The effects of strong interactions on the two-loop electroweak radiative corrections to muon anomalous magnetic moment, ${a}_{\ensuremath{\mu}}{=(g}_{\ensuremath{\mu}}\ensuremath{-}2)/2,$ are examined. Short-distance logarithms shown be unaffected. computation long-distance contributions is improved by use an effective field theory approach that preserves chiral properties QCD and accounts for constraints from operator product expansion. Small, previously neglected, contributions, suppressed...

The results of a comprehensive analysis existing data on the weak neutral current and W Z masses are presented. principal following. (a) There is no evidence for any deviation from standard model. (b) A global fit to all yields ${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$\ensuremath{\equiv}1-${\mathrm{M}}_{\mathrm{W}}$${\mathrm{}}^{2}$/${\mathrm{M}}_{\mathrm{Z}}$${\mathrm{}}^{2}$=0.230\ifmmode\pm\else\textpm\fi{}0.0048, where this error others given here include full...

QED, Hadronic, and Electroweak Standard Model contributions to the muon anomalous magnetic moment, a_mu = (g_mu-2)/2, their theoretical uncertainties are scrutinized. The status implications of recently reported 2.6 sigma experiment vs.theory deviation a_mu^{exp}-a_mu^{SM} 426(165) times 10^{-11} discussed. Possible explanations due supersymmetric loop effects with m_{SUSY} \simeq 55 sqrt{tan beta} GeV, radiative mass mechanisms at 1--2 TeV scale other ``New Physics'' scenarios examined.

An analysis of electroweak radiative corrections to \ensuremath{\tau} decays is presented. Precise predictions for leptonic and some hadronic decay rates are given. The total width shown be relatively enhanced by 2.36% due mainly short-distance loop effects. Implications the extraction ${\ensuremath{\Lambda}}_{\mathrm{MS}\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}$ from lifetime or branching ratios discussed. (MS\ifmmode\bar\else\textasciimacron\fi{} denotes modified minimal-subtraction scheme.)

Effects of physics beyond the standard model on electroweak observables ares studied using Peskin-Takeuchi isospin-conserving, S, and -breaking, T, parametrization ``new'' quantum loop corrections. Experimental constraints S T are presented. Atomic parity-violating experiments shown to be particularly sensitive with existing data giving S=-2.7\ifmmode\pm\else\textpm\fi{}2.0\ifmmode\pm\else\textpm\fi{}1.1. That constraint has important implications for generic technicolor models which predict...

Time dependence of the fundamental "constants" is examined within framework Kaluza-Klein theories. Relationships among low-energy couplings and masses are derived. It suggested that detection a time variation in any these parameters may provide evidence for extra space dimensions. Experimental bounds reviewed new measurements advocated.

General consequences of mass mixing between the ordinary Z boson and a relatively light Z_d boson, "dark" Z, arising from U(1)_d gauge symmetry, associated with hidden sector such as dark matter, are examined. New effects beyond kinetic emphasized. Z-Z_d introduces new source low energy parity violation well explored by possible future atomic planned polarized electron scattering experiments. Rare K (B) meson decays into pi (K) l^+ l^- (l = e, mu) nu anti-nu found to already place tight...

The discrepancy between the Standard Model theory and experimental measurement of muon magnetic moment anomaly, ${a}_{\ensuremath{\mu}}=({g}_{\ensuremath{\mu}}\ensuremath{-}2)/2$, is connected to precision electroweak (EW) predictions via their common dependence on hadronic vacuum polarization effects. same data for total ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\text{hadrons}$ cross section, ${\ensuremath{\sigma}}_{\text{had}}(s)$, are used as input into dispersion relations...

The universal radiative corrections common to neutron and super-allowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found $+2.467(22)\%$, i.e.~about $2.4\sigma$ larger than the previous evaluation. For comparison, we consider several alternative computational methods. All employ an updated perturbative QCD four-loop Bjorken sum rule (BjSR) defined coupling supplemented with nucleon form factor based Born...

