Generalized Supergravity Equations and Generalized Fradkin-Tseytlin Counterterm

The generalized Fradkin-Tseytlin counterterm for the (type I) Green-Schwarz superstring is determined for background fields satisfying the generalized supergravity equations (GSE). For this purpose, we revisit the derivation of the GSE based upon the requirement of kappa-symmetry of the superstring action. Lifting the constraint of vanishing bosonic torsion components, we are able to make contact to several different torsion constraints used in the literature. It is argued that a natural geometric interpretation of the GSE vector field that generalizes the dilaton is as the torsion vector, which can combine with the dilatino spinor into the torsion supervector. To find the counterterm, we use old results for the one-loop effective action of the heterotic sigma model. The counterterm is covariant and involves the worldsheet torsion for vanishing curvature, but cannot be constructed as a local functional in terms of the worldsheet metric. It is shown that the Weyl anomaly cancels without imposing any further constraints on the background fields. In the case of ordinary supergravity, it reduces to the Fradkin-Tseytlin counterterm modulo an additional constraint.Comment: 23 pages, v2: added reference and extended discussion of the counterter

Regular and irregular boundary conditions in AdS/CFT correspondence for spinor field

In a recent paper Klebanov and Witten (hep-th/9905104) proposed to formulate the AdS/CFT correspondence principle by taking an "irregular boundary condition" for a scalar field. In this paper we generalize this idea to the case of spinor field with interaction. The action functional following from the choice of irregular boundary conditions and which must be used in the AdS/CFT correspondence is related to the usual action by a Legendre transform. For the new theory we found the modified Green's function that must be used for internal lines in calculating higher order graphs. It is proved that the considerations are valid to all orders in perturbation theory.Comment: 10 pages, one more reference and comment added, some typos correcte

Precise predictions for MSSM Higgs-boson production in bottom-quark fusion

The main production mechanism for supersymmetric Higgs particles at hadron colliders crucially depends on the size of their Yukawa couplings to bottom quarks. For sufficiently large tan(beta) the total cross section for some of the neutral Higgs bosons in the MSSM is dominated by bottom-quark fusion. After an introduction to bottom-associated Higgs production, we discuss the complete O(alpha) electroweak and O(alpha_s) strong corrections for the bb-fusion channel in the MSSM. Choosing proper renormalization and input-parameter schemes, an improved Born approximation, constructed from previously known results, can absorb the bulk of the corrections so that the remaining non-universal corrections are typically of the order of a few per cent. Numerical results are discussed for the SPS benchmark scenarios.Comment: Submitted for the SUSY07 proceedings, 4 pages, 2 figure

On the number of soft quanta in classical field configurations

A crucial ingredient in the large-N quantum portrait of black holes proposed by Dvali and Gomez is the estimate of the number of soft quanta that make up the classical gravitational field. It is argued here that the coherent state formalism provides a way to calculate that number directly. As a consequence, the average energy of the soft quanta is such that the typical geometric size of the field source can be roughly interpreted as their de Broglie wavelength. The calculation is done for the electromagnetic field and for Newtonian gravity, and it is argued that the number of soft quanta should be unchanged in General Relativity due to the long range nature of gravity.Comment: 5 pages, v.2: small text changes and added reference

An improved correspondence formula for AdS/CFT with multi-trace operators

An improved correspondence formula is proposed for the calculation of correlation functions of a conformal field theory perturbed by multi-trace operators from the analysis of the dynamics of the dual field theory in Anti-de Sitter space. The formula reduces to the usual AdS/CFT correspondence formula in the case of single-trace perturbations.Comment: 6 pages, v.2: minor corrections, v.3: version to appear in PL

Note on the boundary terms in AdS/CFT correspondence for Rarita-Schwinger field

In this letter the boundary problem for massless and massive Rarita-Schwinger field in the AdS/CFT correspondence is considered. The considerations are along the lines of a paper by Henneaux (hep-th/9902137) and are based on the requirement the solutions to be a stationary point for the action functional. It is shown that this requirement, along with a definite asymptotic behavior of the solutions, fixes the boundary term that must be added to the initial Rarita-Schwinger action. It is also shown that the boundary term reproduce the known two point correlation functions of certain local operators in CFT living on the boundary.Comment: 12 pages, one more refernce added, some typos correcte

Gauge Dependence in the AdS/CFT Correspondence

We consider the AdS space formulation of the classical dynamics deriving from the Stueckelberg Lagrangian. The on-shell action is shown to be free of infrared singularities as the vector boson mass tends to zero. In this limit the model becomes Maxwell theory formulated in an arbitrary covariant gauge. Then we use the AdS/CFT correspondence to compute the two-point correlation functions on the boundary. It is shown that the gauge dependence concentrates on the contact terms.Comment: 13 pages, REVTEX, misprints in the abstract corrected. Minor changes. Version to be publishe

Quantum Portrait of a Black Hole with P\"oschl-Teller Potential

We improve upon the simple model studied by Casadio and Orlandi [JHEP 1308 (2013) 025] for a black hole as a condensate of gravitons. Instead of the harmonic oscillator potential, the P\"oschl-Teller potential is used, which allows for a continuum of scattering states. The quantum mechanical model is embedded into a relativistic wave equation for a complex Klein-Gordon field, and the charge of the field is interpreted as the gravitational charge (mass) carried by the graviton condensate.Comment: 12 pages, 1 figure, v2: typos correcte

Resonance-improved parton-shower matching for the Drell-Yan process including electroweak corrections

We use the POWHEG method to perform parton-shower matching for Drell-Yan production of W and Z bosons at the LHC at NLO QCD and NLO electroweak accuracy. In particular, we investigate an improved treatment of the vector-boson resonances within the POWHEG method. We employ an independent implementation of the POWHEG method and compare to earlier results within the POWHEGBOX. On the technical side, we provide the FKS formalism for photon-radiation off fermions within mass regularization.Comment: 29 pages, 6 figures, extended discussions; version published in JHE