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1. The pp→ppπππ reaction channels in the threshold region

Author

Marek Jacewicz, Leif Gustafsson, J. Zabierowski, Pia Thörngren Engblom, W. Oelert, G. Ivanov, B. Morosov, Jozef Zlomanczuk, Roger Ruber, Hans Calén, M. Bashkanov, B. Shwartz, J. Stepaniak, Wolfgang Scobel, I. Koch, C. Pauly, Magnus Wolke, Kjell Fransson, R. Meier, Curt Ekstrom, Pawel Marciniewski, V. Tchernyshev, Filippo Capellaro, V. Tikhomirov, Karin Schönning, Henrik Pettersson, E. Jiganov, A. Turowiecki, G. J. Wagner, Y. Petukhov, D. Bogoslawsky, H. Clement, V. Sopov, Bo Höistad, Andrzej Kupsc, Tord Johansson, Akira Yamamoto, S. Keleta, T. Skorodko, Sven Kullander, A. Povtorejko, A. A. Kuznetsov, and Ulrich Wiedner

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Range (particle radiation), Meson production, Pion, Isobar, Intermediate state, Atomic physics
Abstract

The cross section for direct neutral and charged three pion production in pp interactions was measured at excess energies in the range 160–216 MeV. That comprises the first measurement of the pp→ppπ0π0π0 reaction and the direct comparison with the pp→ppπ+π−π0 process. The experiment was performed above the η meson production threshold and the cross section could be directly normalized to the cross section of the pp→ppη reaction, with the η decaying into 3 pions. Since the same final states are selected, the measurement has a low systematical error. The measured cross section ratio σ(pp→ppπ+π−π0)/σ(pp→ppπ0π0π0) is compared to predictions of dominance of different isobars in the intermediate state.

Published
2007
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2. OBSERVATION OF THE ABC EFFECT IN THE FIRST EXCLUSIVE MEASUREMENTS OF pn → dπ0π0

Author

Magnus Wolke, J. Stepaniak, Akira Yamamoto, R. Meier, Pawel Marciniewski, V. Tikhomirov, G. Ivanov, A. Povtoreyko, T. Skorodko, B. Morosov, Hans Calén, J. Zabierowski, P.-E. Tegnér, C. Bargholtz, S. Keleta, A. A. Kuznetsov, C. Ekström, F. Cappellaro, S. Kullander, B. Shwartz, Murat M. Kaskulov, M. Bashkanov, A. Kupść, K. Lindberg, I. Zartova, K. Fransson, A. Schwick, Marek Jacewicz, R. J. M. Y. Ruber, E. Jiganov, H. Clement, Bo Höistad, D. Bogoslowsky, I. Koch, Wolfgang Scobel, O. Khakimova, P. Thörngren-Engblom, Jozef Zlomanczuk, Leif Gustafsson, V. Sopov, V. Tchernyshev, F. Kren, A. Turowiecki, Y. Petukhov, W. Oelert, L. Geren, T. Johansson, C. Pauly, R. Shafigullin, and G. J. Wagner

Subjects
Physics, Nuclear and High Energy Physics, Complete data, Quantum mechanics, Spectrum (functional analysis), Bound state, Theoretical models, Prove it, Astronomy and Astrophysics, Invariant mass, Atomic physics, Atomic and Molecular Physics, and Optics, Excitation
Abstract

The reaction pn → dπ0π0 constitutes the most fundamental system for the study of the ABC effect - a puzzling threshold enhancement in the ππ invariant mass spectrum of the ππ system in double-pionic fusion to nuclear bound states. The first exclusive measurements of this reaction have now been carried out at CELSIUS-WASA. They exhibit a striking low-mass enhancement in the ππ invariant mass spectrum, prove it to be a σ-channel phenomenon and falsify conventional theoretical models, which predict an associated high-mass enhancement not present in the new exclusive data. In the kinematically complete data sample we observe a ΔΔ excitation, where the interaction between the two Δ obviously plays a crucial role for the generation of the ππ low-mass enhancement.

