The helium dimer is extremely weakly bound. Specifically, two bosonic helium-4 atoms support a single bound state with binding energy of approximately 1.5mK; no rotationally excited states are supported. The mixed isotope dimer (one helium-4 atom and one helium-3 atom), in contrast, does not support a bound state at all. In the trimer sector, three helium-4 atoms support two bound states. The...
With the experimental realization of strongly confined atomic and molecular systems using, for example, optical lattices or tweezers the modification of the few-body physics due to tight confinement is of increasing importance, since the interaction and confinement lengths
can become comparable in these systems. The physics may fundamentally change, if the confinement leads to effectively...
I present results from experiments exploring two types of scattering resonances in the collision of ultracold clouds of atoms — shape resonances$^1$ and Feshbach resonances$^{2,3}$. Using a laser-based accelerator that capitalizes on the energy resolution provided by the ultracold atomic setting, we unveil these resonance phenomena in their quintessential form by literarily photographing the...
One of important subject in hypernuclear physics is to obtain information on Baryon-Baryon interaction. Especially, it is hot topic to obtain information on $\Xi N$ interaction and predict energy spectra of light $\Xi$ hypernuclei theoretically. In this conference, I report the recent progress of $\Xi$ hypernuclei and $\Xi N$ interaction theoretically and experimentally.
Laser spectroscopy of muonic atoms, hydrogen-like atoms formed by a negative muon and a nucleus, has recently provided the charge radii of the lightest nuclei (proton, deuteron, 3He and 4He) with unprecedented accuracy. In this talk we present laser spectroscopy of these exotic atoms and their contribution to nuclear physics. Emphasis will be given to the new results in 3He.
Moreover we...
Nucleons (protons and neutrons) are the building blocks of atomic nuclei and are responsible for more than 99% of the visible matter in the universe. Despite decades of efforts in studying the structure of the proton, the proton remains fascinating and even puzzling. Low-energy experiments play an important role in elucidating the structure of the nucleon and advance our understanding of the...
The size of the proton as measured with electromagnetic probes has been heavily debated in the last decade or so. Here I discuss the dispersion-theoretical framework which is based on elementary principles of quantum field theory like analyticity and unitarity.
It allows to analyse electron-proton scattering data for all values of the momentum transfer, including also the time-like region.
I...
Thermonuclear reactions involving charged particles play a central role in stellar evolution. Knowledge of their rates is needed to answer fundamental questions about the origin of the elements. While direct measurement approaches are a powerful tool to study nuclear cross-section, the hindering effect of the Coulomb barrier makes measurement at energies of stellar interest extremely...
The dynamics of the three-nucleon system can be very extensively tested by means of the deuteron-proton breakup reaction. Experimental studies of the $dp$ system expose various dynamical ingredients, like three-nucleon force (3NF) and Coulomb force, which play an important role in correct description of observables (e.g. cross section). The cross sections as well as polarized observables (e.g....
In this talk, we present a summary of our recent research results on describing systems near the unitary limit using simple potentials, specifically Gaussian potentials[1-5].
In the parameter region where the energy of either the two-particle bound state or the virtual state is small, the physics can be effectively described by the scattering length and the effective range alone. Different...
We present a theoretical study of the $^{6}$Li + p $\to$ $^{3}$He + $\alpha$ direct transfer reaction at collision energies from few keV to around the Coulomb barrier ($\sim$ 1.5 MeV in the center of mass). This lithium-depleting process is of interest from the astrophysical point of view [1.
The dynamics of quantum few- and many-body systems is often modeled with local interaction models, mainly due to simplicity, though more microscopic or fundamental approaches yield nonlocal interactions. For few-cluster nuclear reactions the interactions usually are given in the local form of real binding and complex optical potentials. We made a two-fold extension of that standard dynamics by...
We study a heavy–heavy–light three-body system confined to one or two space dimensions. Both the binding energies and corresponding wave functions are obtained for (i) no heavy-heavy interaction and (ii) a finite-range heavy-light interaction potential. We demonstrate that when the two-body ground-state energy approaches zero, the three-body bound states display a universal behavior,...
