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Spectrum of the doubly heavy tetraquarks is studied in a constituent quark model including one-pion exchange (OPE) potential. Central and tensor forces induced by OPE between two light quarks are considered. Our results show that I(JP)=0(1+) compact bound states are shifted up because of the repulsive central force between q¯q¯. This effect possibly leads to the small binding energy in Tcc. In addition, a I(JP)=1(1+) resonant state is reported with E=10641MeV,Γ=15MeV and E=10640 MeV,Γ=15 MeV, without and with including OPE potential, respectively. The repulsive central force and attractive tensor force almost cancel with each other and leave a small energy difference when OPE potential is included.

Spectrum of the doubly heavy tetraquarks, bbq¯q¯, is studied in a constituent quark model. Four-body problem is solved in a variational method where the real scaling technique is used to identify resonant states above the fall-apart decay thresholds. In addition to the two bound states that were reported in the previous study we have found several narrow resonant states above the BB⁎ and B⁎B⁎ thresholds. Their structures are studied and are interpreted by the quark dynamics. A narrow resonance with spin-parity JP=1+ is found to be a mixed state of a compact tetraquark and a B⁎B⁎ scattering state. This is driven by a strong color Coulombic attraction between the bb quarks. Negative-parity excited resonances with JP=0−, 1− and 2− form a triplet under the heavy-quark spin symmetry. It turns out that they share a similar structure to the λ-mode of a singly heavy baryon as a result of the strongly attractive correlation for the doubly heavy diquark.

Bound states of double-heavy tetraquarks are studied in a constituent quark model. Two bound states are found for isospin and spin-parity I(JP)=0(1+) in the bbu¯d¯ channel. One is deeply bound and compact made of colored diquarks, while the other is shallow and extended as a BB⁎ molecule. The former agrees well with lattice QCD results. A systematic decrease in the binding energy is seen by replacing one of the heavy quarks to a lighter one. Altogether we find ten bound states. It is shown for the first time that hadrons with totally different natures emerge from a single Hamiltonian.

In this paper, we develop an analytical stability criterion for a five-body symmetrical system, called the Caledonian Symmetric Five-Body Problem (CS5BP), which has two pairs of equal masses and a fifth mass located at the centre of mass. The CS5BP is a planar problem that is configured to utilise past–future symmetry and dynamical symmetry. The introduction of symmetries greatly reduces the dimensions of the five-body problem. Sundman's inequality is applied to derive boundary surfaces to the allowed real motion of the system. This enables the derivation of a stability criterion valid for all time for the hierarchical stability of the CS5BP. We show that the hierarchical stability depends solely on the Szebehely constant C 0 which is a dimensionless function involving the total energy and angular momentum. We then explore the effect on the stability of the whole system of varying the relative sizes of the masses. The CS5BP is hierarchically stable for C 0 > 0.065946 . This criterion can be applied in the investigation of the stability of quintuple hierarchical stellar systems and symmetrical planetary systems. [ABSTRACT FROM AUTHOR]

Spectrum of the doubly heavy tetraquarks is studied in a constituent quark model including one-pion exchange (OPE) potential. Central and tensor forces induced by OPE between two light quarks are considered. Our results show that I (J P) = 0 (1 +) compact bound states are shifted up because of the repulsive central force between q ¯ q ¯. This effect possibly leads to the small binding energy in T c c. In addition, a I (J P) = 1 (1 +) resonant state is reported with E = 10641 MeV , Γ = 15 MeV and E = 10640 MeV , Γ = 15 MeV , without and with including OPE potential, respectively. The repulsive central force and attractive tensor force almost cancel with each other and leave a small energy difference when OPE potential is included. [ABSTRACT FROM AUTHOR]

We have measured differential yields for double capture and double capture accompanied by ionization in 75 keV p + Ar collisions. Data were taken for two different transverse projectile coherence lengths. A small effect of the projectile coherence properties on the yields were found for double capture, but not for double capture plus ionization. The results suggest that multiple projectile–target interactions can lead to a significant weakening of projectile coherence effects.

