Related papers: Negative s and Light New Physics
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…
We calculate contributions to the oblique parameters $S$ and $T$ for leptoquarks and bileptons, and find phenomenological constraints on their allowed masses. Leptoquarks suggested by the neutral and charged current anomalies at HERA can…
Scattering polarized electrons provides an important probe of the weak interactions. Precisely measuring the parity-violating left-right cross section asymmetry is the goal of a number of experiments recently completed or in progress. The…
The apparent Lorentz invariance of the laws of physics does not imply that space-time is indeed minkowskian. We consider a scenario where Lorentz invariance is only an approximate property of equations of matter above a certain distance…
We show that an angular analysis of B -> V1 V2 decays yields numerous tests for new physics in the decay amplitudes. Many of these new-physics observables are nonzero even if the strong phase differences vanish. For certain observables,…
We present a simple method for analyzing the impact of precision electroweak data above and below the Z-peak on flavour-conserving heavy new physics. We find that experiments have probed about ten combinations of new physics effects, which…
New particles can manifest their effects in many settings, ranging from effects on sub-atomic to galactic length scales. The nature of these effects depends on the specific particles and their non-gravitational interactions. In this…
If all new particles are too heavy to be directly produced in the future Colliders, then the long sought New Physics (NP) could only appear in the form of new interactions, beyond those of the Standard Model (SM). Many of the processes that…
We discuss the possibilities of extracting the constraints on New Physics by using the current data on the leptonic and semileptonic decays of pseudoscalar mesons. In doing so we use a general low energy Lagrangian that besides the vector…
New unification theories predict Large Extra Dimensions (LEDs). If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In this paper we propose a…
Recently the PVLAS collaboration reported the observation of a rotation of linearly polarized laser light induced by a transverse magnetic field -- a signal being unexpected within standard QED. In this review, we emphasize two mechanisms…
The recent measurement of $R_{K^*}$ is yet another hint of new physics (NP), and supports the idea that it is present in $b\to s\mu^+\mu^-$ decays. We perform a combined model-independent and model-dependent analysis in order to deduce…
Contrary to what is sometimes stated, the current electroweak precision data easily allow for massive composite resonance states at the natural EW scale, i.e., well over the TeV. The oblique parameters S and T are analyzed by means of an…
This paper proves that a particle with mass different of zero cannot be its own antiparticle. Hence, particles such as pi-zero,eta-zero, and Z-zero must have their correspondent antiparticles.
We find that re-analyzing the LEP/SLC data with light superpartners and low $\alpha_s(\mz^2)\simeq 0.112$ yields a better fit to the data than the Standard Model, giving a satisfactory description of the $R_b$ measurement, and a better fit…
The status of the present precision measurements of electroweak observables is reviewed with specific reference to the radiative parameters $S,T,U$ or equivalently $\epsilon_1,\epsilon_2,\epsilon_3$. The significance of the obliqueness…
Experiments have confirmed the presence of a mass gap between the Standard Model and potential New Physics. Consequently, the exploration of effective field theories to detect signals indicative of Physics Beyond the Standard Model is of…
We study the determination of new physics (NP) parameters using the optimal observable technique (OOT) in situations where the standard model (SM) dominates over the NP effects, and when the NP dominates over the SM contribution, using the…
While electron and muon dipole moments are well-established precision probes of physics beyond the standard model, it is notoriously challenging to test realistic new-physics (NP) scenarios for the $\tau$ lepton. Constructing suitable…
The predictions of the MSSM are discussed in the light of recent LEP and SLD precision data. The full supersymmetric one loop corrections to the effective weak mixing angle, experimentally determined in LEP and SLD experiments, are…