Published
2007
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3. ππ PRODUCTION IN PROTON-PROTON COLLISIONS

Author

M. Bashkanov, F. Cappellaro, L. Demiroers, D. Bogoslowsky, Jozef Zlomanczuk, V. Tchernyshev, W. Oelert, Akira Yamamoto, B. Morosov, A. Kupść, Pawel Marciniewski, T. Johansson, C. Ekström, A. A. Kuznetsov, A. Turowiecki, K. Fransson, C. Pauly, V. Tikhomirov, B. Shwartz, R. Shafigullin, G. J. Wagner, A. Schwick, Marek Jacewicz, A. Povtorejko, E. Jiganov, H. Clement, P. Thörngren-Engblom, J. Greiff, Hans Calén, Y. Petukhov, M. Kaskulov, O. Khakimova, V. Sopov, F. Kren, R. Meier, S. Kullander, I. Koch, G. Ivanov, Magnus Wolke, Leif Gustafsson, R. J. M. Y. Ruber, J. Stepaniak, Bo Höistad, J. Zabierowski, S. Keleta, W. Scobel, and T. Skorodko

Subjects
Physics, Nuclear and High Energy Physics, Fusion, Complete data, Range (particle radiation), Proton, Excited state, Astronomy and Astrophysics, Invariant mass, Production (computer science), Atomic physics, Atomic and Molecular Physics, and Optics, Excitation
Abstract

At CELSIUS-WASA the two-pion production in proton-proton collisisons has been measured exclusively from threshold up to the energy regime, where both of the collision partners are expected to be excited to the Δ state. The measurements constitute the first kinematically complete data samples of solid statistics in this energy range. Most of the data have been obtained for the π+π- and π0π0channels. Whereas at near-threshold energies the differential distributions can be succesfully explained by chiral dynamics and Roper excitation, respectively, the data for the π+π- channel in the ΔΔ region can be described only, if the special configuration (ΔΔ)0+ is assumed. The data for the π0π0 channel moreover exhibit a low-mass enhancement in the π0π0 invariant mass spectrum, which is reminiscent of the ABC-effect found in double-pionic fusion to light nuclei.

Published
2007
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4. LOW-MASS ππ ENHANCEMENT IN BARYONIC ππ PRODUCTION: ABC EFFECT REVISED BY EXCLUSIVE MEASUREMENTS

Author

C. Ekström, R. J. M. Y. Ruber, Magnus Wolke, J. Stepaniak, G. Ivanov, B. Morosov, I. Zartova, P. Thörngren-Engblom, W. Scobel, B. Shwartz, R. Shafigullin, G. J. Wagner, Y. Petukhov, Jozef Zlomanczuk, L. Geren, D. Bogoslowsky, S. Kullander, A. A. Kuznetsov, V. Tchernyshev, W. Oelert, M. Bashkanov, F. Cappellaro, C. Bargholtz, Pawel Marciniewski, A. Povtoreyko, O. Khakimova, E. Jiganov, H. Clement, A. Turowiecki, Leif Gustafsson, Hans Calén, V. Tikhomirov, T. Johansson, Akira Yamamoto, A. Kupść, K. Fransson, T. Skorodko, C. Pauly, A. Schwick, Marek Jacewicz, K. Lindberg, P.-E. Tegnér, R. Meier, I. Koch, Bo Höistad, M. Kaskulov, J. Zabierowski, S. Keleta, V. Sopov, and F. Kren

Subjects
Baryon, Physics, Nuclear physics, Nuclear and High Energy Physics, Complete data, Bound state, Prove it, Astronomy and Astrophysics, Production (computer science), Invariant mass, Low Mass, Atomic and Molecular Physics, and Optics, Spectral line
Abstract

The ABC effect - a puzzling threshold enhancement in the ππ invariant mass spectrum of double-pionic fusion to nuclear bound states - has been investigated since 40 years by inclusive measurements without providing a conclusive interpretation. First exclusive measurements to this topic have now been carried out at CELSIUS-WASA. They confirm a huge ππ threshold enhancement, prove it to be of scalar-isoscalar nature, i.e., a σ-channel phenomenon and reveal the theoretically predicted high-mass enhancement in inclusive spectra to be of πππ rather than of ππ nature - falsifying thus corresponding model predictions for the ABC effect. From the kinematically complete data samples we infer that the interaction between the two Δ particles created in this process is of crucial importance.

