Related papers: New physics effects in rare Z decays
We propose to investigate the effects of new physics in the semi-leptonic sequential decay $\Lambda_b \to \Lambda_c (\to \Lambda \pi) \tau{\bar \nu}_{\tau}$. Firstly, we write the general, model independent, non-covariant expression of the…
We consider the possibility that physics beyond the standard model contributes to the decays B -> V1 V2, where V1 and V2 are vector mesons. We show that a time-dependent angular analysis of B -> V1 V2 decays provides many tests for this new…
The impact of new and highly precise neutron \b{eta} decay data is reviewed. We focus on recent results from neutron lifetime, \b{eta} asymmetry, and electron-neutrino correlation experiments. From these results, weak interaction parameters…
Rare K decays are an important testing ground of the electroweak flavour theory. They can provide new signals of CP-violation phenomena and, perhaps, a window into physics beyond the Standard Model. The interplay of long-distance QCD…
Abundance of charm data in the current and future low energy flavor experiments makes it possible to study rare decays of D-mesons with ever increased precision. I discuss theoretical implications of derived constraints on New Physics…
T--odd correlations as physical observables in the $B \rar K^\ast \ell^+ \ell^-$ decay have been studied using the most general form of the effective Hamiltonian. It is observed that these quantities are very sensitive to the new physics.…
Current experimental limits for new physics beyond the Standard Model and hints for deviations from Standard Model expectations will be reviewed, highlighting recent results. Possible signals that will be discussed include Higgs bosons,…
We briefly review the limits on new interactions implied by electroweak precision data. Special attention is payed to the bounds on the Higgs boson mass. We also comment on the required cancellation among the new contributions to precisely…
Determining the spin of new particles is critical in identifying the true theory among various extensions of the Standard Model at the next generation of colliders. Quantum interference between different helicity amplitudes was shown to be…
We discuss the potential of a $0.5\hskip 2pt TeV$ linear collider to explore manifestations of extended (or alternative) electroweak models of current interest, through measurements of the reaction $e^+e^-\to W^+W^-$ with both initial and…
Various extensions of the Standard Model, i.e. string inspired groups like E_6, extra dimensions, 'deconstruction', predict additional vector bosons. In most cases these bosons can mix with the SM Z and this translates into a very high…
The standard model of particle physics is an extremely successful theory of fundamental interactions, but it has many known limitations. It is therefore widely believed to be an effective field theory that describes interactions near the…
The precision data on Z boson decays from LEP-I and SLC colliders are compared with the predictions based on the Minimal Standard Theory. The Born approximation of the theory is based on three most accurately known observables: G_mu -- the…
Astrophysical bounds severely limit the possibility of observing collider signals of gravity with less than 3 flat extra dimensions. However, small distortions of the compactified space can lift the masses of the lightest graviton…
It is shown that if - and only if - ``parallel universes'' exist, an electroweak vacuum that is expected to have decayed since the big bang with a high probability might exist. It would neither necessarily render our existence unlikely nor…
Collider measurements on electroweak physics are summarised. Although the precision on some observables is very high, no deviation from the Standard Model of electroweak interactions is observed. The data allow to set stringent limits on…
Cosmic ray events above 10^19 eV have posed a fundamental problem for more than thirty years. Recent measurements indicate that these events do not show the features predicted by the GZK bound. The events may, in addition, display angular…
Future lepton colliders will be precision machines whose physics program includes close study of the Higgs sector and searches for new physics via polarised beams. The luminosity requirements of such machines entail very intense lepton…
Precision measurements in nuclear beta decay offer a sensitive window to search for new physics beyond the standard electroweak model and allow also the determination of the fundamental weak vector coupling in processes involving the…
R-parity violation and extensions of the Standard Model gauge structure offer two non-minimal realizations of supersymmetry at low energies that can lead to similar new physics signatures at existing and future colliders. We discuss…