Twoloop electroweak fermionic corrections to sin^{}θeffbb̄
Abstract
We present the first calculation of the twoloop electroweak fermionic correction to the flavourdependent effective weakmixing angle for bottom quarks, sinθeffbb̄. For the evaluation of the missing twoloop vertex diagrams, two methods are employed, one based on a seminumerical BernsteinTkachov algorithm and the second on asymptotic expansions in the large topquark mass. A third method based on dispersion relations is used for checking the basic loop integrals. We find that for small Higgsboson mass values, M∝100 GeV, the correction is sizable, of order O(10).
 Publication:

Nuclear Physics B
 Pub Date:
 May 2009
 DOI:
 10.1016/j.nuclphysb.2008.12.031
 arXiv:
 arXiv:0811.1364
 Bibcode:
 2009NuPhB.813..174A
 Keywords:

 12.15.Lk;
 13.38.Dg;
 13.66.Jn;
 14.70.Hp;
 Electroweak radiative corrections;
 Decays of Z bosons;
 Precision mesurements in e<sup></sup>e<sup>+</sup> interactions;
 Z bosons;
 High Energy Physics  Phenomenology
 EPrint:
 17 pages, 2 figures, references added, accepted for publication in Nucl. Phys. B