Abstract
The differential cross section for the quasi-free photoproduction reaction
$$\gamma n\rightarrow K^0\Sigma ^0$$
γ
n
→
K
0
Σ
0
was measured at BGOOD at ELSA from threshold to a centre-of-mass ...energy of
$$2400\,\hbox {MeV}$$
2400
MeV
. Close to threshold the results are consistent with existing data and are in agreement with partial wave analysis solutions over the full measured energy range, with a large coupling to the
$$\Delta (1900)1/2^-$$
Δ
(
1900
)
1
/
2
-
evident. This is the first dataset covering the
$$K^*$$
K
∗
threshold region, where there are model predictions of dynamically generated vector meson-baryon resonance contributions.
.
Results from measurements of the photoproduction of
η
mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron ...accelerator ELSA in Bonn using the
η
→
3
π
0
→
6
γ
decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. The results confirm earlier measurements from Bonn and the MAMI facility in Mainz about the existence of a narrow structure in the excitation function of
γ
n
→
n
η
. The current angular distributions show a forward-backward asymmetry, which was previously not seen, but was predicted by model calculations including an additional narrow
P
11
state. Furthermore, data obtained with a longitudinally polarized, deuterated butanol target and a circularly polarized photon beam were analyzed to determine the double polarization observable
E
. Both data sets together were also used to extract the helicity-dependent cross sections
σ
1
/
2
and
σ
3
/
2
. The narrow structure in the excitation function of
γ
n
→
n
η
appears associated with the helicity-1/2 component of the reaction.
.
This paper reports on a measurement of the double-polarization observable
G
in
π
0
photoproduction off the proton using the CBELSA/TAPS experiment at the ELSA accelerator in Bonn. The observable
G
...is determined from reactions of linearly polarized photons with longitudinally polarized protons. The polarized photons are produced by bremsstrahlung off a diamond radiator of well-defined orientation. A frozen spin butanol target provides the polarized protons. The data cover the photon energy range from 617 to 1325 MeV and a wide angular range. The experimental results for
G
are compared to predictions by the Bonn-Gatchina (BnGa), Jülich-Bonn (JüBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed.
The differential cross section for the quasi-free photoproduction reaction
γ
n
→
K
0
Σ
0
was measured at BGOOD at ELSA from threshold to a centre-of-mass energy of
2400
MeV
. Close to threshold the ...results are consistent with existing data and are in agreement with partial wave analysis solutions over the full measured energy range, with a large coupling to the
Δ
(
1900
)
1
/
2
-
evident. This is the first dataset covering the
K
∗
threshold region, where there are model predictions of dynamically generated vector meson-baryon resonance contributions.
The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the excitation structure of the nucleon. The setup consists of a highly segmented ...BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. In particular, this enables the investigation of strangeness photoproduction where t-channel exchange mechanisms play an important role. This also allows access to a kinematic region where extended, molecular structure may manifest in reaction mechanisms. The extensive strangeness photoproduction programme includes the photoproduction of neutral and charged kaons using both hydrogen and deuterium targets.
The results obtained at the BGO-OD experiment with the BGO calorimeter, equipped with the new electronic readout based on sampling ADCs, during the tests performed with the beam time of March and ...June 2012 are presented. The proper functioning of the apparatus has allowed the reconstruction of the pseudo-scalar mesons π0 and η invariant masses. The simulation of the η' photoproduction reaction prepared for a proposal to the joint ELSA-MAMI Physics Advisory Committee is also presented.
This article describes how the Village of Palm Springs in southeast Florida conducted a study of technologies available to reduce color and dissolved organic carbon (DOC) before disinfection so that ...the Main (6 mgd 23 ML/d) and Pratt (4 mgd 15 ML/d) water treatment plants could be brought into compliance with the Stage 1 and 2 Disinfectants/Disinfection Byproducts Rule requirements.
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