At Duke, Johns Hopkins, Fermilab and the University of Virginia, Cox participated in a number of high-energy physics experiments on fundamental particles of nature such as fermions, quarks, leptons and bosons that constitute the atoms. In his early career, he was involved in experiments revolving around strong and electromagnetic interactions. One of Cox's experiments measured the charge asymmetry of the ɳ->π+π -π 0 decay in a search for C violation.
Research at Fermilab After joining Fermilab, Cox served as scientific spokesman for a series of high-energy experiments that studied the interactions of quarks and gluons by measuring the production of direct photons and lepton pairs. One of the experiments involved observation of direct photon production by hadrons during the 1970s. His work led to one of the first two observations of direct photon production from quark-quark interactions in hadronic collisions. In the early 1980s, Cox served as spokesperson for the Fermilab Experiment E537, which measured the production of high mass muon pairs by antiprotons and confirmed that deep inelastic structure functions as measured in lepton scattering were the same as the structure functions that were appropriate to describe lepton
pair production. After E537, Cox served as spokesperson for the E705 experiment focused on studying the production of direct photons and charmonium states by
antiproton, proton and π± beams.
Research at CERN and University of Virginia In the late 1980s, after taking a position as professor at the University of Virginia to build a Particle Physics experiment group, Cox initiated an effort to design a detector that would measure the CP violating effects in the B meson system at the Superconducting Supercollider (SSC) in Texas. After the demise of the SSC, Cox refocused his research on CP violation in the neutral kaon system at Fermi National Accerator Laboratory in the U.S. He led the UVa effort on the KTeV experiment formed to do this measurement. This experiment made the first statistically significant observation of "direct" CP violation determined by the measurement of a non-zero Re(ɳ'/ɳ),. proving that the CP violation (time reversal violation) is an intrinsic property of the
weak interaction, a result that had been pursued for approximately 50 years. Cox's group at University of Virginia also made significant contributions to the discovery of a large CP violation effect in KL-> π +π - e + e - . Following the KTeV experiment, Cox then turned his efforts to CERN laboratory in Geneva, Switzerland and the design of the LHCb heavy flavor experiment at the
Large Hadron Collider (LHC). At the direction of the US Department of Energy, Cox changed the direction of his research goals and joined the
Compact Muon Solenoid Experiment (CMS), one of the two major collider experiment at the LHC, and directed his UVa group to become involved in the development of the electromagnetic photon and electron calorimeter detector of the CMS under construction at that point in time. Cox's major accomplishment at the LHC was his participation in the discovery of the Higgs Particle. He was named the U.S. manager of the PbW crystal photon calorimeter, the part of the CMS detector that was most instrumental in the early detection of the Higgs particle. The Higgs particles suffuse the entire universe, and their interaction with all other fundamental particles gives mass to all particles. The search for the Higgs had proceeded for 50 years since it was first hypothesized in 1964. The experimental observation of the Higgs at CERN in 2012 is considered to be one of the major physics discoveries of the 21st century. The University of Virginia designated the research of Cox as "one of the 12 most important research achievements in the last fifty years." Cox's later work has involved the search for Supersymmetry in the CMS experiment at the LHC, one of the possible consequences of the Higgs unexpected low mass. ==Awards and honors==