129 research outputs found

    Search for Exotic Mesons in pi- P Interactions at 18 GeV/c

    Full text link
    The recent search for non qqˉq \bar{q} mesons in πp\pi^{-}p interactions at Brookhaven National Laboratory is summarized. Many final states such as ηπ\eta \pi, ηπ\eta' \pi^{-}, a0πa_{0} \pi, f1πf_{1} \pi, a2πa_{2} \pi, b1πb_{1} \pi, which are favored decay modes of exotics, are under investigation.Comment: 9 pages, PostScript, Presented at the International School of Nuclear Physics, Erice, Sicily, Italy, September 199

    A Study of the \eta \pi^{0} Spectrum and Search for a J^{PC} = 1^{-+} Exotic Meson

    Full text link
    A partial wave analysis (PWA) of the of the ηπ0\eta \pi ^0 system (where ηγγ\eta \to \gamma \gamma) produced in the charge exchange reaction πpηπ0n\pi ^-p\to \eta \pi ^0n at an incident momentum of 18 GeV/c/c is presented as a function of ηπ0{\eta \pi ^0} invariant mass, mηπ0m_{\eta\pi^0}, and momentum transfer squared, tπηπt_{\pi^{-}\to\eta\pi}, from the incident π\pi^- to the outgoing ηπ0{\eta\pi ^0} system. SS, PP and DD waves were included in the PWA. The a0(980)a_0(980) and a2(1320)a_2(1320) states are clearly observed in the overall ηπ0{\eta\pi ^0} effective mass distribution as well as in the amplitudes associated with SS wave and DD waves respectively after partial wave decomposition. The observed distributions in moments (averages of spherical harmonics) were compared to the results from the PWA and the two are consistent. The distribution in tπηπt_{\pi^{-}\to\eta\pi} for individual DD waves associated with natural and unnatural parity exchange in the tt-channel are consistent with Regge phenomenology. Of particular interest in this study is the PP wave since this leads to an exotic JPC=1+J^{PC}=1^{-+} for the ηπ\eta \pi system. A PP wave is present in the data, however attempts to describe the mass dependence of the amplitude and phase motion with respect to the DD wave as a Breit-Wigner resonance are problematic. This has implications regarding the existence of a reported exotic JPC=1+J^{PC} = 1^{-+} meson decaying into ηπ0\eta \pi^0 with a mass near 1.4 GeV/c2/c^2.Comment: 19 pages, 29 figures, to appear in Phys. Rev.

    Observation of a New J(PC)=1(+-) Isoscalar State in the Reaction Pi- Proton -> Omega Eta Neutron at 18 GeV/c

    Full text link
    Results are presented on a partial wave analysis of the Omega Eta final state produced in Pi- Proton interactions at 18 GeVc where Omega -> Pi+ Pi- Pi0, Pi0 -> 2 Gammas, and Eta -> 2 Gammas. We observe the previously unreported decay mode Omega(1650) -> Omega Eta and a new 1(+-) meson state h1(1595) with a mass M=1594(15)(+10)(-60) MeV/c^2 and a width Gamma=384(60)(+70)(-100) MeV/c^2. The h1(1595) state exhibits resonant-like phase motion relative to the Omega(1650).Comment: Submitted to Physics Letters B Eight total pages including 11 figures and 1 tabl

    Observation of Pseudoscalar and Axial Vector Resonances in pi- p -> K+ K- pi0 n at 18 GeV

    Get PDF
    A new measurement of the reaction pi- p -> K+ K- pi0 n has been made at a beam energy of 18 GeV. A partial wave analysis of the K+ K- pi0 system shows evidence for three pseudoscalar resonances, eta(1295), eta(1416), and eta(1485), as well as two axial vectors, f1(1285), and f1(1420). Their observed masses, widths and decay properties are reported. No signal was observed for C(1480), an IG J{PC} = 1+ 1{--} state previously reported in phi pi0 decay.Comment: 7 pages, 6 figs, to be submitted to Phys. Let

    Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized 3He

    Get PDF
    We report a measurement of the asymmetry in spin-dependent quasielastic scattering of longitudinally polarized electrons from a polarized 3He target. The neutron magnetic form factor GMn has been extracted from the measured asymmetry based on recent PWIA calculations using spin-dependent spectral functions. Our determination of GMn at Q2=0.19 (GeV/c)2 agrees with the dipole parametrization. This experiment represents the first measurement of the neutron magnetic form factor using spin-dependent electron scattering

    Cultured fish cells metabolize octadecapentaenoic acid (all-cis delta3,6,9,12,15–18∶5) to octadecatetraenoic acid (all-cis delta6,9,12,15–18∶4) via its 2-trans intermediate (trans delta2, all-cis delta6,9,12,15–18∶5)

