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The crystal structure of the a form of octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine, commonly known as cyclotetramethylene-tetranitramine or a-HMX, has been determined by single-crystal X-ray methods. The unit cell is orthorhombic, space group Fdd2 with a=15.14, 5=23.89, c=5-913/~.There are eight molecules in the unit cell. The molecules have a basketlike shape with twofold symmetry. Bond lengths and angles all have normal values, but there are two rather short intermolecular C-O

A search for neutrinoless double-β decay (0νββ) in 136 Xe is performed with the full EXO-200 dataset using a deep neural network to discriminate between 0νββ and background events. Relative to previous Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 .

We have made time-of-flight neutron diffraction measurements on α-manganese metal. Powder diffraction measurements were made at 14 temperatures between 15 and 305 K, and single crystal measurements were made at 15 and 300 K. We found that the crystal structure of α-Mn is tetragonal below its Néel point of 100 K, with crystal symmetry I4̄2m and magnetic (Shubnikov) symmetry PI4̄21c. In agreement with the earlier results of Yamada et al., there are six independent magnetic atoms, and we found that their moments are weakly temperature dependent. The onset of magnetic order causes slight changes in the atomic positions and in the average atomic elastic constant.