Related papers: Limits on the Size of Extra Dimensions and the Str…
The biggest question in beyond the standard model physics is what are the scales of new physics. Ideas about scales, as well as experimental evidence and constraints, are surveyed for a variety of possible forms of new physics:…
The standard picture of viable higher-dimensional theories is that extra dimensions manifest themselves at short distances only, their effects being negligible at scales larger than some critical value. We show that this is not necessarily…
Planck scale physics represents a future challenge, located between particle physics and general relativity. The Planck scale marks a threshold beyond which the old description of spacetime breaks down and conceptually new phenomena must…
String theory requires additional degrees of freedom to maintain world-sheet reparameterisation invariance at the quantum level. These are often interpreted as extra dimensions, beyond the 4 space-time. I discuss a class of quasi-realistic…
These four lectures, addressed to an audience of graduate students in experimental high energy physics, survey some of the basic concepts in string theory. The purpose is to convey a general sense of what string theory is and what it has…
This is a brief discussion of the following features of the Universal Extra Dimension (UED) model: (i) Formulation, (ii) Indirect bounds, (iii) Collider search and the Inverse Problem, (iv) Astrophysical bounds, and (v) UED with two extra…
Using the reduced formulation on large-N Quantum Field Theories we study strings in space-time dimensions higher that one. We present results on possible string susceptibilities, macroscopic loop operators, 1/N -corrections and other…
A review is given of recent research on two-dimensional gauge theories, with particular emphasis on the equivalence between these theories and certain string theories with a two-dimensional target space. Some related open problems are…
Recent work suggests that fundamental and Dirichlet strings, and their (p,q) bound states, may be observed as cosmic strings. The evolution of cosmic string networks, and therefore their observational signals, depends on what happens when…
In this talk, I discuss recent developments concerning the possibility of large extra spacetime dimensions. After briefly reviewing how such dimensions can lower the fundamental GUT, Planck, and string scales, I then outline how these…
After a brief description of the basic theoretical concepts of the string model approach, we discuss the limitations of the method, at low energies, at high energies, and at high particle densities. We also report on recent efforts to…
Theories of quantum gravity suggest the existence of a minimal length scale. We study the consequences of a particular implementation of the idea of a minimal length scale in the model of large extra dimensions, the ADD model. To do this we…
Lowering the string scale in the TeV region provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal…
The complementarity of $e^+e^-$ and $\gamma \gamma$ colliders to discover and explore new physics beyond the Standard Model(SM) is discussed. After briefly surveying a number of various new physics scenarios we concentrate in detail on…
This conference report briefly reviews the potential of the ATLAS and CMS experiments to discover evidence of extra dimensions.
To explain the large difference between the Planck scale and the electroweak scale, models in which gravity propagates in more than four dimensions have recently been proposed. In this paper, results from searches for extra dimensions at…
One of the drawbacks of conventional grand unification scenarios has been that the unification scale is too high to permit direct exploration. In this paper, we show that the unification scale can be significantly lowered (perhaps even to…
Large extra dimensions lower the Planck scale to values soon accessible. Motivated by String Theory, the models of large extra dimensions predict a vast number of new effects in the energy range of the lowered Planck scale, among them the…
Atomic and molecular transitions for high Z objects in the early universe give bounds to the possible existence of extra spatial dimensions $D = 3+\epsilon$. We review the theory and present observational data, based on Lyman and Balmer…
The introduction of extra space dimensions in the theory could be an elegant way tovsolve the hierarchy problem. There could even be one energy scale at which all interactions could unify. The limits coming from our knowledge of the…