# Few-Body Systems Journal Impact Factor & Information

Publisher: Springer Verlag

## Journal description

The journal is devoted to the publication of original research work both experimental and theoretical in the field of few-body systems. Conceptually such systems are understood as consisting of a small number of well-defined constituent structures. Investigations of the behaviour of these systems form the central subject matter of the journal. Systems for which an equivalent one-body description is available or can be designed and large systems for which specific many-body methods are needed are outside the scope of the journal. The focus of interest lies in the research methods properties and results characteristic of few-body systems. Particular examples of few-body systems are light nuclei light atoms small molecules but also celestial systems "elementary" particles (considered as systems of few constituents) or larger systems with a few-particle substructure. The principal aim of the journal is to bring together competent work from various fields of physics such as particle nuclear atomic molecular and condensed-matter physics and also from astrophysics astronomy mathematics and chemistry thereby fostering research done on related problems in different areas of natural sciences. While concentrating on few-body systems which can also be characterized as generally amenable to rigorous solutions the journal stresses interdisciplinarity through the exchange of ideas methods results experience and knowledge gathered in neighbouring fields. Beyond the publication of articles the journal as a forum for the community of scientists engaged in the study of few-body problems also provides for the rapid dissemination of actual scientific and practical information in separate News Sections; these include abstracts of recent preprints a calendar of conferences and meetings book reviews announcements etc. Though the emphasis is on regular research articles the journal publishes also papers in the form of letters rapid communications comments and from time to time reviews or progress reports.

## Impact Factor Rankings

2015 Impact Factor Available summer 2015 1.508 1.047 1.438 0.622 0.468 1.014 0.856 0.765 1.182 1.948 1.034 1.773 1.857 1.552 1.26 1.359 0.582 1.82 1.891 1.377 2.185 1.02

## Impact factor over time

Impact factor
.
Year

5-year impact 0.81 4.60 0.60 0.00 0.32 Few-Body Systems website Few-body systems (Online), Acta physica Austriaca new series 0177-7963 41983736 Document, Periodical, Internet resource Internet Resource, Computer File, Journal / Magazine / Newspaper

## Publisher details

• Pre-print
• Author can archive a pre-print version
• Post-print
• Author can archive a post-print version
• Conditions
• Author's pre-print on pre-print servers such as arXiv.org
• Author's post-print on author's personal website immediately
• Author's post-print on any open access repository after 12 months after publication
• Publisher's version/PDF cannot be used
• Published source must be acknowledged
• Must link to publisher version
• Set phrase to accompany link to published version (see policy)
• Articles in some journals can be made Open Access on payment of additional charge
• Classification
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## Publications in this journal