Combining the hyperspherical harmonics (HH) method with the Rayleigh-Ritz or Kohn variational principle leads to one of the most accurate techniques to study microscopically both bound and scattering states for nuclear systems with a number of nucleons A ≤ 4 [1]. However, describing systems with A ≥ 4 remains a computational challenge. One reason for that is the rapid growth of the number of...
Radiative capture reactions with light neutron-rich nuclei are known to be important constituents at sites of explosive nucleosynthesis while producing seed nuclei for the $r$-process. One such important reaction is the $^{11}$B(n,$\gamma$)$^{12}$B radiative neutron capture reaction, where the total reaction rate has significant contributions from the resonant (narrow-resonances) as well as...
We present an analysis of systems of up to 5 particles which are characterized by a subset of resonantly interacting pairs. The focus is on the renormalization-group (RG) behaviour of the 3-, 4-, and 5-body, equal-mass ground states. The RG/scaling behaviour is studied as a function of the various possibilities to bind the respective systems with resonant pair interactions.
Based on numerical...
We report investigations on dynamical vortex production and quantum turbulence emerging in periodic perturbed Bose-Einstein condensates, considering binary coupled mass-imbalanced systems, submitted to a stirring time-dependent perturbation. We also present some preliminary results on the case of dipolar single-atom systems under time-dependent periodic Gaussian perturbations.
Studies of few-nucleon systems form the basis for understanding nuclear interactions and properties of nuclei. The very accurate theoretical calculations for three nucleon systems should be confronted with a rich set of presice experimental data.
For this purpose, the BINA (Big Instrument for Nuclear-polarization Analysis) detection system has been installed at CCB (Cyclotron Center...
We investigated the radiative proton capture on nitrogen isotopes $^{12}$N, $^{13}$N, and $^{14}$N [1 - 4] in the framework of the MPCM and obtained the reaction rates and their parametrizations. There are two stable nitrogen isotopes $^{14}$N and $^{15}$N, and among short-lived nitrogen isotopes, the longest-lived are $^{12}$N ($t_{1/2} = 11$ ms) and $^{13}$N ($t_{1/2} = 9.965$ min).
We...
In this talk, I discuss discrete scale invariance in one-dimensional many-body problems of identical particles. I first classify all possible scale-invariant two-body contact interactions that respect unitarity, Galilean invariance, permutation invariance, and translation invariance in one dimension. By using these contact interactions, I then construct models of $n(\geq3)$ identical particles...
An experiment to investigate the $^{1}$H$(d,pp)n$ breakup reaction using a deuteron beam of 300, 340, 380 and 400 MeV (150, 170, 190, 200 MeV/nucleon) and the WASA (Wide Angle Shower Apparatus) detector, has been performed at the Cooler Synchrotron COSY-Juelich. Due to almost $4\pi$ acceptance and moderate detection threshold of the WASA system, differential cross section data have been...
A trion is the bound state of an exciton with another charged carrier, which can either be an electron (X⁻ trion) or a hole (X⁺ trion). We develop the theoretical formalism and study the formation of valleytrions in transition metal dichalcogenides monolayers within the framework of a nonrelativistic potential model using the method of hyperspherical harmonics (HH) in four-dimensional space....
I will discuss a new method to compute light-front wave functions and parton distributions using contour deformations. After solving the two-body Bethe-Salpeter equation of a scalar theory, the projection onto the light front is done through a combination of contour deformations and analytic continuation methods. The resulting light-front wave functions and distribution amplitudes are in...
In the last decade, advances in ab-initio atomic structure calculations enabled the determination of the nuclear charge radius purely from laser spectroscopy measurements and related QED calculations. Especially laser spectroscopy of muonic systems achieved remarkable results in μH [1], μD [2] and μHe [3] which led to the famous proton radius puzzle and questioned the lepton universality...
