Related papers: Solving the strong CP problem in string-inspired t…
We formulate general conditions under which the strong CP problem is solved by spontaneous CP violation. Quark-mass matrix elements are polynomials in the CP-breaking order parameters, engineered such that their determinant is a real…
We review recent work on the strong CP problem in the context of realistic string-inspired models. We discuss the various solutions, review the conjecture that CP is generally a gauged discrete symmetry in string theory and then consider…
CP has a natural embedding in superstring models as a gauge symmetry involving inversion of the compactified space. Hence the source of CP violation could be geometrical. Such models face the problem of how to suppress contributions to…
We examine the possibility that the strong CP problem is solved by string-theoretic axions in strong-coupling limit of the E_8 x E_8 heterotic string theory (M-theory). We first discuss some generic features of gauge kinetic functions in…
Modular localization and the theory of string-localized fields have revolutionized several key aspects of quantum field theory. They reinforce the contention that local symmetry emerges directly from quantum theory, but global gauge…
We consider the phenomenological implications of a class of compactified string theories which naturally reproduces the flavour multiplet structure of the Standard Model. The implications for gauge unification depends on which of three…
I briefly review solutions to the strong CP problem based on axions, parity invariance, CP-invariance, and present a new idea based on CP as part of a spontaneously broken flavour symmetry such as a U(1) or modular invariance.
We discuss a possible solution to the strong CP problem which is based on spontaneous CP violation and discrete symmetries. At the same time we predict in a simple way the almost right-angled quark unitarity triangle angle ($\alpha \simeq…
Recently, it was shown that modular symmetry may solve the strong CP problem without axions, by producing a vanishing QCD angle while generating a large quark CP violation phase. We extend this framework to finite modular groups,…
If nature is described by string theory, and if the compactification radius is large (as suggested by the unification of couplings), then the theory is in a regime best described by the low energy limit of $M$-theory. We discuss some…
The dynamics of superstring, supergravity and M theories and their compactifications are probed by studying the various perturbation theories that emerge in the strong and weak coupling limits for various directions in coupling constant…
We present a study of dark matter and the strong CP problem within a globally consistent framework of Type IIA string theory, compactified on a $T^6/(\mathbb{Z}_2 \times \mathbb{Z}_2)$ orientifold with intersecting D6-branes (Model A), for…
We use recently obtained 2-loop string coupling constants to analyze a class of string models based on orbifold compactification. Assuming weak coupling at the string scale and single-scale unification leads to restrictions on the spectrum…
We consider some questions of naturalness which arise when one considers conventional field theories in the presence of gravitation: the problem of global symmetries, the strong CP problem, and the cosmological constant problem. Using…
We present simple effective theory of quark masses, mixing and CP violation with level $N=3$ ($A_4$) modular symmetry, which provides solution to the strong CP problem without the need for an axion. The vanishing of the strong CP-violating…
We discuss the strong CP problem in the context of quantum field theory in the presence of horizons. We argue that general covariance places constraints on the topological structure of the theory. In particular, as in QCD, it means that…
We suggest a new solution to the strong CP problem. The solution is based on the proper use of the boundary conditions for the QCD generating functional integral. We expand the perturbative boundary conditions to both perturbative and…
Strong - weak coupling duality in string theory allows us to compute physical quantities both at the weak coupling end and at the strong coupling end. Furthermore perturbative string theory can be used to compute corrections to the leading…
The role of moduli stabilization in predictions for CP violation is examined in the context of four-dimensional effective supergravity models obtained from the weakly coupled heterotic string. We point out that while stabilization of…
I discuss how anomalies affect classical symmetries and how, in turn, the non-trivial nature of the gauge theory vacuum makes these quantum corrections troublesome. Although no solution seems in sight for the cosmological constant problem,…