THE BGO-OPENDIPOLE SETUP AT ELSA

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1043-1054 ◽  
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.

scholarly journals THE BGO-OD EXPERIMENT AT ELSA

2014 ◽  
Vol 26 ◽  
pp. 1460093 ◽  
Author(s):  
◽  
B. BANTES ◽  
D. BAYADILOV ◽  
R. BECK ◽  
M. BECKER ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Excitation Spectrum ◽  
Final States ◽  
Vector Mesons ◽  
Meson Photoproduction ◽  
Neutral Particles ◽  
Pseudoscalar Mesons ◽  
Initial Program ◽  
The University

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.

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

2010 ◽  
Vol 19 (05n06) ◽  
pp. 869-881 ◽  
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.

THE γp → K0Σ+ PHOTOPRODUCTION REACTION

2014 ◽  
Vol 26 ◽  
pp. 1460087
Author(s):  
◽  
HARTMUT SCHMIEDEN
Keyword(s):  
Cross Section ◽  
Electron Accelerator ◽  
Photon Beam ◽  
Reaction Channel ◽  
Quasibound State ◽  
Accelerator Facility ◽  
Beam Asymmetry ◽  
The Cross ◽  
Photoproduction Reaction ◽  
The University

The photoproduction reaction γp → K0Σ+ was investigated with the CBELSA/TAPS experiment at the electron accelerator facility ELSA of the University of Bonn. A pronounced structure in the cross section was found at the K* threshold. There are indications that this may be associated with the formation of a K*-hyperon quasibound state below the K* threshold. The very first measurements of the photon beam asymmetry in the studied reaction channel are presented and their impact is discussed.

scholarly journals RECENT τ LEPTON RESULTS FROM BABAR

2014 ◽  
Vol 35 ◽  
pp. 1460440
Author(s):  
ALBERTO LUSIANI
Keyword(s):  
Standard Model ◽  
Branching Fractions ◽  
Charged Particles ◽  
Babar Collaboration ◽  
Final States ◽  
Final State ◽  
Experimental Knowledge ◽  
Electron Positron ◽  
The Standard Model ◽  
Positron Collisions

We report recent measurements on τ leptons obtained by the BABAR collaboration using the entire recorded sample of electron-positron collisions at and around the Υ(4S) (about 470fb-1). The events were recorded at the PEP-II asymmetric collider at the SLAC National Accelerator Laboratory. The measurements include high multiplicity τ decay branching fractions with 3 or 5 charged particles in the final state, a search for the second class current the τ decay τ → πη′ν, τ branching fractions into final states containing two KS mesons, [Formula: see text], with h = π, K, and preliminary measurements of hadronic spectra of τ decays with three hadrons (τ- → h-h+h-ντ decays, where h = π, K). The results improve the experimental knowledge of the τ lepton properties and can be used to improve the precision tests of the Standard Model.

scholarly journals 3D DIGITAL TECHNOLOGIES TO RECORD EXCAVATION DATA: THE CASE OF THE CATACOMBS OF ST. LUCY (SIRACUSA, SICILY)

2016 ◽  
Author(s):  
Davide Tanasi ◽  
Ilenia Gradante ◽  
Mariarita Sgarlata
Keyword(s):  
High Resolution ◽  
Middle Ages ◽  
Visual Analysis ◽  
Digital Technologies ◽  
3D Modelling ◽  
Architectural Elements ◽  
Virtual Archaeology ◽  
Frequent Use ◽  
Long Life ◽  
The University