We discuss a systematic method for constructing many-body electromagnetic current operators that are needed to ensure covariance and current conservation in phenomenological relativistic Hamiltonian models of
strongly interacting systems. The construction represents a general Hamiltonian in the Weyl representation. Momentum operators in this representation are replaced by gauge covariant...
The nuclear magnetic dipole moment is one of the major probes to investigate the structure of an atomic nucleus. For odd-mass systems, the simplest limit is to consider only the last unpaired nucleon, known as the single-particle or Schmidt limit. The dominance of the single-particle structure relates to the robustness of a magic number in a nucleus, and therefore the magnetic dipole moment...
We present an extended version of chiral perturbation theory that incorporates vector mesons in addition to pions and nucleons. This extension establishes a consistent framework by treating the mass of vector mesons as heavy and their associated momentum as light, thereby defining a well-defined power counting rule.
In our proposed theory, contrary to the typical vector-meson dominance...
Considering QCD in the limit of the number of colors $N_c$ being large provides important constraints on the nucleon-nucleon interactions. These constraints are particularly valuable for cases for which available data is limited (if it exists at all), such as for interactions that violate symmetries, e.g., parity and time reversal invariance, and operators contributing to neutrinoless double...
In many phenomena of atomic nuclei, the $\alpha$-particle (the ${}^4$He nucleus) can be considered as effective degrees of freedom. In this contribution, recent works on structures of low-energy excited (resonance) states in ${}^{12}$C nucleus in terms of $3\alpha$ model will be presented.
Continuum $3\alpha$ wave functions for angular momentum and parity states: $0^+$, $1^-$, $2^+$, and...
The constituent quark models successfully explain the features of the single hadrons. The hadron interactions are also well-reproduced. For example, the channel dependence of the short-range part of two-baryon interaction corresponds to those given by the Lattice QCD.
In this work, we investigate the exotic hadrons, ($q \bar q$)-($q \bar q$). The spin-dependent term of the one-gluon...
We have investigated both algebraic models and geometric cluster models of alpha clusters in 12C, focusing on the structure of ground state, the first excited 0+ state and the second excited 2+ state in particular
with the purpoese a establishing if the rotational bands are compatible with rigid structures or rather if they are quantum mixture of different configurations.
In a first series...
The ongoing progress in derivation the chiral two- and many-nucleon forces in the framework of chiral perturbation theory (χPT) [1,2] gives better and better understanding of nuclear phenomena, but also brings many challenges for application of these forces beyond the two-nucleon (2N) system. While general operator form of three nucleon force (3NF) is currently known up to N4LO [3-6], its...
Baryon interactions, including nuclear force, are an essential component in nuclear physics especially in studies of few-body systems. There are already some useful phenomenological nuclear forces, thanks to a lot of experimental data. While, we suffer from uncertainty in hyperon interactions due to a lack of experimental data. In such case, it is very useful if we could derive baryon...
The elastic $\alpha$-$^{12}$C scattering at low energies for $l=0,1,2,3,4,5,6$ is studied in effective field theory. We discuss the construction of the $S$ matrices of elastic $\alpha$-$^{12}$C scattering in terms of the amplitudes of sub-threshold bound and resonant states of $^{16}$O, which are calculated from the effective Lagrangian. The parameters appearing in the $S$ matrices are fitted...
Recent breakthroughs in quantum many-body methods, computing, and emulators enabled us to statistically investigate nuclear systems and nuclear interactions. We employed a history matching approach to explore the low-energy constants (LECs) domain in delta-full chiral effective field theory. Different constraints such as scattering phase shift and few-body observables are iteratively...
We solve the Faddeev bound-state equations for three particles with simple two-body nonlocal, separable po- tentials that yield a scattering length twice as large as a positive effective range, as indicated by some lattice QCD simulations. Neglecting shape parameters, the two-body bound state is a double pole. For bosons we obtain a cor- relation between three- and two-body energies. For...
In this paper, we investigated the behavior of non-relativistic particles of two-body system by considering the Dunkl operator and reached two second-order differential equations about even and odd parities. We expressed the even cases and obtained the wave function in terms of the generalized Laguerre polynomials and normed constant. Also, we solved the odd term of Hamiltonian with the QES...
