# Bulletin of the American Physical Society

# 2020 Fall Meeting of the APS Division of Nuclear Physics

## Volume 65, Number 12

## Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA

## Session DP: Mini-Symposium: Hadronic Weak Interactions I |
Hide Abstracts |

Chair: Jason Fry, EKU |

Friday, October 30, 2020 8:30AM - 9:06AM |
DP.00001: Fundamental Symmetry Violations in Nuclear Systems Invited Speaker: Jared Vanasse Parity violation in nuclear systems offers a unique probe of QCD, while time-reversal violation in nuclear systems is a potential path for discovering physics beyond the Standard Model due to the smallness of Standard Model time-reversal violation in nuclear systems. Parity (P) and parity and time-reversal (PT) violating interactions in nuclear systems can be systematically understood through the use of effective field theories, which are model independent and allow for theoretical error estimation. At low energies P and PT violating interactions are each described by a separate set of five low energy constants (LECs). These LECs must either be calculated from lattice QCD or extracted from experiment. To cleanly extract these LECs experiments should be performed on few-body nuclear systems for which P and PT violating processes can be calculated with minimal uncertainty. In this talk I will discuss the current theoretical and experimental landscape for determination of these P and PT violating LECs. In addition I will discuss recent developments in the use of the large-$N_C$ expansion in QCD to estimate the relative size of these LECs and its guidance in further experimental efforts. [Preview Abstract] |

Friday, October 30, 2020 9:06AM - 9:18AM |
DP.00002: Anapole Moments of Light Nuclei from Ab Initio Theory Petr Navratil Measurements of the nuclear spin dependent parity violating effects provide an opportunity to test nuclear models and to search for new physics beyond the Standard Model. Molecules possess closely spaced states with opposite parity which may be tuned to degeneracy to enhance the observed parity violating effects. An improved measurement of such effects with an unprecedented sensitivity using light triatomic molecules composed of light elements Be, Mg, N, and C is in preparation [1]. We applied the no-core shell model (NCSM) [2] to calculate anapole moments of $^{\mathrm{9}}$Be, $^{\mathrm{13}}$C, $^{\mathrm{14,15}}$N and $^{\mathrm{25}}$Mg needed for interpretation of this experiment. The only input for the NCSM calculations is the chiral Effective Field Theory two- and three-nucleon interaction and the parity-violating nucleon-nucleon interaction derived within the meson exchange theory [3]. The NCSM results differ from the predictions of the standard single-particle model and highlight the importance of including many-body effects in the calculations. [1] E. B. Norrgard \textit{et al}., Commun. Phys. \textbf{2}, 77 (2019). [2] B. R. Barrett, P. Navratil, and J. P. Vary, Progress in Particle and Nuclear Physics \textbf{69}, 131 (2013). [3] B. Desplanques, J. F. Donoghue, and B. R. Holstein, Annals of Physics \textbf{124}, 449 (1980). [Preview Abstract] |

Friday, October 30, 2020 9:18AM - 9:30AM |
DP.00003: Parity violation in two-nucleon systems from pionless effective field theory Son Nguyen At leading order, there are five independent nucleon-nucleon parity-violating (PV) interactions at low energies, corresponding to the five leading low energy constants (LECs) that mix $S$-wave and $P$-wave channels. These have been studied in the framework of pionless effective field theory (EFT). In this talk, we present our analysis of the higher-order contributions that occur at three derivatives. These correspond to $P$-$D$ transitions as well as corrections to $S$-$P$ transitions. We show that the renormalization group (RG) behavior of the PV LECs in pionless EFT is driven by the RG scaling of parity-conserving LECs. Under certain assumptions, this constrains the higher order LECs and may reduce the number of experiments needed to understand low energy PV. [Preview Abstract] |

Friday, October 30, 2020 9:30AM - 9:42AM |
DP.00004: NOPTREX: A Precision Measurement of the Parity Violation in the 0.7 eV Resonance in $^{139}$La Danielle Schaper One of the motivations to search for new physics Beyond the Standard Model (BSM) is to understand the baryon asymmetry present in the Universe, namely the discrepancy between the theoretical prediction of the baryon asymmetry based on the SM and the value obtained through observations of the cosmic microwave background. The Neutron OPtics Time Reversal EXperiment (NOPTREX) Collaboration seeks to measure signatures of parity-odd (P-odd) and time-reversal-symmetry-odd (T-odd) interactions in polarized neutron-polarized nucleon interactions. However, preliminary measurements must be made in order to choose a desirable target nucleus for this experiment; one such condition is that the ideal target nucleus contains resonances which have a large amount of parity violation (PV) present. From 2017-2019, the NOPTREX collaboration ran an experiment at the Los Alamos Neutron Science CEnter (LANSCE) facility to characterize the PV present in the 0.7 eV resonance in $^{139}$La to high (1\%) precision. This talk will focus on the experimental setup [1] as well as the subsequent data analysis process to extract the parity violation asymmetry. // $[1]$ D. C. Schaper et al., Nucl. Instrum. Methods Phys. Res. A \textbf{969}, 2020. [Preview Abstract] |

