Search for eta-mesic Helium with the WASA-at-COSY detector

A search for the 4He-eta bound state via exclusive measurement of the excitation function for the dd->3Heppi- reaction, was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta production in the dd -> 4He-eta reaction at 2.336 GeV/c. The corresponding excess energy in the 4He-eta system varied from -51.4 MeV to 22 MeV. The shape of the excitation function for the dd -> 3Heppi- was examined. No signal of the 4He-eta bound state was observed in the excitation function.Comment: 4 pages, 5 figures, to appear in proceedings of MESON201

Pengaruh latihan back-up terhadap kemampuan menyundul bola

The purpose of this study was to determine whether there is an effect of back-up training on the ability to head a ball in eighth grade male students of SMP YPK Merauke. The experimental method used for this study was a pre-test and post-test pattern. In the implementation of this research, the population was used, namely all students of class VIII SMP YPK Merauke for the 2019-2020 academic year. The total population of this study from each class, including; Class VIIIa consists of 28 students, VIIIb has 26 students, VIIIc has 28 students, and class VIIId has 25 students. The total population is 107 students. The number of samples in this study are; 6 students from class VIIIa, 5 students from class VIIIb, 6 students from class VIIIc, and from class VIIId there are 5 students. The total sample in this study was 22 students. The research instrument used a soccer heading test. The results of this study can be concluded that the back up exercise has an effect on the results of students' ball headers. It is proven that students who do back up exercises will produce good ball headers compared to students who head the ball without doing back up exercises

Meson-production experiments at COSY-Juelich

Selected results from experiments at COSY-Juelich are presented: an attempt to measure the mass of the eta meson with high precision (ANKE facility), first steps towards the detection of rare eta decays (WASA), and several measurements of KKbar-pair production (ANKE, COSY-11, MOMO).Comment: Proceedings of QNP2009, Beijing, Sept. 2009; to be published in Chinese Physics C. 6 pages, 5 figure

Preparation and characterization of the defect–conductivity relationship of Ga-doped ZnO thin films deposited by nonreactive radio-frequency–magnetron sputtering

Ga-doped ZnO (ZnO:Ga) thin films were prepared by radio-frequency–magnetron sputtering on conventional glass substrates at room temperature. The structural, electrical, and optical properties of these films as a function of argon pressure and film thicknesses were studied. All the films crystallized with the hexagonal wurtzite structure. The x-ray diffraction studies show that the ZnO:Ga films are highly oriented with their crystallographic c-axis perpendicular to the substrate. We discuss a methodology of using a “standardized platform” for comparison of samples deposited at different pressures, which provides an insight into the defect–resistivity relationship of each sample with respect to their microstructure. After the first annealing, the electrical properties of the films are dependent on the atmosphere used during postdeposition annealing treatment. A resistivity of 2.5 × 10−3 Ω · cm was obtained after vacuum annealing, and the films became an insulator after air annealing. The reproducibility of this treatment was verified. The average transmittance of all ZnO:Ga thin films is more than 85% in the visible range

Finding the Anticover of a String

A k-anticover of a string x is a set of pairwise distinct factors of x of equal length k, such that every symbol of x is contained into an occurrence of at least one of those factors. The existence of a k-anticover can be seen as a notion of non-redundancy, which has application in computational biology, where they are associated with various non-regulatory mechanisms. In this paper we address the complexity of the problem of finding a k-anticover of a string x if it exists, showing that the decision problem is NP-complete on general strings for k-3. We also show that the problem admits a polynomial-time solution for k = 2. For unbounded k, we provide an exact exponential algorithm to find a k-anticover of a string of length n (or determine that none exists), which runs in O(min{3 n-k 3 , ( k(k+1) 2 ) n k+1 }) time using polynomial space. 2012 ACM Subject Classification Mathematics of computing ! Combinatorics on words

