RESUMO
Models of maximal flavor violation (MxFV) in elementary particle physics may contain at least one new scalar SU(2) doublet field Phi(FV)=(eta(0),eta(+)) that couples the first and third generation quarks (q_(1), q_(3)) via a Lagrangian term L(FV)=xi(13)Phi(FV)q(1)q(3). These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb(-1) collected by the Collider Dectector at Fermilab II detector in pp[over ] collisions at sqrt[s]=1.96 TeV are analyzed for evidence of the MxFV signature. For a neutral scalar eta(0) with m_(eta;(0))=200 GeV/c(2) and coupling xi(13)=1, approximately 11 signal events are expected over a background of 2.1+/-1.8 events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling xi(13) for m(eta(0)=180-300 GeV/c(2).
RESUMO
We consider the inclusive reaction l(+)l(-)-->nb+X ( n = number of b jets) in lepton colliders for which we propose a useful approximately conserved quantum number b(P) = (-1)(n) that we call b parity ( b(P)). We make the observation that the standard model (SM) is essentially b(P) even since SM b(P)-violating signals are necessarily Cabibbo-Kobayashi-Maskawa suppressed. In contrast new flavor physics can produce b(P) = -1 signals whose only significant SM background is due to b-jet misidentification. Thus, we show that b-jet counting, that relies primarily on b tagging, becomes a very simple and sensitive probe of new flavor physics (i.e., of b(P) violation).
