scholarly journals MESON PRODUCTION AND BARYON RESONANCES AT CLAS

2011 ◽  
Vol 26 (03n04) ◽  
pp. 493-498 ◽  
Author(s):  
VOLKER D. BURKERT
Keyword(s):  
Meson Production ◽  
Nucleon Resonance ◽  
Recoil Polarization ◽  
Polarized Electrons ◽  
Jefferson Lab ◽  
The Status ◽  
Polarized Targets ◽  
Polarized Photons ◽  
Baryon Resonances

I give a brief overview of the exploration of baryon properties in meson photo- and electroproduction. These processes provide ample information for the study of electromagnetic couplings of baryon resonances and to search for states, yet to be discovered. The CLAS detector, combined with the use of energy-tagged polarized photons and polarized electrons, as well as polarized targets and the measurement of recoil polarization, provide the tools for a comprehensive nucleon resonance program. I briefly present the status of this program, prospects for the next few years, and plans for the Jefferson Lab 12 GeV upgrade.

scholarly journals ELECTROMAGNETIC MESON PRODUCTION IN THE NUCLEON RESONANCE REGION

2004 ◽  
Vol 13 (06) ◽  
pp. 1035-1111 ◽  
Author(s):  
V. D. BURKERT ◽  
T.-S. H. LEE
Keyword(s):  
Meson Production ◽  
Form Factors ◽  
Resonance Region ◽  
Nucleon Resonance ◽  
Transition Form ◽  
Photon Beams ◽  
The Status ◽  
Experimental Facilities ◽  
Electron And Photon ◽  
Nucleon Resonance Region

Recent experimental and theoretical advances in investigating electromagnetic meson production reactions in the nucleon resonance region are reviewed. We give a description of current experimental facilities with electron and photon beams and present a unified derivation of most of the phenomenological approaches being used to extract the resonance parameters from the data. The analyses of π and η production data and the resulting transition form factors for the Δ(1232)P33, N (1535)S11, N (1440)P11, and N (1520)D13 resonances are discussed in detail. The status of our understanding of the reactions with production of two pions, kaons, and vector mesons is also reviewed.

PHOTOREACTIONS ON 3He AND 4He UP TO 1.6 GEV AT JEFFERSON LAB

2003 ◽  
Vol 18 (02n06) ◽  
pp. 225-234
Author(s):  
◽  
B. L. BERMAN
Keyword(s):  
Beam Energy ◽  
Full Range ◽  
Electron Beam Energy ◽  
Polarized Electrons ◽  
Circularly Polarized ◽  
Jefferson Lab ◽  
Incident Electron Beam ◽  
Reaction Channels ◽  
Large Acceptance ◽  
Polarized Photons

We have measured photoreactions on 3 He and 4 He in Hall B at Jefferson Lab, using real photons from the Photon Tagger and the CEBAF Large-Acceptance Spectrometer (CLAS). We obtained data over the full range of the Tagger — 0.33 to 1.56 GeV with an incident electron-beam energy of 1.645 GeV. Tagged, circularly polarized photons, produced by the 70% longitudinally polarized electrons, were incident on 1.2-g/cm2 liquid-helium targets positioned at the center of the CLAS. We were able to collect data at rates exceeding 3 kHz, and succeeded in collecting approximately 1.2 billion events for 3 He and 0.8 billion for 4 He . Over 5 Tb of data were obtained. The data show very good stability throughout the experimental run. Preliminary results from the analysis of several reaction channels are given here.

scholarly journals Studying neutron structure at Jefferson Lab through electron scattering off the deuteron, using CLAS12 and the Central Neutron Detector

2020 ◽  
Vol 1643 (1) ◽  
pp. 012191
Author(s):  
Paul Naidoo ◽  
Daria Sokhan ◽  
Pierre Chatagnon ◽  
Silvia Niccolai ◽  
Katheryne Price
Keyword(s):  
Neutron Detector ◽  
Meson Production ◽  
Deeply Virtual Compton Scattering ◽  
Virtual Compton Scattering ◽  
High Energy ◽  
Neutral Meson ◽  
Deuteron Target ◽  
Jefferson Lab ◽  
3D Tomography ◽  
Large Acceptance

Abstract Generalised Parton Distributions (GPDs) offer a way of imaging nucleons through 3D tomography. They can be accessed experimentally in processes such as Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP), where a high energy electron scatters from a quark inside a nucleon and a high energy photon or meson is produced as a result. Jefferson Lab has recently completed its energy upgrade and Hall B houses the new, large-acceptance CLAS12 detector array optimised for measurements of DVCS and DVMP in the newly accessible kinematic regime. Measurements on the proton and neutron are complementary and both are necessary to facilitate access to the full set of GPDs and enable their flavour separation. Neutron DVCS and DVMP are possible with the use of a deuteron target – the first CLAS12 experiment with which has started taking data this year. To enable exclusive reconstruction of DVCS and neutral-meson DVMP, a dedicated detector for recoiling neutrons – the Central Neutron Detector (CND) – was integrated into CLAS12. We present the first CLAS12 deuteron-target experiment, with a focus on the performance of the CND.

THE SCIENCE OF CONFINEMENT AND THE GLUEX/HALL D PROJECT AT JEFFERSON LAB

2003 ◽  
Vol 18 (03) ◽  
pp. 397-404 ◽  
Author(s):  
Alex R. Dzierba
Keyword(s):  
Degrees Of Freedom ◽  
Meson Production ◽  
First Year ◽  
Jefferson Lab ◽  
Coherent Bremsstrahlung ◽  
Linearly Polarized ◽  
Quantitative Understanding ◽  
Current Maximum ◽  
Photo Production ◽  
Photoproduction Data

One of the outstanding and fundamental questions in physics is the quantitative understanding of the confinement of quarks and gluons in quantum chromodynamics (QCD). Confinement is a unique feature of QCD. Exotic hybrid mesons manifest gluonic degrees of freedom and their spectroscopy will provide the crucial data needed to test assumptions in lattice QCD and phenomenology leading to confinement. Photo-production is expected to be particularly effective in producing exotic hybrids but data using photon probes are sparse. At Jefferson Lab, plans are underway to use the coherent bremsstrahlung technique to produce a linearly polarized photon beam. A solenoid-based hermetic detector will be used to collected data on meson production and decays with statistics that will exceed the current photoproduction data in hand by several orders of magnitude after the first year of running. In order to reach the ideal photon energy of 9 GeV/c for this mapping of the exotic spectra, the energy of the Jefferson Lab electron accelerator, CEBAF, will be doubled from its current maximum of 6 GeV to 12 GeV. The physics and project are described.

Sign in / Sign up

Export Citation Format

Share Document