Renormalization effects are analyzed for a class of supersymmetric grand unified theories which contain the standard $\mathrm{SU}{(3)}_{c}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ model. Predictions ${{sin}^{2}\stackrel{^}{\ensuremath{\theta}}}_{W}({m}_{W})$ and proton lifetime obtained as functions ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}$ ($\stackrel{-}{\mathrm{MS}}$ is modified minimal-subtraction scheme), ${N}_{H}$...

Leading-logarithmic radiative corrections to \ensuremath{\beta} decay are summed via the renormalization group and structure-dependent O(\ensuremath{\alpha}) effects estimated by a form-factor analysis. These refinements reduce Kobayashi-Maskawa quark-mixing-matrix element \ensuremath{\Vert}${V}_{\mathrm{ud}}$\ensuremath{\Vert} 0.13% 0.9729\ifmmode\pm\else\textpm\fi{}0.0012. Combined with ${K}_{e3}$-, hyperon-, b-decay constraints, this implies...

Bosonic two-loop electroweak radiative corrections to the muon's anomalous magnetic moment, ${a}_{\ensuremath{\mu}}\ensuremath{\equiv}\frac{({g}_{\ensuremath{\mu}}\ensuremath{-}2)}{2}$, are presented. We find $\frac{\ensuremath{\Delta}{a}_{\ensuremath{\mu}}^{\mathrm{EW}}(2 \mathrm{loop}\mathrm{bosonic})}{{a}_{\ensuremath{\mu}}^{\mathrm{EW}}(1...

A new method for computing hadronic effects on electroweak radiative corrections to low-energy weak interaction semileptonic processes is described. It employs high order perturbative QCD results originally derived the Bjorken sum rule along with a large N QCD-motivated interpolating function that matches long and short-distance loop contributions. Applying this approach extraction of CKM matrix element V_ud from superallowed nuclear beta decays reduces theoretical uncertainty by about...

Radiative corrections to ${\mathrm{\ensuremath{\pi}}}_{\mathit{l}2}$ (l=e or \ensuremath{\mu}) decays are examined. Higher order electroweak leading logarithms short-distance QCD corrections, and structure dependent effects incorporated. The results employed (1) test e-\ensuremath{\mu} universality in...

Renormalization-group equations and asymptotic conditions are used to obtain top-quark mass predictions. In the standard model with an explicit Higgs mechanism, our analysis becomes identical Kubo-Sibold-Zimmermann coupling-reduction approach. Refining their prediction, we find ${m}_{t}$\ensuremath{\simeq}95 GeV. simplest case of self-consistent dynamical symmetry breaking, ${m}_{t}$\ensuremath{\simeq}115 An illustration how short-distance new physics can alter these predictions is given.

A discussion of the modified minimal-subtraction ($\stackrel{-}{\mathrm{MS}}$) prescription in QCD is presented. Effects flavor thresholds on ${\ensuremath{\alpha}}_{s}(\ensuremath{\mu})$ and ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}$ are examined. Two parametrization options described. In first approach, distinct mass scales ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}^{({N}_{F})}$ associated with ${N}_{F}$, effective number flavors, introduced. second scheme, a standard...

We discuss the role of ${{sin}^{2}\ensuremath{\theta}}_{W}$ (${\ensuremath{\theta}}_{W}=\mathrm{weak}\mathrm{mixing}\mathrm{angle}$) in Weinberg-Salam SU(2)\ifmmode\times\else\texttimes\fi{}U(1) model. A definition renormalized value is given, effects radiative corrections are considered, and possibility precisely determining this parameter experimentally examined. Within framework grand unified gauge thories, we derive an expression for effective quantity...

The muon ${g}_{\ensuremath{\mu}}\ensuremath{-}2$ discrepancy between theory and experiment may be explained by a light vector boson ${Z}_{d}$ that couples to the electromagnetic current via kinetic mixing with photon. We illustrate how existing electron ${g}_{e}\ensuremath{-}2$, pion Dalitz decay, other direct production data disfavor explanation if mainly decays into ${e}^{+}{e}^{\ensuremath{-}}$, ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. Implications of dominant...

Abstract

Electroweak radiative corrections to the $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ parity-violating electron-quark interaction are presented, including axial-vector isoscalar effects induced at one-loop level. Implications of our results for parity-violation searches in ordinary hydrogen, deuterium, and heavy atoms discussed.