Thrust at N{sup 3}LL with power corrections and a precision global fit for {alpha}{sub s}(m{sub Z})

Journal Article · Fri Apr 01 00:00:00 EDT 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.074021· OSTI ID:21537724

Abbate, Riccardo; Stewart, Iain W ^[1]; Fickinger, Michael ^[2]; Hoang, Andre H; Mateu, Vicent ^[3]

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1. Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2. Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)
3. Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany)

We give a factorization formula for the e{sup +}e{sup -} thrust distribution d{sigma}/d{tau} with {tau}=1-T based on the soft-collinear effective theory. The result is applicable for all {tau}, i.e. in the peak, tail, and far-tail regions. The formula includes O({alpha}{sub s}{sup 3}) fixed-order QCD results, resummation of singular partonic {alpha}{sub s}{sup j}ln{sup k}({tau})/{tau} terms with N{sup 3}LL accuracy, hadronization effects from fitting a universal nonperturbative soft function defined with field theory, bottom quark mass effects, QED corrections, and the dominant top mass dependent terms from the axial anomaly. We do not rely on Monte Carlo generators to determine nonperturbative effects since they are not compatible with higher order perturbative analyses. Instead our treatment is based on fitting nonperturbative matrix elements in field theory, which are moments {Omega}{sub i} of a nonperturbative soft function. We present a global analysis of all available thrust data measured at center-of-mass energies Q=35-207 GeV in the tail region, where a two-parameter fit to {alpha}{sub s}(m{sub Z}) and the first moment {Omega}{sub 1} suffices. We use a short-distance scheme to define {Omega}{sub 1}, called the R-gap scheme, thus ensuring that the perturbative d{sigma}/d{tau} does not suffer from an O({Lambda}{sub QCD}) renormalon ambiguity. We find {alpha}{sub s}(m{sub Z})=0.1135{+-}(0.0002){sub expt{+-}}(0.0005){sub hadr{+-}}(0.0009){sub pert}, with {chi}{sup 2}/dof=0.91, where the displayed 1-sigma errors are the total experimental error, the hadronization uncertainty, and the perturbative theory uncertainty, respectively. The hadronization uncertainty in {alpha}{sub s} is significantly decreased compared to earlier analyses by our two-parameter fit, which determines {Omega}{sub 1}=0.323 GeV with 16% uncertainty.

• OSTI ID: 21537724
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 7; Other Information: DOI: 10.1103/PhysRevD.83.074021; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
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CORRECTIONS
DISTRIBUTION
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ELECTRONS
ERRORS
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