THE BGO-OD EXPERIMENT AT ELSA

Meson photoproduction is a key tool for the experimental investigation of the nucleon excitation spectrum. To disentangle the specific couplings of resonances, in addition to the rather well measured pion and eta photoproduction channels it is mandatory to obtain information on channels involving strange and vector mesons and higher mass pseudoscalar mesons, and the associated multi-particle final states with both charged and neutral particles. In this respect, the new BGO-OD experiment at the ELSA accelerator of the University of Bonn's Physikalisches Institut provides unique instrumentation. We describe the experiment, present its status and the initial program of measurements.

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THE BGO-OPENDIPOLE SETUP AT ELSA

International Journal of Modern Physics E ◽

10.1142/s0218301310015485 ◽

2010 ◽

Vol 19 (05n06) ◽

pp. 1043-1054 ◽

Cited By ~ 8

Author(s):

HARTMUT SCHMIEDEN

Keyword(s):

Excited State ◽

High Resolution ◽

Electron Accelerator ◽

Charged Particles ◽

Ground States ◽

Final States ◽

Meson Photoproduction ◽

Accelerator Facility ◽

Photon Detection ◽

The University

At the electron accelerator facility ELSA of the University of Bonn presently the new BGO-OpenDipole experiment is being setup. It is optimized for meson photoproduction final states of mixed charges. The detector combines hermetic coverage for photon detection through the BGO ball of the former GRAAL experiment with high resolution detection of forward going charged particles in the Open Dipole spectrometer. This setup is well suited for many different channels, including pseudoscalar, vectormeson and associated strangeness photoproduction. This contribution highlights the strangeness channels associated with the Λ and Σ ground states and the Λ(1405) excited state.

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N*'s AND Δ's GENERATED IN VECTOR, PSEUDOSCALAR MESON-BARYON SYSTEMS

International Journal of Modern Physics Conference Series ◽

10.1142/s201019451460060x ◽

2014 ◽

Vol 26 ◽

pp. 1460060 ◽

Cited By ~ 6

Author(s):

K. P. KHEMCHANDANI ◽

A. MARTÍNEZ TORRES ◽

H. NAGAHIRO ◽

A. HOSAKA

Keyword(s):

Pseudoscalar Meson ◽

Final States ◽

Vector Mesons ◽

Double Pole ◽

Loop Function ◽

Pseudoscalar Mesons ◽

Pole Structure ◽

Channel Interactions ◽

Coupled Channel ◽

Dynamical Origin

We have recently studied coupled channel interactions of vector and pseudoscalar mesons with octet baryons having total strangeness null and spin-parity 1/2-. We, thus, considered πN, ηN, KΛ, KΣ, ρN, ωN, ϕN, K*Λ, and K*Σ with total isospin 1/2 and 3/2. The interactions between pseudoscalar mesons and baryons are obtained by using the Weinberg-Tomozawa theorem. For the case of vector mesons, we calculate s-, t-, u-exchange diagrams and a contact term. The subtraction constants, required to calculate the loop-function in the scattering equations, are constrained by fitting the available experimental data on some of the reactions with pseudoscalar meson-baryon final states. We end up finding resonances which can be related to N*(1535), N*(1650) (with a double pole structure), N*(1895) and Δ(1620). We conclude that these resonances can be, at least partly, interpreted as dynamically generated resonances and that the vector mesons play an important role in determining the dynamical origin of the low-lying N* and Δ states.

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POLARISED PHOTON BEAMS AT ELSA AND RECENT RESULTS OF DOUBLE POLARISATION MEASURMENTS

International Journal of Modern Physics E ◽

10.1142/s0218301310015321 ◽

2010 ◽

Vol 19 (05n06) ◽

pp. 869-881 ◽

Cited By ~ 2

Author(s):

◽

DANIEL ELSNER

Keyword(s):

Excitation Spectrum ◽

Electron Accelerator ◽

Solid Angle ◽

Neutral Meson ◽

Experimental Setup ◽

Final States ◽

Photon Beams ◽

Beam Asymmetries ◽

Target Asymmetry ◽

The University

The puzzle of the excitation spectrum of the nucleon, composed of broad and overlapping resonances, is still unresolved. For a complete experiment at least 8 well chosen single and double polarisation observables are needed. At the electron accelerator ELSA of the University of Bonn single- and double polarisation experiments are currently performed with the Crystal Barrel/TAPS experiment. The experimental setup includes a ɸ-symmetric calorimeter system covering almost the complete solid angle and it is ideally suited to detect single and multiple neutral meson final states. Circularly or linearly polarised photon beams impinge on a longitudinal polarised butanol target in the center of the setup. The linearly polarised photon beams provide the basis for the measurement of azimuthal beam asymmetries, such as Σ and, in combination with the polarised target, G . Circularly polarised photon beams allow the extraction of the beam-target asymmetry E . Preliminary results for the polarisation observables Σ, G and E will be presented.

