The cross section of the reaction ${}^{197}\mathrm{Au}$($n,\gamma$) was measured with the time-of-flight technique at the n_TOF (neutron time-of-flight) facility in the unresolved resonance region between 5 and 400 keV using a pair of ${\mathrm{C}}_6$D${}_6$ (where D denotes ${}^2\mathrm{H}$) liquid scintillators for the detection of prompt capture $\gamma$ rays. The results with a total uncertainty of $3.9\%–6.7$ $\%$ for a resolution of 20 bins per energy decade show fair agreement with the Evaluated Nuclear Data File Version B-VII.0 (ENDF/B-VII.0), which contains the standard evaluation. The Maxwellian-averaged cross section (MACS) at 30 keV is in excellent agreement with the one according to the ENDF/B-VII.0 evaluation and 4.7$\%$ higher than the MACS measured independently by activation technique. Structures in the cross section, which had also been reported earlier, have been interpreted as being due to clusters of resonances.

We use fits to recent published CPLEAR data on neutral kaon decays to \pi^+\pi^- and \pi e\nu to constrain the CPT--violation parameters appearing in a formulation of the neutral kaon system as an open quantum-mechanical system. The obtained upper limits of the CPT--violation parameters are approaching the range suggested by certain ideas concerning quantum gravity.We use fits to recent published CPLEAR data on neutral kaon decays to $\pi~+\pi~-$ and $\pi e\nu$ to constrain the CPT--violation parameters appearing in a formulation of the neutral kaon system as an open quantum-mechanical system. The obtained upper limits of the CPT--violation parameters are approaching the range suggested by certain ideas concerning quantum gravity.We use fits to recent published CPLEAR data on neutral kaon decays to π + π − and πeν to constrain the CPT-violation parameters appearing in a formulation of the neutral kaon system as an open quantum-mechanical system. The obtained upper limits of the CPT-violation parameters are approaching the range suggested by certain ideas concerning quantum gravity