Bulletin of the American Physical Society
6th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Sunday–Friday, November 26–December 1 2023; Hawaii, the Big Island
Session M03: Time-Reversal Invariance Violation |
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Chair: Chen-Yu Liu, University Illinois Urbana-Champaign Room: Hilton Waikoloa Village Kings 3 |
Friday, December 1, 2023 2:00PM - 2:15PM |
M03.00001: Designing a Chopper Configuration to Improve the Sensitivity of the nEDM@SNS Experiment Rhett A Croley The Baryonic Asymmetry of our Universe has been a source of intrigue for more than fifty years. Unable to reconcile this disparity with the standard model, physicists have sought answers through beyond- standard- model probes. One such measurement is the search for the neutron electric dipole moment (nEDM), which may identify the source of the CP violation needed to satisfy theories seeking to explain the existence of our universe. The nEDM@SNS experiment being conducted at Oak Ridge National Laboratory will use the techniques of Golub and Lamoreaux to measurement the nEDM with unprecedented precision. The measurement is based on the detection of scintillation light created as ultra-cold neutrons (UCNs) are captured on polarized He-3. UCNs are generated by down-scattering neutrons inside a measurement cell containing superfluid He-4. All neutrons coming down the beam line have the potential to scatter inside the measurement cells and produce background processes that obscure our measurements, but only those in a narrow wavelength (energy) slice near 8.9 Angstrom (1.0 meV) will produce the UCNs we need. Choppers periodically block neutron transmission, and we will use them to select only useful neutrons from the total beam. Through use of the McStas ray-tracing software and independent Monte Carlo simulations, we found an ideal setup using a two-chopper configuration making use of the existing Fundamental Physics Beamline chopper drive trains and two new narrow opening wheels rotating at different speeds. |
Friday, December 1, 2023 2:15PM - 2:30PM |
M03.00002: Development of a novel comagnetometer for high-precision measurement of the electron's electric dipole moment using laser-cooled francium atoms Shintaro Nagase, Hiroki Nagahama, Keisuke Nakamura, Motoki Sato, Teruhito Nakashita, Mirai Fukase, Shiko Kumahara, Kota Abe, Yasuhiro Sakemi In this presentation, the current status of a comagnetometer which is dedicated to search for the permanent electric dipole moment of the electron (eEDM) using francium (Fr) wll be discussed. The dominant error factors are Zeeman shift caused by the fluctuation of the static magnetic field and vector light shift caused by the ellipticity of the laser light forming the optical lattice in measuring the eEDM with laser-cooled Fr atoms. The designed comagnetometer consists of laser-cooled Rb-87 and Cs-133 atoms trapped simultaneously in the optical lattice at the same region where Fr atoms are trapped and a stable magnetic field is produced by superconducting coils in order to observe the effects of Zeeman shift and vector light shift independently. This is expected to increase the measurement precision of the eEDM, consequently allows to search for the CP violation with high precision. |
Friday, December 1, 2023 2:30PM - 2:45PM |
M03.00003: Light collection system calibration of the nEDM@SNS experiment using cosmic muons Jordan S O'Kronley The neutron Electric Dipole Moment experiment at the Spallation Neutron Source (nEDM@SNS) is a novel experiment that aims to push the upper limit of the measured nEDM down to $2-3 imes 10^{-28} ecdot cm$. In order to achieve this, precise calibration of the light collection system has to be performed. In the nEDM@SNS experiment, neutrons are captured by ${}^3He$ which deposits energy into the surrounding superfluid helium which produces a burst of photons. Depending on where this capture event happens in the measurement cell of the nEDM@SNS experiment, a slightly differing number of photons can be detected. By using a pair of detectors called the Mini Muon Trackers (MMTs) developed at LANL, cosmic muons can be tracked as they travel through and scintillate in different locations around the measurement cell. By tracking cosmic muons, we can calibrate the light collection system of the nEDM@SNS experiment. This talk will discuss the ongoing work with refurbishing MMTs along with the simulation of cosmic muons interacting with the measurement cell of the nEDM@SNS experiment. |
