The Photon Wave Function in Non-forward Diffractive Scattering with Non-vanishing Quark Masses

The light-cone Photon wave function in explicit helicity states, valid for massive quarks and in both momentum and configuration space, is presented by considering the leading order photon-proton hard scattering, i.e., the splitting quark pair scatters with the proton in the Regge limit. Further we apply it to the diffractive scattering at nonzero momentum transfer and reach a similar factorization as in the case of zero momentum transfer.Comment: 11 pages LaTeX, 2 figures, version to appear in Phys. Rev.

Exclusive J/\psi Productions at e^+ e^- Colliders

Exclusive quarkonium pair production in electron-positron collisions is studied in non-relativistic QCD. The obtained cross section for J/\psi + \eta_c production in the leading order is confronted against the recent measurements by the Belle Collaboration at KEKB. It is shown that a large renormalization K-factor is necessary to explain the experimental data. We point out that the J^{PC}=0^{-+} nature of the hadronic systems that are assigned to be \eta_c should be tested by the triple angular distributions in terms of the scattering angle, and, polar and azimuthal angles of J/\psi into leptons. We further study J/\psi + J/\psi and \Upsilon + \Upsilon productions at LEP energies. Although the axial-vector couplings of the Z-boson to charm and bottom quarks allow production of such pairs when one of them is polarised transversally and the other longitudinally, we find that the integrated luminosity at Z pole accumulated by LEP is not large enough to observe the exclusive pair production of quarkonium.Comment: 11 pages, 2 eps figures, LaTe

Generation of high-energy monoenergetic heavy ion beams by radiation pressure acceleration of ultra-intense laser pulses

A novel radiation pressure acceleration (RPA) regime of heavy ion beams from laser-irradiated ultrathin foils is proposed by self-consistently taking into account the ionization dynamics. In this regime, the laser intensity is required to match with the large ionization energy gap when the successive ionization of high-Z atoms passing the noble gas configurations [such as removing an electron from the helium-like charge state $(\text{Z}-2)^+$ to $(\text{Z}-1)^+$]. While the target ions in the laser wing region are ionized to low charge states and undergo rapid dispersions due to instabilities, a self-organized, stable RPA of highly-charged heavy ion beam near the laser axis is achieved. It is also found that a large supplement of electrons produced from ionization helps preserving stable acceleration. Two-dimensional particle-in-cell simulations show that a monoenergetic $\text{Al}^{13+}$ beam with peak energy $1\ \text{GeV}$ and energy spread of $5\%$ is obtained by lasers at intensity $7\times10^{20}\ \text{W}/\text{cm}^2$.Comment: 5 pages, 4 figure

On the Application of Gluon to Heavy Quarkonium Fragmentation Functions

We analyze the uncertainties induced by different definitions of the momentum fraction $z$ in the application of gluon to heavy quarkonium fragmentation function. We numerically calculate the initial $g \to J / \psi$ fragmentation functions by using the non-covariant definitions of $z$ with finite gluon momentum and find that these fragmentation functions have strong dependence on the gluon momentum $\vec{k}$. As $| \vec{k} | \to \infty$, these fragmentation functions approach to the fragmentation function in the light-cone definition. Our numerical results show that large uncertainties remains while the non-covariant definitions of $z$ are employed in the application of the fragmentation functions. We present for the first time the polarized gluon to $J/\psi$ fragmentation functions, which are fitted by the scheme exploited in this work.Comment: 11 pages, 7 figures;added reference for sec.

The Supersymmetric QCD Radiative Corrections to Top Quark Semileptonic Decays

The one-loop supersymmetric QCD corrections to the top quark semileptonic decays t\to b \bar{l} {\nu_l} are considered. The corrections are found to reduce the decay width. In the still acceptable parameter space the corrections can be as large as a few percent

The Impact of Gastrocnemius Muscle Cell Changes in Chronic Venous Insufficiency

AbstractObjectiveTo investigate the pathological and metabolic changes in the gastrocnemius muscle in patients with chronic vein insufficiency (CVI).MethodThirty-six patients with varicose veins were investigated by ambulatory venous pressure (AVP) and duplex ultrasonography. Twelve age and height-matched controls were used for comparison. Patients and controls consented to participate in this study. Twenty-one patients with primary vein varicose (group AI) and 15 patients (group AII) with primary deep venous valve incompetence (DVI) underwent biopsies of the gastrocnemius muscle during operation. Adductor biopsies obtained from the same limbs served as a control group (group B) and specimens from controls subjects without venous disease served as the second control group (group C). All the specimens were investigated by superoxide dismutase (SOD), nitric oxide (NO), Na+–K+-ATPase, Ca2+-ATPase and lactic acid (LD) determinations. Samples were subjected to light and electron microscopy following H & E staining, special ATPase, cytochrome oxidase/succinate dehydrogenase (COX/SDH) stains.ResultsNormal muscle architecture was seen following H & E, ATPase and COX/SDH staining and normal cell metabolism was observed in specimens of groups B and C. In group A, pathological changes were encountered in the gastrocnemius muscle including disseminated myofibril atrophy, cell denaturation and necrosis, inflammatory cell infiltration, proliferation and dilation of interfascicular veins. ATPase staining (pH 9.4) demonstrated grouping of atrophic fibres, especially type I myofibril grouping, accompanied by moderate to severe atrophy of type II muscle fibres. However, no patient had selective type I fibre atrophy. Enhanced enzymatic activity in single or multiple myofibrils was demonstrated by COX/SDH staining in approximately half of the specimens in group AII. In group AII, electron microscopy showed swelling, myelin figure denaturation of mitochondria, disruption of the myofibrils and increased lipid droplets in the gastrocnemius muscle. Increased concentration of LD was found in most specimens from group A patients. There were also reductions of SOD, NO, biochemical activity of Na+–K+-ATPase, Ca2+-ATPase with increasing concentration of LD in these patients, most prominently in group AII. We found correlation between AVP assessments and the biochemical measurements as well as morphological appearances of the gastrocnemius muscle.ConclusionVenous hypertension results in pathophysiological changes in the gastrocnemius muscles of patients with DVI, associated with decreased calf pump function

D-wave heavy quarkonium production in fixed target experiments

We calculate the $D$-wave heavy quarkonium production at fixed target experiments under the NRQCD factorization formalism. We find that the color octet contributions are two orders of magnitude larger than color-singlet contributions if color-octet matrix elements are taken according to the NRQCD velocity scaling rules. Within the theoretical uncertainties, the prediction for the production rate of $2^{--}$ $D$-wave charmonium state agrees with the preliminary result of E705 and other experiments. Searching for the $1^{--}$ $D$-wave state $\psi(3770)$ is further suggested.Comment: 13pages, 4 PS figures, final vertion to appear in PR

The (gamma^*-q\bar q)-Reggeon Vertex in Next-to-Leading Order QCD

As a first step towards the computation of the NLO corrections to the photon impact factor in the $\gamma^*\gamma^* \to \gamma^* \gamma^*$ scattering process, we calculate the one loop corrections to the coupling of the reggeized gluon to the $\gamma^*\to q\bar{q}$ vertex. We list the results for the Feynman diagrams which contribute: all loop integrations are carried out, and the results are presented in the helicity basis of photon, quark, and antiquark.Comment: 26 pages LaTeX, 3 figures, typos fixe