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 L05: Weak Decays |
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Chair: Alexis Mercenne, Louisiana State University Room: Hilton Waikoloa Village Queens 4 |
Friday, December 1, 2023 9:00AM - 9:15AM |
L05.00001: Precision Beta-Decay Studies in the Mirror Systems of 8Li and 8B Aaron T Gallant, Mary T Burkey, Guy Savard, Nicholas Scielzo, Jason A Clark, Maxime Brodeur, Daniel Burdette, Tsviki Y Hirsh, Kay Kolos McCubbin, Bernhard Maass, Scott T Marley, Peter Mueller, Dipanwita Ray, Kevin Siegl, Kumar S Sharma, Louis Varriano The weak interaction of the Standard Model is well-described by a vector-axial vector, or ‘V-A’, structure, which reproduces both maximal parity violation and left-handed neutrinos in beta-decay. However, there is no first-principles reason that other the interactions, such as scalar (S) or tensor (T), may not be present. Tensor currents were searched through a measurement of the beta-neutrino angular correlation coefficient abn in the beta-delayed alpha decays of 8Li and 8B. These decays were studied with the Beta-decay Paul Trap (BPT) at the ATLAS facility of Argonne National Laboratory. The BPT traps a cloud of ions at rest in a volume of ~1 mm3 for extended periods of time, allowing for a backing-free measurement of the emitted particles. The trapping volume is surrounded by segmented, 1mm thick DSSDs, from which the decay kinematics can be fully constrained by a b-a-a triple coincidence measurement. This enables both a nearly background-free measurement of the b-n angular correlation coefficient abn. We will present the first measurement of abn in 8B and a novel method to constrain CT and C’T in the decay of mirror systems. |
Friday, December 1, 2023 9:15AM - 9:30AM |
L05.00002: Experimental Measurement of Isospin Symmetry Breaking in 47K Beta Decay Brian Kootte, Dan G Melconian, JOZEF KLIMO, James McNeil, John A Behr, Alexandre Gorelov, Brayden M Vargas-Calderon, Hannah Gallop
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Friday, December 1, 2023 9:30AM - 9:45AM |
L05.00003: Ab initio calculations of nuclear structure corrections of super-allowed Fermi transitions Petr Navratil, Michael Gennari, Chien Yeah Seng, Mikhail Gorshteyn, Mack C Atkinson, Mehdi Drissi, Kostas Kravvaris, Guillame Hupin, Sofia Quaglioni CKM unitarity is a sensitive probe of the Standard Model. The top row unitarity is dominated by the Vud matrix element which is most cleanly extracted from nuclear Fermi β decays. The most recent data-driven analyses of measurements suggest a 2σ−3σ discrepancy [1-2]. Several theoretical corrections are required to extract the Vud and, in fact, the current uncertainty in Vud extracted from Fermi transitions is dominated by theory. We perform ab initio calculations of nuclear structure corrections δNS and δC for the 10C→10B Fermi transition that suffer from substantial uncertainties. We apply the no-core shell model (NCSM) [3] to calculate the δNS with the nuclear Green’s function obtained using the continued fraction Lanczos algorithm [4] and NCSM with continuum (NCSMC) [5] to calculate the δC using the recently introduced NCSMC β-decay formalism [6]. We will report preliminary results for the δNS and report our progress towards the δC calculation. Our approach is also applicable to 14O→14N Fermi transition as well as to transitions in light sd shell nuclei. |
Friday, December 1, 2023 9:45AM - 10:00AM |
L05.00004: Precision Half-life Measurement of 33Cl Patrick O'Malley, Maxime Brodeur For the past decade our understanding of fundamental symmetries has really been expanded thanks to new precision measurements. Of particular interest is that the extraction of Vud from superallowed pure fermi decays has shown that the CKM matrix may not be unitary. To confirm this result, an international campaign is underway to extract Vud using precise determinations of ft values for superallowed mixed transitions between mirror nuclides. Calculation of ft values requires the half-life, branching ratio, and Q value. The 33Cl decay half-life is derived from a series of old measurements. The life-time was determined counting β particles from the decay of the implanted 33Cl. The 33Cl beam was produced via the 32S(d, n) transfer reaction and separated by the TwinSol facility of the Nuclear Science Laboratory of the University of Notre Dame. The progress on the 33Cl analysis will be presented. |
Friday, December 1, 2023 10:00AM - 10:15AM |
L05.00005: A new structure for nucleus of elements that could explain the radioactivity of radioactive elements Gh. Saleh Although in the helium nucleus, neutrons and protons are facing each other pairwise, but in terms of height, protons are lower than neutrons. This arrangement of neutrons and protons in the helium nucleus is a logical, balanced, symmetrical structure with sufficient stability for its nucleus. So, its structure could be explained. |
Friday, December 1, 2023 10:15AM - 10:30AM |
