The negative ion of positronium: measurement of the decay rate and prospects for further experiments

2007 ◽  
Vol 85 (5) ◽  
pp. 487-495 ◽  
Author(s):  
F Fleischer ◽  
G Gwinner ◽  
C Hugenschmidt ◽  
K Schreckenbach ◽  
P Thirolf ◽  
...  
Keyword(s):  
Decay Rate ◽  
Bound State ◽  
Negative Ion ◽  
Experimental Result ◽  
Three Body Problem ◽  
Positron Source ◽  
Interesting Object ◽  
Three Body ◽  
Beam Foil

The negative positronium (Ps–) ion consisting of two electrons and a positron (e+e–e–), represents the simplest three-body system with a bound state. Its constituents are stable, point-like particles, and it is essentially free from perturbations by strong interaction effects. Together with the rather unique mass ratio, these properties make the positronium ion an interesting object for studying the quantum-mechanical three-body problem. We present a new determination of the decay rate of Ps–, using a beam-foil method and a stripping-based detection technique. The measured value of Γ = 2.089(15) ns–1 is a factor of six times more precise than the previous experimental result, and there is excellent agreement both with the latter and with the theoretical value. With the new high-intensity positron source NEPOMUC at the FRM-II research reactor in Munich being available, a further improvement in precision seems possible. Moreover, the high flux of low-energy positrons at this facility brings other properties of this exotic system within reach of experiments. The prospects for such investigations are discussed.PACS No.: 36.10Dr

Note on radiationless transitions involving three-body collisions

1936 ◽  
Vol 32 (3) ◽  
pp. 482-485 ◽  
Author(s):  
R. A. Smith
Keyword(s):  
Continuous Spectrum ◽  
Negative Ions ◽  
Bound State ◽  
Excess Energy ◽  
Negative Ion ◽  
Positive Ions ◽  
Continuous State ◽  
Direct Formation ◽  
Three Body ◽  
Positive Ion

When an electron makes a transition from a continuous state to a bound state, for example in the case of neutralization of a positive ion or formation of a negative ion, its excess energy must be disposed of in some way. It is usually given off as radiation. In the case of neutralization of positive ions the radiation forms the well-known continuous spectrum. No such spectrum due to the direct formation of negative ions has, however, been observed. This process has been fully discussed in a recent paper by Massey and Smith. It is shown that in this case the spectrum would be difficult to observe.

scholarly journals Study of the stability of the perturbed solutions of the restricted three body problem

BIBECHANA ◽  
2015 ◽  
Vol 13 ◽  
pp. 18-22
Author(s):  
MAA Khan ◽  
MR Hassan ◽  
RR Thapa
Keyword(s):  
Body Problem ◽  
Restricted Three Body Problem ◽  
Three Body Problem ◽  
Variational Equations ◽  
First Order ◽  
Characteristic Exponents ◽  
Method Of Determination ◽  
The Stability ◽  
Three Body

In this paper we have been examined the stability of the perturbed solutions of the restricted three body problem. We have been restricted ourselves only to the first order variational equations. Our variational equations depend on the periodic solutions. Here the applications of the method of Fuchs and Floquet Proves to be complicated and hence we have been preferred Poincare's Method of determination of the characteristic exponents. With the determination of the characteristic exponents we have been abled to conclude regarding the stability of the generating solution. We have obtained that the motions are unstable in all the cases. By Poincare's implicit function theorem we have concluded that the stability would remain the same for small value of the parameter m and in all types of motion of the restricted three-body problem.BIBECHANA 13 (2016) 18-22 

scholarly journals The ionised hydrogen molecule

1928 ◽  
Vol 118 (780) ◽  
pp. 635-647 ◽  
Keyword(s):  
Hydrogen Molecule ◽  
Classical Problem ◽  
Experimental Result ◽  
Three Body Problem ◽  
Quantum Numbers ◽  
First Approximation ◽  
Integer Quantum ◽  
Analytical Result ◽  
Heat Of Dissociation ◽  
Three Body

The model which has been proposed for the ion of the hydrogen molecule H2+, consists of one electron and two protons. Since the mass of the electron is negligible compared with that of the protons, we may, to a first approximation, consider the protons as at rest. The system is then a particular case of the problem of three bodies, and can be solved completely classically. This has been done by Pauli,* and more recently by Niessen. † The value obtained by Pauli for the energy of the normal state is not in agreement with the experimental result inferred from the ionisation potential and heat of dissociation of the molecule. Niessen obtains the experimental result by the introduction of half integer quantum numbers. The classical problem is separable in elliptic co-ordinates, and so if we apply Schrodinger’s method to the system we shall obtain a wave equation which is separable in the same co-ordinates. The resulting differential equations can be solved exactly. This is the only three-body problem which admits of an exact solution, and it is of interest to obtain an analytical result, and not merely one obtained by a perturbation method, which it may be difficult to justify.

Momentum-space solution of a bound-state nuclear three-body problem with two charged particles

1984 ◽  
Vol 29 (4) ◽  
pp. 1450-1460 ◽  
Author(s):  
D. R. Lehman ◽  
A. Eskandarian ◽  
B. F. Gibson ◽  
L. C. Maximon
Keyword(s):  
Momentum Space ◽  
Body Problem ◽  
Charged Particles ◽  
Bound State ◽  
Three Body Problem ◽  
Space Solution ◽  
Three Body

scholarly journals A New Kind of Periodic Orbit: The Three-Dimensional Asymmetric

1978 ◽  
Vol 41 ◽  
pp. 315-317 ◽  
Author(s):  
V. V. Markellos
Keyword(s):  
Periodic Orbit ◽  
Periodic Orbits ◽  
Body Problem ◽  
Three Dimensional ◽  
Restricted Three Body Problem ◽  
Three Body Problem ◽  
Three Body

AbstractA great deal of human and computer effort has been directed in recent decades to the determination of the periodic orbits of the restricted three-body problem and the study of their properties for well known reasons of significance and feasibility.

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