556 research outputs found

    Amplitude analysis of reactions pi(-)p->etapi(-)p and pi(-)p->etapi(0)n on polarized target and the exotic 1-+ meson

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    Recently several experimental groups analysed data on πpηπp\pi^- p \to \eta \pi^- p and πpηπ0n\pi^- p \to \eta \pi^0 n reactions with exotic 1+1^{-+} PP-wave and found a conflicting evidence for an exotic meson I=11+(1405)I=1 1^{-+} (1405). High statistics data on these reactions are presently analysed by BNL E852 Collaboration. All these analyses are based on the crucial assumption that the production amplitudes do not depend on nucleon spin. This assumption is in sharp conflict with the results of measurements of πpππ+n\pi^- p \to \pi^- \pi^+ n, π+nπ+πp\pi^+ n \to \pi^+ \pi^- p and K+nK+πpK^+ n \to K^+ \pi^- p on polarized targets at CERN which find a strong dependence of production amplitudes on nucleon spin. To ascertain the existence of exotic meson 1+(1405)1^{-+} (1405), it is necessary to perform a model-independent amplitude analysis of reactions πpηπp\pi^- p \to \eta \pi^- p and πpηπ0n\pi^- p \to \eta\pi^0 n. We demonstrate that measurements of these reactions on transversely polarized targets enable the required model independent amplitude analysis without the assumption that production amplitudes are independent on nucleon spin. We suggest that high statistics measurements of reactions πpηπp\pi^- p \to \eta\pi^- p and πpηπ0n\pi^- p \to\eta\pi^0 n be made on polarized targets at BNL and at Protvino IHEP, and that model-independent amplitude analyses of this polarized data be performed to advance hadron spectroscopy on the level of spin dependent production amplitudes.Comment: 23 page

    The preparation, identification and properties of chlorophyll derivatives

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    In the investigation of 10-hydroxy chlorophylls a and b novel techniques included modification of chromatography and the use of fully-deuterated compounds isolated from fully-deuterated autotropic algae to determine the molecular structure of the chlorophylls

    Nitrogen isotope abundance measurements

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    The abundance of the nitrogen isotopes in several sources of nitrogen have been determined. In atmospheric nitrogen the absolute ratio, N14/N15, is 272.0 ± 0.3. Small variations were observed for various sources of compressed gas but the isotopic composition of the nitrogen isotopes of the atmosphere was constant, to 1 part in 7000, in samples collected at different geographical sites and altitudes above these sites

    Unitarity and Interfering Resonances in pipi Scattering and in Pion Production piN->pipiN

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    Additivity of Breit-Wigner phases has been proposed to describe interfering resonances in partial waves in ππ\pi\pi scattering. This assumption leads to an expression for partial wave amplitudes that involves products of Breit-Wigner amplitudes. We show that this expression is equivalent to a coherent sum of Breit-Wigner amplitudes with specific complex coefficients which depend on the resonance parameters of all contributing resonances. We use analyticity of ππ\pi\pi partial wave amplitudes to show that they must have the form of a coherent sum of Breit-Wigner amplitudes with complex coefficients and a complex coherent background. The assumption of additivity of Breit-Wigner phases restricts the partial waves to analytical functions with very specific form of residues of Breit-Wigner poles. We argue that the general form provided by the analyticity is more appropriate in fits to data to determine resonance parameters. The partial wave unitarity can be imposed using the modern methods of constrained optimization. We discuss unitarity and the production amplitudes in πNππN\pi N\to\pi\pi N and use analyticity in the dipion mass variable to justify the common practice of writing the production amplitudes as a coherent sum of Breit-Wigner amplitudes with free complex coefficients and a complex coherent background in fits to mass spectra with interfering resonances.Comment: 31 page

    Relevance of nucleon spin in amplitude analysis of reactions pi(-)p->pi(0)pi(0)n and pi(-)p->eta eta n

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    The measurements of reactions πpππ+n\pi^- p \to \pi^- \pi^+ n and π+nπ+πp\pi^+ n \to \pi^+ \pi^- p on polarized targets at CERN found a strong dependence of pion production amplitudes on nucleon spin. Analyses of recent measurements of πpπ0π0n\pi^- p \to \pi^0\pi^0 n reaction on unpolarized targets by GAMS Collaboration at 38 GeV/c and BNL E852 Collaboration at 18 GeV/c use the assumption that pion production amplitudes do not depend on nucleon spin, in conflict with the CERN results on polarized targets. We show that measurements of πpπ0π0n\pi^- p \to \pi^0\pi^0 n and πpηηn\pi^- p \to \eta\eta n on unpolarized targets can be analysed in a model independent way in terms of 4 partial-wave intensities and 3 independent interference phases in the mass region where SS- and DD-wave dominate. We also describe model-independent amplitude analysis of πpπ0π0n\pi^- p \to \pi^0\pi^0 n reaction measured on polarized target, both in the absence and in the presence of GG-wave amplitudes. We suggest that high statistics measurements of reactions πpπ0π0n\pi^- p \to \pi^0 \pi^0 n and πpηηn\pi^- p \to \eta\eta n be made on polarized targets at Protvino IHEP and at BNL, and that model-independent amplitude analyses of this polarized data be performed to advance hadron spectroscopy on the level of spin dependent production amplitudes.Comment: 54 page

