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We examine theoretical features of $U(1)_X$ extensions of the Standard Model whose quantum anomalies are canceled per generation. Similarly to other versions, the theory consists of a Two-Higgs-Doublet Model plus a scalar singlet embedded…
We construct the complete coupling of $(1,0)$ supergravity in six dimensions to $n$ tensor multiplets, extending previous results to all orders in the fermi fields. We then add couplings to vector multiplets, as dictated by the generalized…
We study a supersymmetry breaking mechanism in the context of a minimal anomalous extension of the MSSM. The anomaly cancellation mechanism is achieved through suitable counterterms in the effective action, i.e. Green-Schwarz terms. We…
We discuss, in conformally invariant field theories such as QCD with massless fermions, a possible link between the perturbative signature of the conformal anomaly, in the form of anomaly poles of the 1-particle irreducible effective…
We study light spin-1 gauge bosons coupled to electroweak-anomalous currents. For generic charge assignments, anomaly cancellation requires new fermions (anomalons) that are chiral under the new abelian symmetry and carry electroweak…
We construct a new set of intersecting D4-brane models that yield the (non-supersymmetric) standard model up to vector-like matter and, in some cases, extra U(1) factors in the gauge group. The models are constrained by the requirement that…
Four-dimensional strings with the standard model gauge group $SU(3)\times SU(2)\times U(1)$ give model-dependent predictions for the tree level weak mixing-angle. In the presence of an extra pseudo-anomalous gauged- ${U(1)}_X$, the value of…
We analyze causality and unitarity constraints in graviton scattering amplitudes, aiming to establish new bounds on theories with $U(1)$-gravitational anomalies, such as axion models or strongly-coupled gauge theories. For this purpose, we…
The five dimensional version of the Green-Schwarz mechanism can be invoked to cancel U(1) anomalies on the boundaries of brane world models. In five dimensions there are two dual descriptions that employ either a two-form tensor field or a…
We apply the path-integral formalism to compute the anomalies in general orbifold gauge theories (including possible non-trivial Scherk-Schwarz boundary conditions) where a gauge group G is broken down to subgroups H_f at the fixed points…
The phenomenon known as ``anomaly mediation" can be understood in a variety of ways. Rather than an anomaly, certain gaugino bilinear terms are required by local supersymmetry and gauge invariance (the derivation of these terms is in some…
We consider a class of gauged $U(1)$ extensions of the Standard Model (SM), where the light neutrino masses are generated by an inverse seesaw mechanism. In addition to the three right handed neutrinos, we add three singlet fermions and…
New $U(1)$ gauge theories involving Standard Model (SM) fermions typically require additional electroweak fermions for anomaly cancellation. We study the non-decoupling properties of these new fermions, called anomalons, in the…
We derive new constraints on light vectors coupled to Standard Model (SM) fermions, when the corresponding SM current is broken by the chiral anomaly. Cancellation of the anomaly by heavy fermions results, in the low-energy theory, in…
Perturbative unitarity is a powerful tool for inferring the range of validity of a given effective field theory. Here, we study such a bound in the parameter space of dimension-5 and dimension-6 effective operators that arise in a scenario…
We present a study of anomalous electroweak gauge-boson couplings which can be measured in e+e- and gamma gamma collisions at a future linear collider like ILC. We consider the gauge-boson sector of a locally SU(2) x U(1) invariant…
We review and clarify the cancellation conditions for gauge anomalies which occur when N=1, D=4 supergravity is coupled to a Kahler non-linear sigma-model with gauged isometries and Fayet-Iliopoulos couplings. For a flat sigma-model target…
I remark that the weak mixing angle in the standard model may be computed even in the absence of a grand unification symmetry. In particular, if there is an additional gauged $U(1)$ symmetry at some large scale which can be made…
In previous work, we showed that an anomaly in the one point function of marginal operators is related by the Wess-Zumino condition to the Euler density anomaly on a two dimensional defect or boundary. Here we analyze in detail the two…
We present a comprehensive analysis of supersymmetry anomalies in the free and massless Wess-Zumino (WZ) model in perturbation theory. At the classical level the model possesses ${\mathcal N}=1$ superconformal symmetry, which is partially…