Synthesis of isoxazolylvinyl ketones from furan derivatives

We developed a new route to isoxazoles with α,β-unsaturated fragment, studied the scope of the reaction, and proposed its mechanism.This work was supported by the scholarship “Promotion of Equal Opportunities for Women in Research and Teaching (FFL)”offered by the Free State of Bavaria, Germany

Detailed comparison of the pp -> \pi^+pn and pp -> \pi^+d reactions at 951 MeV

The positively charged pions produced in proton-proton collisions at a beam momentum of 1640 MeV/c were measured in the forward direction with a high resolution magnetic spectrograph. The missing mass distribution shows the bound state (deuteron) clearly separated from the $pn$ continuum. Despite the very good resolution, there is no evidence for any significant production of the $pn$ system in the spin-singlet state. However, the $\sigma(pp\to \pi^+pn)/\sigma(pp\to \pi^+d)$ cross section ratio is about twice as large as that predicted from $S$-wave final-state-interaction theory and it is suggested that this is due to $D$-state effects in the $pn$ system.Comment: 8 pages, 3 figure

Production of the 1S0 diproton in the pp -> pp pi0 reaction at 0.8 GeV

The pp -> pp pi0 differential cross section has been measured with the ANKE spectrometer at COSY-Juelich for pion cms angles between 0 and 15.4 degrees at a proton beam energy of 0.8 GeV. The selection of diproton pairs with an excitation energy E_{pp} < 3 MeV ensures that the final pp system is dominantly in the spin-singlet 1S0 state. The kinematics are therefore very similar to those of pp -> d pi+ but with different spin and isospin transitions. The results will thus provide a crucial extra test of pion production models in nucleon-nucleon collisions. The cross sections, which are over two orders of magnitude smaller than those of pp -> d pi+, show a forward dip, even stronger than that seen at lower energies. This behaviour is well reproduced in a theoretical model that includes P-wave Delta-N states.Comment: 10 pages, 5 eps figures, prepared using elsart.cl

Delta isobar masses, large N_c relations, and the quark model

Motivated by recent remarks on the Delta+ mass and comparisons between the quark model and relations based on large-N_c with perturbative flavor breaking, two sets of Delta masses consistent with these constraints are constructed. These two sets, based either on an experimentally determined mass splitting or a quark model of isospin symmetry breaking, are shown to be inconsistent. The model dependence of this inconsistency is examined, and suggestions for improved experiments are made. An explicit quark model calculation and mass relations based on the large-N_c limit with perturbative flavor breaking are compared. The expected level of accuracy of such relations is realized in the quark model, except for mass relations spanning more than one SU(6) representation. It is shown that the Delta0 and Delta++ pole masses and Delta0 - Delta+ = (Delta- - Delta++)/3 about 1.5 MeV are more consistent with model expectations than the analogous Breit-Wigner masses and their splittings.Comment: 10 pages, including 1 eps figure, revte

Responses of Pseudovadonia livida adults to olfactory and visual cues

Pseudovadonia livida (F.) (Coleoptera Cerambycidae Lepturinae) is a widely distributed and common species across Europe. This study was undertaken to investigate some aspects of the sensory and behavioural ecology of P. livida adults in relation to flowering plants they visit. First, their electroantennogram (EAG) responses to 42 synthetic plant volatile compounds were recorded.The antennae gave the strongest EAG responses to methyl anthranilate, methyl salicylate and 2-phenylethyl alcohol. In a field trapping experiment, P. livida beetles preferred fluorescent yellow and yellow traps over white, blue and transparent traps. When we compared different chemical lures, loaded with EAG-active compounds and their blends, in fluorescent yellow traps, we found that the beetles responded stronger to the two-component blend of methyl anthranilate and 2-phenylethyl alcohol than to other lures tested. In a subsequent experiment testing different ratios of these two compounds, the highest number of P. livida adults was recorded in traps baited with a ratio of 1:1 (100 mg of each compound) of methyl anthranilate and 2-phenylethyl alcohol, followed by traps with the 10:1 ratio. Thus, 1:1 and 10:1 blends of methyl anthranilate and 2-phenylethyl alcohol in fluorescent yellow traps are suitable for detection and monitoring of P. livida