Published
2007
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5. Measurement of the η→π+π−e+e− decay branching ratio

Author

J. Zabierowski, E. Jiganov, V. Tchernyshev, L. Demiroers, Bo Höistad, P. Thörngren-Engblom, H. Clement, Marek Jacewicz, Wolfgang Scobel, M. Bashkanov, R. Shafigullin, G. J. Wagner, P.-E. Tegnér, H. Pettersson, Karin Schönning, A. A. Kuznetsov, K. Lindberg, W. Oelert, D. Bogoslawsky, A. Turowiecki, Y. Petukhov, Jozef Zlomanczuk, Tord Johansson, V. Sopov, Pawel Marciniewski, V. Tikhomirov, Leif Gustafsson, C. Pauly, R. Meier, Roger Ruber, I. Zartova, Sven Kullander, Akira Yamamoto, L. Geren, I. Koch, T. Skorodko, A. Povtorejko, Chr. Bargholtz, I. V. Laukhin, Hans Calén, Magnus Wolke, Kjell Fransson, Andrzej Kupsc, G. Ivanov, Curt Ekstrom, B. Morosov, B. Shwartz, J. Stepaniak, F. Cappellaro, and S. Negasi Keleta

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Meson, Branching fraction, Detector, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The reaction pd -> He-3 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( ...

Published
2007
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6. Exclusive measurements of pd→He3ππ: The ABC effect revisited

Author

Akira Yamamoto, K. Fransson, S. Kullander, F. Cappellaro, A. Turowiecki, Pawel Marciniewski, V. Tikhomirov, O. Khakimova, E. Jiganov, Leif Gustafsson, H. Clement, D. Bogoslawsky, A. Povtorejko, Jozef Zlomanczuk, P. Thörngren-Engblom, C. Ekström, Hans Calén, W. Scobel, C. Pauly, G. Ivanov, I. Koch, R. J. M. Y. Ruber, Magnus Wolke, B. Morosov, A. Kupść, T. Johansson, M. Bashkanov, B. Shwartz, J. Stepaniak, Y. Petukho, M. Kaskulov, V. Sopov, F. Kren, G. J. Wagner, J. Zabierowski, Marek Jacewicz, V. Tchernyshev, J. Greiff, L. Demiroers, R. Meier, A. A. Kuznetsov, W. Oelert, Bo Höistad, T. Skorodko, and S. Keleta

Subjects
Mass enhancement, Nuclear physics, Physics, Nuclear and High Energy Physics, Angular distribution, Isoscalar, Dalitz plot, Atomic physics, Storage ring
Abstract

Exclusive measurements of the reactions p d → He 3 π + π − and p d → He 3 π 0 π 0 have been carried out at T p = 0.893 GeV at the CELSIUS storage ring using the WASA detector. The π + π − channel evidences a pronounced enhancement at low invariant ππ masses—as anticipated from previous inclusive measurements of the ABC effect. This enhancement is seen to be even much larger in the isoscalar π 0 π 0 channel. The differential distributions prove this enhancement to be of scalar–isoscalar nature. ΔΔ calculations give a good description of the data, if a boundstate condition is imposed for the intermediate ΔΔ system.

