Projective Group Algebras

In this paper we apply a recently proposed algebraic theory of integration to projective group algebras. These structures have received some attention in connection with the compactification of the $M$ theory on noncommutative tori. This turns out to be an interesting field of applications, since the space $\hat G$ of the equivalence classes of the vector unitary irreducible representations of the group under examination becomes, in the projective case, a prototype of noncommuting spaces. For vector representations the algebraic integration is equivalent to integrate over $\hat G$. However, its very definition is related only at the structural properties of the group algebra, therefore it is well defined also in the projective case, where the space $\hat G$ has no classical meaning. This allows a generalization of the usual group harmonic analysis. A particular attention is given to abelian groups, which are the relevant ones in the compactification problem, since it is possible, from the previous results, to establish a simple generalization of the ordinary calculus to the associated noncommutative spaces.Comment: 24 pages, Late

Color superconductivity in high density QCD

In this contributed paper the gapless phases of QCD are discussed.Comment: Contributed paper to the Conference "Quark confinement ant the Hadron Spectrum VI 2004". Latex, 3 page

Algebraic treatment of compactification on noncommutative tori

In this paper we study the compactification conditions of the M theory on D-dimensional noncommutative tori. The main tool used for this analysis is the algebra A(Z^D) of the projective representations of the abelian group Z^D. We exhibit the explicit solutions in the space of the multiplication algebra of A(Z^D), that is the algebra generated by right and left multiplications.Comment: 8 pages, Latex, shortened version as accepted for publication in Physics Letter

Pseudo Goldstones at Future Colliders from the Extended Bess Model

We consider the production of the lightest pseudo-Goldstone bosons at future colliders through the vector resonances predicted by the extended BESS model, which consists of an effective lagrangian parametrization with dynamical symmetry breaking, describing scalar, vector and axial-vector bound states in a rather general framework. We find that the detection of pseudo-Goldstone pairs at LHC requires a careful evaluation of backgrounds. For e+e- collisions in the TeV range the backgrounds can be easily reduced and the detection of pseudo-Goldstone pairs is generally easier.Comment: 17 pages and 12 figures (included as a uuencoded tar file), LaTeX (style article), UGVA-DPT 1994/03-84

Inhomogeneous Color Superconductivity

We discuss the possibility that in finite density QCD an anisotropic phase is realized. This case might arise for quarks with different chemical potential and/or different masses. In this phase crystalline structures may be formed. We consider this possibility and we describe, in the context of an effective lagrangian, the corresponding phonons as the Nambu-Goldstone bosons associated to the breaking of the space symmetries.Comment: LaTex,20 pages, 6 figures. Talk at the International Workshop on QCD: QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614). Change in the CERN preprint numbe

New vector bosons in the electroweak sector: a renormalizable model with decoupling

A linear realization of a model of dynamical electroweak symmetry breaking describing additional heavy vector bosons is proposed. The model is a SU(2)_L x U(1) x SU(2)_L' x SU(2)_R' gauge theory, breaking at some high scale u to SU(2)_weak x U(1)_Y and breaking again in the standard way at the electroweak scale v to U(1)_(em). The model is renormalizable and reproduces the Standard Model in the limit u\to infinity. This decoupling property is shown to hold also at the level of radiative corrections by computing, in particular, the epsilon parameters.Comment: 39 pages, 16 Figures, Late