Wuppertal 2015 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 3: Neue Physik: vektorartige Quarks, Z’, W’
T 3.3: Vortrag
Montag, 9. März 2015, 14:30–14:45, L.09.31 (HS 11)
Model independent search in two-dimensional mass space for events with missing energy in the dilepton final state with CMS — •Sarah Beranek1, Georgios Anagnostou2, Andreas Psallidas2, and Stefan Schael1 — 11. Physikalisches Institut B, RWTH Aachen, Germany — 2Institute of Nuclear and Particle Physics Demokritos, Athens, Greece
A search performed in a model independent way assuming only event topologies similar to dileptonic top pair decays (pp → XX → Yb Ȳb) is presented. No constraints on the masses X and Y are required.
The method uses the solvability of the equation system to scan the whole two-dimensional mass space for the existence of a solution. Since the collision energy gives an upper limit to the allowed mass space, probabilities from pdfs are taken into account. Additionally the measured particle kinematics are smeared with the detector resolution.
Initially, we show that the method works for standard model top pairs as both top quark and W boson are reconstructed as mass peaks in the two-dimensional mass plane using 19.7 fb−1 of data recorded by the CMS detector in pp collisions at √s = 8 TeV. This analysis can set limits on the existence of any particle decaying to the topology and final state mentioned.
A two-dimensional search is performed for both a new heavy top partner T’ and a new heavy gauge boson W’ (pp → T′T' → W′+b W′−b). No deviation from standard model processes is observed over the expected rate of a simplified littlest higgs model. We set 95% confidence level upper limits on the model.