San José State University |
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Binding Energies of Two Nucleons Depends Only Upon the Shells the Two Belong To |
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There is theoretical justification that the second differences in binding energy, the increments in the incremental binding energies of nucleons,
measure the binding energies due to the interactions of the last two nucleons to be added to a nuclide. A previous study
developed a procedure for testing whether the interaction binding energies are constant over the ranges of nucleonic shells. That procedure is to
regress the second difference in binding energy on the number of nucleons of a type and the evenness of that number. If the t-ratio of the coefficient
of the number of nucleons used in the regression is less than 2 in magnitude then the influence of the number of nucleons in the shell is not significantly
different from zero at the 95 percent level of confidence. The t-ratio for a regression coefficient is the ratio of the coefficient's value to the
standard deviation of the coefficient's estimate.
Below are the results of applying this procedure to data arising from incrementing by proton to the incremental binding energies of neutrons.
Typically the graphs of data look like the following:
However there is one case, not shown above, in which there is a definite relationship between the interaction energy and the number of protons.
The extraordinarily high value for p=10 can be ignored because it is due to the proton number being equal to the neutron number, but the values
for p=5 through p=9 show a definite, more or less precise, dependence of the interactive binding energy on the proton number. The t-ratio for the
coefficient of p is about 33.
Typically the graphs of data look like the following:
There are two cases for which the t-ratio is greater than 2. Here are the graphs forthem.
In these cases it is not so much as definite dependences of interactive binding energy on neutron numbers as unusally small standard deveiations of
the estimates of the coefficients.
Of the cases selected only one showed a definite dependence of interactive binding energy on the number of nucleons. For all the others the
interactive binding energy of two nucleons is a function just of the nucleonic shells in which they are located.
The Result of the Regression of Neutron-Proton
Interaction Binding Energy on the Number of Protons
Neutron
Number NRange of
Proton
Number Pt-Ratio of
Coeff of P10 11 to 14 -1.49 20 10 to 14 -1.33 20 15 to 24 -0.410 30 16 to 33 0.944 40 24 to 28 -0.290 40 29 to 39 -0.190 50 29 to 48 -1.74 60 37 to 56 0.015 70 43 to 50 -0.96 70 51 to 62 -1.04 80 51 to70 0.18 90 53 to 77 -1.26 100 60 to 81 -0.605 110 70 to 82 -0105 120 77 to 82 -0.690 120 83 to 89 -1.04 130 83 to 92 -1.32 140 87 to 97 -0.076 150 93 to 103 -1.08 160 103 to 110 1.44 Data arising from incrementing by neutron number
the incremental binding energies of protons
The Result os the Regression of Proton-Neutron
Interaction Binding Energy on the Number of Neutrons
Proton
Number NRange of
Neutron
Number Nt-Ratio of
Coeff of N10 11 to 20 1.425 20 16 to 28 0.041 20 29 to 36 0.054 30 29 to 50 0.543 40 41 to 50 -1.59 40 51 to 67 -0.608- 50 52 to 82 0.811 60 68 to 82 -1.15 60 83 to 100 -2.85 70 83 to 110 -0.319 80 97 to 126 -2.415 90 122 to 126 -0.165 90 127 to 147 -0.640 Conclusions
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