Published
2006
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7. TWO-PION PRODUCTION, γγ LINE AND ASPECTS OF σ MESON, BOSE–EINSTEIN CORRELATIONS AND ISOSPIN BREAKING

Author

T. Johansson, D. Bogoslawsky, Jozef Zlomanczuk, C. Ekström, Akira Yamamoto, A. Kupść, E. Jiganov, P. Thörngren Engblom, G. J. Wagner, H. Clement, O. Khakimova, K. Fransson, W. Oelert, Leif Gustafsson, E. Doroshkevich, S. Kullander, G. Ivanov, Marek Jacewicz, J. Zabierowski, R. Meier, T. Skorodko, S. Keleta, F. Cappellano, L. Demiroers, V. Tchernyshev, Bo Höistad, M. Kaskulov, V. Sopov, F. Kren, C. Pauly, J. Greiff, A. N. Kuznetsov, B. Morosow, Pawel Marciniewski, R. J. M. Y. Ruber, I. Koch, Hans Calén, M. Bashkanov, Ulrich Wiedner, W. Scobel, A. Turowiecki, Magnus Wolke, V. Tikhomirov, J. Stepaniak, Y. Petukhov, B.A. Shwartz, and A. Povtorejko

Subjects
Physics, Nuclear and High Energy Physics, Roper resonance, Particle physics, Hydrogen, Meson, chemistry.chemical_element, Astronomy and Astrophysics, Bose–Einstein correlations, Invariant (physics), Atomic and Molecular Physics, and Optics, Nuclear physics, Pion, chemistry, Isospin, Hermetic detector
Abstract

The pp→ppx(x=γγ, π0π0, π+π-) reactions have been measured at CELSIUS in the energy range Tp=775-1360 MeV using the WASA 4π detector with hydrogen pellet target. Close to threshold the ppπ+π- data are in accordance with the Roper resonance concept and/or a dynamic formation of the σ meson. At higher energies the formation of the ΔΔ system becomes increasingly dominant. The ppπ0π0 channel basically shows similar features, however, develops a peculiar enhancement at small invariant masses Mπ0π0 - in resemblance of Bose-Einstein correlations. Alternatively, the enhancement could be also indicative of a (dynamic) isospin breaking due to ππ rescattering in the σ channel. The latter is favored by the results on pd→3 He x (x=π0π0, π+π-), where the observed π0π0 enhancements are still much larger. In the γγ channel a line at Mγγ=2mπ is observed. The possible nature of this line is discussed.

Published
2005
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8. First results from the CELSIUS/WASA facility

Author

Z. Wilhelmi, V. Tchernyshev, V. Tikhomirov, P.-E. Tegnér, L. Gustafsson, N. Kimura, R. Shafigulin, D. Reistad, M. Bashkanov, K. Lindberg, J. Zabierowski, D. Bogoslawsky, J. Greiff, A. Nawrot, C. Bargholz, Arne Johansson, P. Marciniewski, T. Skorodko, S. Keletea, H. Yamaoka, Hans Calén, H. Clement, L. Demiroers, Y. Petukhov, Bo Höistad, A. Kipsc, F. Cappellaro, S. Kullander, B.A. Shwartz, Kjell Fransson, W. Oelert, Tord Johansson, S. Sandukovsky, B. M. K. Nefkens, V. Sopov, J. Zlomanczuk, A. Povtorejko, E. Jiganov, Ulrich Wiedner, W. Scobel, Marek Jacewicz, E. Dorochkevitch, Curt Ekstrom, I. Koch, Roger Ruber, B. Morosov, P. Thörngren Engblom, J. Stepaniak, G.J. Wagner, M. Gornov, Akira Yamamoto, A. Turowiecki, G. Ivanov, C. Pauly, A. A. Kuznetsov, and C.-J. Fridén

Subjects
Physics, Nuclear and High Energy Physics, Degree Celsius, Nuclear engineering
Published
2003
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9. CELSIUS as an η factory