We present a drag force model for evolving chaotic few-body interactions with the inclusion of orbital energy losses, such as tidal dissipation and gravitational wave (GW) emission. The main effect from such losses is the formation of two-body captures that for compact objects result in GW mergers and for stars lead to either compact binaries, mergers, or disruptions. Studying the inclusion of energy loss terms in few-body interactions is therefore likely to be important for modelling and understanding the variety of transients that soon will be observed by current and upcoming surveys. However, including especially tides in few-body codes has been shown to be technically difficult and computationally heavy, which has led to very few systematic tidal studies. In this paper we derive a drag force term that can be used to model the effects from tidal, as well as other energy losses in few-body interactions, if the two-body orbit averaged energy loss is known a priori. This drag force model is very fast to evolve and gives results in agreement with other approaches, including the impulsive and affine tide approximations. [ABSTRACT FROM AUTHOR]

We review recent progress in S=−2 hypernuclei such as double-Λ hypernuclei and Ξ hypernuclei, which are composed of a nucleus and one or two hyperons, such as a Λ or a Ξ particle. Through observations of He, such as the Nagara event, we obtain important information about the ΛΛ interaction. Using this information, we perform a four-body calculation of ααΛΛ for Be, which was observed at KEK as the Demachi–Yanagi event. We interpret this event as the excited state. We calculate energy levels of Be within the framework of an ααnΛΛ five-body cluster model, and then interpret the Hida event, which was observed at KEK as the ground state of Be. Motivated by observation of the Kiso event of C, by using the Skyrme–Hartree–Fock and relativistic mean-field frameworks, we calculate the energy spectra of this hypernucleus. We interpret this event as the 14N(g.s.)+Ξ−(0p) state. Finally, we propose an experiment on H and Li to extract information about the spin- and isospin-averaged parts of the ΞN interaction. [ABSTRACT FROM AUTHOR]

We present a half-life formalism for describing the disruption of gravitationally bound few-body systems, with a focus on binary–binary scattering. For negative total encounter energies, the four-body problem has three possible decay products in the point-particle limit. For each decay product and a given set of initial conditions, we obtain directly from numerical scattering simulations the half-life for the distribution of disruption times. As in radioactive decay, the half-lives should provide a direct prediction for the relative fractions of each decay product. We test this prediction with simulated data and find good agreement with our hypothesis. We briefly discuss applications of this feature of the gravitational four-body problem to populations of black holes in globular clusters. This paper, the second in the series, builds on extending the remarkable similarity between gravitational chaos at the macroscopic scale and radioactive decay at the microscopic scale to larger-N systems. [ABSTRACT FROM AUTHOR]

These notes are a short summary of a set of lectures givenwithin the frame of the "Critical Stability of Quantum Few-Body Systems" International School held in theMax Planck Institute for the Physics of Complex Systems (Dresden). The main goal of the lectures has been to provide the basic ingredients for the description of few-body systems in coordinate space. The hyperspherical harmonic and the adiabatic expansion methods are introduced in detail, and subsequently used to describe bound and continuum states. The expressions for the cross sections and reaction rates for three-body processes are derived. The case of resonant scattering and the complex scaling method as a tool to obtain the resonance energy and width is also introduced. [ABSTRACT FROM AUTHOR]

We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calculate the time evolution of the system and show that, for a certain ratio of interactions, the minority population travels through the system as an effective wave packet. [ABSTRACT FROM AUTHOR]

This article is based on the notes (arxiv:1710.11228) written for a set of three lectures given in a school at the Max Planck Institute for the Physics of Complex Systems in October/2017 before the workshop "Critical Stability of Quantum Few-Body Systems". The last part of the article includes the specific topic presented in the workshop related to the dimensional effects in three-body systems. These notes are primarily dedicated to the students and are only a tentative to show a technique, among many others, to solve problems in a very rich area of the contemporary physics--the Few-Body Physics. [ABSTRACT FROM AUTHOR]

For the Abner Shimony (AS) inequalities, the simplest unified forms of directions attaining the maximum quantum violation are investigated. Based on these directions, a family of Einstein-Podolsky-Rosen (EPR) steering inequalities is derived from the AS inequalities in a systematic manner. For these inequalities, the local hidden state (LHS) bounds are strictly less than the local hidden variable (LHV) bounds. This means that the EPR steering is a form of quantum nonlocality strictly weaker than Bell nonlocality. [ABSTRACT FROM AUTHOR]

