123098353
Vector Meson Dispersion in Medium
122265337
A QCD Sum Rule Approach with an Explicit Di-quark Field
We introduce a phenomenological QCD sum rule with an explicit diquark field. We investigate certain configurations of hadrons are expected to have a good diquark structure. The parameters of the model are a diquark mass $${(m_\phi)}$$ and condensate $${(\langle \phi^2\rangle)}$$ . Assuming that Λ baryons can be represented by a diquark and a spectator quark configuration, we find the sum rule works well for Λ, Λc, and Λb. We also find a duality relation between the mass and the condensate for which the parameter sets give good Borel curves. To maintain good Borel curve, a smaller diquark condensate is needed for an increased diquark mass. Using these parameter sets, we test the diquark structure in some hadrons which contain both good and bad diquark configurations.
122040769
Vector mesons in nuclear matter
In this talk, I will summarize the progress in understanding the changes the vector meson spectral density in nuclear medium using the constraint equations obtained from the Borel transformed dispersion relation and QCD Operator Product Expansion. We will discuss the results for the scalar mass shift and dispersion effects (three momentum dependence) for the light quark system (ρ,ω), the strange quark system (φ) and the heavy quark system (J/ψ) in nuclear medium. For the light quark systems, a nontrivial change in the mass and/or width are expected, while the dispersion effects are found to be small. Existing model calculations for the dispersion effects are compared to the constraint equation in detail. Very small, but accurate mass shift is obtained for the heavy quark system.
91854570
Effects of chiral symmetry restoration in nuclear medium
119287779
Color spin wave functions of heavy tetraquark states
Abstract Using the variational method, we calculate the mass of the J P = 1 + u d b ¯ b ¯ tetraquark containing two identical heavy antiquarks in a nonrelativistic potential model with color confinement and spin hyperfine interaction. In particular, we extend a previous investigation of the model by Brink and Stancu by investigating the effect of including the color anti-sextet component of the diquark configuration as well as using several more Gaussian parametrization for the L = 0 part of the spatial wave function. We find that for the heavy tetraquark, the 6 6 ¯ component among the color singlet bases is negligible and that the previously used specific Gaussian spatial configuration is good enough in obtaining the ground state energy.
53550475
Subthreshold cascade production in heavy ion collisions
Using a gauged flavor SU(3)-invariant hadronic Lagrangian, we have calculated the cross sections for the strangeness-exchange reactions in the Born approximation. These cross sections are then used in the Relativistic Vlasov-Uehling-Uhlenbeck (RVUU) transport model to study Ξ production in Ar+KCl collisions at incident energy of 1.76A GeV and impact parameter b = 3.5 fm. We find that including the contributions of hyperonhyperon scattering channels strongly enhances the yield of Ξ, leading to the abundance ratio which is essentially consistent with the recently measured value of by the HADES collaboration at GSI.
55331667
The evolution of tensor polarization
Using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization is derived. We study the evolution equation for the tensor polarization in the presence of an isolated spin resonance and in the presence of a spin rotator, or snake.<<ETX>>
55028013
First test of orbit response matrix in proton storage ring
The orbit response matrix method is applied to experimentally determine the Cooler Ring optics at the Indiana University Cyclotron Facility (IUCF). We have carried out two experiments in Oct. And Nov. 1996 to measure the orbit response of the IUCF Cooler Ring. An analysis software was adopted from the NSLS, BNL. In our analysis, strength error in quadrupoles and steering dipoles, and amplifier gain in BPMs are included as fitting parameters. However, effects of the linear and non-linear coupling are excluded in our preliminary analysis. Since the resolution of our BPM system is of the order of 10 /spl mu/m, we will address the effect of BPM resolution on the applicability of the orbit response matrix method in proton storage rings.
118993921
Simple analytic formula for the strength of spin depolarizing resonances
A simple analytic formula is derived to explain the periodicity of spin depolarizing resonance. The spin depolarizing resonance strengths of CPS and SPS at CERN and the lattices of meson factory at TRIUMF are used to compare with the analytic formula.
118620419
Background independent holographic description: from matrix field theory to quantum gravity
A bstractWe propose a local renormalization group procedure where length scale is changed in spacetime dependent way. Combining this scheme with an earlier observation that high energy modes in renormalization group play the role of dynamical sources for low energy modes at each scale, we provide a prescription to derive background independent holographic duals for field theories. From a first principle construction, it is shown that the holographic theory dual to a D-dimensional matrix field theory is a (D + 1)-dimensional quantum theory of gravity coupled with matter fields of various spins. The gravitational theory has (D + 1) first-class constraints which generate local spacetime transformations in the bulk. The (D + 1)-dimensional diffeomorphism invariance is a consequence of the freedom to choose different local RG schemes.
137126267
Electron cooling in high energy colliders