Is MgB2 a Superconductor? Comment on “Evidence against Superconductivity in Flux Trapping Experiments on Hydrides under High Pressure” [J. E. Hirsch and F. Marsiglio in J. Supercond. Novel Magn. 35, 3141 (2022)]

Hirsch and Marsiglio, in their recent publication (J. Supercond. Novel Magn. 35, 3141 (2022)), assert that experimental data on the trapping of magnetic flux by hydrogen-rich compounds clearly demonstrate the absence of superconductivity in hydrides at high pressures. We argue that this assertion is incorrect, as it relies on the wrong model coupled with selective manipulations (hide/delete) of calculated datasets and ignores the reference measurements after the release of pressure. A critical examination of the authors´ claim of having performed fitting of experimental data to the model reveals that, in fact, the authors conducted simulations where all free parameters were fixed. Furthermore, the authors have restricted the publication of their simulation code, which we view as a breach of scientific integrity and open science principles. Importantly, an application of the Hirsch–Marsiglio model to MgB2 leads to the conclusion that it is not a superconductor.