scholarly journals Borromean Feshbach resonance in $^{11}$Li studied via $^{11}$Li($p$,$p'$)

Author(s):  
Takuma Matsumoto ◽  
Junki Tanaka ◽  
Kazuyuki Ogata

Abstract A dipole resonance of $^{11}$Li is found by a $^9$Li + $n$ + $n$ three-body model analysis with the complex-scaling method. The resonance can be interpreted as a bound state in the $^{10}$Li + $n$ system, i.e., a Feshbach resonance in the $^9$Li + $n$ + $n$ system. As a characteristic feature of the Feshbach resonance of $^{11}$Li, the $^{10}$Li + $n$ threshold is open above the $^{9}$Li + $n$ + $n$ one, which reflects a distinctive property of the Borromean system. A microscopic four-body reaction calculation for the $^{11}$Li($p$,$p'$) reaction at 6 MeV/nucleon is performed by taking into account the resonant and nonresonant continuum states of the three-body system. The calculation of angular distributions of the elastic and inelastic scattering as well as the energy spectrum reproduced a recent experimental result. Furthermore, the $E1$ strength distribution from a Coulomb dissociation experiment was also reproduced in this framework. This means that the existence of the Borromean Feshbach resonance may consistently answer a long-standing open question of an excited state of $^{11}$Li.

2007 ◽  
Vol 85 (5) ◽  
pp. 487-495 ◽  
Author(s):  
F Fleischer ◽  
G Gwinner ◽  
C Hugenschmidt ◽  
K Schreckenbach ◽  
P Thirolf ◽  
...  

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


1989 ◽  
Vol 40 (8) ◽  
pp. 2654-2661 ◽  
Author(s):  
M. Komachiya ◽  
M. Ukita ◽  
R. Fukuda

2006 ◽  
Vol 21 (31n33) ◽  
pp. 2351-2358
Author(s):  
C. Kurokawa ◽  
K. Katō

The 3α resonant states of 12 C are investigated by taking into account the correct boundary condition for three-body resonant states. In order to show how the 3α resonant states having complex eigenvalues contribute to the real energy, we calculated the Continuum Level Density in the Complex Scaling Method.


1936 ◽  
Vol 32 (3) ◽  
pp. 482-485 ◽  
Author(s):  
R. A. Smith

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.


1993 ◽  
Vol 312 ◽  
Author(s):  
R. Biswas ◽  
K. Roos ◽  
M. C. Tringides

AbstractLow temperature (T<150 K) RHEED oscillations during the growth of ultrathin films suggest the presence of substantial adatom mobility. In most systems thermal diffusion can not account for the observed oscillations, and the origin of the oscillations is an open question. Experiments on Ag/Si(111) at 150 K demonstrate the absence of thermal diffusion due to the observed scaling in the RHEED intensity for different flux rates. We have performed molecular dynamics simulations to understand the mechanisms of RHEED oscillations at low temperature. Classical two- and three-body Si potentials were used together with an adatom mass that is 3.84 times the Si mass to account for the Ag/Si mass ratio. Results indicate that the landing site for the adatom is very important to predict whether a particular adatom will display lateral motion or not. A fraction of the adatoms incident near a maximum of the potential energy surface display significant lateral motion. The substrate stiffness for Ag/Si results in an energy transfer process which is much slower than that in fcc/fcc systems.


1981 ◽  
Vol 59 (2) ◽  
pp. 225-230 ◽  
Author(s):  
G. Pantis ◽  
H. Fiedeldey ◽  
D. W. L. Sprung

The charge form factor of the model triton clearly exhibits the collapse which occurs in the triton for purely nonlocal two-body interactions with continuum bound states and approaches an asymptotic shape with increasing binding energy. However, partly nonlocal interactions with continuum bound states, which previously have been shown not to produce such a collapse, also show no evidence whatsoever of the presence of the two-particle continuum bound state in the triton charge form factor. In the physically interesting case of partly nonlocal interactions the occurrence of a continuum bound state in the two-body interactions therefore can be completely harmless in the three-body system.


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