Friday, December 1, 2023 2:45PM - 3:00PM |
M03.00004: Ongoing Experiment to Measure the Parity-Odd Asymmetry in the 0.73 eV Neutron Resonance of 139La Using a Polarized 3He Neutron Spin Filter Jorge G Otero Munoz, William M Snow, Kylie A Dickerson, Clayton J Auton Sensitive searches for new sources of time reversal violation in and among nucleons are one of the highest scientific priorities in nuclear/particle/astrophysics. The NOPTREX collaboration proposes a sensitive search for a time-reversal odd (T) and parity-odd (P) term in the neutron-nucleus forward scattering amplitude on the 0.734 eV p-wave resonance in 139La. The 0.7 eV p-wave resonance in 139La can amplify both P-odd and T-odd effects from mixing of s-wave and p-wave resonances [1], and a null test of T is possible for this observable [2]. In preparation for the P-odd T-odd experiment, we are currently conducting a precision measurement of the P-odd asymmetry on the 0.734 eV p-wave resonance in 139La. While a measurement of the P-odd asymmetry has been recently completed to some degree [3], we have already found ways to improve the previous measurement by introducing a new 3He polarizer for much larger (>70%) neutron polarization and a NaI gamma detector array to be used simultaneously with our previous 6Li neutron transmission detector. We describe our experimental design and approach which can achieve a measurement of the P-odd asymmetry to <1%. |
Friday, December 1, 2023 3:00PM - 3:15PM |
M03.00005: Abstract Withdrawn
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Friday, December 1, 2023 3:15PM - 3:30PM |
M03.00006: Advancing EDM searches with ultracold molecules at FRIB Xing Wu Searches for non-zero electric dipole moment (EDM) in fundamental particles shed light on discrete symmetries of nature and constrain new physics beyond the Standard Model. The most sensitive electron EDM and many ongoing nuclear EDM searches are performed with molecules, benefiting from the substantial intra-molecular electric field. At the Facility for Rare Isotope Beams (FRIB), we are building a new generation of EDM searches using ultracold molecules. This project will leverage the unique opportunity to access pear-shaped nuclei (e.g. 225Ra) at FRIB, and the state-of-the-art technology in precision measurement and quantum control of polar molecules. The former further amplifies the Nuclear Schiff Moment thanks to the nuclear octupole deformation, and hence the sensitivity to hadronic CP-violation. The latter, built upon recent advances in atomic and optical physics, aims to bring the 225Ra-containing molecules into the ultracold regime, where both high phase-space density and seconds-long spin precession time have been demonstrated. With the nuclear enhancement and the quantum upgrades combined, this new project envisions to enhance the EDM sensitivity by orders of magnitude from the current best effort. |
Friday, December 1, 2023 3:30PM - 3:45PM |
M03.00007: Fundamental neutron physics at the Spallation Neutron Source Wolfgang Schreyer Free neutrons offer a unique way of probing fundamental properties in subatomic physics. Precision measurements with neutrons have a long history of constraining parameters in the Standard Model of particle physics and theories beyond. With the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor, Oak Ridge National Lab provides two of the most intense sources of free neutrons and offers unique opportunities for new and more precise studies. |
Friday, December 1, 2023 3:45PM - 4:00PM |
M03.00008: Spin transport coils for the nEDM@SNS experiment. Cory A Smith The neutron electric dipole moment is sensitive to BSM physics and is a probe of baryogenic processes. The nEDM@SNS experiment aims to lower the current measured bound on the nEDM by almost two orders of magnitude. The nEDM@SNS experiment relies on polarized He-3 as a comagnetometer and analyzer of the neutron spin precession. Polarized He-3 is introduced into the precession cell from an atomic beam source outside the apparatus's passive magnetic shield. This requires a system of electromagnetic transport coils to maintain polarization as the He-3 travels to the precession chamber. I will describe design, fabrication, and testing of these coils at the University of Kentucky. |
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