• ##### Article: Semileptonic Decays of $${\Xi_{b}}$$ Ξ b and $${\Sigma_{b}}$$ Σ b Baryons via the Three-Body Variational Approach
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ABSTRACT: We consider a nonrelativistic three-body system with a Cornell interaction in hyperspherical formalism. In order to obtain the solution of the system, we use the improved variational method. Next, we investigate the Isgur–Wise function and thereby report the semileptonic decay width of bottom baryons $${\Xi _b}$$ and $${\Sigma _b}$$. We report the branching ratios and partial decay widths as well and make a comparison with present data.
Few-Body Systems 06/2015; DOI:10.1007/s00601-015-1007-7
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##### Article: Few-Nucleon Systems in a Quirky World
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ABSTRACT: I describe how nuclear structure can be predicted from lattice QCD through low-energy effective field theories, using as an example a world simulation with relatively heavy up and down quarks.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0980-1
• ##### Article: Efimov Physics and the Three-Body Parameter for Shallow van der Waals Potentials
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ABSTRACT: Extremely weakly-bound three-boson systems are predicted to exhibit intriguing universal properties such as discrete scale invariance. Motivated by recent experimental studies of the ground and excited helium trimers, this work analyzes the three-body parameter and the structural properties of three helium atoms as the s-wave scattering length is tuned artificially. Connections with theoretical and experimental studies of the Efimov scenario as it pertains to cold atom systems are made.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0996-6
• ##### Article: Momentum-Space Calculation of 4He Triatomic System with Realistic Potential
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ABSTRACT: The system of three ${}^4\mathrm{He}$ atoms with realistic interactions is studied in the momentum-space framework. It is demonstrated that short and long-range difficulties encountered in the coordinate-space calculations can be reliably resolved in the momentum-space calculations. Well-converged and accurate results are obtained for the ground and excited trimer energies, atom-dimer scattering length, phase shifts, inelasticity parameters, and elastic and breakup cross sections. A significant correction to previously published results is found for the elastic cross section at very low energy.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-1006-8
• ##### Article: Nuclear Matter Bulk Parameter Scales and Correlations
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ABSTRACT: We study the arising of correlations among some isovector bulk parameters in nonrelativistic and relativistic hadronic mean-field models. For the former, we investigate correlations in the nonrelativistic (NR) limit of relativistic point-coupling models. We provide analytical correlations, for the NR limit model, between the symmetry energy and its derivatives, namely, the symmetry energy slope, curvature, skewness and fourth order derivative, discussing the conditions in which they are linear ones. We also show that some correlations presented in the NR limit model are reproduced for relativistic models presenting cubic and quartic self-interactions in its scalar field. As a direct application of such linear correlations, we remark its association with possible crossing points in the density dependence of the linearly correlated bulk parameter.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0999-3
• ##### Article: Goldstone’s Theorem on a Light-Like Plane
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ABSTRACT: I review various aspects of chiral symmetry and its spontaneous breaking on null planes, including the interesting manner in which Goldstone’s theorem is realized and the constraints that chiral symmetry imposes on the null-plane Hamiltonians. Specializing to QCD with N massless flavors, I show that there is an interesting limit in which the chiral constraints on the null-plane Hamiltonians can be solved to give the spin-flavor algebra SU(2N), recovering a result originally found by Weinberg using different methods.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0995-7
• ##### Article: Entanglement Properties of the Two-Electron Quasi-One Dimensional Gaussian Quantum Dot
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ABSTRACT: We analyze the entanglement characteristics of the quasi one-dimensional quantum dot containing two Coulombically interacting electrons in an inverted Gaussian potential. The linear entropy of the lowest energy states is calculated in the whole range of the effective interaction strength g for different parameters of the longitudinal potential and the lateral radius of the quantum dot. We employ the configuration interaction method with complex-coordinate rotation, since the considered states become autoionizing resonances at the interaction strength above the critical value g th . We study the dependence of the linear entropy on the parameters of the quantum dot and discuss how the stability properties of the system are characterized by the entanglement between the electrons.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0992-x
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##### Article: Three-Body Continuum Wave Functions with a Box Boundary Condition
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ABSTRACT: In this work we investigate the connection between discretized three-body continuum wave functions, in particular via a box boundary condition, and the wave functions computed with the correct asymptotics. The three-body wave functions are in both cases obtained by means of the adiabatic expansion method. The information concerning all the possible incoming and outgoing channels, which appears naturally when the continuum is not discretized, seems to be lost when the discretization is implemented. In this work we show that both methods are fully equivalent, and the full information contained in the three-body wave function is actually preserved in the discrete spectrum. Therefore, in those cases when the asymptotic behaviour is not known analytically, i.e., when the Coulomb interaction is involved, the discretization technique can be safely used.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0988-6
