10 research outputs found

    Gerasimov-Drell-Hearn Sum Rule and the Discrepancy between the New CLAS and SAPHIR Data

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    Contribution of the K^+\Lambda channel to the Gerasimov-Drell-Hearn (GDH) sum rule has been calculated by using the models that fit the recent SAPHIR or CLAS differential cross section data. It is shown that the two data sets yield quite different contributions. Contribution of this channel to the forward spin polarizability of the proton has been also calculated. It is also shown that the inclusion of the recent CLAS C_x and C_z data in the fitting data base does not significantly change the result of the present calculation. Results of the fit, however, reveal the role of the S_{11}(1650), P_{11}(1710), P_{13}(1720), and P_{13}(1900) resonances for the description of the C_x and C_z data. A brief discussion on the importance of these resonances is given. Measurements of the polarized total cross section \sigma_{TT'} by the CLAS, LEPS, and MAMI collaborations are expected to verify this finding.Comment: 15 pages, 8 figure

    The interference effects of multi-channel pion-pion scattering in final states of charmonia and bottomonia decays

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    There is presented a unified analysis of all available data on the decays Υ(mS)Υ(nS)ππ\Upsilon(mS)\to\Upsilon(nS)\pi\pi (m>nm>n, m=2,3,4,5,m=2,3,4,5, n=1,2,3n=1,2,3), J/ψϕ(ππ,KK)J/\psi\to\phi(\pi\pi, K\overline{K}), and ψ(2S)J/ψππ\psi(2S)\to J/\psi\pi\pi and the data on isoscalar SS-wave processes ππππ,KK,ηη\pi\pi\to\pi\pi,K\overline{K},\eta\eta. The multi-channel ππ\pi\pi scattering is described in our model-independent approach based on analyticity and unitarity and using an uniformization procedure. It is shown that the basic shape of dipion mass distributions in the two-pion transitions of both charmonia and bottomonia states are explained by an unified mechanism based on the contribution of the ππ\pi\pi, KKK\overline{K} and ηη\eta\eta coupled channels including their interference

    The effect of acupuncture on allergic rhinitis: a randomized controlled clinical trial

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    Allergic rhinitis is a common health problem usually treated with drug therapy. Allergic rhinitis is a common health problem usually treated with drug therapy. Some patients experience side effects of drug therapy while others fear the use of drugs. Acupuncture is an interesting alternative to traditional treatment. The few studies evaluating acupuncture indicate a possible clinical effect on allergic rhinitis. This study compared active versus sham acupuncture in 40 consecutive patients with a history of allergic rhinitis and a positive skin test. Patients were randomized and assessed prior to treatment and then reassessed after 12 months. Improvements in symptoms using visual analogue scales, reduction in skin test reactions and levels of specific immunoglobin E (IgE) were used to compare the effect of treatment. For one allergen, mugwort, a greater reduction in levels of specific IgE (p=0.019, 0.039) and skin test reaction (p=0.004) was seen in the group receiving active acupuncture compared to the group receiving sham acupuncture. However, this finding might be an artifact. No differences in clinical symptoms were seen between active versus sham acupuncture, thus the conclusion being that the effect of acupuncture on allergic rhinitis should be further evaluated in larger randomized studies

    Beam-spin asymmetry Σ for Σ− hyperon photoproduction off the neutron

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    We report a new measurement of the beam-spin asymmetry, Σ, for the γ→n→K+Σ− reaction using quasi-free neutrons in a liquid-deuterium target. The new dataset includes data at previously unmeasured photon energy and angular ranges, thereby providing new constraints on partial wave analyses used to extract properties of the excited nucleon states. The experimental data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS), housed in Hall B of the Thomas Jefferson National Accelerator Facility (JLab). The CLAS detector measured reaction products from a liquid-deuterium target produced by an energy-tagged, linearly polarised photon beam with energies in the range 1.1 to 2.3 GeV. Predictions from an isobar model indicate strong sensitivity to N(1720)3/2+, Δ(1900)1/2−, and N(1895)1/2−, which corroborates results from a recent combined analysis of all KΣ channels. When our data are incorporated in the fits of partial-wave analyses, one observes significant changes in γ-n couplings of resonances which have small branching ratios to the πN channel
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