A Precise Determination of $$\alpha_s$$ From LEP Thrust Data Using Effective Field Theory

 Title: A Precise Determination of $$\alpha_s$$ From LEP Thrust Data Using Effective Field Theory Author: Becher, Thomas; Schwartz, Matthew D Note: Order does not necessarily reflect citation order of authors. Citation: Becher, Thomas, and Matthew Schwartz. 2008. A precise determination of $$\alpha_s$$ from LEP thrust data using effective field theory. Journal of High Energy Physics 2008(07): 034. Full Text & Related Files: 0803.0342v2.pdf (696.3Kb; PDF) Abstract: Starting from a factorization theorem in Soft-Collinear Effective Theory, the thrust distribution in e$$^+$$e$$^-$$ collisions is calculated including resummation of the next-to-next-to-next-to leading logarithms. This is a significant improvement over previous calculations which were only valid to next-to-leading logarithmic order. The fixed-order expansion of the resummed result approaches the exact fixed-order distribution towards the kinematic endpoint. This close agreement provides a verification of both the effective field theory expression and recently completed next-to-next-to-leading fixed order event shapes. The resummed distribution is then matched to fixed order, resulting in a distribution valid over a large range of thrust. A fit to ALEPH and OPAL data from LEP 1 and LEP 2 produces $$\alpha_s(m_Z$$)= 0.1172 $$\pm$$ 0.0010 $$\pm$$ 0.0008 $$\pm$$ 0.0012 $$\pm$$ 0.0012, where the uncertainties are respectively statistical, systematic, hadronic, and perturbative. This is one of the world's most precise extractions of $$\alpha_s$$ to date. Published Version: doi:10.1088/1126-6708/2008/07/034 Other Sources: http://arxiv.org/abs/0803.0342v2 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:7473202 Downloads of this work: