Heavy ion physics at CMS and ATLAS: hard probes

Hard probes are indispensable tools to study the hot and dense quark-gluonmatter created in ultra-relativistic heavy ion collisions. These probes arecreated in the collision itself with a small cross section, and they serve asindicators of various properties of the medium, such as temperature, viscosity,energy density, transport coefficients. Hard probes measured by the CMS andATLAS experiments at the LHC include highly energetic jets and chargedparticles, quarkonium states, and electroweak gauge bosons. An overview of thoserecent experimental results will be given that represent the path towards high-precision measurements, even in the challenging, high-multiplicity environmentcreated by colliding heavy ions.