Cornell University Unit Name

"Calorimetry-assisted tracking and reconstruction of long-lived particles"

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Dima Onoprienko (Kansas State), Eckhard von Toerne (Kansas State U. and Bonn U.)

The high energy physics group at Kansas State University participates in the Silicon Detector (SiD) design study. The SiD has excellent prospects for the application of particle flow algorithms, resulting in improved energy and momentum measurements. One of the main challenges with respect to the SiD concept has been the reconstruction of long-lived particles, because the standard tracking approach relies on Vertex detector hits as seeds for tracks, assuming that the Tracker with only five layers is not capable of providing pattern recognition. Tracks from the decay of long-lived particles usually lack the vertex detector hits necessary to generate a track seed and these tracks are therefore lost.

The Garfield Trackfinder Package reconstructs tracks by extrapolating ECAL cluster (MIP-stubs) into the tracker volume. This calorimeter-assisted tracking is crucial in reconstructing long-lived particles with the SiD, such as K0-shorts and Lambdas, or more exotic, long-lived particles like the decay of a supersymmetric particle shown in the picture gallery. Long-lifetime supersymmetric particles occur in gauge mediated supersymmetry breaking scenarios and also within the MSSM assuming certain parameter tunings.

This work is funded by the University-based ILC Detector R&D program. Most recently we have ported the reconstructed algorithm into the org.lcsim (see http ://www.lcsim.org) framework. Our code is thus compliant with the LCIO standard.

We are working on reconstruction algorithms that will improve the ECAL to track matching and the identification of long-lived particles. A first release is planned for early next year with improved releases coming out on a regular basis.

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