K0πand K0Σ+ photoproduction off the proton Nanova, M.; Bacelar, J. C. S.; Bantes, B. ...
The European physical journal. A, Hadrons and nuclei,
3/2008, Letnik:
35, Številka:
3
Journal Article
Recenzirano
Odprti dostop
.
The exclusive reactions γ
p
→
K
*0
Σ
+
(1189) and γ
p
→
K
0
π
0
Σ
+
(1189) , leading to the
p
4π
0
final state, have been measured with a tagged photon beam for incident energies from threshold up ...to 2.5GeV. The experiment has been performed at the tagged photon facility of the ELSA accelerator (Bonn). The Crystal Barrel and TAPS detectors were combined to a photon detector system of almost 4π geometrical acceptance. Differential and total cross-sections are reported. At energies close to the threshold, a flat angular distribution has been observed for the reaction γ
p
→
K
0
π
0
Σ
+
suggesting dominant
s
-channel production. Σ
*
(1385) and higher-lying hyperon states have been observed. An enhancement in the forward direction in the angular distributions of the reaction γ
p
→
K
*0
Σ
+
indicates a
t
-channel exchange contribution to the reaction mechanism. The experimental data are in reasonable agreement with recent theoretical predictions.
Nucleon resonance decay by the K0Σchannel Castelijns, R.; Anisovich, A. V.; Bacelar, J. C. S. ...
The European physical journal. A, Hadrons and nuclei,
2008/1, Letnik:
35, Številka:
1
Journal Article
Recenzirano
.
Hyperon production off the proton in the
K
0
Σ
+
channel has been studied at the tagged-photon beam facility at the ELSA electron accelerator in Bonn. This experiment was part of a series of ...neutral meson production experiments on various targets. For this purpose, the Crystal Barrel and TAPS photon spectrometers have been combined to provide a 4π detector for multi-neutral-particle final states. A high-quality excitation function, recoil polarizations, and angular distributions from threshold up to 2.3GeV center-of-mass energy were obtained. The results are compared with predictions of recent coupled-channel calculations within the
K
-matrix formalism and are interpreted by the partial-wave analysis within the Bonn-Gatchina model.
Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which ...has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.
Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of ...approximately 98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gammap-->N(*)(Delta(*))-->ppi(0). A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D15.
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