scholarly journals Ultraperipheral vs. Ordinary Nuclear Interactions

Universe ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 4 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Heavy Nuclei ◽  
Perturbative Approach ◽  
Hadronic Interactions ◽  
High Energies ◽  
Nuclear Interactions ◽  
The Cross ◽  
Energy Thresholds

It is argued that the cross sections of ultraperipheral interactions of heavy nuclei can become comparable in value to those of their ordinary hadronic interactions at high energies. Simple estimates of corresponding “preasymptotic energy thresholds” are provided. The method of equivalent photons is compared with the perturbative approach. The situation at NICA/FAIR energies is discussed.

scholarly journals Thresholds of ultraperipheral processes

2020 ◽  
Vol 35 (18) ◽  
pp. 2050087
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Threshold Behavior ◽  
Total Cross Sections ◽  
Nuclear Interactions ◽  
The Cross ◽  
Energy Thresholds

Threshold behavior of the cross-sections of ultraperipheral nuclear interactions is studied. Production of [Formula: see text] and [Formula: see text] pairs as well as [Formula: see text] and parapositronium is treated. The values of corresponding energy thresholds are presented and the total cross-sections of these processes at the newly constructed NICA and FAIR facilities are estimated.

scholarly journals Quark correlations in the ground and excited nucleon states via the photo-absorption sum rules

2019 ◽  
Vol 204 ◽  
pp. 01008
Author(s):  
Sergo Gerasimov
Keyword(s):  
Cross Sections ◽  
Sum Rules ◽  
Valence Quark ◽  
Visual Representation ◽  
Nucleon Resonances ◽  
Nuclear Interactions ◽  
The Cross ◽  
Quark Correlation

The account of the dynamical correlations of quarks composing the nucleons is necessary for relevant description of nucleon and nuclear interactions. The present work is devoted to the use of the technique of known integral sum rules for the cross-sections and amplitude of the photo-hadron processes. In particular, a kind of the visual representation and quantification of the valence quark correlation characteristics referring to the photo-excitation of the nucleon resonances can be presented.

The dissociation of fast H 2 + ions by hydrogen

1960 ◽  
Vol 256 (1286) ◽  
pp. 416-426 ◽  
Keyword(s):  
Triplet State ◽  
Energy Dependence ◽  
Cross Sections ◽  
Large Fraction ◽  
Exchange Process ◽  
Hydrogen Gas ◽  
High Energies ◽  
Scintillation Crystals ◽  
The Cross ◽  
Simple Dissociation

H 2 + ions of energy 100 to 800 keV have been passed through hydrogen gas and the cross-sections for the following four processes determined : (1) H 2 + → H + + H O , (2) H 2 + → H + + H + , (3) H 2 + → H O + H O , (4) H 2 + → H 2 O . A magnetic field was used to separate the fast dissociation products of different e / m , and CsI(Tl) scintillation crystals were used as detectors. Double-height pulses resulted when two particles of the same e / m , simultaneously entered one of the crystals and were clearly resolved from single pulses. Processes (3) and (4) were separated by moving a fine slit across the neutral-particle counter which thus counted only H 2 O particles as double pulses. The partial cross-sections for processes (1) and (2) show an E -1 dependence at high energies. The energy dependence is less marked below 300 keV, where the Born approximation might be expected to be invalid. The partial cross-sections for processes (3) and (4) show the strong energy dependence characteristic of an electron-exchange process. The angular distribution for process (3) is consistent with the reaction proceeding via the 1 3 Ʃ u repulsive triplet state. The large fraction of the capture reactions proceeding this way (70%), is reasonable considering the high probability of formation in the triplet state. The large values of the cross-sections for processes other than simple dissociation account, in part, for the considerable discrepancies between the results of other workers.