Starting from a complete set of relativistic nucleon-nucleon contact operators preserving parity and time reversal up to order $O(p^4)$ of the expansion in soft momenta $p$, we show that non-relativistic expansions of relativistic operators involve twenty-six independent combinations, two starting at $O(p^0)$, seven at order $O(p^2)$ and seventeen at order $O(p^4)$. This demonstrates the...
We propose a systematic approach to study the nucleon-nucleon interaction by applying time-ordered perturbation theory (TOPT) to covariant chiral effective field theory. Diagrammatic rules of TOPT, for the first time, are worked out for particles with non-zero spin and interactions involving time derivatives. They can be applied to derive chiral potentials at any chiral order. The effective...
Electroweak properties of light nuclei not only shed light on the rich interplay between the electroweak and strong nuclear interactions but also help us provide constraints on astrophysical phenomena such as stellar/big-bang nucleosynthesis and on tests of fundamental symmetries. In this talk, I discuss recent progress in progress in chiral-effective-field-theory studies of electroweak...
The importance of the Higgs boson in the evolution of the Universe is well known. Yet, only a tiny fraction of the mass of the visible universe can be attributed to the Higgs mechanism alone. In fact, the overwhelming majority arises from the strong interactions of quantum chromodynamics, through a mechanism nowadays dubbed Emergent Hadronic Mass (EHM). Thus, weak and strong mass generation...
A fundamental aspect in low-energy nuclear physics is the interaction and correlation of neutrons at extreme conditions of very large neutron-to-proton asymmetry and low-density environment. Multi-neutron systems provide an exclusive way to address such correlations. Their high impact potential has led to many experimental searches for such isolated systems over the last decades.
In this talk...
Exploring and understanding the structure of the most neutron-rich nuclei is a primary goal of present day nuclear physics: this activity is due to advent of the RIBF and are driven by interest to understand better the interaction between the neutrons and the dynamics of neutron-proton unbalanced unstable nuclei.
In this presentation I will present an overview of our recent studies on...
In 2002, when the quest for multineutrons had been running for 40 years without success and was already fading, a first positive signal consistent with a tetraneutron was observed at GANIL. We will go back to the motivations and anecdotes around that experiment, review the impact of this first result on the theoretical and experimental communities but also on the general public, and discuss...
In this contribution, we present some recent studies of the excited states of 4He nucleus, performed by accurately solving the four body scattering problem in the framework of the ab-initio hyperspherical harmonic method. The considered nuclear Hamiltonians include modern two- and three-nucleon interactions, derived using the chiral effective field theory approach.
First of all, we study...
Hypernuclear physics is a highly active field in the few-body sector, with significant astrophysical implications, such as in the description of neutron stars. However, hypernuclear systems are more difficult to be studied experimentally than standard nuclei, resulting in a shortage of data for model development and for the fit of realistic hypernuclear interactions. Past models have struggled...
I will present our results on the properties and non-equilibrium dynamics of few-body quantum systems based on ultracold polar molecules, Rydberg atoms, or their mixtures, and their applications as quantum simulators. On the one hand, we investigated interacting ultracold molecules in a one-dimensional harmonic trap as a fundamental building block of molecular quantum simulators, where we...
Neutrino oscillation experiments require good understanding of neutrino-nucleus interactions in the range of medium-mass nuclei, especially 40Ar and 16O relevant for DUNE and HyperK. Recently, we have started a program of calculating cross sections in the range of the quasi-elastic peak within the coupled cluster method combined with Lorentz integral transform.
In the first step we...
Ultracold quantum gases provide a pristine platform to study few-body and many-body quantum phenomena with an exquisite degree of control. The achievement of quantum degeneracy in gases of atoms with large magnetic dipole moments in their electronic ground states has opened new avenues of research in which anisotropic and long-range interactions play a crucial role. In my talk I will present...
