Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session G08: Precision Tests of Physics Laws IRecordings Available
|
Hide Abstracts |
Sponsoring Units: GPMFC Chair: Shannon Hoogerheide, NIST Room: Juilliard |
Sunday, April 10, 2022 8:30AM - 8:42AM |
G08.00001: Status of the development of the LANL nEDM experiment Douglas Wong A nonzero permanent electric dipole moment of particles, atoms and molecules requires a violation of time reversal symmetry. At Los Alamos National Laboratory (LANL), a new experiment to search for the permanent electric dipole moment of the neutron is being developed. This experiment, based on Ramsey’s separated oscillatory field method at room temperature, will use ultracold neutrons (UCN) from the LANL UCN source. The sensitivity goal is 3x10-27 e-cm. In this talk, the status of the development will be presented. |
Sunday, April 10, 2022 8:42AM - 8:54AM |
G08.00002: UCNτ: An Experimental Method for High-Precision Determination of the Free Neutron Lifetime Adam T Holley, Daniel J Salvat The neutron is an unstable but long-lived neutral baryon, characteristics that conspire to make it a versatile laboratory for testing the Standard Model (SM) at the precision frontier. β-decay of the free neutron, for example, plays a central role in tests of symmetries that underlie fundamental particle interactions. τn, the mean lifetime for free neutron decay, is an interesting empirical target because, in combination with other β-decay observables, it can provide sensitive tests for physical phenomena not currently included in the SM. The interesting precision band for measurements of τn is between 0.1% and 0.01%, and current experimental techniques have demonstrated the capability to reach precisions in this range. A clear application of the resulting measurements is hampered by a nearly four-sigma discrepancy between the two prevalent techniques, called "beam" and "bottle," which could be due to a mundane experimental issue or itself an indication of new physics. Taken on its own, however, the most recent bottle result from UCNτ has for the first time demonstrated a level of precision sufficient to probe current theoretical understanding of neutron decay. We will describe the new UCNτ result and discuss the precision achieved in relation to tests of CKM matrix unitarity. |
Sunday, April 10, 2022 8:54AM - 9:06AM |
G08.00003: Energy Integrating Ratio Analysis of Muon Spin Precession Frequency Data in Fermilab Muon g − 2 Experiment Ritwika Chakraborty The new Fermilab Muon g − 2 experiment is currently taking data with the aim of experimentally determining the muon anomalous magnetic moment, aμ , with a final precision of 140 ppb. The energy integrating method is a new reconstruction approach in which the total energy of the decay positrons deposited in the electromagnetic calorimeters is continuously recorded. This reconstruction method for the muon spin precession frequency (ωa ) analysis is less sensitive to systematic bias arising from effects like pile-up and gain compared to the traditional method which reconstructs individual positron events. Furthermore, we employ a ratio histogramming procedure which mitigates the need for incorporating slow effects in the fit function. Combining the energy integrating reconstruction with the ratio histogramming provides a robust alternative way of determining ωa . In this talk we present an overview and a status update on the energy integrating ratio analysis of the precession frequency for the Run 2 and 3 datasets. |
Sunday, April 10, 2022 9:06AM - 9:18AM |
G08.00004: Ratio Method to Extract the Anomalous Muon Spin Precession Frequency in the Fermilab Muon g-2 Experiment Sean B Foster The Fermilab Muon g-2 Experiment published its first measurement of the muon magnetic anomaly in April 2021. This measurement, based on Run 1 data, achieved a precision of 0.46 ppm. It confirmed the Brookhaven measurement and pushed the discrepancy with the Standard Model theory prediction to 4.2 sigma. Run 1 accounts for just 6% of the total anticipated data, and analysis of Runs 2 & 3 data is ongoing. The additional statistics from these datasets, as well as improved treatments of systematic effects, is expected to improve the measurement's precision by a factor of two compared to Run 1. One of the measurement's key inputs, the anomalous muon spin precession frequency, is extracted from the time modulation of the decay-positron energy spectrum. One technique for performing this analysis, known as the Ratio Method, time shifts the positron counts to reduce sensitivities to slowly varying effects over the measurement period. This talk will motivate the Ratio Method, describe its methodology, highlight improvements since Run 1, and provide a preliminary look at blinded Runs 2 & 3 data. |
