lichen and h5hep: moving toward a ROOT-less workflow for HEP analyses

High-Energy Physics (HEP) analyses are almost entirely performed using ROOT which contains everything from its own file format to HEP-specific classes to plotting utilities. This monolithic structure means that most internal aspects of ROOT are optimized by hiding much of the inner workings and by keeping users in this walled garden. Python has become a dominant interface or “glue” language for both HEP and non-HEP science and there are multiple python interfaces to ROOT. But these are just other portals to this walled garden. In order to move away from ROOT and interface more organically with the broader python ecosystem, we developed h5hep, a file format that builds upon the widely-used HDF5 and mimics the ROOT file functionality, and lichen, a set of tools that provide basic plotting and fitting utilities familiar to HEP analysts. Both modules make use of standard python libraries so installation is trivial. While these libraries have primarily been used for education and outreach we suggest that they could also be useful for data preservation, open data analyses, and perhaps bioinformatics. Speed, memory, and file size performance will be presented and compared to the analogous ROOT applications.