The reconstruction of the state of a multipartite quantum mechanical system represents a fundamental task in quantum information science. At its most basic, it concerns a state of a bipartite quantum system whose subsystems are subjected to local operations. We compare two different methods for obtaining the original state from the state resulting from the action of these operations. The first method involves quantum operations called Petz recovery maps, acting locally on the two subsystems. The second method is called matrix (or state) reconstruction and involves local, linear maps that are not necessarily completely positive. Moreover, we compare the quantities on which the maps employed in the two methods depend. We show that any state that admits Petz recovery also admits state reconstruction. However, the latter is successful for a strictly larger set of states. We also compare these methods in the context of a finite spin chain. Here, the state of a finite spin chain is reconstructed from the reduced states of a few neighbouring spins. In this setting, state reconstruction is the same as the matrix product operator reconstruction proposed by Baumgratz et al. [Phys. Rev. Lett. 111, 020401 (2013)]. Finally, we generalize both these methods so that they employ long-range measurements instead of relying solely on short-range correlations embodied in such local reduced states. Long-range measurements enable the reconstruction of states which cannot be reconstructed from measurements of local few-body observables alone and hereby we improve existing methods for quantum state tomography of quantum many-body systems. [ABSTRACT FROM AUTHOR]

We re-formulate a classical numerical method for the solution of systems of linear equations to tackle problems with latent data, that is, linear systems of dimension that is a priori unknown. This type of systems appears in the solution of few-body Coulomb problems for Atomic Simulation Physics, in the form of multidimensional partial differential equations (PDEs) that require the numerical solution of a sequence of recurrent dense linear systems of growing scale. The large dimension of these systems, with up to several hundred thousands of unknowns, is tackled in our approach via a task-parallel implementation of a solver based on the QR factorization. This method is parallelized using the OmpSs framework, showing fair strong and weak scalability on a multicore processor equipped with 12 Intel cores. [ABSTRACT FROM AUTHOR]

Para- and ortho-Ps atoms are formed in the photodetachment of positronium negative ion. Since the lifetime against the pair annihilation is much shorter for para-Ps( ns) than for ortho-Ps( ns), the production ratio of para- and ortho-Ps atoms is important for the photodetachment experiments. We have derived the ratio explicitly. [ABSTRACT FROM AUTHOR]

The photoproduction of π0-mesons from the nucleon and deuteron has been studied for incidents of photon energies up to 1.5 GeV. By using the MAID-2007 model for the process on the nucleon, we predict results for the unpolarized and helicity-dependent total cross sections of the semi-exclusive reaction γd→π 0X (X=np+d) with the inclusion of rescattering effects. We find that rescattering effects yield a substantially large contribution. The extracted results are compared with the available experimental data and a satisfactory agreement is obtained. In addition, the contribution of γd→π0X (X=np+d) to the finite GDH integral has been evaluated by explicit integration up to 1.5 GeV and a total value of 256.96 μb has been obtained. Convergence of the GDH integral has been reached. [ABSTRACT FROM AUTHOR]

The Efimov scenario is a universal three-body effect addressing many areas of modern quantum physics. It plays an important role in the transition between few- and many-body physics and has enabled important breakthroughs in the understanding of the universal few-body theory. We review the basic concepts of the Efimov scenario with specific emphasis on the similarities and differences between homonuclear and heteronuclear systems. In the latter scenario, the existence of a second, independently tunable interaction parameter enables novel few-body phenomena that are universal and have no counterexamples in the homonuclear case. We discuss recent experimental approaches using ultracold atomic gases with magnetically tunable interactions and elucidate the role of short-range interactions in the emergence of universal and non-universal behavior. [ABSTRACT FROM AUTHOR]

The light double hypernuclei, and , are studied as three-body and cluster systems in halo/cluster effective field theory at leading order. We find that the system in spin-0 channel does not exhibit a limit cycle whereas the system in spin-1 channel and the system in spin-0 channel do. The limit cycle is associated with the formation of bound states, known as Efimov states, in the unitary limit. For the system in the spin-0 channel we estimate the scattering length for -wave hyperon-hypertriton scattering as fm. We also discuss that studying the cutoff dependences in the and systems, the bound state of is not an Efimov state but formed due to a high energy mechanism whereas that of may be regarded as an Efimov state. [ABSTRACT FROM AUTHOR]

We present a quantum reaction approach that unambiguously quantifies the complete and incomplete fusion of weakly-bound few-body nuclei. Calculations carried out within a simple model for $${\text{}^{6}}$$ Li + $${\text{}^{209}}$$ Bi at energies near the Coulomb barrier show that converged probabilities for the total, complete and incomplete fusion as well as for the scattering process can be obtained with the time-dependent wave-packet dynamics. [ABSTRACT FROM AUTHOR]

