Engineering topics

Freitas, A

Publications and source records attributed to Freitas, A.

2 records

DOE OSTI2011

Matrix element method and QCD radiation

The matrix element method has been extensively used for the analysis of top-quark and W-boson physics at the Tevatron but in general without dedicated treatment of initial-state QCD radiation. At the LHC, the increased center-of-mass energy leads to a significant increase in the amount of QCD radiation, which makes it mandatory to carefully account for its effects. We here present several methods for inclusion of QCD radiation effects in the matrix element method and apply them to mass determination in the presence of multiple invisible particles in the final state. We demonstrate significantly improved results compared to the standard treatment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Multi-photon signals from composite models at LHC.

We analyze the collider signals of composite scalars that emerge in certain little Higgs models and models of vectorlike confinement. Similar to the decay of the pion into photon pairs, these scalars mainly decay through anomaly-induced interactions into electroweak gauge bosons, leading to a distinct signal with three or more photons in the final state. We study the standard model backgrounds for these signals, and find that the LHC can discover these models over a large range of parameter space with 30 fb{sup -1} at 14 TeV. An early discovery at the current 7 TeV run is possible in some regions of parameter space. We also discuss possibilities to measure the spin of the particles in the {gamma}{gamma} and Z{gamma} decay channels.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