The emission and absorption of heavy electrons

1939 ◽  
Vol 35 (1) ◽  
pp. 84-94 ◽  
Author(s):  
H. S. W. Massey ◽  
H. C. Corben
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Relativistic Energy ◽  
Photoelectric Absorption ◽  
Radiative Emission ◽  
High Energies ◽  
Heavy Electron ◽  
Nuclear Particle ◽  
Electron Field ◽  
The Cross

The quantum theory of the heavy electron field is applied to calculate approximately the cross-sections for “photoelectric” absorption of heavy electrons by a bound nuclear particle and for emission of a heavy electron by a free nuclear particle on collision with a nucleus. The absorption cross-section per nuclear particle is of the order 10−26 cm.2 for heavy electrons with energies up to 108 e.V., but probably decreases rapidly at higher energies. Although the energy loss of a proton, of energy 108 e.V. or higher, due to heavy electron emission is found to be greater than that due to radiation, the cross-section is very small (⋍ 10−29 cm.2) and the phenomenon is unlikely to be observed in a cloud chamber. In the present state of theory it is impossible to decide whether radiative emission of heavy electrons by nuclear particles is capable of contributing appreciably to the heavy electrons observed at sea-level but, if so, the cross-section for the process must be very much greater at high energies than in the non-relativistic energy region which we have investigated.

Measurement of the cross sections for fissioning of heavy nuclei by 16-MeV neutrons

1986 ◽  
Vol 60 (6) ◽  
pp. 494-496 ◽  
Author(s):  
A. A. Goverdovskii ◽  
A. K. Gordyushin ◽  
B. D. Kuz'minov ◽  
V. F. Mitrofanov ◽  
A. I. Sergachev
Keyword(s):  
Cross Sections ◽  
Heavy Nuclei ◽  
The Cross

scholarly journals Nonlinear light absorption in many-electron systems excited by an instantaneous electric field: a non-perturbative approach

2021 ◽  
Vol 23 (16) ◽  
pp. 10059-10069
Author(s):  
Alberto Guandalini ◽  
Caterina Cocchi ◽  
Stefano Pittalis ◽  
Alice Ruini ◽  
Carlo Andrea Rozzi
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
Time Evolution ◽  
Cross Sections ◽  
Light Absorption ◽  
Nonlinear Optical ◽  
Nonlinear Optical Properties ◽  
Electron Systems ◽  
Perturbative Approach ◽  
The Cross

The time-evolution of many-electron systems induced by an electric field in the instantaneous limit is an effective tool for investigating computationally nonlinear optical properties. It works well also for those cases in which the convergence of the perturbative expansions of the cross sections is challenging.

PAIR PRODUCTION OF CHARGINOS IN e+e− ANNIHILATION AT HIGH ENERGIES

1992 ◽  
Vol 07 (17) ◽  
pp. 1535-1543 ◽  
Author(s):  
M.H. NOUS ◽  
M. EL-KISHEN ◽  
T.A. EL-AZEM
Keyword(s):  
Pair Production ◽  
Cross Sections ◽  
High Energies ◽  
The Cross

The cross-sections for pair production of charginos in e+e− annihilation are calculated. At [Formula: see text] charginos with a mass smaller than MZ/2 could clearly be seen at [Formula: see text] through the exchange of the scalar neutrino or at Z0.

scholarly journals Phenomenological Description of Neutron Capture Cross Sections at 30 keV

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
M. Kiss ◽  
Z. Trócsányi
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
Phenomenological Description ◽  
Capture Cross ◽  
Heavy Nuclei ◽  
Proton Number ◽  
The Cross ◽  
Capture Cross Sections

Studying the published values of Maxwellian-averaged neutron capture cross sections, we found simple phenomenological rules obeyed by the cross sections as a function of proton and neutron numbers. We use these rules to make predictions for cross sections of neutron capture on nuclei with proton number above 83, where very few MACS data are available. These predictions may be useful in certain models of nucleosynthesis of heavy nuclei in stars.

scholarly journals Response functions and cross sections for inclusive neutrino scattering off $^2$H, $^3$H and $^3$He

2020 ◽  
Author(s):  
Alessandro Grassi ◽  
Jacek Golak ◽  
Roman Skibiński ◽  
Kacper Topolnicki ◽  
Henryk Witała ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Weak Interactions ◽  
Light Nuclei ◽  
Response Functions ◽  
Neutrino Scattering ◽  
Nuclear Interactions ◽  
Break Up ◽  
The Cross ◽  
Nuclear Response

For several decades there has been an interest in studying neutrino scattering on light nuclei, with the hope of increasing knowledge about the theory of weak interactions and electroweak unification. A study of several neutrino induced reactions on light nuclei (^22H, ^33H and ^33He) is presented here. The cross section for these reactions is evaluated using the nuclear response functions, which holds the information about the nuclear interactions and structure. This approach has been tested for break-up reactions on the deuteron before and is now extended to three-nucleon break-up reactions.

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