Between 2013 and 2015, Arcadia University in partnership with the Pontifical Commission for Sacred Archaeology and the University of Catania undertook new excavation campaigns in the Catacombs of St. Lucy at Siracusa. The research focuses on some very problematic parts of Region C of the complex, including Oratory C, the so-called Pagan Shrine and Crypt VI. These areas document most effectively the long life of this Christian hypogeum, which incorporated previous structures and artefacts related to the Greek period and continued to be used until the Middle Ages. During the excavation an array of 3D digital techniques (3D scanning, 3d Modelling, Image-based 3D modelling) was used for the daily recording of the archaeological units, but also to create high-resolution virtual replicas of certain districts of the catacombs. Furthermore, the same techniques were applied to support the study of certain classes of materials, such as frescoes and marble architectural elements that could otherwise only be studied in the dark environment of the catacombs, making the visual analysis of such complex artifacts difficult and sometimes misleading, not to mention that the frequent use of strong sources of light for study can also endanger them. The virtual archaeology research undertaken at the Catacombs of St. Lucy represents the first systematic application of 3D digital technologies to the study of such a special archaeological context in Sicily.

scholarly journals K0SΣ0 photoproduction at the BGO-OD experiment

2020 ◽  
Vol 241 ◽  
pp. 01009
Author(s):  
Katrin Kohl ◽  
Stefan Alef ◽  
Patrick Bauer ◽  
Reinhard Beck ◽  
Alessandro Braghieri ◽  
...  
Keyword(s):  
Vector Meson ◽  
Momentum Transfer ◽  
Cross Section ◽  
Photon Beam ◽  
Bremsstrahlung Photon ◽  
Meson Photoproduction ◽  
Accelerator Facility ◽  
Transfer Processes

The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremsstrahlung photon beam to investigate the excitation structure of the nucleon via meson photoproduction. The setup with a BGO calorimeter surrounding the target and an open dipole spectrometer covering the for ward region is ideally suited for investigating low momentum transfer processes, in particular in strangeness photoproduction. The associated photoproduction of K0S and hyperons is essential to understand the role of K* exchange mech anisms. A cusp-like structure observed in the yp → K0SΣ+ reaction at the K* threshold is described by models including dynamically generated resonances from vector meson-baryon interactions. Such interactions are pre dicted to give a peak like structure in K0SΣ0 photoproduction off the neutron. A very preliminary cross section is determined and compared to the prediction, the results appear to support the model

Vibrational Analysis of the 2800 Å Band System of para-Dibromobenzene

1972 ◽  
Vol 50 (12) ◽  
pp. 1402-1408 ◽  
Author(s):  
S. M. Japar
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Ground State ◽  
Band System ◽  
Vibrational Analysis ◽  
Type A ◽  
Strong Type ◽  
Type B ◽  
Sequence Structure ◽  
Extensive Sequence

The 2800 Å band system of p-dibromobenzene has been photographed under high resolution and an extended vibrational analysis has been carried out. The analysis is not inconsistent with the assignment of the system to a 1B2u ← 1Ag transition, by analogy with other p-dihalogenated benzenes. The observed spectrum can be explained in terms of a number of strong type-B vibronic bands and a considerably smaller number of type-A vibronic bands. The extensive sequence structure is adequately accounted for, and can be related to observations on other halogenated benzene molecules. Thirteen ground state and nine excited state fundamental vibrational frequencies have been assigned.

Study of Corona Discharge on 160 KeV, 10 mA Electron Accelerator Facility Using FEM

2008 ◽  
Author(s):  
Abu Bakar Mhd Ghazali ◽  
Rokiah Mohd Sobri ◽  
H. B. Senin ◽  
G. Carini ◽  
J. B. Abdullah ◽  
...  
Keyword(s):  
Corona Discharge ◽  
Electron Accelerator ◽  
Accelerator Facility

scholarly journals Timothy W Linick October 29, 1946–June 4, 1989

Radiocarbon ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. iii-iii
Author(s):  
Ajt Jull ◽  
Hans E Suess
Keyword(s):  
Tree Ring ◽  
Time Scale ◽  
Accelerator Facility ◽  
Radiocarbon Dates ◽  
University Of Arizona ◽  
The University

Timothy Weiler Linick died on June 4th, 1989. He was a dedicated researcher, and an important part of the NSF Accelerator Facility for Radioisotope Analysis at the University of Arizona. He will be remembered for his care and attention to details, especially in the calculation and reporting of radiocarbon dates. He made important contributions to the fields of oceanography and tree-ring calibration of the 14C time scale.

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