Effective Lagrangians for orientifold theories

Abstract

We construct effective Lagrangians of the Veneziano-Yankielowicz (VY) type for two non-supersymmetric theories which are orientifold daughters of supersymmetric gluodynamics (containing one Dirac fermion in the two-index antisymmetric or symmetric representation of the gauge group). Since the parent and daughter theories are planar equivalent, at N → ∞ the effective Lagrangians in the orientifold theories basically coincide with the bosonic part of the VY Lagrangian.We depart from the supersymmetric limit in two ways. First, we consider finite (albeit large) values of N . Then 1/N effects break supersymmetry. We suggest seemingly the simplest modification of the VY Lagrangian which incorporates these 1/N effects, leading to a non-vanishing vacuum energy density. We analyze the spectrum of the finite-N non-supersymmetric daughters. For N = 3 the two-index antisymmetric representation (one flavor) is equivalent to one-flavor QCD. We show that in this case the scalar quark-antiquark state is heavier than the corresponding pseudoscalar state, " η ′ ". Second, we add a small fermion mass term. The fermion mass term breaks supersymmetry explicitly. The vacuum degeneracy is lifted. The parity doublets split. We evaluate the splitting. Finally, we include the θ-angle and study its implications.

(In)validity of largeNorientifold equivalence

“…6 To summarize, the status of the large N "orientifold equivalence" discussed in Refs. [21][22][23][24][25][26][27] is no better (or worse) than that of similar large N orbifold equivalences. For all large N equivalences based on orbifold or orientifold projections, appropriate symmetry realization conditions are an unavoidable, and non-trivial, necessary condition for a useful equivalence.…”

“…(See also Refs. [25][26][27].) This latter theory will be abbreviated as QCD(AS) or QCD(S) in the antisymmetric or symmetric case, respectively.…”

QCD with one quark flavor: II. Analysis and chiral perturbation theory

“…The lightest hadron is the pseudoscalar η meson (see Table 2 and Figure 1) while the scalar meson, the σ , is about a factor 1.5 heavier. It is interesting to compare our data with the estimate in [47] m σ /m η N c /(N c − 2) = 3 for N c = 3. The above prediction applies for the massless theory and one could expect the agreement to improve for smaller quark masses.…”

Predictions for LHC from SO(4) MWT

“…The specific spectral properties of the composite states can be calculated via lattice simulations and depend on the specific underlying gauge theory. The first general classification of SU(N) gauge theories that can lead to phenomenologically acceptable composite electroweak theories appeared in [1,2,3], including the presence of a light composite Higgs-like state [4,5,6]. The generalization to SO, Sp and exceptional groups appeared in [7,8].…”

“…Second, the theory contains possibly light composite dark matter particles. These new light states emerge because the techni-fermions belong to a real representation, and therefore the chiral symmetry breaking pattern is expected to be SU(4)→SO (4). This leads to nine Goldstone bosons.…”