Related papers: Type I anomaly cancellation revisited
We elaborate on an extension of the Standard Model with a gauge structure enlarged by a single anomalous U(1), where the presence of a Wess-Zumino term is motivated by the Green-Schwarz mechanism of string theory. The additional gauge…
Redefining the vacuum state of a free two-fold $N=1$ covariant supersymmetric string action as the one with all the excited states of world-sheet fermions occupied, makes the theory anomaly free in (3+1)+4 dimensions. While in the $NS$…
T-duality is a symmetry of the heterotic string to all orders in string perturbation theory. This results in an effective four dimensional supergravity theory with desirable features for phenomenology. T-duality, as well as, generically, an…
Using the Atiyah-Singer index theorem, we formally compute gravitational anomalies for fermionic higher-spin fields in two, six and ten dimensions, as well as the U(1) mixed gauge-gravitational anomaly in four dimensions. In all cases,…
We show that a choice of Pauli-Villars regulators allows the cancellation of all conformal and chiral anomalies in an effective field theory from Z_3 compactification of the heterotic string with two Wilson lines and an anomalous U(1).
We report on progress made in the construction of higher-derivative superinvariants for type-II theories in ten dimensions. The string amplitude calculations required for this analysis exhibit interesting features which have received little…
We study RR charge cancellation consistency conditions in string compactifications with open string sectors, by introducing D-brane probes in the configuration. We show that uncancelled charges manifest as chiral gauge anomalies in the…
In theories with chiral couplings, one of the important consistency requirements is that of the cancellation of a gauge anomaly. In particular, this is one of the conditions imposed on the hypercharges in the Standard Model. However,…
We describe a topological effect on configurations of D-branes in the presence of NS-NS and RR field strength fluxes. The fluxes induce the appearance of chiral anomalies on lower dimensional submanifolds of the D-brane worldvolume. This…
We investigate a Lorentz-violating chiral model composed by two fermions, a complex scalar field and a gauge field. We show that by convenientely adjusting the parameters of the model, it is possible to generate an unambiguous…
We consider a toroidal configuration of cosmic string in 3+1 dimensions in an abelian Higgs model, a compactification of the Nielsen-Olesen string. This object is classically unstable. We explicitly compute the number of permitted zero…
The restrictions imposed by anomaly cancellation on the chiral fermion content of nonsupersymmetric gauge theories based on various groups are studied in spacetime dimension D=6, 8, and 10. In particular, we show that the only…
In models with low-energy supersymmetry breaking, an anomalous Abelian horizontal gauge symmetry can simultaneously explain the fermion mass hierarchy and the values of the $\mu$ and $B$ terms. We construct an explicit model where the…
By dealing with the evaluation of string theory correlators of $<V_C V_T V_{\bar\Psi} V_\Psi>$, the complete and closed form of the amplitude of two fermion fields, one tachyon and one closed string Ramond-Ramond field in type IIB…
A gauged phase symmetry with its anomalies cancelled by a Green-Schwarz mechanism, broken at a large scale by an induced Fayet-Iliopoulos term, is a generic feature of a large class of superstring theories. It induces many desirable…
We consider, in a string theory framework, physical processes of phenomenological interest in models with a low string scale. The amplitudes we study involve tree-level virtual gravitational exchange, divergent in a field-theoretical…
In this paper we study the consistency of generalized global symmetries in theories of quantum gravity, in particular string theory. Such global symmetries arise in theories with $(p+1)$-form gauge fields, and for spacetime dimension $d\leq…
We compute the corrections to heterotic-string backgrounds with (2,0) world-sheet supersymmetry, up to two loops in sigma-model perturbation theory. We investigate the conditions for these backgrounds to preserve spacetime supersymmetry and…
We establish the non-perturbative validity of the gauge anomaly cancellation condition in an effective electroweak theory of massless fermions with finite momentum cut-off and Fermi interaction. The requirement that the current is conserved…
The Wess-Zumino consistency condition allows more exotic forms of anomalies than those we usually encounter. For example in two-dimensional conformal field theories in the curved background with space-time dependent coupling constant…