Denis Parganlija, A Linear Sigma Model with Vector Mesons and Global Chiral Invariance Denis Parganlija In collaboration with Francesco Giacosa, Dirk H. Rischke (Frankfurt University) Institut für Theoretische Physik Goethe-Universität Frankfurt am Main
Denis Parganlija, Motivation Sakurai: Vector Meson Dominance - EM processes mediated by vector mesons Calculation of scattering lengths and and decay widths of Sigma, Rho(770) and (1260) from a locally symmetric Linear Sigma Model (up to vector mass terms) Local vs. Global Symmetry: Mesonic decay widths require global symmetry FAIR: in-medium properties of hadrons as a signature of chiral symmetry restoration [Source: CBM Progress Report 2007]
Denis Parganlija, Lagrangian of a Gauged Linear Sigma Model with Vector Mesons (N f =2) (Gasiorowicz and Geffen, 1969) scalars pseudoscalars vectors axialvectors
Denis Parganlija, Spontaneous Symmetry Breaking (SSB): Shift: Shift (Diagonalise): Renormalise Pseudoscalar Wave Functions: [R. Pisarski, hep-ph/ (1995)] [S. Gasiorowicz and D. A. Geffen, Rev. Mod. Phys. 41, 531 (1969)]
Denis Parganlija, Relevant Vertices for Pion-Pion Scattering Feynman Diagrams At Tree Level:
Denis Parganlija, Tree-Level Scattering Amplitude s-channel isospin I components of the scattering amplitude: scattering lengths (on the threshold): partial wave amplitude
Denis Parganlija, Results I
Denis Parganlija, Results I: as function of Experiment: = R. Wanke, arXiv: [hep-ex] (NA 48/2 Ke4)
Denis Parganlija, Results I: as function of E865 NA48/2 Ke4
Denis Parganlija, Results II: Decay Widths Sigma Decay 100 MeV Width at 800 MeV Mass
Denis Parganlija, Results II: Decay Widths Neutral Rho(770) Decay (1260) Decay
Denis Parganlija, Results II: Decay Widths Decay Widths For Sigma And Rho(770) Do Not Match Experiments How To Improve Decay Widths? All Parameters Fixed Via Tree Level Masses and No Free Parameters Need At Least One Additional Parameter To Try Adjusting Rho Width ( )MeV
Denis Parganlija, Improvements of the Lagrangian Strategy 1: Higher-dimension terms (local invariance) Strategy 2: Non-vanishing meson masses becomes global QCD chiral symmetry: global LSM chiral symmetry global [S. Gasiorowicz and D. A. Geffen (1969), P. Ko and S. Rudaz (1994), U. G. Meissner (1988)] [M. Urban, M. Buballa and J. Wambach, Nucl. Phys. A 697, 338 (2002)] [D. Parganlija, F. Giacosa and D. Rischke, arXiv: [hep-ph] ]
Denis Parganlija, Globally Invariant Model
Denis Parganlija, Parameter Determination Masses: Decays: Scattering Lengths:
Denis Parganlija, Results III: Rho Decay Width
Denis Parganlija, Ongoing Work: Nature of Scalar Mesons Decay Widths Scattering Lengths states under 1 GeV (600) (980) states above 1 GeV (extra scalar states below 1 GeV needed: tetraquarks?) (1370) (1450) Origin of rho mass: quark condensate vs. CL mass
Denis Parganlija, Summary LSM With Local Symmetry: Scattering Lengths Favour But: Poor Results On Decay Widths (Rho) Globally Invariant LSM Lagrangian: Rho Width Fixed Exactly Insight into Assignment of Scalars ( states above 1GeV?)
Denis Parganlija, Outlook Parameters and Consequences of Global Invariance up to 4 th Order Low Energy Constants of QCD p, d Wave Scattering Lengths Chiral Models With Three Flavours Include Tensor, Pseudotensor Mesons, Baryons (Nucleons) Extension to Non-Zero Temperature: Study Chiral Symmetry Restoration