相关论文: Negative s and Light New Physics
The combined LEP/SLD data on the b\bar b forward-backward asymmetry from the Z-pole measurements may imply the presence of new physics in the $Zb\bar b$ couplings. In general, the effect of new physics can be parameterized by $SU_C(3)\times…
We study in an effective operator approach how the effects of new physics from various scenarios that contain an extra $Z'$ neutral gauge boson or doubly charged scalars, can affect and thus be tested by the precision polarized M\o{}ller…
Searches for New Physics focus either on the direct production of new particles at colliders or at deviations from known observables at low energies. In order to discover New Physics in precision measurements, both experimental and…
Motivated by a small but intriguing excess observed in the decay mode $ H\rightarrow \ell^+\ell^- \gamma$ reported by both the ATLAS and CMS collaborations, we explore the possibility that new physics contributes directly to the effective $…
We analyze LEP and SLC data from the 1995 Winter Conferences for signals of new physics. We compare the data with the Standard Model (SM) as well as a number of test hypotheses concerning the nature of new physics: (i) nonstandard Zbb…
We analyze LEP and SLC data from the 1995 Summer Conferences as well as from low energy neutral current experiments for signals of new physics. The reasons for doing this are twofold, first to explain the deviations from the standard model…
The implications of the recent measurement of the left-right asymmetry, $A_{LR}$, by the SLD Collaboration for theories with extended gauge sectors is examined. We show that it is possible to arrange for large, negative values of $S$, based…
The oblique parameters $S$ and $T$ are studied in electroweak theory with two massless Higgs doublets. The effect of quadratic dependence on the charged Higgs mass in the parameter $T$ could be cancelled. %when mass differences between the…
We consider whether a discrepancy between the SLAC and LEP measurements of $\Sw$ can be explained by new physics. We find that only the contribution of a new neutral gauge boson, $Z^\prime$, nearly degenerate with the Z can affect the SLAC…
Despite the impressive precision of the Z-pole measurements made at LEP and SLC, the allowed region for the principle Standard Model parameters responsible for radiative corrections (the mass of the Higgs, the mass of the top and alpha(Mz))…
The best way to search for new physics is by using a diverse set of probes - not just experiments at the energy and the cosmic frontiers, but also the low-energy measurements relying on high precision and high luminosity. One example of…
We survey the implications for new physics of the discrepancy between the LEP measurement of $R_b$ and its Standard Model prediction. Two broad classes of models are considered: ($i$) those in which new $Z\bbar b$ couplings arise at tree…
In this work, we study the $B^+\to K^+ E_{\mathrm{miss}}$, $B^0\to K^{*0} E_{\mathrm{miss}}$, and $\Lambda_b^0\to \Lambda^0 E_{\mathrm{miss}}$ decays under three different new physics hypotheses: the heavy new particles, the light neutral…
We discuss New Physics effects in fermion pair production at LC in the framework of the ``Z-peak subtracted approach'', a theoretical scheme that exploits the experimental measurements at LEP1 and SLC as input parameters. In particular, we…
Polarized $\Lambda_b \to \Lambda \gamma$ decays at the Z pole are shown to be well suited for probing a large variety of New Physics effects. A new observable is proposed, the angular asymmetry between the $\Lambda_b$ spin and photon…
Precision probes of new physics are often interpreted through their indirect sensitivity to short-distance scales. In this proceedings contribution, we focus on the question of which precision observables, at current sensitivity levels,…
I show that breaking $B-L$ by one unit of this charge is suitable for neutrino mass generation through an inverse seesaw mechanism, stabilizing a dark matter candidate without supersymmetry, as well as solving the muon anomalous magnetic…
New observables \sigma_\pm for the process e^+e^-\to\mu^+\mu^- allow one to get more direct information on additional Z' boson effects than what is obtained from the canonical ones, \sigma and A_{FB}. Their deviations from the Standard…
Using a general effective Lagrangian implementing the chiral symmetry breaking SU(2)L x SU(2)R -> SU(2){L+R}, we present a one-loop calculation of the oblique S and T parameters within electroweak strongly-coupled models with a light…
We discuss how new physics not encompassed within the STU oblique correction framework can be constrained from precision electroweak measurements via vertex corrections to Z-pole observables.