Friday, October 30, 2020 9:42AM - 9:54AM |
DP.00005: A Proposed Search for Time Reversal Violation in Polarized Neutron Transmission Through Polarized $^{117}$Sn Jonathan Curole We describe work towards an experimental search for a P-odd and T-odd term in the polarized neutron-polarized nucleus forward scattering amplitude [1] on the 1.33 eV p-wave resonance in $^{117}$Sn, which exhibits a $10^{5}$ amplification of P-odd amplitude. $$ \frac{\Delta \sigma _{PT}}{\Delta \sigma _{P}}= \kappa (J) \frac{W}{V} $$ This formula relates the P-odd T-odd over P-odd amplitude ratio $W/V$ to the ratio $\sigma_{PT} \over \sigma_{P}$ of the P-odd T-odd to P-odd cross sections, and a spectroscopic parameter $\kappa(J)$ involving the partial neutron resonance widths in the $J=I \pm 1/2$ channels. We present a reevaluation of ($\vec{n}$,$\gamma$) angular distribution from the resonance [2] which implies a large, nonzero value for $\kappa$ that controls the T-odd sensitivity. The $I=1/2$ $^{117}$Sn nucleus can be polarized with a technique known as SABRE which we will describe. [3] \newline References \newline [1]V. P. Gudkov, Physics Reports 212, 77 (1992).\newline [2]Vo Van Tkhuan Yu. D. Mareev L.B. Pikelner I.M. Frank A.S. Khrykin V.P. Alfimenkov, S.B. Borzakov and E.I. Sharapov. Pis’maZh. Eksp. Teor. Fiz., 39(8):346–348, 1984.\newline [3]A.M. Olaru, A. Burt, P.J. Rayner, S.J. Hart, A.C. Whitwood, G.G.R. Green, S.B. Duckett Chem. Commun. 52 14482 2016 [Preview Abstract] |

Friday, October 30, 2020 9:54AM - 10:06AM |
DP.00006: "Bulk" Hyperpolarized $^{131}$Xe with $P_{Xe}\sim 7\%$: a Potential Target for Neutron Optics Searches for Time-Reversal Invariance Violation Boyd Goodson The very large parity-odd asymmetry seen in the 3.2 eV p-wave resonance in $^{131}$Xe [1,2] makes it an interesting nucleus for NOPTREX. However this isotope is notoriously difficult to hyperpolarize owing to its strong nuclear quadrupole moment. We investigate the bulk preparation of hyperpolarized $^{131}$Xe via spin exchange optical pumping (SEOP). Isotopic enrichment and next-generation spectrally-narrowed laser diode arrays allow for real-time observation of polarization dynamics via in situ low-field NMR, and optimization as a function of temperature, alkali metal choice (Rb and Cs), resonance offset, and other parameters. $^{131}$Xe polarization values as high as 7.6$\%$$\pm$1.5$\%$ were achieved at 0.37 amagat in a ~0.1 L cell ($8.5\times10^{20}$ $^{131}$Xe spins), demonstrating feasibility for use in spin-polarized neutron-scattering targets. Ongoing efforts to scale up $^{131}$Xe SEOP to aluminosilicate cells with larger volumes for use in measurements of pseudomagnetic precession of polarized neutrons will also be described. [1] J. J. Szymanski, W. M. Snow et al., Phys. Rev. C 53, R2576 (1996). [2] V. Skoy et al., Phys. Rev. C 53, R2573 (1996). [Preview Abstract] |

Friday, October 30, 2020 10:06AM - 10:18AM |
DP.00007: Sensitivity of The NOPTREX experiment to Axion-like Particles William Snow The NOPTREX collaboration proposes to conduct searches for parity-odd and time-reversal-odd neutron-nucleus interactions on certain p-wave resonances in heavy nuclei where symmetry-breaking amplitudes are known to be amplified by several orders of magnitude [1]. A true null test of T is possible for this type of forward transmission polarized neutron optical observable [2]. Axion-like particles (ALPs) appear in several extensions of the Standard Model and can generate a P-odd and T-odd neutron-nucleus interaction. We compare the sensitivity of NOPTREX and electric dipole moment measurements to ALPs, which are not connected to the usual Peccei-Quinn axions. [1] V. P. Gudkov, Phys. Rep. 212, 77 (1992). [2] J. D. Bowman and V. P. Gudkov, Phys. Rev. C 90, 065503 (2014). [Preview Abstract] |

## 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