Due to the scarcity of hyperon-nucleon (YN) and the almost lack of hyperon-hyperon (YY) scattering data, hypernuclei with strangeness $S=-1,-2$ are indispensable laboratories to explore the underlying baryon-baryon (BB) interactions. In this work we study s- and light p-shell hypernuclei from a microscopic level employing the ab initio Jacobi no-core shell model (J-NCSM) in combination with BB...
Isospin correlations in isotopic yields of fragments produced in peripheral asymmetric reaction systems $^{80}$Kr + $^{40,48}$Ca at 35 MeV/nucleon performed recently by FAZIA collaboration [1], have been studied in the framework of a statistical ensemble approach. Isotopic yields of light and intermediate mass fragments, emitted from the quasiprojectile (QP) sources, are compared both with...
The system consisting of positronium ($\rm Ps$) and antihydrogen ($\bar{\rm H}$) atoms is known to exist in only one bound state of the positronium hydride (${\bar{\rm H}\rm Ps}$) which is a hybrid atomcule that possesses both atomic and molecular properties. $\bar{\rm H}\rm Ps$ cannot be formed in purely 2-body $\bar{\rm H} + \rm Ps$ collisions, but it can be obtained when $\rm Ps$ collides...
The energy levels of light hypernuclei are experimentally accessible observables that contain valuable information about the poorly known interaction between hyperons and nucleons. In this contribution, I will report on our recent efforts to establish a reliable link between the low-energy properties of hypernuclei and the underlying hyperon-nucleon interactions.
In the first step, we...
We study how short range correlations emerge from the nuclear wave-function.
To this end we analyze the asymptotic behaviour of the coupled cluster
many-body wave-function in the limit of highly excited two- and three-particles states.
We find that in this limit the different coupled cluster amplitudes
exhibit a recurring behaviour, factorizing into a common asymptotic two- or...
The Second Flavor of Hydrogen Atoms (SFHA) has been discovered theoretically and proven experimentally to exist for the 1st time – by analyzing atomic experiments related to the distribution of the linear momentum in the ground state of hydrogen atoms (J. Phys. B: At. Mol. Opt. Phys. 34 (2001), 2235). It was motivated by the huge discrepancy: the ratio of the experimental and previous...
The attractive nature of $\bar{K}N$ interaction has stimulated theoretical and experimental searches for $K^-$ bound states in different systems. In particular, many theoretical calculations devoted to the lightest possible system $\bar{K}NN$ were performed using different methods. All of them agree that a quasi-bound state in the $K^- pp$ system exists, but they yield quite diverse binding...
Understanding the dynamics of hadrons with different quark content is crucial to solve fundamental aspects of QCD as well as for the implications on the structure of dense stellar objects, such as neutron stars. The scarce statistics and lack of data in reactions for unstable hadrons, containing in particular strange and charm quarks, affect the accuracy of the current theoretical description...
In the no-core shell model, the Jacobi coordinates are often used to describe few-body systems [1]. These coordinates are convenient as they allow the explicit removal of a center of mass coordinate satisfying the requirement of translational invariance within the model space. For the description of the nucleus, the intrinsic coordinates are more natural, as it is independent of the external...
Tritium bearing hydrogen molecules are of a significant scientific interest, see Ref. [1] and, for instance, Tritium Laboratory Karlsruhe (TLK) reports at Karlsruhe Institute of Technology (Germany). In this work a quantum-mechanical close-coupling calculation is performed for elastic and inelastic 4-atomic collisions:
$ {\rm HT}(j_1)+{\rm HT}(j_2) \rightarrow {\rm HT}(j^{\prime}_1)+{\rm...
Discrete scale symmetry exhibited by few-particle systems for resonant s-wave interactions is affected by squeezing or by reducing the embedding dimension. The Efimov geometrical separation ratio between the AAB bosonic bound states energies increases as the system is squeezed until the geometrical spectrum disappears for a critical non-integer dimension. This is found either by solving the ...
In this presentation, a new measurement of the monopole transition form factor of the ground state to the first exited state of the alpha-particle will be presented [1]. The precision of the measurement exceeds significant the precision of existing data sets and allows for the determination of two coefficients in a low energy expansion.
