Related papers: Width effects in slepton production e+ e- --> ~mu_…
This study investigates the potential of the TESLA Linear Collider for measuring resonance parameters of Higgs bosons beyond the mass range studied so far. The analysis is based on the reconstruction of events from the Higgsstrahlung…
The width of the $f_1 (1285) \to e^+e^-$ decay is calculated in the vector meson dominance model. The result depends on the relative phase between two coupling constants describing $f_1 \to \rho^0\gamma$ decay. The width $\Gamma (f_1 \to…
The recent developments on the computation of non-resonant corrections to the e+ e- -> W+ W- b bbar cross section in the top-antitop resonance region are reviewed in this talk. Non-resonant production of the final state W+ W- b bbar starts…
We consider the prospects for detecting effects due to the Higgs exchange diagram in high energy mu^+ mu^-$, e^+ e^-, and tau^+ tau^- collisions producing a pair of W bosons. The processes l^+l^- -> W^+W^- (with l=mu,e,tau) are analyzed,…
In supersymmetric theories with R-parity breaking, sleptons could be produced singly in $e^+e^-$ collisions at LEP2 and in $q\bar{q}$ annihilation at the Tevatron through interactions in which two quark or two lepton fields are coupled to a…
In this contribution we report $e^{+}e^{-}$ spectra with various invariant mass and p$_{T}$ differentials in Au$+$Au collisions at $\sqrt{s_{NN}}$=200 GeV and U$+$U collisions at $\sqrt{s_{NN}}$=193 GeV. The structure of the t ($t\approx…
This paper explores the effects of both finite width and interference (with background) in the pair production and decay of extra heavy quarks with charge 2/3 at the Large Hadron Collider (LHC). This dynamics is normally ignored in standard…
I give a short summary on scenarios with new physics scalars that could be investigated at future $e^+e^-$ colliders. I concentrate on cases where at least one of the additional scalar has a mass below 125 GeV, and discuss both models where…
The exchange of gluons between heavy quarks produced in $e^+e^-$ interactions results in an enhancement of their production near threshold. We study QCD threshold effects in $\gamma\gamma$ collisions. The results are relevant to heavy quark…
The present Standard Model fit of precision data has a low confidence level, and is characterized by a few inconsistencies. We look for supersymmetric effects that could improve the agreement among the electroweak precision measurements and…
The lepton-number violating process \nu_\mu N \to \mu^- \mu^+ \mu^+ X is studied for the first time in connection with Majorana neutrino masses of the second generation. The sensitivity for light and heavy Majorana neutrinos is…
The effect of the lepton's mass is significantly enhanced when the beam's energy is on the order of the lepton's mass. In the case of electrons, this corresponds to beam momenta on the order of a few MeV and is negligible in higher energy…
Hadron production and lepton-pair production in e+e- collisions are studied with data collected with the L3 detector at LEP at centre-of-mass energies sqrt{s}=192-208GeV. Using a total integrated luminosity of 453/pb, 36057 hadronic events…
We analyze the associated production at future high--energy $e^+e^-$ colliders, of first generation sleptons with neutralinos and charginos in the modes $e^+ e^-$ and $e \gamma$, in the framework of the Minimal Supersymmetric extension of…
The cross section for the reaction $e^{-}e^{-} \to \ell^-\ell^-$ ($\ell=\mu,\tau$) is calculated in models with heavy Majorana neutrinos mediating lepton number violating amplitudes at the loop level. The contributing four-point functions…
The mass shift and width broadening of rho-mesons produced in heavy ion collisions is estimated using general formulae which relate the in-medium mass shift of a particle to the real part of the forward scattering amplitude of this particle…
We discuss effects of fragmentation and hard gluon radiation on the signal for the pair production of the lighter scalar top eigenstate $\tilde{t}_1$ at e^+e^- colliders. The main emphasis is on scenarios with small stop--LSP mass…
Direct production of the charmonium-like state $X(3872)$ in $e^+e^-$ collisions is considered in the framework of the vector meson dominance model. An order-of-magnitude estimate for the width $\Gamma(X\to e^+e^-)$ is found to be…
A novel method of determining the mass of the W boson in the W+W- -> lnu lnu channel is presented and applied to 667pb^-1 of data recorded at the center-of- mass energies in the range 183-207 GeV with the OPAL detector at LEP. The Measured…
Subtle field-theoretical effects suggest the presence of additional Higgs contributions in standard model processes. This has been supported by electroweak lattice calculation, e.\ g.\ for vector boson scattering. These effects can be…