Jacek Pawelczyk

SU(2) WZW D-branes and their noncommutative geometry from DBI action

Using properties of the DBI action we find D-branes on S3 of the radius Q5 corresponding to the conjugacy classes of SU(2). The branes are stable due to nonzero 2-form NSNS background. In the limit of large Q5 the dynamics of branes is governed by the non-commutative Yang-Mills theory.

Note on anomalies in the AdS-CFT correspondence

We test the AdS-CFT correspondence in the case of a d=4 N=2 superconformal field theory by comparing chiral anomalies which are of order [ital N] in the [close quote]t Hooft large [ital N] limit. These include corrections of order 1/N to the conformal anomaly, thus testing the correspondence beyond the extreme large [ital N] limit. The field theory anomalies are reproduced by terms in the 7-brane effective action in the bulk. [copyright] [ital 1999] [ital The American Physical Society]

Ramond–Ramond flux stabilization of D-branes

Abstract In AdS n × S m threaded by N -units of Ramond–Ramond flux, the dynamics of a D m -brane wrapped partially on S m −1 ⊂ S m is investigated. Under the condition that flux of the dual gauge field on the D-brane world-volume is quantized integrally, it is found that the wrapped D-brane is stable both locally and globally and, on AdS n , behaves effectively as a fundamental string. It is also claimed that the semi-infinite, partially wrapped D m -brane can ‘lasso’ around the S m .

A quantum algebraic description of D-branes on group manifolds

Abstract We propose an algebraic description of (untwisted) D-branes on compact group manifolds G using quantum algebras related to U q ( g ) . It reproduces the known characteristics of stable branes in the WZW models, in particular their configurations in G, energies as well as the set of harmonics. Both generic and degenerate branes are covered.

On low-energy predictions of unification models inspired by F-theory

Abstract The aim of this Letter is to discuss phenomenological consequences of a particular unification model ( Z 3 model) inspired by F-theory. The most distinctive feature of this model is a variety of (cosmologically feasible) options for the NLSP and NNLSP, beyond the usually considered benchmark scenarios.

Matrix description of D-branes on 3-spheres ⁄

We discuss a matrix model for D0-branes on S3 × M7 based on quantum group symmetries. For finite radius of S3, it gives results beyond the reach of the ordinary matrix model. For large radius of S3 all known static properties of branes on S3 are reproduced.

F-theory inspired GUTs with extra charged matter

Abstract We consider GUT models inspired by recent local F-theory constructions. We show that after switching on vevs to scalars the extra matter becomes messengers. We discuss conditions on these vevs under which the models do not lead to unacceptable baryon/lepton number violating processes.

Algebraic brane dynamics on SU(2): excitation spectra

We analyze the dynamics of D2-branes on SU(2) within a recently proposed matrix model, which works for finite radius of SU(2). The spectrum of single-brane excitations turns out to be free of tachyonic modes. It is similar to the spectrum found using DBI and CFT calculations, however the triplet of rotational zero modes is missing. This is attributed to a naive treatment of the quantum symmetries of the model. The mass of the lightest states connecting two different branes is also calculated, and found to be proportional to the arc length for small angles.

Light elementary pseudoscalars within the framework of effective lagrangians

Abstract The total, effective, low energy lagrangian for K → π + pseudoscalar decays has been derived for any model involving light elementary pseudoscalars. As an illustration, branching ratios for those decays have been calculated for a two-Higgs doublet model in which only one Higgs doublet couples to quarks. Experimentally allowed regions in the parameter space have been found.

Hierarchy of Yukawa couplings from orbifold compactification

Abstract It is shown that “blown-up” orbifolds may provide a natural mechanism for generating a realistic hierarchy of Yukawa couplings. An explicit example on the Z 3 orbifold is given.