scholarly journals Possible Consequences of the Quark Model for Fragmentation Processes

1973 ◽  
Vol 26 (3) ◽  
pp. 291
Author(s):  
CS Lai ◽  
SY Lo
Keyword(s):  
Model Selection ◽  
Quark Model ◽  
Cross Section ◽  
Sum Rules ◽  
Optical Theorem ◽  
Selection Rules ◽  
Experimental Values ◽  
Limiting Fragmentation ◽  
Fragmentation Processes ◽  
Initial Combination

The quark model is used to predict various sum rules for limiting fragmentation. In particular, the ratio of the cross section of p --+ p to that of n --+ n is found to be 9 : 4. An initial combination of the quark model with the generalized optical theorem is found to produce results which violate the quark-model selection rules and differ from experimental values by a factor of 103-106 ? A possible modification is proposed and further tests are suggested.

Cross-section sum rules and inequalities in a quark model for light and heavy flavour productions

Pramana ◽  
1993 ◽  
Vol 40 (3) ◽  
pp. 213-225
Author(s):  
D K Choudhury ◽  
Pratibha Das
Keyword(s):  
Quark Model ◽  
Cross Section ◽  
Sum Rules

Quark model selection rules for Hadron couplings

1969 ◽  
Vol 13 (2) ◽  
pp. 237-245 ◽  
Author(s):  
P.G.O. Freund ◽  
R. Waltz ◽  
J. Rosner
Keyword(s):  
Model Selection ◽  
Quark Model ◽  
Selection Rules

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

scholarly journals The 7Be(p, ?)8B Cross Section at Low Energies

1980 ◽  
Vol 33 (2) ◽  
pp. 177 ◽  
Author(s):  
FC Barker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Solar Neutrinos ◽  
Model Calculations ◽  
Spectroscopic Factors ◽  
Low Energies ◽  
Standard Values ◽  
Experimental Values ◽  
Parameter Values ◽  
Potential Parameters

The nonresonant part of the 7Be(p, )I)8B cross section at low energies is recalculated by means of a direct-capture potential model, using parameter values determined by fitting 7Li(n, n)7Li and 7Li(n, )I)8Li data. Standard values of the potential parameters and spectroscopic factors give values of the 7Li(n,)I) cross section that are too large. Modified values that fit the thermal-neutron capture cross section predict 7Be(p,)I) cross sections that are much less than the experimental values. Also, shell model calculations predict resonant 7Be(p,)I) cross sections that are smaller than the experimental values. It is suggested that the accepted experimental values of the 7Be(p, )I) cross section may be too large, perhaps due partly to an overlarge accepted value for the 7Li(d, p)8Li cross section, which has been used for normalization purposes. A decrease in the 7Be(p,)I) cross section would reduce the calculated detection rate of solar neutrinos and lessen the discrepancy with the measured value.

The determination of the cross sections for the reactions 27 Al( n , α ) and 56 Fe( n , p ) for 14 MeV neutrons by an absolute method

1966 ◽  
Vol 292 (1429) ◽  
pp. 180-192 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Standard Error ◽  
Particle Method ◽  
Systematic Errors ◽  
Aluminium Foil ◽  
The Mean ◽  
The Cross ◽  
Experimental Values

Measurements of the cross sections for the reactions 27 Al( n , α ) 24 Na and 56 Fe( n, p ) 56 Mn for neutrons of energy 13.5 ± 0.1 MeV have been made by a radioactivation method. The neutron flux was determined by a variant of the 'associated particle’ method, in which the α -particles produced concurrently with the neutrons from the D + T reaction were estimated in terms of the volume of helium which accumulated when they were brought to rest in an aluminium foil. Cross section values obtained at 13.5 MeV were: for 27 Al( n , α ): 118.1 ± 6.0 mb : for 56 Fe( n, p ): 106.7 ± 4.7 mb. The errors quoted include both the standard error on the mean of the experimental values and an estimate of possible residual systematic errors. The excitation functions for both reactions in the energy region 13.5 to 14.8 MeV have also been investigated, in order to provide secondary cross section values over this range of energies. At 14.8 MeV the values found were: 27 Al( n , α )103.6 ± 5.5 mb; 56 Fe( n, p )96.7 ± 4.5 mb.

scholarly journals Neutron inelastic cross section measurements on 54Fe

2020 ◽  
Vol 239 ◽  
pp. 01010
Author(s):  
Adina Olacel ◽  
Catalin Borcea ◽  
Marian Boromiza ◽  
Philippe Dessagne ◽  
Gregoire Henning ◽  
...  
Keyword(s):  
Cross Section ◽  
Optical Model ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Analysis Procedure ◽  
Model Parameters ◽  
Electron Linear Accelerator ◽  
Section Measurement ◽  
Data Analysis Procedure ◽  
Experimental Values

A 54Fe(n, n'γ) cross section measurement was performed at the Geel Electron LINear Accelerator of EC-JRC, Geel using the Gamma Array for Inelastic Neutron Scattering spectrometer and a 235U fission chamber for flux normalization. The experimental results are presented in comparison with talys 1.9 default and tuned calculations. The tuned calculation, implying modifications of the optical model parameters, improved significantly the description of the experimental values and led to interesting conclusions regarding the interaction of the 54Fe nucleus with neutrons. Since the results of these calculations were already presented extensively in a dedicated paper, the present article focuses on details related to the experimental particularities and data analysis procedure.

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