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Jets from massive unstable particles: Top-mass determination

Fleming, Sean and Hoang, Andre H. and Mantry, Sonny and Stewart, Iain W. (2008) Jets from massive unstable particles: Top-mass determination. Physical Review D, 77 (7). Art. No. 074010. ISSN 2470-0010.

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We construct jet observables for energetic top quarks that can be used to determine a short-distance top quark mass from reconstruction in e+e- collisions with accuracy better than LambdaQCD. Using a sequence of effective field theories we connect the production energy, mass, and top width scales, Q>>m>>Gamma, for the top jet cross section, and derive a QCD factorization theorem for the top invariant mass spectrum. Our analysis accounts for alphas corrections from the production and mass scales, corrections due to constraints in defining invariant masses, nonperturbative corrections from the cross talk between the jets, and alphas corrections to the Breit-Wigner line shape. This paper mainly focuses on deriving the factorization theorem for hemisphere invariant mass distributions and other event shapes in e+e- collisions applicable at a future linear collider. We show that the invariant mass distribution is not a simple Breit-Wigner function involving the top width. Even at leading order it is shifted and broadened by nonperturbative soft QCD effects. We predict that the invariant mass peak position increases linearly with Q/m due to these nonperturbative effects. They are encoded in terms of a universal soft function that also describes soft effects for massless dijet events. In a future paper we compute alphas corrections to the jet invariant mass spectrum, including a summation of large logarithms between the scales Q, m, and Gamma.

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Additional Information:©2008 The American Physical Society. (Received 9 April 2007; published 14 April 2008) We would like to thank A. Juste, S. Kluth, S. Menke, and M. Wise for helpful discussions. We also thank C. Bauer and M. Dorsten for collaboration in an early stage of this work. S.F. and S.M. thank the visitor program of the Max-Planck-Institute for Physics for support. This work was supported in part by the Offices of Nuclear and Particle Physics of the U.S. Department of Energy under DEFG02-94ER40818, DE-FG03-92ER40701, and DEFG02-06ER41449, and in part by the EU network Contract No. MRTN-CT-2006-035482 (FLAVIAnet). I.S. and S.F. were supported in part by the DOE OJI program, and I.S. was supported in part by the Sloan Foundation.
Issue or Number:7
Record Number:CaltechAUTHORS:FLEprd08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10247
Deposited By: Archive Administrator
Deposited On:18 Apr 2008
Last Modified:03 Oct 2019 00:07

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