scholarly journals Exclusive $\rho^0$ Meson Photoproduction with a Leading Neutron at HERA

2016 ◽  
Author(s):  
Sergey Levonian
Author(s):  
V. Andreev ◽  
A. Baghdasaryan ◽  
K. Begzsuren ◽  
A. Belousov ◽  
A. Bolz ◽  
...  

1968 ◽  
Vol 20 (16) ◽  
pp. 877-878 ◽  
Author(s):  
A. Boyarski ◽  
F. Bulos ◽  
W. Busza ◽  
R. Diebold ◽  
S. Ecklund ◽  
...  

2020 ◽  
Vol 241 ◽  
pp. 01009
Author(s):  
Katrin Kohl ◽  
Stefan Alef ◽  
Patrick Bauer ◽  
Reinhard Beck ◽  
Alessandro Braghieri ◽  
...  

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


2020 ◽  
Vol 241 ◽  
pp. 01007
Author(s):  
Takatsugu Ishikawa ◽  
Hisako Fujimura ◽  
Hiroshi Fukasawa ◽  
Ryo Hashimoto ◽  
Qinghua He ◽  
...  

The B = 2 bound/resonance state (dibaryon) is an interesting object, which can be a molecule consisting of two baryons or a spatially compact hexaquark hadron object. The yd ^ n°n°d reaction has been experimentally investigated at incident energies ranging from 0.58 to 1.15 GeV to study non-strange dibaryons. The angular distributions of deuteron emission in the yd center-of-mass energy cannot be reproduced by quasi-free production of two neutral pions followed by deuteron coalescence. Additionally a 2.14-GeV peak is observed in the n°d invariant mass distribution. These suggest a sequential process such as yd ^ RIS ^ n°RIV ^ n°n°d with an isoscalar dibaryon RIS and an isovector dibaryon RIV. Since the mass of the observed isoscalar dibaryons are close to the sum of the nucleon (N) and nucleon resonance (N*) masses, an S-wave NN* molecule may play a role as a doorway to a dibaryon.


2017 ◽  
Vol 96 (9) ◽  
Author(s):  
V. P. Gonçalves ◽  
M. V. T. Machado ◽  
B. D. Moreira ◽  
F. S. Navarra ◽  
G. Sampaio dos Santos

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1910-1913 ◽  
Author(s):  
QIANG ZHAO ◽  
FRANK E. CLOSE

We show how deviations from the dimensional scaling laws for exclusive processes may be related to a breakdown in the locality of quark-hadron duality, i.e. the "restricted locality". For exclusive reactions like meson photo- and electroproduction above the resonance region, we explore the effects arising from such a local duality breaking and propose that it can be a possible source for oscillations about the smooth quark counting rule predicted by pQCD in the 90-degree differential cross sections.


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