LHC physics at Los Alamos

The Large Hadron Collider (LHC) is studying the structure of matter at sub-nucleon distance scales by colliding protons together at high center of mass energy. The LHC has a broad scientific program, performing studies of QCD, heavy quarks, the W and Z electroweak gauge bosons, the top quark, and the recently discovered Higgs boson. The LHC experiment also has a dedicated effort to search for evidence of new laws of physics, in the form of new particles or anomalies. The discovery of the Higgs boson and the null-findings of direct searches for new particles conducted during the 8 TeV run of the LHC places acute attention on the hierarchy problem and on the origin of masses for the quarks, leptons and electroweak gauge bosons.

Figure: (Above) Simulated distributions of topness at 8 TeV in the b-quark+lepton+missing energy final state, demonstrating topness can be used as a robust suppressant of dominant backgrounds. Shown are the distributions for the top squark signal and dominant backgrounds after pre-selection. These are the top squark signal (orange) and dominant Standard Model backgrounds arising from dileptonic top quarks (blue) and leptonic-tau top quarks (purple). From M. L. Graesser and J. Shelton, Phys. Rev. Lett. 111 (2013) 121802.

The HEP effort at Los Alamos in LHC physics is focused on a number of related questions.

• How can the discovery potential of new physics searches at the LHC be improved?
• Where should we be looking for new physics where we currently are not?
• What new physics can contribute to the decay of the Higgs boson?
• Can interactions between dark matter and neutrinos be important?
• What are the implications of direct searches for new physics at the LHC on indirect searches for new physics in low-energy experiments?