L05.00006: Systematic Uncertainty due to Energy Reconstruction and Scattering in Beta Asymmetry Experiments Albert Young An analysis of sources of systematic uncertainty associated with conventional beta asymmetry experiments such as UCNA and PERKO III will be presented, focusing on effects associated with beta energy reconstruction and scattering. The impact of conventional calibration strategies using conversion line sources, sensitivity to hardware energy thresholds and some aspects of scattering will be analyzed, focusing on strategies for reducing systematic uncertainty in next generation experiments. Some aspects of the impact of energy reconstruction uncertainties on the sensitivity to Fierz terms will also be presented. |
Friday, December 1, 2023 10:30AM - 10:45AM |
L05.00007: Beta-Neutrino Angular Correlation Measurements for Mixed Mirror Nuclei with St. Benedict Regan Zite, Tan Ahn, Dan W Bardayan, Maxime Brodeur, Daniel Burdette, Jason A Clark, Aaron T Gallant, Driss Guillet, Alicen M Houff, James J Kolata, Biying Liu, Patrick O'Malley, William S Porter, Ryan Ringle, Fabio Rivero, Guy Savard, Adrian A Valverde Precision beta-decay measurements offer unique insight into the electroweak part of the Standard Model through a variety of tests including the unitarity of the Cabbibo-Kobayashi-Maskawa (CKM) quark mixing matrix. A reliable unitarity test of the CKM matrix requires a precise and accurate value of Vud. Recent theoretical improvements of the transition-independent radiative corrections have shown a roughly 3σ tension with unitarity [1]. Hence, there is currently a strong effort aimed at testing and improving other theoretical corrections entering in the determination of the Vud matrix element. The Superallowed Transition BEta- NEutrino Decay Ion Coincidence Trap (St. Benedict), currently under construction at the Nuclear Science Laboratory (NSL) at the University of Notre Dame falls in that vein as it aims to measure the beta-neutrino angular correlation parameter for superallowed mixed mirror beta decays in order to extract Vud in more of these transitions. St. Benedict will achieve this using several elements including a large volume gas cell, a differentially pumped chamber containing both a radio-frequency carpet and a radio frequency quadrupole (RFQ) ion guide, an RFQ cooler and buncher and a Paul trap. Background, motivation, and the first planned measurements for St. Benedict will be presented. This work is supported by the National Science Foundation under grant numbers PHY-1725711, 2011890, as well as the University of Notre Dame. |
Friday, December 1, 2023 10:45AM - 11:00AM |
L05.00008: Improvements in the analysis of radiative decay channels in the PEN experiment Charles J Glaser The PEN collaboration, an international collaboration led by the University of Virginia, has sought to measure Γ(π→eν(γ))/Γ(π→μν(γ)) to relative precision of 5 × 10-4 or better. This measurement provides a key confirmation of the V-A nature of the electroweak interaction and serves as a sensitive probe to physics beyond the Standard Model, manifested in lepton non-universality. Radiative decays, π→eνγ and μ→eννγ are integral parts of the signal for the decay of interest πe2 and the normalizing μ→eνν decay. We report on advances in controlling the systematics associated with these radiative decay channels, as well as in controlling backgrounds that mask or mimic the radiative decay channels, e.g., split electromagnetic shower photons. |
Friday, December 1, 2023 11:00AM - 11:15AM |
L05.00009: The St. Benedict facility for precise measurements of nuclear beta decays: Developments and Commissioning William S Porter, Maxime Brodeur, Daniel Burdette, Jason A Clark, Aaron T Gallant, Driss Guillet, Alicen M Houff, Biying Liu, Patrick D O'Malley, Fabio Rivero, Guy Savard, Adrian A Valverde, Regan Zite Precise measurements of nuclear beta decays provide a unique insight into the Standard Model due to their connection to electroweak interactions. These decays can provide constraints on the unitarity or non-unitarity of the Cabbibo-Kobayashi-Maskawa (CKM) quark mixing matrix, where non-unitarity would signal potential physics beyond the Standard Model. The most precise of these tests involves the matrix element Vud as determined from superallowed pure Fermi beta decays, and indicates a deviation from unitarity on the order of ~3σ . As such, cross-checks from additional methods, including superallowed mixed mirror beta decays, are necessary. Vud precision from mirror decays is currently limited by the absence of precise Fermi-to-Gamow Teller mixing ratios, which are most sensitively determined via the angular correlation of the neutrino and beta particle emitted during the decay. At the Nuclear Science Laboratory (NSL) at the University of Notre Dame, the Superallowed Transition Beta-Neutrino Decay Ion Coincidence Trap (St. Benedict) is being constructed to determine the beta-neutrino angular correlation parameter of various mirror decays. We plan on measuring this correlation parameter for the beta decays of nuclei ranging from 11C to 41Sc using radioactive ion beams from the NSL’s TwinSol separator, which will result in significantly improved precision of the Vud element of the CKM matrix from superallowed mirror transitions. The status of the development and commissioning of St. Benedict, including its beam preparation and measurement stages, will be presented. |
Friday, December 1, 2023 11:15AM - 11:30AM |
L05.00010: Abstract Withdrawn |
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