Erratum: Quantum Bipolaron Superconductivity from Quadratic Electron-Phonon Coupling [Phys. Rev. Lett. 132, 226001 (2024)].

This corrects the article DOI: 10.1103/PhysRevLett.132.

Dark-Sector Search via Pion-Produced η and η^{'} Mesons Decaying Invisibly in the NA64h Detector.

We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar η and η^{'} mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV π^{-} on nuclei of an active target as the source of neutral mesons. The η,η^{'}→invisible events would exhibit themselves via a striking signature-the complete disappearance of the incoming beam energy in the detector.

Selenium Transfer from Secondary Phosphine Selenides to Aminoacetylenic Ketones: Access to 1,2-Dihydro-3-pyrrole-3-selones with a Stable C═Se Bond.

Secondary phosphine selenides were found to react with γ-aminoacetylenic ketones (80-85 °C, MeCN, 17-40 h) to afford 1,2-dihydro-3-pyrrole-3-selones in 48-80% yields, products of unprecedented selenium transfer from the P═Se bond to replace the carbonyl oxygen and to form dihydro-3-pyrrole-3-selones having a C═Se bond stable under ambient conditions.

The diamond-silicon carbide composite Skeleton as a promising material for substrates of intense X-ray beam optics.

The paper considers the possibility of using the diamond-silicon carbide composite Skeleton with a technological coating of polycrystalline silicon as a substrate for X-ray mirrors used with powerful synchrotron radiation sources (third+ and fourth generation). Samples were studied after polishing to provide the following surface parameters: root-mean-square flatness ≃ 50 nm, micro-roughness on the frame 2 µm × 2 µm σ ≃ 0.15 nm.