Vector meson and associated strangeness production using a linearly polarized photon beam at Jefferson lab

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

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

International Journal of Modern Physics A ◽

10.1142/s0217751x03014319 ◽

2003 ◽

Vol 18 (03) ◽

pp. 397-404 ◽

Cited By ~ 2

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.

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VECTOR MESON MODIFICATION IN NUCLEAR MATTER AT CLAS

Modern Physics Letters A ◽

10.1142/s0217732308029514 ◽

2008 ◽

Vol 23 (27n30) ◽

pp. 2417-2420 ◽

Cited By ~ 1

Author(s):

CHADEN DJALALI ◽

MIKE WOOD ◽

RAKHSHA NASSERIPOUR ◽

DENNIS WEYGAND ◽

The CLAS COLLABORATION

Keyword(s):

Vector Meson ◽

Nuclear Matter ◽

Leptonic Decay ◽

Meson Mass ◽

Combinatorial Background ◽

Vector Mesons ◽

Jefferson Lab ◽

Mass Distributions ◽

Collisional Broadening ◽

Large Acceptance

Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The properties of the ρ vector mesons were investigated via their rare leptonic decay to e+e−. After subtracting the combinatorial background, the ρ meson mass distributions were extracted for each of the targets. We observe no effects on the mass of the ρ meson, some widening in titanium and iron is observed consistent with the collisional broadening.

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