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Csaba Csaki

Publications and source records attributed to Csaba Csaki.

At least 109 records · Page 6Linked to original sources
arXiv1998

Glueball Mass Spectrum From Supergravity

We calculate the spectrum of glueball masses in non-supersymmetric Yang-Mills theory in three and four dimensions, based on a conjectured duality between supergravity and large N gauge theories. The glueball masses are obtained by solving supergravity wave equations in a black hole geometry. We find that the mass ratios are in good numerical agreement with the available lattice data. We also compute the leading (g_{YM}^2 N)^{-1} corrections to the glueball masses, by taking into account stringy corrections to the supergravity action and to the black hole metric. We find that the corrections to the masses are negative and of order (g_{YM}^2N)^{-3/2}. Thus for a fixed ultraviolet cutoff the masses decrease as we decrease the 't Hooft coupling, in accordance with our expectation about the continuum limit of the gauge theories.

hep-th↗
arXiv1998

't Hooft Anomaly Matching for Discrete Symmetries

We show how to extend the 't Hooft anomaly matching conditions to discrete symmetries. We check these discrete anomaly matching conditions on several proposed low-energy spectra of certain strongly interacting gauge theories. The excluded examples include the proposed chirally symmetric vacuum of pure N=1 supersymmetric Yang-Mills theories, certain non-supersymmetric confining theories and some self-dual N=1 supersymmetric theories based on exceptional groups.

hep-th↗
arXiv1998

Instantons in Partially Broken Gauge Groups

We discuss the effects of instantons in partially broken gauge groups on the low-energy effective gauge theory. Such effects arise when some of the instantons of the original gauge group G are no longer contained in (or can not be gauge rotated into) the unbroken group H. In cases of simple G and H, a good indicator for the existence of such instantons is the ``index of embedding.'' However, in the general case one has to examine π_3(G/H) to decide whether there are any instantons in the broken part of the gauge group. We give several examples of supersymmetric theories where such instantons exist and leave their effects on the low-energy effective theory.

hep-th↗
arXiv1998

Gauge Theories with Tensors from Branes and Orientifolds

We present brane constructions in Type IIA string theory for N=1 supersymmetric SO and Sp gauge theories with tensor representations using an orientifold 6-plane. One limit of these set-ups corresponds to N=2 theories previously constructed by Landsteiner and Lopez, while a different limit yields N=1 SO or Sp theories with a massless tensor and no superpotential. For the Sp-type orientifold projection comparison with the field theory moduli space leads us to postulate two new rules governing the stability of configurations of D-branes intersecting the orientifold. Lifting one of our configurations to M-theory by finding the corresponding curves, we re-derive the N=1 dualities for SO and Sp groups using semi-infinite D4 branes.

hep-th↗
arXiv1998

Classification of the N=1 Seiberg-Witten Theories

We present a systematic study of N=1 supersymmetric gauge theories which are in the Coulomb phase. We show how to find all such theories based on a simple gauge group and no tree-level superpotential. We find the low-energy solution for the new theories in terms of a hyperelliptic Seiberg-Witten curve. This work completes the study of all N=1 supersymmetric gauge theories where the Dynkin index of the matter fields equals the index of the adjoint (mu=G), and consequently all theories for which mu<G.

hep-th↗
arXiv1997

Discrete Anomaly Matching

We extend the well-known 't Hooft anomaly matching conditions for continuous global symmetries to discrete groups. We state the matching conditions for all possible anomalies which involve discrete symmetries explicitly. There are two types of discrete anomalies. For Type I anomalies, the matching conditions have to be always satisfied regardless of the details of the massive bound state spectrum. The Type II anomalies have to be also matched except if there are fractionally charged massive bound states in the theory. We check discrete anomaly matching in recent solutions of certain N=1 supersymmetric gauge theories, most of which satisfy these constraints. The excluded examples include the chirally symmetric phase of N=1 pure supersymmetric Yang-Mills theories described by the Veneziano-Yankielowicz Lagrangian and certain non-supersymmetric confining theories. The conjectured self-dual theories based on exceptional gauge groups do not satisfy discrete anomaly matching nor mapping of operators, and are viable only if the discrete symmetry in the electric theory appears as an accidental symmetry in the magnetic theory and vice versa.

