Anomalous 4-Jet Events at LEP: a Signal of Low Scale Technicolour?

In multiscale and topcolor-assisted models of walking technicolor, light, spin-one technihadrons can exist with masses of a few hundred GeV; they are expected to decay as rho_T -> W pi_T. For technirho masses ~200 GeV and technipion masses ~100 GeV, the process pbar p -> rho_T -> W pi_T has a cross section of about a picobarn at the Tevatron. We demonstrate the detectability of this process with simulations appropriate to Run II conditions, for the challenging case where the ...

The motivations for studying dynamical scenarios of electroweak and flavor symmetry breaking are reviewed and the latest ideas, especially topcolor-assisted technicolor, are summarized. Technicolor's observable low-energy signatures are discussed. The superb energy resolution of the First Muon Collider may make it possible to resolve the extraordinarily narrow technihadrons that occur in such models--$\pi_T^0$, $\rho_T^0$, $\omega_T$--and produce them at very large rates comp...

LEPI and LEPII data can be used to constrain technicolor models with light, neutral pseudo-Nambu-Goldstone bosons, Pa. We use published limits on branching ratios and cross sections for final states with photons, large missing energy, jet pairs, and b bbar pairs to constrain the anomalous Pa Z0 Z0, Pa Z0 photon, and Pa photon photon couplings. From these results, we derive bounds on the size of the technicolor gauge group and the number of technifermion doublets in models suc...

We report the results of a search for second and third generation leptoquarks using 88 ${pb}^{-1}$ of data recorded by the Collider Detector at Fermilab. Color triplet technipions, which play the role of scalar leptoquarks, are investigated due to their potential production in decays of strongly coupled color octet technirhos. Events with a signature of two heavy flavor jets and missing energy may indicate the decay of a second (third) generation leptoquark to a charm (bottom...

If pairs of new colored particles are produced at the Large Hadron Collider, determining their quantum numbers, and even discovering them, can be non-trivial. We suggest that valuable information can be obtained by measuring the resonant signals of their near-threshold QCD bound states. If the particles are charged, the resulting signatures include photons and leptons and are sufficiently rich for unambiguously determining their various quantum numbers, including the charge, ...

Recently has been shown that the physical (mass eigenstate) color-octet technirho does not couple to two gluons. In this letter we study how this result affects the presently accepted limits for the color-octet technirho mass obtained from the study of dijets production at the Tevatron. First we show that data from Tevatron Run 1b can not exclude any mass range. Finally, we obtain limits for the Tevatron Run II.

In multiscale models of walking technicolor, relatively light color-singlet technipions are produced in $q \ol q$ annihilation in association with longitudinal $W$ and $Z$ bosons and with each other. The technipions decay as $\tpiz \ra b \ol b$ and $\tpip \ra c \ol b$. Their production rates are resonantly enhanced by isovector technirho vector mesons with mass $M_W + M_{\tpi} \simle M_{\tro} \simle 2 M_{\tpi}$. At the Tevatron, these associated production rates are 1--10 pic...

We discuss the production and decay rates of the lightest color-singlet technihadrons, spin-one rho_T and omega_T and spin-zero pi_T, in a minimal ``straw-man'' model of low-scale techicolor. The revised rho_T and omega_T decay rates affect the technicolor searches planned for Run II of the Tevatron Collider.

We consider the detection of the technirho in technicolor models that include a weak scalar doublet. In these models, the scalar develops a vacuum expectation value when the technifermions condense, and fermion masses are generated through Yukawa couplings, as in the standard model. Unlike ordinary technicolor models, the technicolor scale is generally smaller than the electroweak scale, and the entire technicolor spectrum is shifted to lower energies. In addition, the techni...

The Tevatron experiments CDF and DO are close to making definitive statements about the technicolor discovery mode rho_T -> W pi_T for M(rho_T) <~ 230 GeV and M(pi_T) <~ 125 GeV. We propose new incisive tests for this mode and searches for others that may be feasible at the Tevatron and certainly are at the LHC. The other searches include two long discussed, namely, omega_T -> gamma pi_T and l+l-, and a new one -- for the I^G J^{PC} = 1^- 1^{++} partner, a_T, of the rho_T. Ad...