Related papers: Bounds to strong gravity from electron-positron an…
We discuss the interplay between direct constraints on non-Newtonian gravity and particle-physics bounds in models with large extra dimensions. Existing and future bounds and the most effective ways of further testing these models in…
We study the process e^+e^- --> W^+W^- to probe low-scale gravity at high energy linear colliders. A characteristic signature of extra-dimensions models is the forward-backward asymmetry due to the interference of spin-2 graviton and spin-1…
Dark matter annihilation into charged particles is necessarily accompanied by gamma rays, produced via radiative corrections. Internal bremsstrahlung from the final state particles can produce hard gamma rays up to the dark matter mass,…
A procedure to derive bounds on coupling strengths of exotic particles to nucleons from the neutrino signal of supernovae is outlined. The analysis is based on a model independent calculation for the emissivities for the exotic, detailed…
The total cross-sections measured at LEP for e+e- annihilation into tau+tau-, c\bar{c} and b\bar{b} at 2E ~ 200 GeV are used to derive the upper limits 3*10^{-17}, 5*10^{-17}, 2*10^{-17} e*cm for the electric dipole moments and 4*10^{-17},…
Radiative corrections due to pair production in process of electron-positron annihilation are considered. The main attention is paid to the corrections of the third order. Simultaneous emission of photons and pairs is taken into account.…
The BESS-Polar collaboration has recently performed a precise measurement of the local antiproton flux which is consistent with a pure secondary production of antiprotons. We constrain a possible primary component originating from dark…
In this paper we investigate supersymmetric effects to the threshold production cross section of top quark pairs in electron positron annihilation. In particular, we consider the complete one-loop corrections from the strong and weak sector…
Recent results on production and decays of polarized top quarks are reviewed. Top quark pair production in $e^+e^-$ annihilation is considered near energy threshold. For longitudinally polarized electrons the produced top quarks and…
It is shown that the processes of electron(positron) scattering and $e^+e^-$ pair production in the Coulomb fields of two relativistic ions, can be expressed through the amplitudes of lepton scattering off the ion Coulomb field via Watson…
High intensity back-scattered laser beams will allow the efficient conversion of a substantial fraction of the incident lepton energy into high energy photons, thus significantly extending the physics capabilities of an electron-electron or…
A process of the electron--positron pair production by neutrino propagating in a strong magnetic field is investigated in the framework of the Standard Model. The process probability and the mean values of the neutrino energy and momentum…
Annihilation of dark matter can result in the production of stable Standard Model particles including electrons and positrons that, in the presence of magnetic fields, lose energy via synchrotron radiation, observable as radio emission.…
The vanishing of the cross section for particular points in phase space - radiation zeros - is examined for the process $ q \bar q \to W^+W^- \gamma$ at high energy. Unlike the process $q \bar q' \to W^\pm \gamma$, actual zeros only occur…
Unparticles as suggested recently by Georgi have surprising phenomenological implications, distinctive from any other new physics that we know of. But they must interact very feebly with ordinary matter to have avoided detection thus far.…
An electron-positron linear collider in the energy range between 500 and 1000 GeV is of crucial importance to precisely test the Standard Model and to explore the physics beyond it. The physics program is complementary to that of the Large…
Limits on spin-0 axion-like-particles (ALPs) coupling to photons are reinterpreted as constraints on massive spin-2 graviton-like-particles (GLPs) with universal coupling $\alpha_\text{G}/M_\text{P}$ (where $M_\text{P}$ is the reduced…
Several recent studies have considered modifications to the standard weakly-interacting massive particle (WIMP) scenario in which the cross section (times relative velocity v) for pair annihilation is enhanced by a factor 1/v. Since…
Polarization studies for heavy quarks can lead to important tests of the Standard Model. Top quark pair production in $e^+e^-$ annihilation is considered near energy threshold. It is shown that for longitudinally polarized electrons the…
At the Large Hadron Collider, heavy particles may be produced in pairs close to their kinematic threshold. If these particles have strong enough attractive interactions they may form bound states. Consequently, the bound states may decay…