• ##### Article: Elastic Scattering of Neutron Halo Projectiles
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ABSTRACT: Elastic scattering angular distributions of 6He on light, medium and heavy mass targets have been analysed using a simple diffractive model for the S-matrix. The results show that a very large diffuseness in the angular momentum space is necessary to reproduce the data in the case of scattering on heavy targets.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0987-7
• ##### Article: Using Analytical Solutions at Large Momentum Transfer to Obtain Zero-Energy, Bound-State, Bethe–Salpeter Solutions of a Scalar and Spin-1/2 Fermion Exchanging Photons
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ABSTRACT: The existence of families of leptons and quarks plus the properties of their mass and spin spectra suggest that leptons and quarks might be relativistic bound states of a scalar and a spin-1/2 fermion interacting via minimal electrodynamics. To begin exploring the properties of this bound-state system, the Bethe-Salpeter equation describing bound states of a minimally interacting scalar and spin-1/2 fermion with arbitrary masses is solved in the ladder approximation when the bound-state energy is zero. At large momentum transfer solutions are calculated analytically, yielding boundary conditions that are determined by the coupling constant. Zero-energy solutions, including the coupling constant that is calculated as an eigenvalue, are obtained by expanding the solution in terms of basis functions that obey the boundary conditions, discretizing the Bethe-Salpeter equation, and solving the resulting generalized matrix eigenvalue equation numerically. Since the coupling constant appears both in the Bethe-Salpeter equation as an eigenvalue and in the basis functions, the generalized matrix eigenvalue equation is nonlinear in the coupling constant and is solved iteratively. The spectrum of the coupling constant is discrete.
Few-Body Systems 05/2015; 56(4-5). DOI:10.1007/s00601-015-0975-y
• ##### Article: Three-Body Protonium Formation in a Collision Between a Slow Antiproton ({\bar{\rm p}}) and Muonic Hydrogen: {{\rm H}_{\mu}}—Low Energy {\bar{\rm p} + ({\rm p} \mu^-)_{1s} \rightarrow (\bar{\rm p} {\rm p})_{1s} + \mu^-} Reaction
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ABSTRACT: A bound state of a proton, p, and its counterpart antiproton, $${\bar{\rm p}}$$ , is a protonium atom $${Pn = (\bar{\rm p} {\rm p})}$$ . The following three-charge-particle reaction: $${\bar{\rm p} +({\rm p} \mu^-)_{1s} \rightarrow (\bar{\rm p} \rm{p})_{1s} + \mu^-}$$ is considered in this work, where $${\mu^-}$$ is a muon. At low-energies muonic reaction $${Pn}$$ can be formed in the short range state with α = 1s or in the first excited state: α = 2s/2p, where $${\bar{\rm p}}$$ and p are placed close enough to each other and the effect of the $${\bar{\rm p}}$$ -p nuclear interaction becomes significantly stronger. The cross sections and rates of the Pn formation reaction are computed in the framework of a few-body approach based on the two-coupled Faddeev-Hahn-type (FH-type) equations. Unlike the original three-body Faddeev method the FH-type equation approach is formulated in terms of only two but relevant components: $${{\it \Psi}_1}$$ and $${\it \Psi_2}$$ , of the system’s three-body wave function $${\it \Psi}$$ , where $${{\it \Psi}={\it \Psi}_1+{\it \Psi}_2}$$ . In order to solve the FH-type equations $${\it \Psi_1}$$ is expanded in terms of the input channel target eigenfunctions, i.e. in this work in terms of the $${(\rm{p} \mu^-)}$$ eigenfunctions. At the same time $${\it \Psi_2}$$ is expanded in terms of the output channel two-body wave function, that is in terms of the protonium $${(\bar{\rm{p}} \rm{p})}$$ eigenfunctions. A total angular momentum projection procedure is performed, which leads to an infinite set of one-dimensional coupled integral-differential equations for unknown expansion coefficients.
Few-Body Systems 05/2015; DOI:10.1007/s00601-015-0977-9
• ##### Article: Lattice QCD Studies of Transverse Momentum-Dependent Parton Distribution Functions
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ABSTRACT: Transverse momentum-dependent parton distributions (TMDs) relevant for semi-inclusive deep inelastic scattering and the Drell-Yan process can be defined in terms of matrix elements of a quark bilocal operator containing a staple-shaped gauge link. Such a definition opens the possibility of evaluating TMDs within lattice QCD. By parametrizing the aforementioned matrix elements in terms of invariant amplitudes, the problem can be cast in a Lorentz frame suited for the lattice calculation. Results for selected TMD observables are presented, including a particular focus on their dependence on a Collins-Soper-type evolution parameter, which quantifies proximity of the staple-shaped gauge links to the light cone.
Few-Body Systems 04/2015; DOI:10.1007/s00601-015-0976-x
• ##### Article: Multicomponent Strongly Interacting Few-Fermion Systems in One Dimension
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ABSTRACT: The paper examines a trapped one-dimensional system of multicomponent spinless fermions that interact with a zero-range two-body potential. We show that when the repulsion between particles is very large the system can be approached analytically. To illustrate this analytical approach we consider a simple system of three distinguishable particles, which can be addressed experimentally. For this system we show that for infinite repulsion the energy spectrum is sixfold degenerate. We also show that this degeneracy is partially lifted for finitely large repulsion for which we find and describe corresponding wave functions.