Author

A. Martemyanov, G. J. Wagner, V. Tikhomirov, Hans Calén, M. Gornov, H. Clement, J. Moehn, B. Morosov, Kjell Fransson, Akira Yamamoto, A. Nawrot, W. Oelert, G. M. Kolachev, R. Bilger, J. Zabierowski, A.E. Bondar, A. Turowiecki, Roger Ruber, S. Dahlgren, W. Brodowski, B. Shwartz, J. Stepaniak, Pawel Marciniewski, Yu. B. Gurov, S. Sandukovsky, A. Zernov, V. Tchernyshev, Z. Pawlowski, A. A. Kuznetsov, Leif Gustafsson, Andrzej Kupsc, D. Reistad, A. Povtorejko, T. Johansson, Y. Yuasa, K. Kilian, M. Komogorov, Bo Höistad, L. Komogorova, V.A. Sidorov, T. Purlatz, R. Shafigullin, V. B. Dunin, Hiromi Hirabayashi, I. Chuvilo, A. Jansson, M. Blom, Z. Wilhelmi, B. Chernyshev, V. Sopov, S. Häggström, C.-J. Fridén, S. Kullander, A.I. Sukhanov, H. Ikegami, Jozef Zlomanczuk, Y. Mizuno, A. Kuzmin, D. Bogoslawsky, Arne Johansson, A. Yamaoka, and C. Ekström

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Degree Celsius, Factory (object-oriented programming), High Energy Physics::Experiment, Nuclear Experiment, Ring (chemistry), Physics::Atmospheric and Oceanic Physics, Storage ring
Abstract

The WASA project at the CELSIUS storage ring is being prepared for high-luminosity experiments to study rare decays of light mesons, in particular the η meson. The CELSIUS ring together with the newly developed pellet target will serve as an efficient η factory.

Published
1997
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10. K +-meson production inpBe interactions atT p=2.9 GeV

Author

Y. Kiselev, V. Koptev, V. Goryachev, K. Sistemich, A. Franzen, S. Mikirtychyants, V. Ergakov, V. Demechin, V. Tchernyshev, V. Kostromin, L. v. Horn, B. Rimarzig, V. Sopov, A. A. Sibirtsev, R. Eßer, A. Gerasimov, H. Müller, A. V. Akindinov, H. Seyfarth, B. Prietzschk, M. Chumakov, H. Ohm, Markus Büscher, V. Kruglov, A. Petrus, C. Schneider, D. Kopyto, and C. Schneidereit

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Meson production, Pion, Meson, Proton Synchrotron, Nuclear fusion
Abstract

The production ofK + andπ + mesons and protons inpBe collisions atT p=2.9 GeV has been studied at the ITEP proton synchrotron. Ejectiles with a momentum ofp=545 MeV/c were observed under an emission angle ϑ=17°. The detectors which have been developed for the identification of kaons out of a six orders of magnitude more intense background of pions and protons are described. A cross-section ratio d2σ K +/dΩdp: d2 σ p /dΩdp: d2σ p /dΩdp of (1±0.34):(85±1):(31±1) has been measured. Normalization with existing pion data yields an invariant differential cross sectionE·d3σ K +/d3 p=(3.1±1.2) mbGeV−2c3sr−1 and a total cross section of σtot(pBe)=(3.7±1.5) mb. These cross sections are compared with existing data and theoretical predictions. TheA dependence ofK + production in the few-GeV range is analyzed.

Published
1996
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11. Detector setup for a storage ring with an internal target

Author

H. Calén, S. Carius, K. Fransson, L. Gustafsson, S. Häggström, B. Höistad, A. Johansson, T. Johansson, S. Kullander, A. Mörtsell, J. Möhn, R. Ruber, U. Schuberth, J. Złomańczuk, C. Ekström, C.-J. Fridén, D. Reistad, K. Kilian, W. Oelert, V. Renken, T. Sefzick, M. Waters, A. Bondar, G. Kolachev, A. Kuzmin, T. Purlatz, B. Shwartz, V. Sidorov, A. Sukhanov, A. Kupść, P. Marciniewski, A. Nawrot, J. Stepaniak, D. Bogoslawsky, V. Dunin, A. Kuznetsov, B. Morosov, A. Povtorejko, S. Sandukovsky, A. Zernov, J. Zabierowski, A. Turowiecki, Z. Wilhelmi, Z. Pawlowski, R. Bilger, W. Brodowski, H. Clement, G. Kurz, G.J. Wagner, A. Martemyanov, V. Sopov, V. Tchernyshev, E. David, M. Price, and C. Rivoiron

