The low-energy theorem for the forward compton amplitude of a stationary composite system and the FW additive external electromagnetic interaction

1977 ◽  
Vol 42 (2) ◽  
pp. 259-266 ◽  
Author(s):  
K. J. Sebastian
1986 ◽  
Vol 34 (6) ◽  
pp. 2029-2042 ◽  
Author(s):  
J. L. Friar ◽  
S. Fallieros

2007 ◽  
Vol 16 (04) ◽  
pp. 969-981 ◽  
Author(s):  
VALERY ZAGREBAEV ◽  
WALTER GREINER

Low energy collisions of very heavy nuclei (238 U +238 U , 232 Th +250 Cf and 238 U +248 Cm ) have been studied within the realistic dynamical model based on multi-dimensional Langevin equations. Large charge and mass transfer was found due to the "inverse quasi-fission" process leading to formation of survived superheavy long-lived neutron-rich nuclei. In many events lifetime of the composite system consisting of two touching nuclei turns out to be rather long; sufficient for spontaneous positron formation from super-strong electric field, a fundamental QED process.


2020 ◽  
Vol 80 (12) ◽  
Author(s):  
J. Gasser ◽  
H. Leutwyler ◽  
A. Rusetsky

AbstractThe Cottingham formula expresses the leading contribution of the electromagnetic interaction to the proton-neutron mass difference as an integral over the forward Compton amplitude. Since quarks and gluons reggeize, the dispersive representation of this amplitude requires a subtraction. We assume that the asymptotic behaviour is dominated by Reggeon exchange. This leads to a sum rule that expresses the subtraction function in terms of measurable quantities. The evaluation of this sum rule leads to $$m_{\mathrm{QED}}^{p-n}=0.58\pm 0.16\,\text {MeV}$$ m QED p - n = 0.58 ± 0.16 MeV .


2007 ◽  
Vol 16 (02n03) ◽  
pp. 141-152
Author(s):  
WALTER GREINER ◽  
VALERY ZAGREBAEV

Low-energy damped collisions of very heavy nuclei (238 U +238 U , 232 Th +250 Cf and 238 U +248 Cm ) are investigated within the realistic model based on multi-dimensional Langevin equations. Large charge and mass transfer was found in these reactions due to the inverse (anti-symmetrizing) quasi-fission process leading to formation of survived superheavy long-lived neutron-rich nuclei. In many events lifetime of the composite system consisting of two touching nuclei (giant quasi-atoms) turns out to be rather long; sufficient for spontaneous positron formation from a super-strong electric field, a fundamental QED process.


Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.


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