    STRUCTURE OF METHYLPHEOPHORBIDE-RCI

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    he methanolic extract of the cyanobacterium (blue-green alga) Spirulina geitleri has been treated with methanolic acid to convert all chlorophyllous pigments to their methylpheophorbides. Fractionation of the latter from methylpheophorbide a by thin layer chromatography and high pressure liquid chromatography yielded methylpheophorbide-RCI. Its structure has been determined as 132S-hydroxy-20-chloro-methylpheophorbide a by 1H-nuclear magnetic resonance, absorption and circular dichroism spectroscopy, mass spectrometry and by partial synthesis from chlorophyll a. The pigment is isolated from Spirulina geitleri irrespective of the use or omission of chlorinated substances during the isolation procedure

    Mass and width of sigma(750) scalar meson from measurements of piN->pi(-)pi(+)N on polarized targets

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    The measurements of reactions πpππ+n\pi^- p_\uparrow \to \pi^- \pi^+ n at 17.2 GeV/c and π+nπ+πp\pi^+ n_\uparrow \to \pi^+ \pi^- p at 5.98 and 11.85 GeV/c made at CERN with polarized targets provide a model-independent and solution-independent evidence for a narrow scalar state sigma(750). The original chi^2 minimization method and the recent Monte Carlo method for amplitude analysis of data at 17.2 GeV/c are in excellent agreement. Both methods find that the mass distribution of the measured amplitude S2Σ|\overline S |^2\Sigma with recoil transversity ``up'' resonates near 750 MeV while the amplitude S2Σ|S|^2\Sigma with recoil transversity ``down'' is large and nonresonating. The amplitude S2Σ|S|^2\Sigma contributes as a strong background to S-wave intensity I_S = (|S|^2 + |\overline S |^2)\Sigmaanddistortsthedeterminationsof and distorts the determinations of \sigmaresonanceparametersfrom resonance parameters from I_S.ToavoidthisproblemweperformaseriesofBreitWignerfitsdirectlytothemeasureddistribution. To avoid this problem we perform a series of Breit-Wigner fits directly to the measured distribution |\overline S |^2\Sigma.Theinclusionofvariousbackgroundscausesthewidthofsigma(750)tobecomeverynarrow.Ourbestfitwith. The inclusion of various backgrounds causes the width of sigma(750) to become very narrow. Our best fit with taveragedcoherentbackgroundyields-averaged coherent background yields m_\sigma = 753 \pm 19MeVand MeV and \Gamma_\sigma = 108 \pm 53MeV.ThesevaluesareinexcellentagreementwithEllisLaniktheoremforthewidthofscalargluonium.Thegluoniuminterpretationof MeV. These values are in excellent agreement with Ellis-Lanik theorem for the width of scalar gluonium. The gluonium interpretation of \sigma(750)isalsosupportedbytheabsenceof is also supported by the absence of \sigma(750)inreactions in reactions \gamma\gamma \to \pi\pi.Wealsoshowhowdataonpolarizedtargetinvalidateessentialassumptionsofpastdeterminationsof. We also show how data on polarized target invalidate essential assumptions of past determinations of \pi\pi$ phase shifts .Comment: 77 page

    ππ\pi\pi scattering S wave from the data on the reaction πpπ0π0n\pi^-p\to\pi^0\pi^0n

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    The results of the recent experiments on the reaction πpπ0π0n\pi^-p\to\pi^0\pi^0n performed at KEK, BNL, IHEP, and CERN are analyzed in detail. For the I=0 ππ\pi\pi S wave phase shift δ00\delta^0_0 and inelasticity η00\eta^0_0 a new set of data is obtained. Difficulties emerging when using the physical solutions for the π0π0\pi^0\pi^0 S and D wave amplitudes extracted with the partial wave analyses are discussed. Attention is drawn to the fact that, for the π0π0\pi^0\pi^0 invariant mass, m, above 1 GeV, the other solutions, in principle, are found to be more preferred. For clarifying the situation and further studying the f0(980)f_0(980) resonance thorough experimental investigations of the reaction πpπ0π0n\pi^-p\to\pi^0\pi^0n in the m region near the KKˉK\bar K threshold are required.Comment: 17 pages, 5 figure

    Vector and Scalar Meson Resonances in KπππK\rightarrow\pi\pi\pi Decays

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    Corrections to KπππK\rightarrow\pi\pi\pi induced by vector and scalar meson exchange are investigated within chiral perturbation theory.Comment: 15pages, Latex-file, TUM-T31-41/9
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