Well, there's also nuclear physics in the ultrarelativistic energy regime, i.e., heavy-ion research, and there some of the most interesting questions are asked, e.g., where does the mass of the matter surrounding us (and we are made of) come from, and the answer is not the Higgs field, which makes only about 2% of the mass; the rest is due to the strong interaction and not very well understood yet. Another question to be answered is about the equation of state of hot and dense strongly interacting matter, including phase (or cross-over) transitions between a partonic (quark-gluon plasma) and hadron-resonance gas phase, how everything is related to confinement and chiral symmetry (and its breaking), how to understand neutron stars, including neutron-star mergers and gravitational-wave signals related to them (maybe being announced in October by LIGO/Virgo), supernova explosions, and what not. Related is also the question about the processes creating the heavy elements in the universe going on not only in stars during their usual lifecylce (leading to the elements up to iron) but also in supernova explosions and neutron-star mergers, involving neutron-rich nuclei which can only be investigated in heavy-ion facilities.
Such research is going on for quite some decades now. At the moment active are the Relativistic Heavy Ion Collider at the Brookhaven National Lab on Long Island, at the LHC@CERN, and at GSI (Helmholtz Center for Heavy Ion Research) in Darmstadt, Germany. There a new accelerator is built up in the new Facility for Antiproton Ion Research, FAIR. Another one under construction is the Nuclotron-based Ion Collider fAcility (NICA) in Dubna, Russia and one more planned at JPARC in Japan. Here are some links to these labs:
https://www.bnl.gov/rhic/
http://aliceinfo.cern.ch/Public/Welcome.html
https://www.gsi.de/en/about_us.htm
https://www.gsi.de/en/researchaccelerators/fair.htm
http://nica.jinr.ru/
https://j-parc.jp/index-e.html