# Constraining Light Colored Particles with Event Shapes

 Title: Constraining Light Colored Particles with Event Shapes Author: Kaplan, David; Schwartz, Matthew D Note: Order does not necessarily reflect citation order of authors. Citation: Kaplan, David, and Matthew Schwartz. 2008. Constraining light colored particles with event shapes. Physical Review Letters 101(2): 022002. Full Text & Related Files: 0804.2477v1.pdf (154.0Kb; PDF) Abstract: Using recently developed techniques for computing event shapes with Soft-Collinear Effective Theory, LEP event shape data is used to derive strong model-independent bounds on new colored particles. In the effective field theory computation, colored particles contribute in loops not only to the running of $${\alpha}_s$$ but also to the running of hard, jet and soft functions. Moreover, the differential distribution in the effective theory explicitly probes many energy scales, so event shapes have strong sensitivity to new particle thresholds. Using thrust data from ALEPH and OPAL, colored adjoint fermions (such as a gluino) below 51.0 GeV are ruled out to 95% confidence level. This is nearly an order-of-magnitude improvement over the previous model-independent bound of 6.3 GeV. Published Version: doi:10.1103/PhysRevLett.101.022002 Other Sources: http://arxiv.org/PS_cache/arxiv/pdf/0804/0804.2477v1.pdf Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8003958 Downloads of this work: