Browsing by Author "Grant, Aaron K."
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- An analysis of nonoblique corrections to the Zb¯b vertexTakeuchi, Tatsu; Grant, Aaron K.; Rosner, Jonathan L. (1994)We present a model–independent analysis of the Zb¯b vertex, with the aim of constraining contributions of new physics to the left- and right–handed couplings of the b. We find that the left–handed coupling of the b is quite narrowly constrained by present data, but that the right–handed coupling is still largely unconstrained.
- An analysis of Precision Electroweak Measurements: Summer 98 UpdateGrant, Aaron K.; Takeuchi, Tatsu (1998-07)We update our analysis of precision electroweak measurements using the latest data announced at Moriond, March 1998. Possible oblique corrections from new physics are parametrized using the STU formalism of Ref.[1], and non-oblique corrections to the Zbb vertex are parametrized using the xi_b zeta_b formalism of Ref.[2]. The implications of the analysis on minimal SU(5) grand unification is discussed.
- Choice of dispersion relation to calculate the QCD correction to Gamma(H->l(+)l(-))Takeuchi, Tatsu; Grant, Aaron K.; Worah, Mihir P. (American Physical Society, 1996-02-01)We use the Operator Product Expansion (OPE) of quark vacuum polarization functions to show that the dispersion relation of Kniehl and Sirlin will yield the correct result to all orders in αs when applied to the QCD correction to the leptonic decay width of the Higgs boson.
- Comment on the Dispersion Relations used to Calculate ΔρTakeuchi, Tatsu; Grant, Aaron K.; Worah. Mihir (American Physical Society, 1995-06-01)We use the operator product expansion (OPE) to show that nonperturbative QCD corrections to Δρ can be calculated using unsubtracted dispersion relations for either the transverse or the longitudinal vacuum polarization functions. Recent calculations of the nonperturbative contribution to Δρ based on a non-relativistic calculation of corrections to the t¯t threshold are inconsistent with this result.
- The difficulties involved in calculating $δρ$Takeuchi, Tatsu; Grant, Aaron K.; Worah, Mihir P. (1995-04)We discuss the difficulties that arise when one tries to calculate $\delta\rho$ using dispersion relations.
- Precision Tests of Electroweak PhysicsTakeuchi, Tatsu; Loinaz, William; Grant, Aaron K. (1999-04)We review the current status of precision electroweak measurements and the constraints they impose on new physics. We perform a model independent analysis using the STU-formalism of Ref. 1, and then discuss how the Z-pole data from LEP and SLD can be used to constrain models that are not covered within that framework.