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PHOTOPRODUCTION OF MESONS OFF LIGHT NUCLEI

International Journal of Modern Physics E ◽

10.1142/s0218301310015369 ◽

2010 ◽

Vol 19 (05n06) ◽

pp. 915-926 ◽

Cited By ~ 1

Author(s):

B. KRUSCHE

Keyword(s):

Excitation Function ◽

Light Nuclei ◽

Final States ◽

Meson Photoproduction ◽

Crystal Ball ◽

Series Of Experiments ◽

Nuclear Targets ◽

Narrow Structure ◽

Surprising Finding

In a series of experiments at the tagged photon facilities of the Bonn ELSA accelerator and the Mainz MAMI accelerator photoproduction of mesons from light nuclear targets (deuteron, 3 He ) has been studied. The experiments used the combined Crystal Barrel/TAPS setup in Bonn and the Crystal Ball/TAPS setup in Mainz. Meson photoproduction off the neutron has been investigated for the πo, πoπo, πoπ-, η, η′, and ηπo final states. A surprising finding was a narrow structure in the γn → nη excitation function, which is not seen in the proton case. Measurements of η- and πo-photoproduction off a liquid 3 He -target have provided further evidence for the formation of η-mesic 3 He .

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An Experimental Investigation of the Trim Effect on the Behaviour of a Containership in Shallow Water

Volume 7B: Ocean Engineering ◽

10.1115/omae2019-95790 ◽

2019 ◽

Author(s):

Khaled Elsherbiny ◽

Tahsin Tezdogan ◽

Mohamed Kotb ◽

Atilla Incecik ◽

Sandy Day

Keyword(s):

Experimental Investigation ◽

Water Depth ◽

Experimental Work ◽

Water Resistance ◽

Suez Canal ◽

Shallow Waters ◽

Container Ship ◽

Ship Model ◽

New Suez Canal ◽

The University

Abstract A new division of the Suez Canal in Egypt, termed the New Suez Canal, was opened for international navigation in August 2015. It is therefore important to ensure the safety of ships navigating this new section of the canal. Measures to avoid grounding and/or drifting to the canal banks are necessary. Additionally, accurate prediction data for ship squat and under keel clearance is crucial. This paper presents the results of experimental work carried out at the Kelvin Hydrodynamic Laboratory at the University of Strathclyde, Glasgow, to study the effect of trim on containership sailing characteristics in shallow waters using Kriso Container Ship (KCS) model. A series of model tests were conducted to measure the resistance, sinkage variations with speed, water depth and loading conditions under different trimming angles at 1:75 scale. The objective of this work is to examine the range of ship trim for safe and efficient sailing in restricted water in both depth and width. The study also aimed to provide data to be used in validating numerical computations to be carried on the same type of vessel to detect the best trim angle for ships during sailing in restricted waters to reduce resistance and therefore fuel consumption. For depth Froude numbers higher than 0.4, the results show that the ship model sinkage is less for aft trim than for level trim or forward trim. Concurrently, it can be observed that there is less water resistance for aft trim than for forward trim, albeit level trim shows the least resistance. The test was conducted for one value of model draft which was 0.144 m. Side bank effect were also examined.

