Background field method in the Wilson formulation

A cutoff regularization for a pure Yang-Mills theory is implemented within the background field method keeping explicit the gauge invariance of the effective action. The method has been applied to compute the beta function at one loop order.Comment: LaTex 13 pages, 1 figure; to appear in Nucl.Phys.

Spontaneous symmetry breaking with Wilson renormalization group

We study the conditions under which a symmetry is spontaneously broken in the Wilson renormalization group formulation. Both for a global and local symmetry, the result is that in perturbation theory one has to perform a fine tuning of the boundary conditions for the flow of the relevant couplings. We consider in detail the discrete $Z_2$ case and the Abelian Higgs model.Comment: 19 pages, latex, no figure

Beta function and infrared renormalons in the exact Wilson renormalization group in Yang-Mills theory

We discuss the relation between the Gell-Mann-Low beta function and the ``flowing couplings'' of the Wilsonian action S_\L[\phi] of the exact renormalization group (RG) at the scale \L. This relation involves the ultraviolet region of \L so that the condition of renormalizability is equivalent to the Callan-Symanzik equation. As an illustration, by using the exact RG formulation, we compute the beta function in Yang-Mills theory to one loop (and to two loops for the scalar case). We also study the infrared (IR) renormalons. This formulation is particularly suited for this study since: $i$) \L plays the r\^ole of a IR cutoff in Feynman diagrams and non-perturbative effects could be generated as soon as \L becomes small; $ii$) by a systematical resummation of higher order corrections the Wilsonian flowing couplings enter directly into the Feynman diagrams with a scale given by the internal loop momenta; $iii$) these couplings tend to the running coupling at high frequency, they differ at low frequency and remain finite all the way down to zero frequency.Comment: 19 pages, 6 figures, LaTex, uses epsfig, rotatin

Gauge invariant action at the ultraviolet cutoff

We show that it is possible to formulate a gauge theory starting from a local action at the ultraviolet (UV) momentum cutoff which is BRS invariant. One has to require that fields in the UV action and the fields in the effective action are not the same but related by a local field transformation. The few relevant parameters involved in this transformation (six for the $SU(2)$ gauge theory), are perturbatively fixed by the gauge symmetry.Comment: 5 pages, Latex, no figure

Factorization and Discrete States in C=1 Superliouville Theory

We study the discrete state structure of $\hat c=1$ superconformal matter coupled to 2-D supergravity. Factorization properties of scattering amplitudes are used to identify these states and to construct the corresponding vertex operators. For both Neveu-Schwarz and Ramond sectors these states are shown to be organized in SU(2) multiplets. The algebra generated by the discrete states is computed in the limit of null cosmological constant.Comment: 23 pages, revtex, CNEA-CAB-92-036 and UPRF-92-35

Dilatation operator and Cayley graphs

We use the algebraic definition of the Dilatation operator provided by Minahan, Zarembo, Beisert, Kristijansen, Staudacher, proper for single trace products of scalar fields, at leading order in the large-N 't Hooft limit to develop a new approach to the evaluation of the spectrum of the Dilatation operator. We discover a vast number of exact sequences of eigenstates.Comment: 30 pages and 3 eps figures, v2: few typos correcte

Phosphoproteins associated with cyclic nucleotide stimulation of ciliary motility in Paramecium

Permeabilized, MgATP-reactivated cells of Paramecium (models) respond to cyclic AMP and cyclic GMP by increasing forward swimming speed. In association with the motile response, cyclic AMP and 8-bromo-cyclic GMP (8-Br-cyclic GMP) stimulated protein phosphorylation. Cyclic AMP addition to permeabilized cells reproducibly stimulated the phosphorylation of 10 proteins, ranging in molecular weight from 15 to 110K (K = 10^3 M_r). 8-Br-cyclic GMP, which selectively activates the cyclic GMP-dependent protein kinase of Paramecium, stimulated the phosphorylation of a subset of the proteins phosphorylated by cyclic AMP. Ca^(2+) addition caused backward swimming and stimulated the phosphorylation of four substrates, including a 25K target that may also be phosphorylated in response to cyclic nucleotide addition. Ba^(2+) and Sr^(2+) also induced backward swimming, but did not cause detectable phosphorylation. To identify ciliary targets of cyclic nucleotide-dependent protein kinase activity, permeabilized cells were deciliated following reactivation of motility with Mg-[y-^(32)P]ATP in the presence or absence of cyclic nucleotide. Soluble proteins of the deciliation supernatant were enriched in 15 cyclic AMP-stimulated phosphoproteins, ranging in molecular weight from 15 to 95K. Most of the ciliary substrates were axonemal and could be released by high salt solution. A 29K protein that copurified in sucrose gradients with the 22S dynein, and a high molecular weight protein (greater than 300K) in the 19 S region were phosphorylated when cyclic AMP was added to permeabilized, motile cells. These data suggest that regulation of ciliary motility by cyclic AMP may include phosphorylation of dynein-associated proteins