hep-th↗
arXiv1997

Duality in Sp and SO Gauge Groups from M Theory

We describe fivebrane configurations in M theory whose 4-d spacetime contains N=1 supersymmetric Sp or SO gauge fields and fundamentals of these groups. We show how field-theory dualities for Sp and SO groups can be derived using these fivebrane configurations in M theory.

hep-th↗
arXiv1997

Confinement in N=1 SUSY Gauge Theories and Model Building Tools

We develop a systematic approach to confinement in N=1 supersymmetric theories. We identify simple necessary conditions for theories to confine without chiral symmetry breaking and to generate a superpotential non-perturbatively (s-confine). Applying these conditions we identify all N=1 theories with a single gauge group and no tree-level superpotential which s-confine. We give a complete list of the confined spectra and superpotentials. Some of these theories are of great interest for model building. We give several new examples of models which break supersymmetry dynamically.

hep-th↗
arXiv1997

Self-Dual N=1 SUSY Gauge Theories

We present a large set of new self-dual N=1 SUSY gauge theories. Examples include SU(N) theories with tensors and SO(N) theories with spinors. Using these dualities as starting points, new non-trivial duals can be derived by higgsing the gauge group or by integrating out matter. General lessons that can be learned from these duals are: ``accidental" infrared symmetries play an important role in duality, many theories have more than one ``dual", and there seems to be no simple organizing pattern which relates duals of theories with different number of flavors.

hep-th↗
arXiv1996

Are the Supersymmetric Higgs Particles Pseudo-Goldstone Bosons?

A promising solution to the doublet-triplet splitting problem of SUSY GUT's is the Higgs as pseudo-Goldstone boson mechanism. We present two models which naturally implement this idea and extend one of them to include fermion masses. We examine the phenomenological consequences of this mechanism and present the favored parameter region.

hep-ph↗
arXiv1996

A Systematic Approach to Confinement in N=1 Supersymmetric Gauge Theories

We give necessary criteria for N=1 supersymmetric theories to be in a smoothly confining phase without chiral symmetry breaking and with a dynamically generated superpotential. Using our general arguments we find all such confining SU and Sp theories with a single gauge group and no tree level superpotential.

hep-th↗
arXiv1996

Exact Results and Duality for SP(2N) SUSY Gauge Theories with an Antisymmetric Tensor

We study supersymmetric Sp(2N) gauge theories with matter in the antisymmetric tensor representation and F fundamentals. For F=6 we solve the theory exactly in terms of confined degrees of freedom and a superpotential. By adding mass terms we obtain the theories with F<6 which we find to exhibit a host of interesting non-perturbative phenomena: quantum deformed moduli spaces with N constraints, instanton-induced superpotentials and non-equivalent disjoint branches of moduli spaces. We find a simple dual for F=8 and no superpotential. We show how the F=4 and F=2 theories can be modified to break supersymmetry spontaneously and point out that the Sp(6) theory with F=6 may be very interesting for model builders.

hep-th↗
arXiv1996

Supersymmetry Breaking Through Confining and Dual Theory Gauge Dynamics

We show that theories in the confining, free magnetic, and conformal phases can break supersymmetry through dynamical effects. To illustrate this, we present theories based on the gauge groups $SU(n)\times SU(4)\times U(1)$ and $SU(n) \times SU(5) \times U(1)$ with the field content obtained by decomposing an $SU(m)$ theory with an antisymmetric tensor and $m-4$ antifundamentals.

hep-th↗
arXiv1996

The Minimal Supersymmetric Standard Model (MSSM)

