28 research outputs found

    The local RG equation and chiral anomalies

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    We generalize the local renormalization group (RG) equation to theories with chiral anomalies. We find that a new anomaly is required by the Wess-Zumino consistency conditions. Taking into account the new anomaly, the trace of the energy momentum tensor is expressed in terms of the covariant flavor currents, instead of the consistent ones. This result is used to show that a flavor rotation induced by the RG flow can be eliminated by a choice of scheme even in the presence of chiral anomalies. As part of a general discussion of chiral anomalies in the presence of background sources, we also derive non-renormalization theorems. Finally, we introduce the θ\theta parameter as a source, and derive constraints on a perturbative running of this parameter

    The local Callan-Symanzik equation: structure and applications

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    The local Callan-Symanzik equation describes the response of a quantum field theory to local scale transformations in the presence of background sources. The consistency conditions associated with this anomalous equation imply non-trivial relations among the β\beta-function, the anomalous dimensions of composite operators and the short distance singularities of correlators. In this paper we discuss various aspects of the local Callan-Symanzik equation and present new results regarding the structure of its anomaly. We then use the equation to systematically write the n-point correlators involving the trace of the energy-momentum tensor. We use the latter result to give a fully detailed proof that the UV and IR asymptotics in a neighbourhood of a 4D CFT must also correspond to CFTs. We also clarify the relation between the matrix entering the gradient flow formula for the β\beta-function and a manifestly positive metric in coupling space associated with matrix elements of the trace of the energy momentum tensor.Comment: v2: Modified discussion of the amplitude; v3: typos fixe

    Direct Mediation and a Visible Metastable Supersymmetry Breaking Sector

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    We analyze an R-symmetry breaking deformation of the ISS model for a direct mediation of supersymmetry breaking from a metastable vacuum. The model is weakly coupled and calculable. The LSP gravitino is light (m_{3/2}<16 eV) and the MSSM spectrum is natural with a light Higgs. The supersymmetry breaking sector, which is usually hidden, is observable (m~1 TeV) and may be a candidate for cold dark matter. We discuss its production and signature at LHC. We propose a UV completion of the model in terms of a duality cascade.Comment: 28 pages, 19 figures; reference added, improved section 7; modified decay diagrams, figures and related paragraph

    Testing confining potentials through meson/baryon hyperfine splitting ratio

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    In this paper we discuss a quantity that can be derived from the hadronic spectrum - the ratio between the color hyperfine splitting of a K meson and that of a Sigma baryon. It will be shown that within the constituent quark model this ratio depends only on the ratio of contact probabilities within the hadrons. We compute this ratio assuming several phenomenological potential models, and show that the best agreement with data is obtained from the Cornell potential - Coulomb + linear. Thus the analysis of color hyperfine interactions corroborat es the preference for the Cornell potential based on quarkonium spectra.Comment: RevTeX, 16 pages + 5 eps figures; v2:Shorter versio

    Hydrodynamics and the Detection of the QCD Axial Anomaly in Heavy Ion Collisions

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    We consider the experimental implications of the axial current triangle diagram anomaly in a hydrodynamic description of high density QCD. We propose a signal of an enhanced production of spin-excited hadrons in the direction of the rotation axis in off-central heavy ion collisions.Comment: 15 pages, 19 figures; v2: refs added, minor changes to the plots; v3, comments adde

    Dark Matter and Pseudo-flat Directions in Weakly Coupled SUSY Breaking Sectors

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    We consider candidates for dark matter in models of gauge mediated supersymmetry breaking, in which the supersymmetry breaking sector is weakly coupled and calculable. Such models typically contain classically flat directions, that receive one-loop masses of a few TeV. These pseudo-flat directions provide a new mechanism to account for the cold dark matter relic abundance. We discuss also the possibility of heavy gravitino dark matter in such models.Comment: 16 pages, 2 figures. v2: comments, refs adde

    The Quark Model and bb Baryons

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    The recent observation at the Tevatron of Σb±\Sigma_b^{\pm} (uubuub and ddbddb) baryons within 2 MeV of the predicted Σb−Λb\Sigma_b - \Lambda_b splitting and of Ξb−\Xi_b^- (dsb)(dsb) baryons at the Tevatron within a few MeV of predictions has provided strong confirmation for a theoretical approach based on modeling the color hyperfine interaction. The prediction of M(Ξb−)=5790M(\Xi^-_b) = 5790 to 5800 MeV is reviewed and similar methods used to predict the masses of the excited states Ξb′\Xi_b^\prime and Ξb∗\Xi_b^*. The main source of uncertainty is the method used to estimate the mass difference mb−mcm_b - m_c from known hadrons. We verify that corrections due to the details of the interquark potential and to Ξb\Xi_b--Ξb′\Xi_b^\prime mixing are small. For S-wave qqbqqb states we predict M(Ωb)=6052.1±5.6M(\Omega_b) = 6052.1 \pm 5.6 MeV, M(Ωb∗)=6082.8±5.6M(\Omega^*_b) = 6082.8 \pm 5.6 MeV, and M(Ξb0)=5786.7±3.0M(\Xi_b^0) = 5786.7 \pm 3.0 MeV. For states with one unit of orbital angular momentum between the bb quark and the two light quarks we predict M(Λb[1/2])=5929±2M(\Lambda_{b[1/2]}) = 5929 \pm 2 MeV, M(Λb[3/2])=5940±2M(\Lambda_{b[3/2]}) = 5940 \pm 2 MeV, M(Ξb[1/2])=6106±4M(\Xi_{b[1/2]}) = 6106 \pm 4 MeV, and M(Ξb[3/2])=6115±4M(\Xi_{b[3/2]}) = 6115 \pm 4 MeV. Results are compared with those of other recent approaches.Comment: 20 pages, 1 figure, to be published in Annals of Physics. Eq. (58) correcte
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