Observable signals of gauge-mediated supersymmetry breaking

The observable consequences of gauge-mediated supersymmetry breaking (GMSB) are reviewed here. Implications of scenarios both with a neutralino and a slepton as the next lightest supersymmetric particle (NLSP) are surveyed in relation to hadronic ande ⁺ e ^- colliders. We also discuss the phenomenological consequences of the NLSP decaying slowly, giving rise to delayed events in the detectors.The importance of distinguishing signals of GMSB models from those of the commonly discussed supergravity-type theories is emphasized.     

Working group report: Neutrino and astroparticle physics

This is the report of neutrino and astroparticle physics working group at WHEPP-7. Discussions and work on CP violation in long baseline neutrino experiments, ultra high energy neutrinos, supernova neutrinos and water Cerenkov detectors are discussed.     

Incoherent X-ray scattering by K-shell electrons

Values of the incoherent scattering function S_K for scattering of photons from K-shell electrons are computed for ₂He, ₃Li, ₄Be and ₅B at photon energies 6, 10, 14, and 18 keV by using screened hydrogenic wavefunctions. The screening has been taken into account by the Thomas-Fermi model of the neutral atom. Unlike the previous calculations we have used a distorted Coulomb wavefunction for the ejected electron. The effects of Coulomb distortion and of screening corrections are discussed. It is shown that the screening correction and the Coulomb distortion in the ejected electron wavefunction play significant roles in the study of incoherent X-ray scattering by bound electrons.     

Are messages of R-parity violating supersymmetry hidden within top quark signals?

In an R-parity nonconserving supersymmetric theory, the lighter stop can dominantly decay into b&mgr; and btau if R-parity breaking has to explain the neutrino mass and mixing pattern suggested by the data on atmospheric muon neutrinos. This should give rise to dilepton + dijet and single - lepton + jets, signals identical with those of the top quark at the Fermilab Tevatron. One can thus constrain the stop parameter space using the current top search data and can similarly look for the first signals of supersymmetry at the upgraded runs of the Tevatron.     

The impossibility of heavy neutrino dark matter in the Littlest Higgs Model with T-parity: Constraints from direct search

We consider the Littlest Higgs Model with T-parity (LHT), in the parameter region where a heavy neutrino is the lightest T-odd particle (LTP). Having emphasized that this corresponds to a sizable region in the parameter space of the theory, we show that both the Cryogenic Dark Matter Search (CDMS) and Xenon10 experiments disallow the entire region where the masses of the new particles in LHT can lie within several TeV. Therefore, any observation of the signals of a heavy neutrino LTP is likely to seriously reopen the issue of cold dark matter in the universe.