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We discuss the sensitivity of the $e^+ e^- rightarrow W^+ W^-$ cross section at a future $e^+ e^-$ collider with $sqrt{s}=500$GeV to the non-decoupling effects of a techni-$rho$ like vector resonance. The non-decoupling effects are parametrized by the chiral coefficients of the electroweak chiral perturbation theory. We define renormalization scale independent chiral coefficients by subtracting the Standard Model loop contributions. We also estimate the size of the decoupling effects of the techni-$rho$ resonance by using a phenomenological Lagrangian including the vector resonance.
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Using the SU(3) flavor symmetry, we construct the chiral Lagrangians for the light and heavy pentaquarks. The correction from the nonzero quark is taken into account perturbatively. We derive the Gell-Mann$-$Okubo type relations for various pentaquark multiplet masses and Coleman-Glashow relations for anti-sextet heavy pentaquark magnetic moments. We study possible decays of pentaquarks into conventional hadrons. We also study the interactions between and within various pentaquark multiplets and derive their coupling constants in the symmetry limit. Possible kinematically allowed pionic decay modes are pointed out.
A revised and complete list of the electroweak chiral lagrangian operators up to dimension-four is provided. The connection of these operators to the $S$, $T$ and $U$ parameters and the parameters describing the triple gauge boson vertices $WWgamma$ and $WWZ$ is made, and the size of these parameters from new heavy physics is estimated using a one flavor-doublet model of heavy fermions. The coefficients of the chiral lagrangian operators are also computed in this model.
We add a nonstandard higgs into the traditional bosonic part of electroweak chiral Lagrangian, in purpose of finding out the contribution to EWCL coefficients from processes with internal line higgs particle. To construct the effective Lagrangian with higgs, we use low energy expansion scheme and write down all the independent terms conserving $SU(2)times U_Y(1)$ symmetry in the nonlinear representation which we show is equivalent to the linear representation. Then we integrate out higgs using loop expansion technique at 1-loop level, contributions from all possible terms are obtained. We find three terms, $mathcal{L}_5$, $mathcal{L}_7$, $mathcal{L}_{10}$ in EWCL are important, for which the contributions from higgs can be further expressed in terms of higgs partial decay width $Gamma_{hto ZZ}$ and $Gamma_{hto WW}$. Higg mass dependence of the coefficients in EWCL are discussed.
We present the results obtained by the WW Cross-sections and Distributions working group during the CERN Workshop Physics at LEP2 (1994/1995)
We present a consistent implementation of weak decays involving an axion or axion-like particle in the context of an effective chiral Lagrangian. We argue that previous treatments of such processes have used an incorrect representation of the flavor-changing quark currents in the chiral theory. As an application, we derive model-independent results for the decays $K^-topi^- a$ and $pi^-to e^-bar u_e a$ at leading order in the chiral expansion and for arbitrary axion couplings and mass. In particular, we find that the $K^-topi^- a$ branching ratio is almost 40 times larger than previously estimated.
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