Responses of Pseudovadonia livida adults to olfactory and visual cues

Pseudovadonia livida (F.) (Coleoptera Cerambycidae Lepturinae) is a widely distributed and common species across Europe. This study was undertaken to investigate some aspects of the sensory and behavioural ecology of P. livida adults in relation to flowering plants they visit. First, their electroantennogram (EAG) responses to 42 synthetic plant volatile compounds were recorded.The antennae gave the strongest EAG responses to methyl anthranilate, methyl salicylate and 2-phenylethyl alcohol. In a field trapping experiment, P. livida beetles preferred fluorescent yellow and yellow traps over white, blue and transparent traps. When we compared different chemical lures, loaded with EAG-active compounds and their blends, in fluorescent yellow traps, we found that the beetles responded stronger to the two-component blend of methyl anthranilate and 2-phenylethyl alcohol than to other lures tested. In a subsequent experiment testing different ratios of these two compounds, the highest number of P. livida adults was recorded in traps baited with a ratio of 1:1 (100 mg of each compound) of methyl anthranilate and 2-phenylethyl alcohol, followed by traps with the 10:1 ratio. Thus, 1:1 and 10:1 blends of methyl anthranilate and 2-phenylethyl alcohol in fluorescent yellow traps are suitable for detection and monitoring of P. livida

Measurement of p + d -> 3He + eta in S(11) Resonance

We have measured the reaction p + d -> 3He + eta at a proton beam energy of 980 MeV, which is 88.5 MeV above threshold using the new ``germanium wall'' detector system. A missing--mass resolution of the detector system of 2.6% was achieved. The angular distribution of the meson is forward peaked. We found a total cross section of (573 +- 83(stat.) +- 69(syst.))nb. The excitation function for the present reaction is described by a Breit Wigner form with parameters from photoproduction.Comment: 8 pages, 2 figures, corrected typos in heade

Forward K+ production in subthreshold pA collisions at 1.0 GeV

K+ meson production in pA (A = C, Cu, Au) collisions has been studied using the ANKE spectrometer at an internal target position of the COSY-Juelich accelerator. The complete momentum spectrum of kaons emitted at forward angles, theta < 12 degrees, has been measured for a beam energy of T(p)=1.0 GeV, far below the free NN threshold of 1.58 GeV. The spectrum does not follow a thermal distribution at low kaon momenta and the larger momenta reflect a high degree of collectivity in the target nucleus.Comment: 4 pages, 3 figure

Decuplet contribution to the meson-baryon scattering lengths

We calculate decuplet contributions to the s-wave pseudoscalar meson octet-baryon scattering lengths to the third order in heavy baryon chiral perturbation theory (HB$\chi$PT). Using experimental pion-nucleon and kaon-nucleon scattering lengths as inputs, we determine low-energy constants and predict other meson-baryon scattering lengths. Numerically we consider three cases: (1) the case with only baryon octet contributions; (2) with decuplet contributions and (3) in the large $N_c$ limit. Hopefully, the analytical expressions and the predictions are helpful to future investigations of the meson-baryon scattering lengths

Energy dependence of forward 1S0 diproton production in the pp -> pp pi0 reaction

The pp -> {pp}_s pi0 differential cross section has been measured with the ANKE spectrometer at COSY-Juelich for seven proton beam energies T_p between 0.5 and 1.97 GeV. By selecting proton pairs with an excitation energy of less than 3 MeV it is ensured that the final {pp}_s system is in the 1S0 state. In the measured region of theta_{pp}^{cm} < 18 deg, the data reveal a forward dip for T_p =< 1.4 GeV whereas a forward peaking is seen at 1.97 GeV. The energy dependence of the forward cross section shows a broad peak in the 0.6-0.8 GeV region, probably associated with Delta(1232) excitation, and a minimum at 1.4 GeV. Some of these features are similar to those observed for the spin-isospin partner reaction, pp -> d pi+. However, the ratio of the forward differential cross sections of the two reactions shows a significant suppression of single pion production associated with a spin--singlet final nucleon pair.Comment: 12 pages, 4 figure