Heavy ions Hadrons 19 Nuclear Physics, Heavy Ions, Hadrons 19 Nuclear physics 19 Physics 17 Quantum field theory 6 Elementary Particles, Quantum Field Theory 4 Particles (Nuclear physics) 4 Quantum Field Theories, String Theory 4 Spectrum analysis 4 String models 4 Microscopy 3 Particle Acceleration and Detection, Beam Physics 3 Particle acceleration 3 Spectroscopy and Microscopy 3 Astrophysics 2 Atoms 2 Atoms and Molecules in Strong Fields, Laser Matter Interaction 2 Characterization and Evaluation of Materials 2 Classical and Quantum Gravitation, Relativity Theory 2 Gravitation 2 Materials science 2 Matter 2 Measurement 2 Measurement Science and Instrumentation 2 Physical measurements 2 Applications of Graph Theory and Complex Networks 1 Astronomy 1 Astronomy, Astrophysics and Cosmology 1 Astrophysics and Astroparticles 1