Tests of the fundamental symmetries in eta meson decays

Patterns of chiral symmetry violation and tests of the conservation of the fundamental C, P and CP symmetries are key physics issues in studies of the pi0, eta and eta' meson decays. These tests include searches for rare or forbidden decays and searches for asymmetries among the decay products in the not-so-rare decays. Some examples for the rare decays are eta-->2pi, eta-->4pi0 (CP tests), decays into an odd number of photons (e.g., eta-->3g) and the decay eta-->pi0e+e- (C tests). The experimental studies of the pi0, eta and eta' meson decays are carried out at four European accelerator research facilities: KLOE/KLOE-2 at DAFNE (Frascati), Crystal Ball at MAMI (Mainz), WASA at COSY (J\"ulich), Crystal Barrel at ELSA (Bonn).Comment: 9 pages, 2 figures, proceedings of Symposium on Prospects in the Physics of Discrete Symmetries, DISCRETE 2010, 6 - 11 December, Rome; v2: added reference

Luminosity determination for the pd reaction at 2.14 GeV with WASA-at-COSY

The luminosity for a WASA-at-COSY experiment involving the pd reaction at 2.14 GeV proton-beam energy is determined by the forward pd elastic scattering, which yields an average beam-on-target value of [5.2\pm0.3(stat)\pm0.3(syst)]*10^{30} s^{-1}cm^{-2}. In addition, the forward pd elastic-scattering angular distribution is obtained with four-momentum transfer squared -t between 0.16 (GeV/c)^{2} and 0.78 (GeV/c)^{2} at this beam energy, which is compared with other experimental data and the pd double scattering model.Comment: 5 pages, 6 figure

Measurement of the eta->pi+pi-e+e- decay branching ratio

The reaction pd->3He eta at threshold was used to provide a clean source of eta mesons for decay studies with the WASA detector at CELSIUS. The branching ratio of the decay eta->pi+pi-e+e- is measured to be (4.3+/-1.3+/-0.4)x10^-4.Comment: 10 pages,6 figures revised versio

Scope and Mechanistic Study of the Coupling Reaction of α,β-Unsaturated Carbonyl Compounds with Alkenes: Uncovering Electronic Effects on Alkene Insertion vs Oxidative Coupling Pathways

The cationic ruthenium-hydride complex [(C6H6)(PCy3)(CO)RuH]+BF4– (1) was found to be a highly effective catalyst for the intermolecular conjugate addition of simple alkenes to α,β-unsaturated carbonyl compounds to give (Z)-selective tetrasubstituted olefin products. The analogous coupling reaction of cinnamides with electron-deficient olefins led to the oxidative coupling of two olefinic C–H bonds in forming (E)-selective diene products. The intramolecular version of the coupling reaction efficiently produced indene and bicyclic fulvene derivatives. The empirical rate law for the coupling reaction of ethyl cinnamate with propene was determined as follows: rate = k[1]1[propene]0[cinnamate]−1. A negligible deuterium kinetic isotope effect (kH/kD = 1.1 ± 0.1) was measured from both (E)-C6H5CH═C(CH3)CONHCH3 and (E)-C6H5CD═C(CH3)CONHCH3 with styrene. In contrast, a significant normal isotope effect (kH/kD = 1.7 ± 0.1) was observed from the reaction of (E)-C6H5CH═C(CH3)CONHCH3 with styrene and styrene-d8. A pronounced carbon isotope effect was measured from the coupling reaction of (E)-C6H5CH═CHCO2Et with propene (13C(recovered)/13C(virgin) at Cβ = 1.019(6)), while a negligible carbon isotope effect (13C(recovered)/13C(virgin) at Cβ = 0.999(4)) was obtained from the reaction of (E)-C6H5CH═C(CH3)CONHCH3 with styrene. Hammett plots from the correlation of para-substituted p-X-C6H4CH═CHCO2Et (X = OCH3, CH3, H, F, Cl, CO2Me, CF3) with propene and from the treatment of (E)-C6H5CH═CHCO2Et with a series of para-substituted styrenes p-Y-C6H4CH═CH2 (Y = OCH3, CH3, H, F, Cl, CF3) gave the positive slopes for both cases (ρ = +1.1 ± 0.1 and +1.5 ± 0.1, respectively). Eyring analysis of the coupling reaction led to the thermodynamic parameters, ΔH⧧ = 20 ± 2 kcal mol–1 and ΔS⧧ = −42 ± 5 eu. Two separate mechanistic pathways for the coupling reaction have been proposed on the basis of these kinetic and spectroscopic studies