scholarly journals Analysis of Isolated Photons in Photoproduction in PYTHIA

Collision of particles at high energies at accelerators is the main source of data used to obtain deeper understanding of the fundamental interactions and the structure of the matter. Processes of isolated photon production have provided many tests of theoretical descriptions of the universe on scales smaller than the proton. This work is dedicated to the analysis of the large amount of collision data that has been accumulated at ZEUS in 2004-2007 period and new methods of processing isolated photons that have been proposed. The authors develop software algorithms that allow obtaining the signal of isolated photons from the data collected on the ZEUS detector at electron-proton collider HERA, calculating the differential cross sections, and comparing the measured data with PYTHIA Monte Carlo predictions. Taking into account the features of the ZEUS detector, the photon signal is separated from the background events and the number of isolated photons is calculated. Computational mathematical and numerical methods have been used to simulate the interaction of particles in the detector. Monte Carlo predictions for differential cross sections as functions of the pseudorapidity and transverse energy of the photon ηg, ETg and the jet ηjet, ETjet, and the fraction of the photon momentum хgmeas carried by the interacting parton have been calculated and compared with the experimental data. The results of the study are compared with the previous studies and show for the first time that all isolated photon HERA measurements are consistent with each other. New results show improved uncertainties. The formation of isolated inclusive photons and photons with the accompanying jet was measured in photoproduction with ZEUS detector at HERA collider using the integrated luminosity of 374 ± 7 pb-1. For the first time, more complex Monte-Carlo simulation models of isolated photons for ZEUS detector were generated and applied, and the description of the photon signal was improved. It has been found that PYTHIA describes the shape of the cross section as a function of ηg well enough, but does not fully reproduce the shape of ETg, ETjet, and the middle region of хgmeas, while ηjet is described not very well. The reason for this discrepancy can be the lack of corrections of higher orders in the predictions for cross sections of direct photons. Scaling of the cross sections obtained with PYTHIA improves the description of ETg and ηg. The unsatisfactory description of ηjet indicates that further studies are required.

2021 ◽  
Author(s):  
M. Salimi ◽  
O. Kakuee ◽  
S. F. Masoudi ◽  
H. R. kheiri ◽  
E. Briand ◽  
...  

Abstract The cross-sections of deuteron-induced nuclear reactions suitable for ion beam analysis, measured in different laboratories, are often significantly different. In the present work, differential cross-sections of 27 Al(d,p) and 27 Al(d,α) reactions were measured, and the cross sections benchmarked with thick target spectra obtained from pure aluminium for the first time in two independent laboratories. The 27 Al(d,p) and (d,alpha) differential cross-sections were measured between 1.4 and 2 MeV at scattering angles of 165°, 150°, and 135° in the VDGT laboratory in Tehran (Iran), and the same measurements for detector angle of 150° were repeated from scratch, including target making, with independent equipment on the SAFIR platform at INSP in Paris (France). The results of these two measurements at 150° are in good agreement, and for the first time a fitted function is proposed to describe the Al-cross sections for which no suitable theoretical expression exists. The obtained differential cross-sections were validated through benchmarking, by fitting with SIMNRA deuteron-induced particle spectra obtained from a high purity bulk Al target at both labs for deuteron incident energies between 1.6 and 2 MeV. The thick target spectra are well-reproduced. The evaluated and benchmarked cross sections have been uploaded to the ion beam analysis nuclear data library database (www-nds.iaea.org/ibandl/).


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Salimi ◽  
O. Kakuee ◽  
S. F. Masoudi ◽  
H. Rafi-kheiri ◽  
E. Briand ◽  
...  

AbstractThe cross-sections of deuteron-induced nuclear reactions suitable for ion beam analysis, measured in different laboratories, are often significantly different. In the present work, differential cross-sections of 27Al(d,p) and 27Al(d,α) reactions were measured, and the cross sections benchmarked with thick target spectra obtained from pure aluminium for the first time in two independent laboratories. The 27Al(d,p) and (d,α) differential cross-sections were measured between 1.4 and 2 MeV at scattering angles of 165°, 150°, and 135° in the VDGT laboratory in Tehran (Iran), and the same measurements for detector angle of 150° were repeated from scratch, including target making, with independent equipment on the SAFIR platform at INSP in Paris (France). The results of these two measurements at 150° are in good agreement, and for the first time a fitted function is proposed to describe the Al-cross sections for which no suitable theoretical expression exists. The obtained differential cross-sections were validated through benchmarking, by fitting with SIMNRA deuteron-induced particle spectra obtained from a high purity bulk Al target at both labs for deuteron incident energies between 1.6 and 2 MeV. The thick target spectra are well-reproduced. The evaluated and benchmarked cross sections have been uploaded to the ion beam analysis nuclear data library database (www-nds.iaea.org/ibandl/).


2009 ◽  
Vol 24 (02n03) ◽  
pp. 450-453
Author(s):  
◽  
T. SKORODKO ◽  
M. BASHKANOV ◽  
D. BOGOSLOWSKY ◽  
H. CALÉN ◽  
...  

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.


2012 ◽  
Vol 9 (3) ◽  
pp. 554-558 ◽  
Author(s):  
Baghdad Science Journal

The differential cross section for the Rhodium and Tantalum has been calculated by using the Cross Section Calculations (CSC) in range of energy(1keV-1MeV) . This calculations based on the programming of the Klein-Nashina and Rayleigh Equations. Atomic form factors as well as the coherent functions in Fortran90 language Machine proved very fast an accurate results and the possibility of application of such model to obtain the total coefficient for any elements or compounds.


1973 ◽  
Vol 28 (10) ◽  
pp. 1642-1653
Author(s):  
G.-P. Raabe

Scattering processes of atoms, molecules and ions with two crossing electronic potentials may be treated in the Stueckelberg-Landau-Zener-(SLZ) model. In this paper the WKB-solutions for the radial wave functions, given by Stueckelberg are used to calculate differential cross sections. The effects on the cross sections are explained in a semiclassical picture, following the procedures of Ford and Wheeler, and Berry. In the scattering of H+ by rare gases, some effects in the elastic cross sections are observed which can be explained by the influence of the potential of the chargeexchanged particles, using the SLZ-model. The structure in the elastic cross sections for H2+-Kr can be explained as a rainbow structure with superimposed Stueckelberg oscillations.


1973 ◽  
Vol 51 (20) ◽  
pp. 2197-2201 ◽  
Author(s):  
P. W. Martin ◽  
R. McFadden ◽  
B. L. White

The differential cross sections for 4.3 MeV neutrons elastically scattered from natural samples of U, Bi, and Pb have been measured at laboratory angles of 5, 10, and 15°. In the case of uranium, the data are consistent with calculations based on the nuclear optical model and known electromagnetic interactions. Less satisfactory agreement to the data is obtained in the cross section measurements for lead and bismuth.


1999 ◽  
Vol 08 (03) ◽  
pp. 197-212 ◽  
Author(s):  
S. L. MINTZ ◽  
G. M. GERSTNER ◽  
M. A. BARNETT ◽  
M. POURKAVIANI

Cross sections for the exclusive reactions, [Formula: see text], and [Formula: see text] are obtained from threshold to 1 GeV. We find the contributions of the individual form factors as well as all interference terms to the cross sections of both of these reactions. We find that the cross sections for these processes are relatively large making them possible candidates for experiments. We also obtain differential cross sections for suitable energies for these reactions and note the presence of sharp minima which might be observable with a well peaked neutrino flux. We also estimate the cross sections for the inclusive reactions [Formula: see text] and [Formula: see text] from threshold to a few hundred MeV.


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