Conveners
Tests of Symmetries and the Electroweak Interaction: Parallel 1
- Jason fry (Eastern Kentucky University)
Tests of Symmetries and the Electroweak Interaction: Parallel 9
- William Terrano (ASU)
Tests of Symmetries and the Electroweak Interaction: Parallel 5: Joint Symmetries-EW/HF-CKM
- Fred Wietfeldt (Tulane University)
Tests of Symmetries and the Electroweak Interaction: Parallel 6
- Jason fry (Eastern Kentucky University)
Tests of Symmetries and the Electroweak Interaction: Parallel 8: Joint with HF-CKM
- Paul Huffman (North Carolina State University)
We discuss model-independent contributions to the electron EDM, focusing on those contributions emerging from a heavy scalar sector linearly realized. To provide a concrete new-physics realization, we investigate the aligned 2HDM in the decoupling limit. We point out that logarithmically-enhanced contributions generated from Barr-Zee diagrams with a fermion loop are present in the aligned...
A next generation cryogenic neutron electric dipole moment (EDM) experiment based on an idea to combine ultracold neutron (UCN) production in superfluid 4He with real-time measurement of the precession frequency using the capture of polarized neutrons on polarized 3He. A previous version of the experiment utilizing the Fundamental Neutron Physics Beamline (FnPB) at the Oak Ridge National...
Ultracold neutrons (UCNs) are an ideal tool to measure the fundamental properties of neutrons, like their electric dipole moment (EDM). A non-zero neutron EDM would be an indication of CP violation beyond the Standard Model and provide a possible explanation of the observed matter-antimatter asymmetry in the universe. However, these searches are limited by the number of UCNs that are delivered...
The Superconducting Array for Low Energy Radiation (SALER) experiment aims to search for BSM electroweak physics by precisely measuring the eV-scale recoiling nucleus following beta decay of short-lived neutron deficient nuclei. To do so, SALER couples a superconducting precision sensor array to the ReA3 beamline at the Facility for Rare Isotope Beams. During beam delivery, isotopes of...
Electric Dipole Moments, or EDMs, are a clean signature of Charge Parity, or CP violation. Measurements of EDMs in different atoms and molecules correspond to different sources of CP violation. This makes measuring multiple EDMs in different mediums important. One of the best atoms to measure is Ra-225, due to the octupole deformation in its nucleus. This gives it an enhancement factor on the...
Nuclear Schiff moments (NSMs) present a hadronic signature of new physics through their connection to CP-symmetry violation. Such symmetry violations are needed to explain the observed baryon asymmetry of the Universe. We are investigating the application of molecular matrix methods[1] to the search for NSMs of pear-shaped nuclei in heavy polar radioactive molecules[2]. Pear-shaped nuclei...
The baryon asymmetry of the universe (BAU) is not sufficiently explained by the Standard Model requiring Beyond Standard Model (BSM) extensions to account for the discrepancy between the observed and predicted BAU. New sources of combined charge-parity (CP) symmetry violation are required to account for this discrepancy. Permanent electric dipole moments (EDMs) and nuclear Schiff moments...
The Nab experiment, currently taking data on the Fundamental Neutron Physics Beamline at the ORNL Spallation Neutron Source, uses an unpolarized neutron beam to precisely measure two of the free neutron beta decay correlation parameters to probe physics beyond the Standard Model. The electron-neutrino correlation coefficient, a, will give us access to investigate CKM unitarity, and the Fierz...
The primary goal of the PNab experiment is to provide a high precision value for the axial coupling constant, gA, in neutron decay through measurement of angular correlations in the decay of polarized neutrons. The precision goal for the axial coupling constant is roughly the 0.02% for PNab, about a factor of two more precise than the highest precision measurements to date. A measurement at...
The electroweak interaction in the Standard Model is described by a pure vector–axial-vector structure, though other Lorentz-invariant terms could also contribute. Recent high-precision measurements of beta decays in 8Li and 8B have imposed stringent constraints on the potential contributions from Lorentz-invariant tensor currents in weak interactions. One of the significant sources of...
The neutron lifetime is a precision observable of the Standard Model probing the CKM matrix element |V_{ud}| and beyond the Standard Model physics. For nuclear beta decay, in the region of small electron velocity or the limit of large nuclear charge Z, a Fermi function is used to account for enhanced perturbative effects. In this talk, I will present the derivation of the quantum field...
The magneto-gravitational trap at Los Alamos National Laboratory traps Ultracold Neutrons (UCN) for various holding periods. The free neutron lifetime is measured by detecting the UCN surviving beta decay at the end of each holding period in the trap. The experiment has yielded the world’s most precise neutron lifetime of 877.75 ± 0.28$_{stat}$ + 0.22 – 0.16$_{sys}$ s without the large...
BL3 is a next-generation beam neutron lifetime experiment with the intent to 1) explore, cross check, and reduce all systematic uncertainties in the beam method to the 10-4 level; and 2) reduce the neutron lifetime uncertainty from the beam method to <0.3 s. The project received funding in 2022 and subsystems are now being developed and constructed. The apparatus will be integrated offline in...
Unique forbidden β-decays have recently emerged as powerful probes of physics beyond the Standard Model, providing increased sensitivity to exotic weak interactions and right-handed couplings, and are now the focus of growing experimental efforts in the US and internationally. In this talk, I will present our recent study revealing that radiative corrections enable unique forbidden decays at...
Bhabha scattering will be one of several e+e- reactions available at the JLab fixed target, polarized e+ facility, and will arguably be the easiest to cleanly measure. Rates will be high enough to measure asymmetries with ppm level uncertainties. What physics can we then explore? Because the Higgs-electron coupling to the electron is highly suppressed by the small electron mass, the s-channel...
The Fermi function F(Z,E) accounts for QED corrections to beta decays that are enhanced at either small electron velocity β or large nuclear charge Z. For precision applications, the Fermi function must be combined with other radiative corrections and with scale- and scheme-dependent hadronic matrix elements. We formulate the Fermi function as a field theory object and present a new...
Radiative corrections from nuclear structure effects are a key theoretical input to precision extractions of $V_{ud}$ from superallowed $0^{+}\hspace{-2pt}\rightarrow 0^{+}$ beta decays, and currently limit the sensitivity of CKM unitarity tests to new physics. We present a formalism to compute two-body transition densities in medium-mass nuclei using deformed coupled-cluster theory and its...
Proton-proton fusion (pp-fusion), in which two protons fuse to form a deuteron and emit a positron and neutrino, is a critical process in the life and death of stars and thus understanding it is essential for stellar simulations. However, due to the dominant Coulomb repulsion at energies much less than the nucleon mass like those found in the cores of stars, experimental measurements of the...
Tests of the Standard Model and beyond with unitarity of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix have recently received attention in view of an apparent deficit in the first row: $|V_{ud}|^2+|V_{us}|^2+|V_{ub}|^2-1=-0.15(6)\%$. At the current precision level, the element $V_{ub}$ is too small to be relevant, so that the unitarity constraint reduces to the two-flavor Cabibbo pattern....
