Tue·May 17, 2022Tuesday·May 17, 2022

1. 01*

   Observation of the X17 anomaly in the ${}^7$Li($p$,$e^{+}{e}^{-}$)${}^8$Be direct proton-capture reaction

   N.J. Sas🇭🇺 · A.J. Krasznahorkay🇭🇺 · M. Csatlós🇭🇺 · J. Gulyás🇭🇺 · B. Kertész🇭🇺 · A. Krasznahorkay🇭🇺 · J. Molnár🇭🇺 · I. Rajta🇭🇺 · J. Timár🇭🇺 · I. Vajda🇭🇺 · M.N. Harakeh🇳🇱

   Angular correlation spectra of $e^{+}{e}^{-}$ pairs produced in the ${}^7$Li($p$,$\gamma$)${}^8$Be nuclear reaction have been studied at the sharp $E_p$= 441 keV resonance as well as at $E_p$= 650 keV, 800 keV and 1100 keV proton beam energies. The spectra measured at the resonance can be understood through the M1 internal pair creation process, but in the case of the off-resonance regions (direct proton capture) significant anomalies were observed in the $e^{+}{e}^{-}$ angular correlations supporting the X17 hypothetical particle creation and decay.

   nucl-ex23 citations
2. 02*

   Gaussian Processes and Bayesian Optimization for High Precision Experiments

   Max Lamparth🇩🇪 · Mattis Bestehorn🇩🇪 · Bastian Märkisch🇩🇪

   High-precision measurements require optimal setups and analysis tools to achieve continuous improvements. Systematic corrections need to be modeled with high accuracy and known uncertainty to reconstruct underlying physical phenomena. To this end, we present Gaussian processes for modeling experiments and usage with Bayesian optimization, on the example of an electron energy detector, achieving optimal performance. We demonstrate the method's strengths and outline stochastic variational Gaussian processes for physics applications with large data sets, enabling new solutions for current problems.

   ↳ physics.data-anhep-exnucl-ex4 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.