We discuss possible searches for the new particles predicted by Little Higgs Models at the LHC. By using a simulation of the ATLAS detector, we demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained.

We present the results of the gluino and scalar quark contribution to the flavor-changing top quark decay into a charm quark and a photon, gluon, or a Z0 boson within the minimal supersymmetric standard model. We include the mixing of the scalar partners of the left-and right-handed top quark. This mixing has several effects, the most important of which is to greatly enhance the cZ decay mode for large values of the soft SUSY-breaking scalar mass ms and to give rise to a GIM-like suppression in the cy mode for certain combinations of parameters. PACS number(s): 12.60.Jv, 14.65.Ha Recent experimental evidence of the top quark [I] makes its rare decay modes a promising test ground for the standard model (SM) and physics beyond the SM. The flavor-changing decay mode of the top quark was calculated within the SM in [2-61 and their branching ratioswere shown to be -10-l2 for t + CY, -10-12-10-13 for t + c Z and for t -+ cg in the top mass range 90-200 GeV, thus far away from experimental reach; this makes it a n excellent probe for models beyond the SM. Two-Higgs-doublet models (THDM's) were considered in [6,7], where it was shown that the decay rate is enhanced by several (3-4) orders of magnitude. Recently [8], the

No abstract

We calculate the contribution of second generation scalar leptoquarks to the anomalous magnetic moment of the muon (AMMM). In the near future, E-821 at Brookhaven will reduce the experimental error on this parameter to ∆a exp µ < 4 × 10 −10 , an improvement of 20 over its current value. With this new experimental limit we obtain a lower mass limit of m Φ L > 186 GeV for the second generation scalar leptoquark, when its Yukawa-like coupling λ Φ L to quarks and leptons is taken to be of the order of the electroweak coupling g 2 .

No abstract