Bose-Einstein Correlations for Mixed Neutral Mesons

Correlations are shown to arise in nonidentical mixed-particle pairs like $K^o \bar K^o$ when observed in identical decay modes like $K_S K_S$ in multiparticle final states containing many partial waves. No enhancement is found in any single partial wave and all partial wave analyses of the s-wave threshold resonance $a_o$ and $f_o$ should give the same results for all decay modes. In CP violation experiments where $B^o - \bar B^o$ pairs are inclusively produced and correlated decays into $\psi K_S$ and leptonic modes are observed, the CP-violating lepton asymmetry is enhanced by a factor of two in the kinematic region where Bose enhancement occurs.Comment: 11 page

Projection and ground state correlations made simple

We develop and test efficient approximations to estimate ground state correlations associated with low- and zero-energy modes. The scheme is an extension of the generator-coordinate-method (GCM) within Gaussian overlap approximation (GOA). We show that GOA fails in non-Cartesian topologies and present a topologically correct generalization of GOA (topGOA). An RPA-like correction is derived as the small amplitude limit of topGOA, called topRPA. Using exactly solvable models, the topGOA and topRPA schemes are compared with conventional approaches (GCM-GOA, RPA, Lipkin-Nogami projection) for rotational-vibrational motion and for particle number projection. The results shows that the new schemes perform very well in all regimes of coupling.Comment: RevTex, 12 pages, 7 eps figure

Generator Coordinate Truncations

We investigate the accuracy of several schemes to calculate ground-state correlation energies using the generator coordinate technique. Our test-bed for the study is the $sd$ interacting boson model, equivalent to a 6-level Lipkin-type model. We find that the simplified projection of a triaxial generator coordinate state using the $S_3$ subgroup of the rotation group is not very accurate in the parameter space of the Hamiltonian of interest. On the other hand, a full rotational projection of an axial generator coordinate state gives remarkable accuracy. We also discuss the validity of the simplified treatment using the extended Gaussian overlap approximation (top-GOA), and show that it works reasonably well when the number of boson is four or larger.Comment: 19 pages, 6 eps figure

Isoscalar-isovector mass splittings in excited mesons

Mass splittings between the isovector and isoscalar members of meson nonets arise in part from hadronic loop diagrams which violate the Okubo-Zweig-Iizuka rule. Using a model for these loop processes which works qualitatively well in the established nonets, I tabulate predictions for the splittings and associated isoscalar mixing angles in the remaining nonets below about 2.5 GeV, and explain some of their systematic features. The results for excited vector mesons compare favorably with experiment.Comment: 8 RevTeX pages, including 1 LaTeX figure. CMU-HEP93-23/DOE-ER-40682-4

The Ursinus Weekly, November 2, 1936

Lantern to stage new type contest • Dorm rules made by men\u27s council • Albright conquers bear eleven, 35-0 • Second issue of Grizzly Gridder to make appearance Saturday • Penn Quakers to play for Varsity Club dance, Nov. 7 • Large crowd attends Hallowe\u27en party; games, dancing enjoyed • Shakespearean revival current trend of drama • Heiges injured at Albright; stellar end has leg broken • Administration approves costs for new recreational center • Senior class play chosen; tryout Wednesday night • Weekly poll discloses Landon greatly favored by faculty • Y organization to conduct fireside discussion Wednesday • Bears to tackle Dragons in league game Saturday • Temple and Haverford prolong losing streak of soccer team • Don Kellett\u27s frosh gridders to play Drexel Jay Vees Friday • Hockeyites setback 1-0 at hands of Bryn Mawr • Brodbeck undefeated, untied in touch football tournamenthttps://digitalcommons.ursinus.edu/weekly/1910/thumbnail.jp

Chiral dynamics and B to 3 pi decay

I discuss our knowledge of the scalar sector of QCD and how it impacts the determination of the CKM angle \alpha from the isospin analysis of B\to \rho\pi decay.Comment: invited talk at International Workshop on Heavy Quarks and Leptons, Vietri sul Mare, Salerno, Italy, 27 May - 1 Jun 200

SU(3) Breaking Effects in Hyperon Semi-Leptonic Decays and the extraction of F and D

The analysis of hyperon semi-leptonic decay data is re-examined in the light of a recent suggestion that SU(3) symmetry breaking effects may be taken into account by applying a correction to the $F/D$ ratio obtained via naive linear extrapolation in the hyperon masses. Comparison is made with the physically better motivated approach of applying so-called centre-of-mass corrections. This study (including all available data) reveals certain short-comings of the former of the above treatments, highlights some interesting aspects of this type of analysis and attempts to pinpoint the decay data that might usefully be improved. A tantalising result of the SU(3) breaking analysis performed here is that the magnitude of recoil correction required by the data corresponds closely to that required for the standard explanation of the reduction of \gA from its SU(6) value of 5/3. We also comment on other recent suggestions for taking into account the effects of SU(3) breaking. Finally a few remarks are made on the relevance for predicting the flavour non-singlet contribution to the proton $g_1$ and the Ellis-Jaffe sum rule.Comment: 12 pages, latex, no figures. Removed extended ascii set characters in the source file that were being corrupted by some mailer

Conventional and manipulated growth of Cu-Cu(111)

Molecular beam epitaxy of Cu on Cu(111) was studied using thermal energy He scattering, in the temperature range between 100 and 450 K. Three-dimensional growth was observed in the whole temperature range. To determine the onset of various diffusion processes, submonolayer films formed by deposition at low temperature were annealed. Annealing proceeds in two steps. The first step is interpreted as a change in island shape, the second as Ostwald-ripening. A comparison with homoepitaxy on Pt(111) and Ag(111) is made. Growth manipulation was carried out by artificially increasing the island number density via intervention in the nucleation stage of each layer. The procedures applied were temperature reduction during nucleation as well as pulsed ion bombardment. These techniques enabled the convenient growth of good quality films consisting of a large number of monolayers. Finally, the use of oxygen as a surfactant modifying the growth mode was investigated. Under some growth conditions, pre-exposure of the surface to oxygen was found to induce weak He-intensity oscillations during deposition. The quality of the films grown in this way was, however, low

Strange vector currents and the OZI-rule

We investigate the role of correlated $\pi\rho$ exchange in the extraction of matrix elements of the strange vector current in the proton. We show that a realistic isoscalar spectral function including this effect leads to sizeably reduced strange vector form factors based on the dispersion--theoretical analysis of the nucleons' electromagnetic form factors.Comment: 8 pp, plain LaTeX, uses epsf, 3 figure

Borna disease.

Borna disease virus, a newly classified nonsegmented negative-strand RNA virus with international distribution, infects a broad range of warm-blooded animals from birds to primates. Infection causes movement and behavioral disturbances reminiscent of some neuropsychiatric syndromes. The virus has not been clearly linked to any human disease; however, an association between infection with the virus and selected neuropsychiatric disorders has been suggested. We reviewed recent advances in Borna disease virus research, focusing on evidence of infection in humans