The structure of the MSSM is reviewed. We first motivate the particle content of the theory by examining the quantum numbers of the known standard model particles and by the requirement of anomaly cancellation. Once the particle content is fixed we can write down the most general renormalizable superpotential. However such a superpotential will contain terms breaking lepton and baryon number which leads us to the concept of R-parity conservation. The question of supersymmetry breaking is discussed next. We list the possible soft breaking terms. However the Lagrangian involving the most general soft breaking terms is phenomenologically intractable because of the appearance of the many new parameters. It also leads to some unacceptable predictions. To reduce the number of parameters we restrict ourself to the case with universal soft breaking terms at the GUT scale. We motivate the need for universal soft breaking terms by the apparent unification of gauge couplings in the MSSM and by the absence of flavor changing neutral currents. Then we discuss radiative electroweak symmetry breaking. Radiative breaking arises because the one loop corrections involving the large top Yukawa coupling change the sign of the soft breaking mass parameter of the up-type Higgs doublet, this way introducing a nontrivial minimum in the Higgs potential. Finally we give an overview of the possible mixings in the MSSM and enumerate the physical (mass eigenstate) fields together with the mass matrices.

hep-ph↗
arXiv1996

More Dynamical Supersymmetry Breaking

In this paper we introduce a new class of theories which dynamically break supersymmetry based on the gauge group SU(n)xSU(3)xU(1) for even n. These theories are interesting in that no dynamical superpotential is generated in the absence of perturbations. For the example SU(4)xSU(3)xU(1) we explicitly demonstrate that all flat directions can be lifted through a renormalizable superpotential and that supersymmetry is dynamically broken. We derive the exact superpotential for this theory, which exhibits new and interesting dynamical phenomena. For example, modifications to classical constraints can be field dependent. We also consider the generalization to SU(n)xSU(3)xU(1) models (with even n>4). We present a renormalizable superpotential which lifts all flat directions. Because SU(3) is not confining in the absence of perturbations, the analysis of supersymmetry breaking is very different in these theories from the n=4 example. When the SU(n) gauge group confines, the Yukawa couplings drive the SU(3) theory into a regime with a dynamically generated superpotential. By considering a simplified version of these theories we argue that supersymmetry is probably broken.

hep-th↗
arXiv1995

Phenomenological Constraints on the Higgs as Pseudo-Goldstone Boson Mechanism in Supersymmetric GUT Theories

There are few robust solutions to the doublet-triplet splitting problem in supersymmetric GUT theories. One of the more promising solutions is the Higgs as pseudo-Goldstone boson mechanism. In its minimal implementation, such a solution places an additional restriction on the parameter space of the minimal supersymmetric standard model. A testable consequence of this constraint is an equation for $\tan β$. We present this restriction and study its solutions in order to constrain the allowed parameter space. Thus the assumptions on the GUT scale Higgs sector should yield testable predictions for weak scale physics. If the SUSY parameters are measured then it should be possible to check the predictions, yielding insight into GUT scale physics.

hep-ph↗
arXiv1995

Could the Supersymmetric Higgs Particles Naturally be Pseudo-Goldstone Bosons?

The doublet-triplet splitting problem is perhaps the most problematic aspect of supersymmetric grand unified theories. It can be argued that the most natural reason for the Higgs doublets to be light is that they are pseudo-Goldstone bosons associated with the spontaneous breakdown of an accidental global symmetry. In this paper we discuss the possibility of implementing this idea in the SU(6) model of refs. \cite{Zur,Bar2,Bar3,Bar4}. We show that although it is simple to generate an accidental symmetry of the renormalizable terms of the potential, it is quite difficult to construct a model which allows for the preservation of the accidental symmetry in the nonrenormalizable terms. We summarize the constraints on such models and then give three different ways to construct a superpotential where the dangerous mixing terms are sufficiently suppressed even in the presence of nonrenormalizable operators. With these examples we demonstrate the existence of consistent models implementing the Higgs as pseudo-Goldstone boson scheme. We extend one of the three examples to include fermion masses. We also show that when restricted to regular group embeddings the only possible models without light triplets are trivial generalizations of the SU(6) model we consider.

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