The result are confronted with state-of-the art...
The optical potential is a well-known and successful framework to describe nucleon-nucleus scattering processes. Within this approach it is possible to compute the scattering observables for elastic processes across wide regions of the nuclear landscape and extend its usage to inelastic processes and other types of reactions such as nucleon transfer, capture or breakup. A phenomenological...
We applied a many-configurational microscopic cluster model to study the nature of high-energy resonance states in $^{9}$Be and $^{9}$B near $^{7}$Li$+d$ and $^{7}$Be$+d$ decay thresholds and to reveal the influence of the states on the astrophysical $S$-factors of the reactions $^{7}$Li$\left( d,n\right)\alpha\alpha$ and $^{7}$Be$\left( d,p\right) \alpha\alpha$ related to the cosmological...
The High Intensity Gamma-Ray Source (HIGS) at Duke University delivers monoenergetic photon beams with high linear or circular polarization by backscattering of free-electron laser (FEL) photons [1]. To exploit the unique capabilities of this facility, we are conducting an ambitious program of Compton scattering studies on light nuclei aimed at determining the nucleon electromagnetic...
In the framework of the effective mass approximation and assuming a logarithmic interaction between constituent charged particles, compact and locally accurate wave functions that describe bound states of the two-particle neutral and three-particle charged complexes in two dimensions are designed. Prime examples of these complexes are excitons and trions that appear in monolayers of...
The three-nucleon force (3NF) is essentially important to clarify various nuclear phenomena, such as the binding energy of light mass nuclei [1], the equation of state of nuclear matter [2] and few-nucleon scattering systems [3]. The isospin $T=3/2$ components of the 3NF also play an important role in many-nucleon systems especially for neutron-rich nuclei as well as neutron matter...
A gas of interacting particles is a paradigmatic example of chaotic systems. It is shown [1] that, even if all but one particle are fixed in generic positions, the excited states of the moving particle are chaotic. They are characterized by the number of principal components (NPC)—the number of integrable system eigenstates involved into the nonintegrable one, which increases linearly with the...
The p-p-p correlation function is defined as
$$C_{123} (Q) = \int \rho^5 d\rho\,d\Omega\, S_{123}|\Psi_s|^2$$ where $\rho,\Omega$ are the hyperspherical coordinates and $\hbar^2Q^2/M$ is the total energy of the system. The source is represented by a gaussian hypercentral profile $$S_{123}=\frac{1}{\pi^3\rho_0^6}e^{-\rho^2/\rho_0^2}$$ The three-proton wave function, $\Psi_s$, is...
We present a comprehensive theoretical study of low-energy few nucleon scattering for systems with A≤4. To this end, we utilize pionless effective field theory, which we employ at next-to-leading order. Our results indicate that the theory provides accurate predictions for the low-energy scattering parameters in all studied channels. These predictions match the best experimental evaluations...
We theoretically study the lifetimes of three-body resonance (quasi-bound) states. In particular, we are interested in how these lifetimes vary between one-dimensional and three-dimensional geometries. As an example, we consider a two-component three-body system with short-range pair-interactions that support several two-body bound states. Three-body resonance states are discrete eigenstates...
Resonances in open quantum systems have been actively studied since the very birth of quantum mechanics [1,2]. Their linewidth broadenings caused by the finite lifetimes can be analytically estimated only in a few particular cases [3]. In this sense, the analytically estimated linewidth broadenings of the electron-impurity resonant states by Monozon and Schmelcher [4] is a remarkable...
An important feature of an effective field theory is its renormalizability, which implies that
one can apply a certain power counting to renormalized quantities and perform a systematic expansion of the calculated observables in terms of some small parameter.
When nonperturbative effects become relevant, the requirement of the renormalizability imposes nontrivial constraints on a choice of...
We would like to show one more fruitful application of the clothed-particle notion in the theory of electromagnetic interactions with nuclei. A constructing element of our consideration is the Campbell–Hausdorff expansion formula applied to the initial Noether current density operator
$\phantom{Eq. (1)} J^{\mu}(0) = e^R J^{\mu}_{c}(0)...
