arXiv subjects
Publications and source records attributed to Leonard S. Kisslinger.
Possible CMBR correlations are estimated with a model in which a Hubble-size magnetic wall is formed during the QCD chiral phase transition. Measurable polarization correlations are found for l greater than 1000. Metric perturbations from the wall were found to give rise to observable correlations.
Using the liquid instanton model continued into Minkowski space and modified for finite temperature, the energy momentum tensor and the surface tension for buble walls during the QCD phase transition are derived. The resulting surface tension is in agreement with lattice calculations. Application to bubble collisions is discussed.
We include instanton effects in QCD sum rules for coupled scalar glueballs and mesons. We find a light glueball/sigma as in earlier studies without instantons, but in a lattice-type pure instanton model the light glueball/sigma is not found. In the 1-2 Gev region we now find that lightest I=0 meson, in the region of the f$_o$(1370), has no direct glueball mixing, with the instanton loop replacing the glueball component. The lightest scalar mainly glueball in the region of the f$_o$(1500) is sensitive to the choice of nonperturbative gluonic parameters.
Recently the D$^+$ charm meson was observed to have a clear branching ratio into the low energy $π-π$ sigma resonance, while this channel was not detected in the D$_s^+$ decay. It is shown that this is consistent with the standard treatment of exclusive charm meson decays and a proposed glueball/sigma picture.
The Pomeron, which dominates high energy elastic and diffractive hadronic processes, must be largely gluonic in nature. We use a recent picture of a scalar glueball/sigma system with coupling of the sigma to glue determined from experiment to predict strong peripheral sigma production seen in the p p $π^oπ^o$ final state.
It has long been believed that the Pomeron, which has been successful in phenomenological fits to high energy scattering data, is associated with gluonic exchange. By determining the Regge-nucleon vertex in terms of previously determined glueball-quark coupling we show that the Pomeron might be related to the Regge trajectory defined by a light scalar glueball/sigma system and a tensor glueball, which involves complicated nonperturbative QCD. We predict a tensor glueball at 2.8 GeV.
We study the mass of a nucleon in a nucleus using a model recently introduced for a nucleon current with a pion cloud component. The method of QCD sum rules is used to determine the mass shifts for nucleons to first order in nuclear density in oxygen-16 and calcium-40, with the pion propagator determined by an optical potential for pion-nucleus scattering. Mass shifts due to the pionic contributions range from negligible in oxygen to -100 MeV in calcium at central nuclear density, with larger shifts in the nuclear surface. The consistency of this model with chiral perturbation theory is demonstrated.
We introduce a model for nucleons with correlators that include the propagation of pseudo Goldstone bosons as well as the standard correlators for nucleons used in QCD sum rules. From the comparison with experimental nucleon magnetic dipole moments we estimate the probability of a pion cloud in a nucleon. The masses obtained from the sum rules are almost independent of the cloud contributions. We show that the model is consistent with chiral perturbation theory, and solves a long-standing problem on obtaining the leading non-analytic correction to the nucleon mass in QCD sum rules.
We propose an analog of the familiar gap equation for the case of four-quark condensates at finite temperature. The condensates of interest correspond to scalar, vector, psudoscalar, axial vector, and tensor Dirac structures. Working with correlators at zero chemical potential without factorization, we arrive at coupled equations for these four-quark condensates and the masses of certain light-quark mesons. We study the temperature dependence of the four-quark condensates and masses; in one of our models, factorization of the four-quark condensates is shown to be increasingly violated as the temperature is increased toward $T_c$. The 2$^{++}$ tensor mesons a$_2$(1320)-f$_2$(1270) are identified as especially sensitive probes of the four-quark condensates.
Using a recently developed three-point formalism within the method of QCD Sum Rules we determine the vacuum susceptibilities needed in the two-point formalism for the coupling of axial, vector, tensor and pseudoscalar currents to hadrons. All susceptibilities are determined by the space-time scale of condensates, which is estimated from data for deep inelastic scattering on nucleons.
We develop an ansatze of the sigma enhancement of the I=0, L=0 $π$-$π$ scattering amplitude as arising from a low-energy glueball pole. Using this picture we estimate the $π^0π^0$ to $π^0$ branching ratio for the decays of the Roper resonance, which we previously found to be a hybrid in our QCD sum rule calculation. We find that the sigma decay might be a good signal for gluonic components of hadrons.
We develop a three-point formalism to treat vacuum susceptibilities used for the coupling of currents to hadrons within the method of QCD Sum Rules. By introducing nonlocal condensates, with the space-time structure taken from fits to experimental parton distrbutions, we show that one can treat hadronic coupling at zero or low momentum transfer as well as medium and asmptotic momentum transfers and obtain a general expression for the vacuum susceptibilities of the two-point formalism. The pion susceptibility, for which there has been a major uncertainty, is evaluated successfully with no new parameters.
In a study of the elastic pion form factor for large momentum transfers based on a modified perturbative QCD (PQCD) approach we have included helicity components that are customarily neglected. Along with the inclusion of transverse momentum, this gives a large suppression of the form factor from the prediction of the original hard scattering model based on PQCD in the $Q^{2}$ domain where experimental data are available. We conclude that nonperturbative contributions will dominate in this region.
We have reexamined the elastic pion form factor over a broad range of momentum transfers with the mass evolution from current quark to constituent quark being taken into account. We have also studied the effect of Sudakov form factors, of anomalous quark magnetic moments and of alternative soft wave functions. Our calculation shows a power-law falloff from the present experimental values to near-asymptotic values in the few $GeV^{2}$ range.
The mass splittings of the pseudoscalar and vector D and B light-heavy quark systems have been calculated using the method of QCD sum rules. Electromagnetic, quark mass, and nonperturbative QCD effects are all included. The results are in good agreement with experiment. A measurement of isospin splitting for the vector B mesons would give valuable information about quark mass splittings.