Rigorous QCD Predictions for Decays of P-Wave Quarkonia

Rigorous QCD predictions for decay rates of the P-wave states of heavy quarkonia are presented. They are based on a new factorization theorem which is valid to leading order in the heavy quark velocity and to all orders in the running coupling constant of QCD. The decay rates for all four P states into light hadronic or electromagnetic final states are expressed in terms of two phenomenological parameters, whose coefficients are perturbatively calculable. Logarithms of the binding energy encountered in previous perturbative calculations of P-wave decays are factored into a phenomenological parameter that is related to the probability for the heavy quark-antiquark pair to be in a color-octet S-wave state. Applying these predictions to charmonium, we use measured decay rates for the \chione and \chitwo to predict the decay rates of the \chizero and $h_c$.Comment: 13 page

Effects of finite arm-length of LISA on analysis of gravitational waves from MBH binaries

Response of an interferometer becomes complicated for gravitational wave shorter than the arm-length of the detector, as nature of wave appears strongly. We have studied how parameter estimation for merging massive black hole binaries are affected by this complicated effect in the case of LISA. It is shown that three dimensional positions of some binaries might be determined much better than the past estimations that use the long wave approximation. For equal mass binaries this improvement is most prominent at \sim 10^5\sol.Comment: 10 pages, 3 figures, to appear in Phys.Rev.

Glueball plus Pion Production in Photon-Photon Collisions.

We here compute the reaction $\gamma \; \gamma \rightarrow G \; \pi^{0}$ for various glueball candidates $G$ and their assumed quantum states, using a non-relativistic gluon bound-state model for the glueball.Comment: To appear in Zeit. fur Phys. C; Plain Latex file, 16 pages; 5 figures appended as a uuencoded postscript file

Noise characterization for LISA

We consider the general problem of estimating the inflight LISA noise power spectra and cross-spectra, which are needed for detecting and estimating the gravitational wave signals present in the LISA data. For the LISA baseline design and in the long wavelength limit, we bound the error on all spectrum estimators that rely on the use of the fully symmetric Sagnac combination ($\zeta$). This procedure avoids biases in the estimation that would otherwise be introduced by the presence of a strong galactic background in the LISA data. We specialize our discussion to the detection and study of the galactic white dwarf-white dwarf binary stochastic signal.Comment: 9 figure

Aspects of Nucleon Compton Scattering

We consider the spin-averaged nucleon forward Compton scattering amplitude in heavy baryon chiral perturbation theory including all terms to order ${\cal O} (q^4)$. The chiral prediction for the spin-averaged forward Compton scattering amplitude is in good agreement with the data for photon energies $\omega \le 110$ MeV. We also evaluate the nucleon electric and magnetic Compton polarizabilities to this order and discuss the uncertainties of the various counter terms entering the chiral expansion of these quantities.Comment: 17 pp, TeX, 7 figures available from the authors, preprint CRN-93/5

Nuclear Photoabsorption at Photon Energies between 300 and 850 Mev

We construct the formula for the photonuclear total absorption cross section using the projection method and the unitarity relation. Our treatment is very effective when interference effects in the absorption processes on a nucleon are strong. The disappearance of the peak around the position of the $D_{13}$ resonance in the nuclear photoabsorption can be explained with the cooperative effect of the interference in two-pion production processes,the Fermi motion, the collision broadenings of $\Delta$ and $N^*$, and the pion distortion in the nuclear medium. The change of the interference effect by the medium plays an important role.Comment: 22pages,7figures,revtex

Strange quark matter in a chiral SU(3) quark mean field model

We apply the chiral SU(3) quark mean field model to investigate strange quark matter. The stability of strange quark matter with different strangeness fraction is studied. The interaction between quarks and vector mesons destabilizes the strange quark matter. If the strength of the vector coupling is the same as in hadronic matter, strangelets can not be formed. For the case of beta equilibrium, there is no strange quark matter which can be stable against hadron emission even without vector meson interactions.Comment: 19 pages, 8 figure

Lyashko-Looijenga morphisms and submaximal factorisations of a Coxeter element

When W is a finite reflection group, the noncrossing partition lattice NCP_W of type W is a rich combinatorial object, extending the notion of noncrossing partitions of an n-gon. A formula (for which the only known proofs are case-by-case) expresses the number of multichains of a given length in NCP_W as a generalised Fuss-Catalan number, depending on the invariant degrees of W. We describe how to understand some specifications of this formula in a case-free way, using an interpretation of the chains of NCP_W as fibers of a Lyashko-Looijenga covering (LL), constructed from the geometry of the discriminant hypersurface of W. We study algebraically the map LL, describing the factorisations of its discriminant and its Jacobian. As byproducts, we generalise a formula stated by K. Saito for real reflection groups, and we deduce new enumeration formulas for certain factorisations of a Coxeter element of W.Comment: 18 pages. Version 2 : corrected typos and improved presentation. Version 3 : corrected typos, added illustrated example. To appear in Journal of Algebraic Combinatoric

Covariance of Antiproton Yield and Source Size in Nuclear Collisions

We confront for the first time the widely-held belief that combined event-by-event information from quark gluon plasma signals can reduce the ambiguity of the individual signals. We illustrate specifically how the measured antiproton yield combined with the information from pion-pion HBT correlations can be used to identify novel event classes.Comment: 8 pages, 5 figures, improved title, references and readability; results unchange

Regge description of two pseudoscalar meson production in antiproton-proton annihilation

A Regge-inspired model is used to discuss the hard exclusive two-body hadronic reactions (pbar p ----> pi+ pi-, pi0 pi0, K+ K-, Kbar0 K0) for the FAIR facility project at GSI with the Panda detector. The comparison between the differential cross sections predictions and the available data is shown to determine the values of the few parameters of the model.Comment: 9 pages, 13 figure