Comprehensive study of the three- and four-neutron systems at low energies

Higgins, Michael D.; Greene, Chris H.; Kievsky, A.; Viviani, M.

doi:10.1103/physrevc.103.024004

Cited by 16 publications

(12 citation statements)

References 57 publications

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“…Further studies based on the Alt-Grassberger-Sandhas (AGS) equations for transition operators [5] and response functions [8] found no evidence of a three-neutron resonance. Higgins et al [9,10] confirmed this further with calculations in a hyperspherical framework. They pointed out that there is significant attraction compared to free neutrons.…”

Section: Introductionmentioning

confidence: 76%

“…Following this convention, we refer to τ as the dimer propagator. Together with the explicit representation of the three-body interaction (10), the Faddeev equation can be written as…”

Section: Faddeev Formalismmentioning

confidence: 99%

“…The search for few-neutron resonances and bound states has a long history with ambiguous results [1,2]. In this work we focus on the topic of three-neutron resonances, motivated by a controversial discussion of this topic in the recent literature [3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Three-body resonances in pionless effective field theory

Dietz,

Hammer,

König

et al. 2021

Preprint

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We investigate the appearance of resonances in three-body systems using pionless effective field theory at leading order. The Faddeev equation is analytically continued to the unphysical sheet adjacent to the positive real energy axis using a contour rotation. We consider both, the three-boson system and the three-neutron system. For the former, we calculate the trajectory of Borromean three-body Efimov states turning into resonances as they cross the three-body threshold. For the latter, we find no sign of three-body resonances or virtual states at leading order. This result is validated by exploring the level structure of three-body states in a finite volume approach.

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Section: Introductionmentioning

confidence: 76%

“…Following this convention, we refer to τ as the dimer propagator. Together with the explicit representation of the three-body interaction (10), the Faddeev equation can be written as…”

Section: Faddeev Formalismmentioning

confidence: 99%

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Three-body resonances in pionless effective field theory

Dietz,

Hammer,

König

et al. 2021

Preprint

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“…Neutrons are unique particles that are of interest from both a fundamental and an applied point of view. Of the unsolved experimental fundamental problems, we note the problem of neutron lifetime [5], the question of the presence of the electric dipole moment of the neutron [6], and the search for neutron clusters [7]. In addition, neutron registration still represents an uneasy problem.…”

Section: Introductionmentioning

confidence: 99%

Production and Monitoring of Neutron Flux by Activation Detectors

et al. 2021

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The neutron generation technique was tested on the microtron M-10 with an output electron beam of 8.7 MeV. Given the low energy that the microtron can provide to electrons, the bremsstrahlung induced photonuclear reaction 9Be (γ, n), which has a low threshold, was chosen for neutron generation. Cobalt and indium targets were tested as activation detectors to estimate the neutron flux density. In the cobalt target, the isomeric state of 60mCo with an energy of 58.6 keV and a half-life of 10.5 minutes is well activated. Two well-known additional gamma lines of standard cobalt source permit to clarify the absolute value of the neutron flux. The activated indium target has four gamma lines bound to the 116mIn isomer β- decaying with the half-life of 54.4 minutes, what is convenient for measurement of gamma spectrum. Despite the low energy of the output electron beam, at a beam intensity of 5 μA it is possible to obtain an almost isotropic neutron flux of 107 n/(s∙cm2).

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“…This reduction appears to be a universal effect that occurs at unitarity, and has previously been demonstrated at s-wave unitarity for many 3-body systems and for some 4-body systems. (See, for instance, recent evidence presented for 3-and 4-nucleon systems with their s-wave interactions tuned to unitarity [22,23]). Only in some cases, such as three equal mass bosons with all pairwise scattering lengths infinite, does this asymptotic coefficient become reduced all the way to negative values, in which case there is a true Efimov effect with the usual infinite sequence of weakly-bound energy levels converging geometrically to zero energy.…”

Section: Introductionmentioning

confidence: 99%

Efimov physics implications at $p$-wave fermionic unitarity

Chen

Greene

2021

Preprint

Self Cite

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Efimov physics at p-wave unitarity for three equal mass fermions in multiple symmetries interacting via Lennard-Jones potentials is predicted to modify the long range interaction potential energy, but without producing a true Efimov effect. This analysis treats the following total orbital angular momenta and parities, J Π = 0 + , 1 + , 1 − and 2 − , for either three spin-polarized fermions (↑↑↑), or two spin-up and one spin-down fermion (↓↑↑). Our results for the long range interaction in some of those cases agree with previous work by Werner and Castin and by Blume et al., namely in cases where the s-wave scattering length goes to infinity. The present results extend those calculated interaction energies to small and intermediate hyperradii comparable to the van der Waals length, and we consider additional unitarity scenarios where the p-wave scattering volume approaches infinity. The crucial role of the diagonal hyperradial adiabatic correction term is identified and characterized.

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Comprehensive study of the three- and four-neutron systems at low energies

Cited by 16 publications

References 57 publications

Three-body resonances in pionless effective field theory

Three-body resonances in pionless effective field theory

Production and Monitoring of Neutron Flux by Activation Detectors

Efimov physics implications at $p$-wave fermionic unitarity

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