Test of nuclear decay rate variation due to an antineutrino flux

Background: Unexplained variations of the decay rate parameter for weak interaction decays such as ${\ensuremath{\beta}}^{\ifmmode\pm\else\textpm\fi{}}$ decay, electron capture, well strong $\ensuremath{\alpha}$ have been reported. Because these presented by a number groups, at various locations, using types detectors, different isotopes, and over extended periods time, some researchers interpreted source not from ambient environmental factors temperature, pressure, humidity but via an unexplained fundamental interaction.Purpose: The state experiments is reviewed, reported results are placed into common comparable context defining phenomenological cross section. Then we make measurements function time level ${10}^{\ensuremath{-}5}$ in presences antineutrino flux with on-off cycle $\ensuremath{\approx}$30 days. This precision requires detailed understanding both systematic statistical errors; otherwise, errors measurement may mimic events interactions.Methods: experiment searched variation $_{25}^{54}\mathrm{Mn}$, ${e}^{\ensuremath{-}}$ capture $_{55}^{137}\mathrm{Cs}$, ${\ensuremath{\beta}}^{\ensuremath{-}}$ to 1 part $\ensuremath{\approx}{10}^{5}$ comparing difference between presence $\ensuremath{\approx}3\ifmmode\times\else\texttimes\fi{}{10}^{12}$ $\overline{\ensuremath{\nu}}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{s}}^{\ensuremath{-}1}$ no measurements. was located 6.53 m reactor core High Flux Isotope Reactor Oak Ridge National Laboratory. Two decays, one other were selected because final reverse each contain neutrino antineutrino, covering arguments that interact differently or all cases.Results: $\ensuremath{\gamma}$ spectra collected analyzed independently. measured parameters found be $\ensuremath{\delta}\ensuremath{\lambda}/\ensuremath{\lambda}=(0.034\ifmmode\pm\else\textpm\fi{}1.38)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ $_{25}^{54}\mathrm{Mn}$ $\ensuremath{\delta}\ensuremath{\lambda}/\ensuremath{\lambda}=(0.67\ifmmode\pm\else\textpm\fi{}1.56)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ $_{55}^{137}\mathrm{Cs}$. These consistent measurable due flux, yielding $68%$ confidence upper limit sensitivity $\ensuremath{\delta}\ensuremath{\lambda}/\ensuremath{\lambda}\ensuremath{\le}1.31\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ $\ensuremath{\sigma}\ensuremath{\le}1.29\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}25}$ ${\mathrm{cm}}^{2}$ section $_{55}^{137}\mathrm{Cs}$ $\ensuremath{\delta}\ensuremath{\lambda}/\ensuremath{\lambda}\ensuremath{\le}2.23\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ $\ensuremath{\sigma}\ensuremath{\le}5.69\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$.Conclusions: cross-section obtained null observable effect $\ensuremath{\approx}{10}^{4}$ times more sensitive than past reporting positive $^{54}\mathrm{Mn}$ $^{137}\mathrm{Cs}$.