Speaker
Description
This journal-club-style coverage of published results of "Fundamental Symmetries and Interactions in Nuclei" since INPC2022 will leave out exciting experiments in progress. References will be in the slides. The speaker is showing his own work in a parallel session.
Parity:
The weak changed current in low- and medium-energy experiments has been mostly, but not entirely, explained by vector and axial vector Lorentz-transforming currents to precision part per thousand. E.g. LHC p+p -> e + missing Etransverse shows no events above background, which after EFT analysis excludes most Lorentz currents exchanging high-mass bosons.
A significant discrepany of the neutron beta-neutrino correlation experiment aSPECT can be explained by a Lorentz tensor interaction coupling to wrong-handed nu's, in tension with recent A=8 beta decay Paul trap results consistent with SM. Isospin-breaking 2nd-class currents can depend on nucleus, perhaps explaining such discrepancies, although lower-mass charged degrees of freedom are strongly constrained indirectly by observables like the running of alpha with energy.
New nuclear beta decay techniques seek to measure energy distortions of the beta spectrum from production of wrong-helicity beta's. Spectroscopy using cyclotron radiation (CRES) of the beta's has first results in PRL.
A PRL of no-core shell model with continuum calculations of nuclear virtual excitation better defines radiative corrections to Vud, where theory improvements suggest a significant SM discrepancy. Progress understanding the Nolen-Schiffer anomaly in isobaric mirror masses from strong interaction isospin breaking is producing possible additional tests of the isospin breaking in the critical wavefunction overlap calculation.
The weak neutral current is the main prediction of the SM. Deviations can be due to many things, including new particles coupling to nuclei. Observation by the COHERENT collaboration of stopped pion decay nu scattering from active detectors tests the weak neutral current strength. Interpreting atomic parity violation in cesium requires resolution of recent experimental discrepancies between two atomic physics methods. A relativity-produced M1 transition recently measured in francium atoms tests similar many-body calculations. The 2018 np -> d gamma 2 sigma unique evidence of weak neutral currents in nuclei lies outside the allowed timescale.
Time Reversal: (generally motivated by Sakharov's mechanism for matter-antimatter asymmetry, though the extra CP violation does not have to be observable now)
T odd, P odd TOPO:
J\=0 atomic EDM's (sensitive to electron EDM and semileptonic interactions involving nuclei) have reached similar null precision in HfF+ and ThO. Ambitious new neutron EDM searches have recent progress.
J=0 EDM 199Hg maintains the most precise null measurement, with Yb atomic trap methods becoming becoming competitive. Schiff moment and magnetic quadrupole moment experiments are publishing progress. Theory efforts to quantify the required nuclear matrix elements of difficult operators like sigma dot p are making progress. Recent creative phenomenology is clarifying sensitivity in abundant stable rare earth nuclei that do not have static octupole deformation-caused parity doublets but may have some degree of virtual octupole effects.
T odd, parity even TOPE: NOPTREX neutron scattering is progressing with sensitivity complementary to TOPO EDM's.
Pseudo-T violation in Decays: [Entangled K meson production allows true reversal of initial and final states PLB 2023, uniquely together with entangled B meson PRL 2012]. Final-state effects are likely under control for ambitious pseudo-time reversal beta decay test MORA. There is TOPE sensitivity in isospin-hindered beta decay.
The first new CP violation in 50 years in nu sector may have critical nucleus-dependent contributions, but along with double beta decay and sterile nu constraints from 7Be EC will hopefully be covered by others.