Sunday, April 10, 2022 9:18AM - 9:30AM |
G08.00005: Weighing the Axion with Muon Haloscopy Noah Bray-Ali The axion was introduced over forty years ago to explain the apparent symmetry of the strong nuclear force under time-reversal T and space inversion P. Later, it became a leading dark matter candidate when laboratory searches indicated its decay constant is large compared to the electroweak symmetry breaking scale. Yet, the most sensitive direct searches for axions in the local dark matter halo of the galaxy using radio-frequency electromagnetic cavities have yielded no positive results. In this talk we argue that measurements of the muon magnetic moment at the level of precision currently achieved using muon beams in storage rings can directly detect such axions in a couple runs provided the axion mass lies in the near-infrared regime and the beam cross-section can be increased to 10 cm2 while keeping fixed the number of muons in the beam. We give a symmetry argument that leads to a mass in this range provided axions form the bulk of the dark matter in the observable universe. Finally, we show that axions saturate the dark matter density in the local halo by evaluating their contribution to the T and P breaking decay of the long-lived neutral K meson into a pair of charged pions. |
Sunday, April 10, 2022 9:30AM - 9:42AM |
G08.00006: The TRIUMF UltraCold Advanced Neutron source and EDM experiment Wolfgang Schreyer The TUCAN collaboration is installing a new ultracold-neutron source using a superfluid-helium converter driven by a spallation source at TRIUMF’s proton cyclotron. Its world-leading ultracold-neutron-production rate will allow us to search for a neutron electric dipole moment with a sensitivity of 10-27 ecm, an improvement by one order of magnitude over the currently best limit. Such an electric dipole moment would be direct evidence for a new CP-violating mechanism beyond the Standard Model of particle physics and could explain the matter-antimatter asymmetry in the universe. |
Sunday, April 10, 2022 9:42AM - 9:54AM |
G08.00007: Machine Learning for Monte Carlo Simulation in the Fermilab Muon g-2 experiment Jun Kai Ng, Kim Siang Khaw, Cheng Chen, Yonghao Zeng, Tianqi Hu The Muon g −2 experiment at Fermilab aims to measure the muon magnetic anomaly 4 times more precise than the BNL E821 experiment. Geant4-based simulation package gm2ringsim has been developed to study the systematic errors arising from beam dynamics and detector acceptance. Gm2ringsim, while providing high-fidelity simulation needed for the experiment, is time-consuming and has limited the amount of dataset that can be produced for a systematic study. To provide an alternative solution, a "divide and conquer" approach is proposed where the typical Monte Carlo simulation is divided into beam and spin dynamics, muon decay, and positron detection. The last part which involves positron tracking and electromagnetic shower development in the calorimeter, is modeled using machine learning algorithms. In this presentation, I will present the status of this fast simulation together with a benchmark of the performance. |
Sunday, April 10, 2022 9:54AM - 10:06AM |
G08.00008: Beta-decay Paul Trap Mk. IV Commissioning Louis Varriano, Guy Savard, Jason A Clark, Nicholas D Scielzo, Daniel P Burdette, Mary T Burkey, Aaron T Gallant, Tsviki Y Hirsh, Brenden Longfellow The Beta-decay Paul Trap (BPT) at Argonne National Lab measures the beta-neutrino angular correlation coefficient aβν in the decay of Li-8 and B-8 to search for a tensor contribution to the weak interaction, a beyond-Standard Model possibility. The BPT has an ultimate measurement goal of 0.1% uncertainty in aβν. A new BPT Mk. IV has been built and will be commissioned in winter 2022 with Li-8. This new trap reduces systematic uncertainties associated with electron scattering and features other improvements. This talk will present the final design of the trap and results of the commissioning experiment, with preliminary expectations for new limits from a Li-8 data run in spring 2022. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700