    Get PDF
    Octadecapentaenoic acid (all-cis Δ3,6,9,12,15-18:5; 18:5n-3) is an unusual fatty acid found in marine dinophytes, haptophytes and prasinophytes. It is not present at higher trophic levels in the marine food web but its metabolism by animals ingesting algae is unknown. Here we studied the metabolism of 18:5n-3 in cell lines derived from turbot (Scophthalmus maximus), gilthead sea bream (Sparus aurata) and Atlantic salmon (Salmo salar). Cells were incubated in the presence of approximately 1 μM [U-14C] 18:5n-3 methyl ester or [U-14C] 18:4n-3 (octadecatetraenoic acid; all-cis Δ6,9,12,15-18:4) methyl ester, both derived from the alga Isochrysis galbana grown in H14CO3, and also with 25 μM unlabelled 18:5n-3 or 18:4n-3. Cells were also incubated with 25 μM trans Δ2, all-cis Δ6,9,12,15-18:5 (2-trans 18:5n-3) produced by alkaline isomerization of 18:5n-3 chemically synthesized from docosahexaenoic acid (all-cis Δ4,7,10,13,16,19-22:6; 22:6n-3). Radio- and mass analyses of total fatty acids extracted from cells incubated with 18:5n-3 were consistent with this fatty acid being rapidly metabolized to 18:4n-3 which was then elongated and further desaturated to eicosatetraenoic acid (all-cis Δ8,11,14,17,19-20:4; 20:4n-3) and eicosapentaenoic acid (all-cis Δ5,8,11,14,17-20:5; 20:5n-3). Similar mass increases of 18:4n-3 and its elongation and further desaturation products occurred in cells incubated with 18:5n-3 or 2-trans 18:5n-3. We conclude that 18:5n-3 is readily converted biochemically to 18:4n-3 via a 2-trans 18:5n-3 intermediate generated by a Δ3,Δ2-enoyl-CoA-isomerase acting on 18:5n-3. Thus, 2-trans 18:5n-3 is implicated as a common intermediate in the β-oxidation of both 18:5n-3 and 18:4n-3

    Toward an internally consistent astronomical distance scale

    Full text link
    Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to determine accurate distances, using a wide range of methods, tracers, and techniques, an internally consistent astronomical distance framework has not yet been established. We review current efforts to homogenize the Local Group's distance framework, with particular emphasis on the potential of RR Lyrae stars as distance indicators, and attempt to extend this in an internally consistent manner to cosmological distances. Calibration based on Type Ia supernovae and distance determinations based on gravitational lensing represent particularly promising approaches. We provide a positive outlook to improvements to the status quo expected from future surveys, missions, and facilities. Astronomical distance determination has clearly reached maturity and near-consistency.Comment: Review article, 59 pages (4 figures); Space Science Reviews, in press (chapter 8 of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Age

    Patient blood management in Europe

    Get PDF
    Preoperative anaemia is common in patients undergoing orthopaedic and other major surgery. Anaemia is associated with increased risks of postoperative mortality and morbidity, infectious complications, prolonged hospitalization, and a greater likelihood of allogeneic red blood cell (RBC) transfusion. Evidence of the clinical and economic disadvantages of RBC transfusion in treating perioperative anaemia has prompted recommendations for its restriction and a growing interest in approaches that rely on patients' own (rather than donor) blood. These approaches are collectively termed ‘patient blood management’ (PBM). PBM involves the use of multidisciplinary, multimodal, individualized strategies to minimize RBC transfusion with the ultimate goal of improving patient outcomes. PBM relies on approaches (pillars) that detect and treat perioperative anaemia and reduce surgical blood loss and perioperative coagulopathy to harness and optimize physiological tolerance of anaemia. After the recent resolution 63.12 of the World Health Assembly, the implementation of PBM is encouraged in all WHO member states. This new standard of care is now established in some centres in the USA and Austria, in Western Australia, and nationally in the Netherlands. However, there is a pressing need for European healthcare providers to integrate PBM strategies into routine care for patients undergoing orthopaedic and other types of surgery in order to reduce the use of unnecessary transfusions and improve the quality of care. After reviewing current PBM practices in Europe, this article offers recommendations supporting its wider implementation, focusing on anaemia management, the first of the three pillars of PBM

    CUORE and CUORE-0 experiments

    Get PDF
    Neutrino oscillation experiments proved that neutrinos have mass and this enhanced the interest in neutrinoless double-beta decay (0vßß). The observation of this very rare hypothetical decay would prove the leptonic number violation and would give us indications about neutrinos mass hierarchy and absolute mass scale. CUORE (Cryogenic Underground Observatory for Rare Events) is an array of 988 crystals of TeO2, for a total sensitive mass of 741 kg. Its goal is the observation of 0vßß of 130Te. The crystals, placed into the a dilution cryostat, are operated as bolometers at a temperature close to 10 mK. CUORE commissioning phase has been concluded recently in Gran Sasso National Laboratory, Italy, and data taking is expected to start in spring 2017. If target background rate is reached (0.01counts/day/keV/kg), the sensibility of CUORE will be, in five years of data taking, T1/21026years (1? CL). In order to test the quality of materials and optimize the construction procedures, the collaboration realized CUORE-0, that took data from spring of 2013 to summer 2015. Here, after a brief description of CUORE, I report its commissioning status and CUORE-0 results
    corecore