Few-Body Systems 04/2015; 55(8-10). DOI:10.1007/s00601-013-0776-0
• ##### Article: Limit Cycles from the Similarity Renormalization Group
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ABSTRACT: We investigate renormalization group limit cycles within the similarity renormalization group (SRG) and discuss their signatures in the evolved interaction. A quantitative method to detect limit cycles in the interaction and to extract their period is proposed. Several SRG generators are compared regarding their suitability for this purpose. As a test case, we consider the limit cycle of the inverse square potential.
Few-Body Systems 04/2015; DOI:10.1007/s00601-015-1001-0
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##### Article: Strongly Interacting Few-Fermion Systems in a Trap
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ABSTRACT: Few- and many-fermion systems on the verge of stability, and consisting of strongly interacting particles, appear in many areas of physics. The theoretical modeling of such systems is a very difficult problem. In this work we present a theoretical framework that is based on the rigged Hilbert space formulation. The few-body problem is solved by exact diagonalization using a basis in which bound, resonant, and non-resonant scattering states are included on an equal footing. Current experiments with ultracold atoms offer a fascinating opportunity to study universal properties of few-body systems with a high degree of control over parameters such as the external trap geometry, the number of particles, and even the interaction strength. In particular, particles can be allowed to tunnel out of the trap by applying a magnetic-field gradient that effectively lowers the potential barrier. The result is a tunable open quantum system that allows detailed studies of the tunneling mechanism. In this Contribution we introduce our method and present results for the decay rate of two distinguishable fermions in a one-dimensional trap as a function of the interaction strength. We also study the numerical convergence. Many of these results have been previously published (R. Lundmark, C. Forss\'en, and J. Rotureau, arXiv: 1412.7175). However, in this Contribution we present several technical and numerical details of our approach for the first time.
Few-Body Systems 04/2015; DOI:10.1007/s00601-015-0989-5
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##### Article: Adiabatic Hyperspherical Analysis of Realistic Nuclear Potentials
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ABSTRACT: Using the hyperspherical adiabatic method with the realistic nuclear potentials Argonne V14, Argonne V18, and Argonne V18 with the Urbana IX three-body potential, we calculate the adiabatic potentials and the triton bound state energies. We find that a discrete variable representation with the slow variable discretization method along the hyperradial degree of freedom results in energies consistent with the literature. However, using a Laguerre basis results in missing energy, even when extrapolated to an infinite number of basis functions and channels. We do not include the isospin $T=3/2$ contribution in our analysis.
Few-Body Systems 03/2015; DOI:10.1007/s00601-015-1012-x
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##### Article: Analytic Expression for Three-Body Recombination Rates into Deep Dimers
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ABSTRACT: We investigate three-body recombination rates into deep dimers in cold atomic gases with large scattering length within hyper-spherical adiabatic zero-range approach. We derive closed analytic expressions for the rates for one- and two-species gases. Although the deep dimers are beyond the zero-range theory the latter can still describe the recombination into deep dimers by use of one additional short-range absorption parameter. The recombination rate, as function of the scattering length, retains the known universal behavior --- the fourth power trend with characteristic log-periodic peaks --- however increasing the short-range absorption broadens the peaks until they are eventually completely smeared out. Increasing the heavy-to-light mass ratio in a two-species system decreases the distance between the peaks and increases the overal scale of the recombination rate.
Few-Body Systems 03/2015; DOI:10.1007/s00601-015-1005-9
• ##### Article: Static and Restricted Rigid Rotor Configurations of Three Classical 12-6-Lennard-Jones Particles
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ABSTRACT: Motivated by the continuous search for stable geometric configurations of atom and molecule clusters, we analyse the planar evolution of two freely movable point particles around a third immovable one subject to the 12-6-Lennard-Jones potential. This tailors our discussion to systems with one very heavy particle that can be assumed to be permanently at rest in the moving reference frame for the whole ensemble. Relating to Lennard-Jones interactions, we allow all three point particles to take different parameters. This breaks the symmetry conditions that are usually imposed on such systems. Through a classical non-regularized Hamiltonian description of our restricted three particle system, we study the existence of genuine equilibria and rigid rotor solutions around a single axis of rotation. We prove, depending on the choice of the Lennard-Jones parameters, that for these genuine equilibria, collinear alignments and triangular configurations of any shape can occur. Moreover, for the discussed type of relative equilibria a complete classification is provided by proving the existence of rigid rotor configurations in the plane of rotation (collinear cis and trans as well as triangle shaped configurations) and out of the plane of rotation (triangle shaped and flag-like configurations). Furthermore, we show that there are no further rigid rotor solutions of the underlying equations of motion.
Few-Body Systems 03/2015; 56(2-3). DOI:10.1007/s00601-015-0958-z