scholarly journals Effect of Rapidly Rising Proton?Proton Total Cross Sections on Idealized Extensive Air Showers

1972 ◽  
Vol 25 (6) ◽  
pp. 679
Author(s):  
JA Campbell

A simulation of extensive air showers above 1013 eV in which proton?proton scattering takes place partly through a medium-strong interaction is reported. In previous papers the simulation has been shown to be in fair agreement with observational data. The present version includes for the first time the assumption that the total cross section for proton-proton scattering increases with energy, as concluded in a recent paper by Yodh, Pal, and Trefil. The effect of the assumption is to make a noticeably better agreement between the simulation and the data.

The main features of the C. E. R. N. Intersecting Storage Rings (I. S. R.) are reviewed, together with results obtained in 1971 and 1972 on elastic scattering and total cross-sections. The main result is a 10% increase of the total proton-proton cross-section in the I. S. R. energy range. The simplest picture of high energy proton-proton scattering which emerges from this and the other data, is briefly discussed.


2008 ◽  
Vol 23 (27n30) ◽  
pp. 2313-2316 ◽  
Author(s):  
◽  
H. KANDA ◽  
N. CHIGA ◽  
Y. FUJII ◽  
K. FUTATSUKAWA ◽  
...  

The total cross sections for the π+π− photoproduction on the deuteron were measured in an energy range of 0.8 to 1.1 GeV. The obtained total cross section for the quasi-free π+π− photoproduction on the deuteron was about 60 % of those on the free proton. The cross section for Δ++Δ− photoproduction was derived from the non-quasi-free π+π− photoproduction events. It was smaller than the previous data.


In proton-proton scattering, when both incident and target protons have polarizations of P 1 and P 2 respectively in a direction normal to the plane of scattering, the differential cross-section, σ, at angle θ is given by σ( θ ) = σ 0 ( θ ) {1 + ( P 1 + P 2 ) P 3 ( θ ) + P 1 P 2 C NN ( θ )}. P 3 ( θ ) and C NN ( θ ) are the polarization and spin-correlation parameters of proton-proton scattering, and are functions of incident proton energy and scattering angle. The Harwell synchrocyclotron provides a choice of two proton beams at an energy of 142MeV ( a ) high intensity P 1 = 0, and ( b ) low intensity P 1 = ±0.48. P 3 ( θ ) is a well-known quantity, and the two remaining unknowns, P 2 and C NN ( θ ) can be obtained by comparing differential cross-sections measured with beams ( a ) and ( b ). Somewhat higher precision is obtainable in such a measurement of the target polarization P 2 than by either of the existing solid-state methods (Schmugge & Jeffries 1962; Abragam, Borghini & Chapellier 1962).


2021 ◽  
Vol 129 (12) ◽  
pp. 1471
Author(s):  
И.В. Чернышова ◽  
Е.Э. Контрош ◽  
О.Б. Шпеник

Abstract– The interactions of low-energy electrons (<20 eV) with D-ribose molecules, namely, electron scattering and dissociative attachment, are studied. The results of these studies showed that the fragmentation of D-ribose molecules occurs effectively even at an electron energy close to zero. as well as in the energy range 5.50–9.50 eV. In the total cross section of electron scattering by molecules, resonance features at energies of 5.00–9.00 eV in the region of formation of ionic fragments C3H4O2–, C2H3O2–, OH–, associated with the destruction of molecular heterocycles, were experimentally discovered for the first time. The correlation of the features observed in the scattering and dissociative electron attachment cross sections is analyzed.


Precise measurements of the total cross sections of positive and negative π mesons on hydrogen have revealed the presence of structure or enhancements in these cross sections at various momenta up to 3 GeV/ c . The present paper discusses measurements of this type and in particular, a recent experiment to search for structure in the region 3 to 7 GeV/ c , where previous experiments have shown that, if structure were present, it was likely to reveal itself as an amplitude in the total cross section of 1 mb or less. The recent measurements indicate four regions of structure, two in each of the isotopic spin states 3/2 and 1/2. The possible relation of these regions of structure to the formation of pion-nucleon resonances is discussed.


1998 ◽  
Vol 13 (09) ◽  
pp. 1515-1522 ◽  
Author(s):  
E. A. ANDREEVA ◽  
M. N. STRIKHANOV ◽  
S. B. NURUSHEV

The experimental data on the pp-total cross-sections including the spin-dependent parts are analyzed with the goal to determine the contribution of spin interactions at high energies. Based on the Regge model with cuts, the energy dependencies of such contributions are estimated for two spin-dependent terms: (1) the total spin dependent term, σ1 and (2) the spin projection dependent term, σ2. The estimates show that their contributions to the unpolarized total cross section, σ0, decrease with energy from several % around 2 GeV/c to 10-2% around 200 GeV/c. The assumption σ1= -σ2 does not seem to be correct, while the hypothesis 3 σ1=-σ2 is more preferable, especially in the measured energy interval 2-6 GeV. There is a clear indication that the spin effects are sensitive to the pomeron intercept at - t=0 (GeV/c)2. In order to pin down such effects the spin dependent total cross-sections must be measured with precisions better than 10 μb at 200 GeV/c.


2010 ◽  
Vol 19 (12) ◽  
pp. 2393-2399 ◽  
Author(s):  
T. Ishikawa

The differential and total cross sections were measured for the γp → ηp and γd → ηpn reactions at Eγ ≤ 1150 MeV by using an electro-magnetic (EM) calorimeter SCISSORS II at the Laboratory of Nuclear Science (LNS), Tohoku University. The total cross section on the deuteron shows a bump around Eγ = 1 GeV , while no bump is observed in the same energy region of that on the proton. This bump is attributed to be a nucleon resonance excited from the neutron, and it is a candidate of anti-decuplet penta-quark baryons with hidden strangeness. It was difficult, however, to detect all the γ's coming from η decay since the solid angle of SCISSORS II was only 12.6% in total. Statistics of the detected η produced events is poor and systematic uncertainty of the obtained cross section is not small due to low acceptance. A new EM calorimeter complex called FOREST with a solid angle of about 4π sr has been constructed. The spin and parity of the relevant resonance are expected to be determined by the experiments with FOREST.


2016 ◽  
Vol 94 (1) ◽  
pp. 75-78 ◽  
Author(s):  
S.A. Elkilany ◽  
A.A. Al-Dhawi

The collisions of a proton with a lithium atom are treated for the first time as a three-channel problem under the assumption that the elastic and hydrogen formation in non-excited, H(1s), and excited, H(2s), channels are open. The effect of polarization potentials of the target and hydrogen formation is considered. A one-valence-electron model for the target, based on the Clementi–Roetti Slater-type basis functions, as well as a modified coupled-static approximation are used to calculate the partial and total cross sections of seven partial waves (0 ≤ ℓ ≤ 6, where ℓ is the total angular momentum) at incident energies between 50 and 500 keV. Our values of the total cross section are in good agreement with previous results.


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