Three-body recombination between helium and silver atoms is studied using hyperspherical coordinates. The three-body Schrodinger equation, represented in the slow variable discretized approach at short distances and in the adiabatic method at large distances [1] and using the potential-energy surface represented as the addition of realistic He-He and He-Ag pair interaction potentials [2][3],...
The formalism of finite-volume quantisation allows for a rigorous treatment of hadronic resonances and interactions in lattice QCD. I review the status of calculations of baryon-baryon states by the Mainz and BaSc collaborations, with a particular focus on the H dibaryon and nucleon-nucleon interactions. The binding energy of the H dibaryon in
three-flavour QCD in the continuum limit has...
Quantum computers hold great promise for exact simulations of nuclear dynamical processes (e.g., scattering and reactions), which are paramount to the study of nuclear matter at the limit of stability and in the formation of chemical elements in stars. However, achieving this goal presents both conceptual and technological challenges, from formulating model mapping, quantum algorithms and...
Antihydrogen, the bound state of an antiproton and a positron is an eminent system for testing fundamental symmetries of nature. It is calculable from first principles, and the standard model predicts that its energy spectrum should be identical to that of hydrogen to any precision. Its neutrality lends itself to also be a probe of the weak equivalence principle for antimatter free fall....
The radiative capture α(d,γ)6Li is the dominant process in the Big Bang Nucleosynthesis (BBN) of 6Li. It therefore strongly influences the abundance ratio of 6Li/7Li, for which observational data are three orders of magnitude higher than BBN predictions. Because of the low cross section and the large experimental uncertainties, it is crucial to have accurate predictions. In this talk, I will...
Neutrinoless double beta decay (NLDBD) is the most sensitive probe of lepton-number violation. Its discovery would be a clear signal of physics beyond the Standard Model, confirm the Majorana nature of neutrinos, and provide insight into scenarios of baryogenesis through leptogenesis. In this talk, I will show how the calculation of the decay rate can be organized in a systematic way using...
A first-principle description of atomic nuclei requires the use of two- and three-nucleon interactions combined with an efficient many-body solution for the nuclear state. In particular the treatment of chiral three-body operators provides a significant computational challenge due to high memory requirements. In the first part of my talk, I will discuss two complementary ways to cope with that...
About three decades ago, Steven Weinberg came up with a beautiful idea of using the effective chiral Lagrangian to derive nuclear interactions, which has had a long lasting impact on nuclear physics. I will discuss achievements and challenges in advancing chiral effective field theory into a precision tool to study low-energy nuclear structure and reactions.
Understanding the nuclear properties from bare nuclear forces is one of the main topic in nuclear physics. The importance of three-nucleon forces ($3N$Fs), which appear when more than two nucleons interact, has been indicated in various nuclear phenomena, such as few-nucleon scattering, binding energies of nuclei, and equation of state of nuclear matter.
Nucleon-deuteron ($Nd$) scattering,...
Simulating quantum systems in a finite volume is a powerful theoretical tool for extracting information about them. The observation that the real-world properties of states are encoded in how their discrete energy levels change with the size of the volume gives rise to a versatile approach that is relevant not only for nuclear physics, where lattice methods are now able to calculate few- and...
Rare Isotope Beam (RIB) facilities provide a unique opportunity to investigate the structures and reactions of atomic nuclei near the drip line. Experiments have observed that some light nuclei with excess neutron or proton numbers exhibit a molecular-like structure consisting of a tightly bound core surrounded by a few loosely bound halo nucleons referred to as halo nuclei. The stability of...
We develop a formalism of nonrelativistic conformal field theory, which is then used to describe neutrons at low energies. We show that the rates of nuclear reactions with emission of a few neutrons in the final state show a power-law behavior in the kinematic region where the emitted neutrons have almost the same momentum. We show how corrections to this power-law behavior can be computed...