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Photon, Physics::Instrumentation and Detectors, Nuclear Theory, Detector, Scintillator, Particle detector, Charged particle, Scintillation counter, Atomic physics, Nuclear Experiment, Instrumentation, Storage ring
Abstract

A detector setup for the cooler storage ring CELSIUS is described. The setup detects particles produced in interactions between the internal beam and a cluster-jet target. Particles emitted in the forward direction are measured by means of arrays of plastic scintillators and proportional counters. Particles, particularly photons, emitted more isotropically are measured by means of two calorimeters containing CsI(Na) crystals. The performance of the setup is given for neutral meson production in proton-proton and proton-deuteron interactions in the energy range 290–1360 MeV.

Published
1996
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12. Beam test of Cherenkov counter prototype for ZDF setup

Author

V. Tchernyshev, V. Sopov, A.K. Kacharava, G.G. Macharashvili, M. S. Nioradze, and V. Komarov

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Total internal reflection, Range (particle radiation), Physics::Instrumentation and Detectors, business.industry, Cherenkov detector, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Particle detector, Charged particle, law.invention, Nuclear physics, Optics, law, Detectors and Experimental Techniques, business, Instrumentation, Cherenkov radiation, Beam (structure)
Abstract

In this paper we describe a Cherenkov counter of total internal reflection for particle separation in the momentum range where all types of particles radiate Cherenkov light. The Cherenkov counter prototype with the lucite radiator was tested on the secondary beam of the ITEP (Moscow) accelerator. Dependence of the photomultiplier pulse height on the particle entrance angle was clearly observed.

Published
1996
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13. The pp → ppπ0 reaction near the kinematical threshold

Author

Staffan Carius, C. Ekström, Arne Johansson, A.E. Bondar, A. Kupść, M. Waters, K. Kilian, Leif Gustafsson, Z. Wilhelmi, D. Reistad, S. Häggström, B. Morosov, Bo Höistad, Roger Ruber, A. Kuzmin, B. Shwartz, J. Stepaniak, Tord Johansson, Hans Calén, U. Schuberth, V. Tchernyshev, S. Sandukovsky, J. Zabierowski, A. Povtorejko, A. Mörtsell, Kjell Fransson, S. Kullander, J. Zlomanczuk, A. Sukhanov, and W. Oelert

Subjects
Physics, Nuclear and High Energy Physics, Jet (fluid), Photon, Spectrometer, Nuclear Theory, Dalitz plot, Scintillator, Nuclear physics, Invariant mass, Atomic physics, Nuclear Experiment, Storage ring, Event reconstruction
Abstract

The pp → ppη reaction has been measured at six energies close to threshold, from 1258 MeV to 1352 MeV, using an internal cluster gas jet target in the CELSIUS storage ring. The η is detected through its decay photons, in an array of CsI detectors, and the forward-going protons are detected in a plastic scintillator spectrometer. A complete event reconstruction is obtained at the higher energies in the measured interval. The new data, together with earlier data, give an accurate determination of the energy dependence close to threshold. The influence of the η-proton FSI is seen in the total cross section data as well as in a Dalitz plot of the η-p invariant mass distributions.

Published
1995
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14. The WASA Detector Facility at CELSIUS