We have investigated in this paper the few-body bound systems in a simple semi-relativistic scheme. For this aim, we introduced a spin independent relativistic description for a few-identical body system by presenting the analytical solution of few-particle Klein-Gordon equation. Performing calculations in D-dimensional configuration on the basis of the hypercentral approach, we reduced the few-body Klein-Gordon equation to a Schrödinger-like form. This equation is solved by using the Nikiforov-Uvarov method, through which the energy equations and eigenfunctions for a few-body bound system are obtained. We used the spin- and isospin-independent generalized Yukawa potential in our calculations, and the dependence of the few-body binding energies on the potential parameters has been investigated. [ABSTRACT FROM AUTHOR]

We develop the single-channel local potential for the K¯N system, which is applicable to quantitative studies of K¯ bound states in nuclei. Because the high-precision measurement of the kaonic hydrogen by SIDDHARTA reduces the uncertainty of the K¯N amplitude below the K¯N threshold, the local potential should be calibrated in a wide energy region. We establish a new method to construct the local potential focusing on the behavior of the scattering amplitude in the complex energy plane. Applying this method, we construct the K¯N potential based on the chiral coupled-channel approach with the SIDDHARTA constraint. The wave function from the new potential indicates the K¯N molecular structure of Λ(1405). [ABSTRACT FROM AUTHOR]

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 = 1 s or in the first excited state: α = 2 s/2 p, 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. [ABSTRACT FROM AUTHOR]

Results obtained by the authors in recent works on the exploration of universality in systems living inside the Efimov window are critically analyzed. We discuss how to take into account finite-range corrections by introducing a finite-range parameter necessary to make comparisons to the universal predictions of the Efimov zero-range theory. Firstly we apply our analysis to two different calculations published by other authors. The first one has been used with success to describe ultracold Cs atoms close to a Feshbach resonance and the second one describes a four He atom system with a realistic interaction. Finally we use the finite-range parameter to analyze recombination data in experiments with ultracold Li atoms. The three selected cases support the introduction of the finite-range parameter as a valuable tool to extend the use of the zero-range theory to describe systems having finite-range interactions. [ABSTRACT FROM AUTHOR]

We extend the continuum discretized coupled channel method (CDCC) to a microscopic version, where the projectile is described by a microscopic cluster model. This generalization (MCDCC) only relies on nucleon-target interactions, and therefore presents an important predictive power. We briefly present an outline of the model, and provide recent examples with Li and B elastic scattering on different light and heavy targets. We show that the model can be applied to high energies, as well as to low energies. [ABSTRACT FROM AUTHOR]

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 with two identical bosons and a third particle decreases the distance between the peaks and increases the overall scale of the recombination rate. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, we review our main results involving the single particle momentum distribution of bosonic trimer states in two and three dimensions. A summary table makes easier the comparison between the matrix elements and the different terms of the momentum distributions. We also show a practical method to continuously interpolate between different dimensions. [ABSTRACT FROM AUTHOR]

We study the quenched dynamics of the momentum distribution of a unitary Bose gas under isotropic harmonic confinement within a time-dependent density functional approach based on our recently calculated Monte Carlo bulk equation of state. In our calculations the inter-atomic s-wave scattering length of the trapped bosons is suddenly increased to a very large value and the real-time evolution of the system is studied. Prompted by the very recent experimental data of Rb atoms at unitarity (Makotyn et al. in Nat Phys 10:116, ) we focus on the momentum distribution as a function of time. Our results suggest that at low momenta, a quasi-stationary momentum distribution is reached after a long transient, contrary to what found experimentally for large momenta which equilibrate on a time scale shorter than the one for three body losses. [ABSTRACT FROM AUTHOR]

We present a detailed analysis of the charged four-body system in hyperspherical coordinates in the large hyperradial limit. In powers of R for any masses and charges, the adiabatic Hamiltonian is expanded to third order in the dimer-dimer limit and to first order in the particle-trimer limit. [ABSTRACT FROM AUTHOR]

A formalism based on the complex-scaling method is used to solve a four-nucleon scattering problem above the breakup threshold using the realistic nuclear Hamiltonians. This method allows to solve diverse scattering problems based on very trivial boundary conditions and is compatible with the techniques used to solve bound state problems. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]