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Measurement of π0π+/− photoproduction off the deuteron and dbutanol targets

EPJ Web of Conferences ◽

10.1051/epjconf/201919902010 ◽

2019 ◽

Vol 199 ◽

pp. 02010

Author(s):

Debdeep Ghosal

Keyword(s):

Excitation Spectrum ◽

Cross Section ◽

Crucial Role ◽

Electromagnetic Coupling ◽

Polarization Observable ◽

Cross Section Data ◽

Meson Photoproduction ◽

Crystal Ball ◽

Preliminary Results ◽

Section Data

Recent experiments using the Crystal Ball/TAPS setup at the MAMI accelerator in Mainz, Germany continue to study the properties and the excitation spectrum of the nucleon with meson photoproduction. Electromagnetic excitations of the proton and neutron are essential for understanding their isospin decomposition. The electromagnetic coupling of photons to protons is different than that of neutrons in certain states. Cross-section data alone is not sufficient for separating resonances, whereas polarization observables play a crucial role being essential in disentangling the contributing resonant and non-resonant amplitudes. Preliminary results of the polarization observable E of double π production off an unpolarized (LD2) and polarized (dButanol) target are shown with comparison to predictions of recent analyses.

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Experimental Investigation and CFD Simulation of the Behaviour of Mineral Wool in the Reactor Sump

Volume 2: Fuel Cycle and High Level Waste Management; Computational Fluid Dynamics, Neutronics Methods and Coupled Codes; Student Paper Competition ◽

10.1115/icone16-48121 ◽

2008 ◽

Author(s):

Eckhard Krepper ◽

Gregory Cartland-Glover ◽

Alexander Grahn ◽

Frank-Peter Weiss ◽

So¨ren Alt ◽

...

Keyword(s):

Experimental Investigation ◽

Cfd Simulation ◽

Mineral Wool ◽

Cfd Modeling ◽

Joint Research ◽

Cooling Systems ◽

Safety Research ◽

Joint Research Project ◽

Core Cooling ◽

The University

The investigation of insulation debris generation, transport and sedimentation becomes important with regard to reactor safety research for PWR and BWR, when considering the long-term behavior of emergency core cooling systems during all types of loss of coolant accidents (LOCA). The insulation debris released near the break during a LOCA incident consists of a mixture of disparate particle population that varies with size, shape, consistency and other properties. Some fractions of the released insulation debris can be transported into the reactor sump, where it may perturb/impinge on the emergency core cooling systems. Open questions of generic interest are the sedimentation of the insulation debris in a water pool, its possible re-suspension and transport in the sump water flow and the particle load on strainers and corresponding pressure drop. A joint research project on such questions is being performed in cooperation between the University of Applied Sciences Zittau/Go¨rlitz and the Forschungszentrum Dresden-Rossendorf. The project deals with the experimental investigation of particle transport phenomena in coolant flow and the development of CFD models for its description. While the experiments are performed at the University at Zittau/Go¨rlitz, the theoretical modeling efforts are concentrated at Forschungszentrum Dresden-Rossendorf. In the current paper the basic concepts for CFD modeling are described and feasibility studies including the conceptual design of the experiments are presented.

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Charmless B decays to final states with radially excited vector mesons

Physics Letters B ◽

10.1016/s0370-2693(02)02129-9 ◽

2002 ◽

Vol 540 (1-2) ◽

pp. 97-103 ◽

Cited By ~ 4

Author(s):

Alakabha Datta ◽

Harry J. Lipkin ◽

Patrick J. O'Donnell

Keyword(s):

Final States ◽

Vector Mesons ◽

B Decays ◽

Charmless B Decays

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NJL INTERACTION DERIVED FROM QCD: VECTOR AND AXIAL-VECTOR MESONS

International Journal of Modern Physics A ◽

10.1142/s0217751x09043377 ◽

2009 ◽

Vol 24 (13) ◽

pp. 2415-2430 ◽

Cited By ~ 9

Author(s):

B. A. ARBUZOV ◽

M. K. VOLKOV ◽

I. V. ZAITSEV

Keyword(s):

Quark Mass ◽

Light Quark ◽

Axial Vector ◽

Vector Mesons ◽

Strong Decay ◽

Njl Model ◽

Pseudoscalar Mesons ◽

Decay Widths ◽

Light Quark Mass ◽

Existing Data

In previous works effective nonlocal SU (2)× SU (2) NJL model was proposed in which all the parameters are expressed through those of the fundamental QCD: current light quark mass m0 and average nonperturbative αs. The results for scalar and pseudoscalar mesons are in satisfactory correspondence to existing data. In the present work the same model without introduction of any additional parameters is applied for a description of masses and strong decay widths of ρ- and a1-mesons. The results for both scalar and vector sectors agree with data up to accuracy of the model.

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