing the field, an ongoing observational program to understand the evolutionary growth of massive galaxies that sit at the centres of giant galaxy clusters. With a focus on key systems and multiwaveIength data, I will argue that we do not yet fully understand how these giant beasts build up their stellar mass, but that progress is being made through efforts to push our observations to earlier epochs with new tools. 

Jeyhan Kartaltepe

Associate Professor

School of Physics and Astronomy

Rochester Institute of Technology

Host: Ryan Sanders

Title: TBA

Abstract: TBA