Problems of Double Charm Production in e+e−e^+e^- Annihilation at s=10.6\sqrt{s}=10.6 GeV

Using the nonrelativistic QCD(NRQCD) factorization formalism, we calculate the color-singlet cross sections for exclusive production processes ${e^++e^-\to J/\psi+\eta_c}$~ and ~$e^++e^-\to J/\psi + \chi_{cJ}$~$(J=0,1,2)$ at the center-of-mass energy $\sqrt{s}$=10.6 GeV. The cross sections are estimated to be 5.5fb, 6.7fb, 1.1fb, and 1.6fb for $\eta_c, \chi_{c0}, \chi_{c1}$ and $\chi_{c2}$, respectively. The calculated $J/\psi+\eta_c$ production rate is smaller than the recent Belle data by about an order of magnitude, which might indicate the failure of perturbative QCD calculation to explain the double-charmonium production data. The complete $\cal{O}$$(\alpha^2_{s})$ color-singlet cross section for ${e^++e^-\to \chi_{c0}+ c\bar {c}}$ is calculated. In addition, we also evaluate the ratio of exclusive to inclusive production cross sections. The ratio of $J/\psi\eta_c$ production to $J/\psi c\bar{c}$ production could be consistent with the experimental data.Comment: 10 pages, 4 figures. A few references added, errors and typoes correcte

Lithography-Free Route to Hierarchical Structuring of High-chi Block Copolymers on a Gradient Patterned Surface

A chemically defined patterned surface was created via a combined process of controlled evaporative self-assembly of concentric polymer stripes and the selective surface modification of polymer brush. The former process involved physical adsorption of poly (methyl methacrylate) (PMMA) segments into silicon oxide surface, thus forming ultrathin PMMA stripes, whereas the latter process was based on the brush treatment of silicon native oxide surface using a hydroxyl-terminated polystyrene (PS-OH). The resulting alternating PMMA- and PS-rich stripes provided energetically favorable regions for self-assembly of high <mml:semantics>chi</mml:semantics> polystyrene-block-polydimethylsiloxane (PS-b-PDMS) in a simple and facile manner, dispensing the need for conventional lithography techniques. Subsequently, deep reactive ion etching and oxygen plasma treatment enabled the transition of the PDMS blocks into oxidized groove-shaped nanostructures

Color-octet mechanism in the inclusive D-wave charmonium productions in B decays

The inclusive D-wave charmonium production rates in B decays are considered in the Bodwin-Braaten-Lepage (BBL) approach. We find that the color-octet subprocesses B->cc_(^3S_1^(8) or ^3P_J^(8))+s,d, followed by the transition cc_(^3S_1^(8) or ^3P_J^(8)) -> ^3D_J, strongly dominate over any other subprocess, due to the large Wilson coefficient for the \Delta B = 1 effective lagrangian. Assuming that the numerical values of the matrix elements and are the same order of magnitudes with the , we find that the ^{1,3}D_{2} can be observed at future B-factories.Comment: 11 pages, LaTeX, Phys. Lett. B in pres

J/psi Production: Tevatron and Fixed-Target Collisions

In this talk I show the results of a fit of the NRQCD matrix elements to the CDF data for direct $J/\psi$ production, by including the radiative corrections to the colour-singlet channel and the effect of the $k_T$-smearing. Furthermore I perform the NLO NRQCD analysis of $J/\psi$ production in fixed-target proton-nucleon collisions and I fit the colour-octet matrix elements to the available experimental data. The results are compared to the Tevatron ones.Comment: 6 pages, 3 figures. Talk given at the QCD99 Euroconference, Montpellier, France, July 199

The neuronal and physical aspects of adaptive cytoprotection against ethanol-induced gastric mucosal damage

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