Mon·Apr 3, 2023Monday·April 3, 2023

1. 01*

   Search for an interaction mediated by axion-like particles with ultracold neutrons at the PSI

   N. J. Ayres🇨🇭 · G. Bison🇨🇭 · K. Bodek🇵🇱 · V. Bondar🇨🇭 · T. Bouillaud🇫🇷 · E. Chanel🇨🇭 · P.-J. Chiu🇨🇭 · B. Clement🇫🇷 · C. B. Crawford🇺🇸 · M. Daum🇨🇭 · C. B. Doorenbos🇨🇭 · S. Emmenegger🇨🇭 and 35 other authors

   We report on a search for a new, short-range, spin-dependent interaction using a modified version of the experimental apparatus used to measure the permanent neutron electric dipole moment at the Paul Scherrer Institute. This interaction, which could be mediated by axion-like particles, concerned the unpolarized nucleons (protons and neutrons) near the material surfaces of the apparatus and polarized ultracold neutrons stored in vacuum. The dominant systematic uncertainty resulting from magnetic-field gradients was controlled to an unprecedented level of approximately 4 pT/cm using an array of optically-pumped cesium vapor magnetometers and magnetic-field maps independently recorded using a dedicated measurement device. No signature of a theoretically predicted new interaction was found, and we set a new limit on the product of the scalar and the pseudoscalar couplings $g_s{g}_p{\lambda }^2<8.3\times 10^{-28}{\text{m}}^2$ (95% C.L.) in a range of $5\mu \text{m}<\lambda <25\text{mm}$ for the monopole-dipole interaction. This new result confirms and improves our previous limit by a factor of 2.7 and provides the current tightest limit obtained with free neutrons.

   nucl-exNew J.Phys.(2023)·8 citations
2. 02*

   Detecting Nanometer-Scale New Forces with Coherent Neutron Scattering

   Zachary Bogorad🇺🇸 · Peter W. Graham🇺🇸 · Giorgio Gratta🇺🇸

   Significant effort has been devoted to searching for new fundamental forces of nature. At short length scales (below approximately 10 nm), the strongest experimental constraints come from neutron scattering from individual nuclei in gases. The leading experiments at longer length scales instead measure forces between macroscopic test masses. We propose a hybrid of these two approaches: scattering neutrons off of a target that has spatial structure at nanoscopic length scales. Such structures will give a coherent enhancement to small-angle scattering, where the new force is most significant. This can considerably improve the sensitivity of neutron scattering experiments for new forces in the 0.1 - 100 nm range. We discuss the backgrounds due to Standard Model interactions and a variety of potential target structures that could be used, estimating the resulting sensitivities. We show that, using only one day of beam time at a modern neutron scattering facility, our proposal has the potential to detect new forces as much as two orders of magnitude beyond current laboratory constraints at the appropriate length scales.

   ↳ hep-phhep-exnucl-exPRD(2023)·8 citations
3. 03*

   Interaction of solar neutrinos with ${}^{98,100}$Mo isotopes and the influence of nuclear resonances

   Yu. S. Lutostansky🇷🇺 · A. N. Fazliakhmetov🇷🇺 · G. A. Koroteev🇷🇺 · V. N.Tikhonov🇷🇺 · A. Yu. Lutostansky🇷🇺 · N. V. Klochkova🇷🇺 · A. P. Osipenko🇷🇺 · N. A. Belogortseva🇷🇺 · E. Yu. Zemskov🇷🇺

   The process of neutrino interaction with ${}^{98}$Mo and ${}^{100}$Mo isotopes is studied taking into consideration the effect of charge-exchange resonances. The experimental data on the strength functions $S(E)$ obtained in charge-exchange reactions $(p;n)$ and ${(}^3\mathrm{He},t)$ and the strength functions $S(E)$ calculated within the theory of finite Fermi systems were used. We studied the effect of the resonance structure of $S(E)$ on the cross sections for solar-neutrino. We investigated the contribution of each high-lying resonance to the capture cross section $\sigma (E_{\nu })$. The contributions of all components of the solar neutrino spectrum are calculated. We estimate the contribution of different components of solar neutrinos as the background for the double-beta decay experiments on ${}^{100}$Mo.

   ↳ nucl-thnucl-ex0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.