Author

Chr. Bargholtz, M. Bashkanov, M. Berłowski, A. Bondar, D. Bogoslawsky, W. Brodowski, J. Brudvik, H. Calén, F. Capellaro, A. Chilingarov, H. Clement, J. Comfort, L. Demirörs, C. Ekström, K. Fransson, C.-J. Fridén, L. Gerén, M. Gornov, V. Grebenev, J. Greiff, Y. Gurov, L. Gustafsson, B. Höistad, G. Ivanov, M. Jacewicz, E. Jiganov, A. Johansson, T. Johansson, S. Keleta, O. Khakimova, A. Khoukaz, K. Kilian, N. Kimura, I. Koch, G. Kolachev, F. Kren, S. Kullander, A. Kupść, A. Kuzmin, A. Kuznetsov, K. Lindberg, P. Marciniewski, R. Meier, O. Messner, B. Morosov, A. Nawrot, B.M.K. Nefkens, G. Norman, W. Oelert, C. Pauly, H. Pettersson, A. Pivovarov, J. Pätzold, Y. Petukhov, A. Povtorejko, D. Reistad, R.J.M.Y. Ruber, S. Sandukovsky, K. Schönning, W. Scobel, T. Sefzick, R. Shafigullin, B. Shwartz, V. Sidorov, T. Skorodko, V. Sopov, A. Starostin, J. Stepaniak, A. Sukhanov, V. Tchernyshev, P.-E. Tegnér, P. Thörngren Engblom, V. Tikhomirov, H. Toki, A. Turowiecki, G.J. Wagner, U. Wiedner, Z. Wilhelmi, M. Wolke, A. Yamamoto, H. Yamaoka, J. Zabierowski, I. Zartova, and J. Złomańczuk

Subjects
Nuclear and High Energy Physics, Particle physics, Meson production, Meson, data acquisition, electromagnetic [calorimeter], Nuclear Theory, decay modes [eta], pellet target, FOS: Physical sciences, scintillators, multidetector system, Particle detector, Nuclear physics, Degree Celsius, calorimeter, ddc:530, hadroproduction [meson], Nuclear Experiment (nucl-ex), Nuclear Experiment, Instrumentation, scintillation counter, forward spectrometer, Physics, Eta meson, Detector, trigger, scattering [ion], Uppsala CELSIUS Stor, mini drift chambers, performance [four-pi-detector], drift chamber, target [hydrogen], solenoid [superconductivity], High Energy Physics::Experiment, Storage ring
Abstract

The WASA 4pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A detailed description of the design, together with the anticipated and achieved performance parameters are given., 25 pages, 20 figures

Published
2008
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15. Measurement of the slope parameter for theη→3π0decay in thepp→ppηreaction

Author

Hans Calén, V. Tikhomirov, J. Zabierowski, G. J. Wagner, R. J. M. Y. Ruber, Jozef Zlomanczuk, E. Jiganov, Magnus Wolke, T. Skorodko, A. A. Kuznetsov, P. Thörngren Engblom, Marek Jacewicz, H. Clement, Wolfgang Scobel, R. Meier, C. Pauly, Ulrich Wiedner, V. Tchernyshev, L. Demirörs, D. Bogoslawsky, H. Pettersson, Karin Schönning, F. Capellaro, S. Kullander, A. Turowiecki, A. Povtorejko, C. Ekström, W. Oelert, M. Bashkanov, Leif Gustafsson, A. Kupść, T. Johansson, V. Sopov, B. Höistad, Y. Petukhov, G. Ivanov, I. Koch, S. Keleta, Pawel Marciniewski, Akira Yamamoto, K. Fransson, B. Morosov, B. Shwartz, and J. Stepaniak

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, Dalitz plot, Kinetic energy, Measure (mathematics), Particle identification, Nuclear physics, Particle decay, Distribution (mathematics), High Energy Physics::Experiment, Nuclear Experiment, Beam (structure)
Abstract

The CELSIUS-WASA setup is used to measure the 3{pi}{sup 0} decay of {eta} mesons produced in pp interactions with beam kinetic energies of 1.36 and 1.45 GeV. The efficiency-corrected Dalitz plot and density distributions for this decay are shown, together with a fit of the quadratic slope parameter {alpha} yielding {alpha}=-0.026{+-}0.010(stat){+-}0.010(syst). This value is compared to recent experimental results and theoretical predictions.

