Jets from massive unstable particles: Top-mass determination

Journal Article · Tue Apr 01 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.074010· OSTI ID:21249935

Fleming, Sean ^[1]; Hoang, Andre H ^[2]; Mantry, Sonny ^[3]; Stewart, Iain W ^[4]

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1. Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)
2. Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany)
3. California Institute of Technology, Pasadena, California 91125 (United States)
4. Department of Physics, Massachusetts Institute of Technology, Boston, Massachusetts 02139 (United States)

We construct jet observables for energetic top quarks that can be used to determine a short-distance top quark mass from reconstruction in e{sup +}e{sup -} collisions with accuracy better than {lambda}{sub QCD}. 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 {alpha}{sub s} 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 {alpha}{sub s} 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{sup +}e{sup -} 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 {alpha}{sub s} corrections to the jet invariant mass spectrum, including a summation of large logarithms between the scales Q, m, and {gamma}.

• OSTI ID: 21249935
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 7 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BREIT-WIGNER FORMULA
CORRECTIONS
CROSS SECTIONS
ELECTRON-POSITRON COLLISIONS
FACTORIZATION
LINEAR COLLIDERS
MASS
MASS DISTRIBUTION
MASS SPECTRA
PARTICLES
QUANTUM CHROMODYNAMICS
T QUARKS