Published
2007
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16. Branching ratio and mass spectrum of the decay ϒ′ → ϒπ+π−

Author

R. S. Orr, A. Philipp, V. Nagovitsin, V. Lubimov, K. R. Schubert, S. Weseler, D. Wegener, V. Sopov, Yu. Zaitsev, J. Spengler, W. Schmidt-Parzefall, D. Coppage, Viktor Matveev, A. Markees, H. Schröder, R. Davis, C. W. Darden, K. W. Edwards, R. Ammar, J. Stiewe, P. C. H. Kim, A. Arefiev, V. Tchistilin, V. Tchernyshev, Wr Frisken, H. Albrecht, Roland Waldi, R. Childers, Y. Oku, R. Wurth, V. Shevchenco, R. Heller, H. Gennow, H. Hasemann, P. Böckmann, P. M. Patel, M. Goddard, I. Tichomirov, J. D. Prentice, C. Fukunaga, G. Drews, B. Gräwe, H. Seywerd, A. Drescher, F. Selonke, Mikhail Danilov, T. S. Yoon, V. Soloshenko, Werner Hofmann, Holger Schulz, Yu. Semenov, U. Matthiesen, N. Kwak, and Leif J. Jönsson

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Branching fraction, Electron–positron annihilation, Mass spectrum, Analytical chemistry, Matrix element, Invariant mass, computer, computer.programming_language
Abstract

The reaction e + e − → ϒ ′ → ϒπ + π − , with ϒ → anything, has been measured using the ARGUS detector at DORIS . We obtain a mass difference M ( ϒ ′) − M ( ϒ ) = (562 ± 3) MeV and a decay branching ratio BR( ϒ ′→ ϒπ + π − )=(17.9±0.9±2.1)%. The invariant mass spectrum of the π + π − system differs from phase space, but is well described by a matrix element of the form ( M ππ 2 − λM π 2 ) with λ =2.6±0.5. We also report preliminary results on the exclusive decay ϒ′ → ϒπ + π − , with ϒ → e + e − , and obtain BR( ϒ → e + e − ) = (2.8 ± 0.4 ± 04±0.3)%.

Published
1984
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17. Analysis of undiagnosed tuberculosis-related deaths identified at post-mortem among HIV-infected patients in Russia: a descriptive study.

Author

Balabanova Y, Tchernyshev V, Tsigankov I, Maximova S, Mikheeva N, Fedyukovitch L, Kuznetsov S, Fedorin I, and Drobniewski F

Subjects
Adult, Autopsy, Female, Humans, Latent Tuberculosis diagnosis, Male, Middle Aged, Retrospective Studies, Russia epidemiology, Survival Analysis, HIV Infections complications, HIV Infections epidemiology, Latent Tuberculosis epidemiology, Latent Tuberculosis mortality
Abstract

Background: Tuberculosis remains a serious public health threat and economic burden in Russia with escalating rates of drug resistance against a background of growing HIV-epidemic. Samara Oblast is one of the regions of the Russian Federation where more than 1% of the population is affected by the HIV-epidemic; almost half of the cases are concentrated in the largely-industrial city of Togliatti with a population of 800 000., Methods: We conducted a retrospective analysis of errors leading to death of HIV-positive patients in general health care hospitals in Togliatti, Russia, in 2008. All (n = 29) cases when tuberculosis was established at autopsy as a cause of death were included., Results: Median length of hospital stay was 20 days; in 11 cases the death occurred within the first 24 hours of admission. All cases were known to be HIV-positive prior to admission, however HAART was not initiated for any case, and no relevant tests to assess severity of immunosupression were performed despite their availability. No appropriate diagnostic algorithms were applied to confirm tuberculosis. Major gaps were identified in the work of hospital and consulting physicians including insufficient records keeping. In almost all patients earlier regular HIV-relevant tests were not performed due to poor compliance of patients, many of whom abused alcohol and drugs., Conclusions: We conclude that introduction of prompt and accurate diagnostics tests, adequate treatment protocols and intensive training of physicians in management of AIDS and TB is vital. This should include reviewing standards of care for HIV-positive individuals with accompanying social problems.

Published
2011
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