Impurity atoms or molecules are often used by theorists and experimenters for studying a crossover from few to many-body physics in condensed matter systems, such as superfluid helium and ultracold degenerate gases. The presentation will offer a few examples of such studies in the context of quasi-one- and two-dimensional cold-atom systems with impurities. These examples provide insight into...
The 11Be neutron halo nucleus decays into 10Be with a rate that exceeds expectations. Neutron disappearance into dark matter, beta decay of a halo neutron, or beta delayed proton decay have been offered as explanations. The discovery of an exotic near-threshold resonance supports the latter. The observations, however, also highlight a remarkable and not fully understood...
In this talk, I would like to discuss the theory of light muonic atoms in view of upcoming experiments, e.g., the measurement of the muonic-hydrogen ground-state hyperfine splitting with ppm accuracy. A particular focus will be on predictions of the two-photon-exchange corrections in muonic hydrogen and deuterium. Furthermore, I would like to discuss the hadronic-vacuum-polarization...
Due to their large spatial extension, two-neutron halo nuclei display a significant enlargement in the low-energy $E1$ strength distribution parameterizing the Coulomb dissociation cross section. Thereby the $E1$ strength is an important observable for halo nuclei, and by comparing theoretical calculations with experimental data, we can test our understanding of these exotic nuclear...
In this presentation, I will discuss the results for the $O(\alpha^5)$ effects of the nuclear structure, the two-photon-exchange (TPE) corrections, in the energies of S-levels in muonic ($\mu$D) and ordinary (D) deuterium. They were recently obtained at next-to-next-to-next-to-leading order (N3LO) in the pionless effective field theory (EFT). At this order, there is a single low-energy...
Small helium clusters are peculiar few body quantum systems. The helium dimer has a single weakly bound state of a huge spatial extent. About 80% of its probability distribution resides in the classically forbidden tunneling region [1]. This is why such objects are termed “quantum halos”. The helium trimer has two bound states, excited one of which is of Efimov nature [2]. We utilize...
Spectroscopy in light muonic atoms provides a precision probe of the electroweak structure of light nuclei and has the potential to elucidate new physics. However, the uncertainties in the energy levels of muonic atoms are currently dominated by nuclear theory. In particular, theoretical predictions of the nuclear polarizabilities entering the two-photon exchange contribution to the energy...
Generalization of the Wilsonian renormalization group approach to few-body problems by introducing a multitude of cutoff parameters has been suggested in Ref. [1]. In the framework of an effective field theory, similarly to the Gell-Mann and Low renormalization group, this approach offers the freedom of choosing optimal renormalization scheme in multi-dimensional space of renormalization scale...
A system of a few attractively interacting atoms of lithium in one-dimensional harmonic confinement is investigated. Non-trivial interparticle correlations induced by interactions in a particle-imbalanced system are studied in the framework of the noise correlation. In this way, it is shown that evident signatures of strongly correlated fermionic pairs in the Fulde-Ferrell-Larkin-Ovchinnikov...
Pionless effective field theory (EFT) represents a highly convenient tool to describe the nuclear interaction at low energies. This theory has been used at its leading order (LO) to study various nuclear systems, however, it has failed to give bound nuclei with A > 4 [1,2,3,4].
In our recent study [5] we adressed low-energy $p$-wave $n^3\text{H}$ scattering and the position of the $^4...
The leading-order (LO) Halo EFT interactions for shallow states beyond $S$-waves exhibit non-negligible energy dependencies leading to difficulties related to the normalization. Recently, purely momentum-dependent potentials with square-root form factors have been investigated for the NN and the 3N system [e.g., S. R. Beane et al. (2022), R. Peng et al. (2022) , V. S. Timoteo et al. (2023)]....
S. Oryu, T. Watanabe, and Y. Hiratsuka
Tokyo University of Science, Noda, Chiba 278-8510 Japan
Three-body ${\rm CsH_2}$ eigenvalues in a cuboctahedron CsH$_2$Pd$_{12}$ molecule are calculated in the range from 0.01fm to several ten nano-meter in one stretch, by using 100 significant figure. We utilized five traditional potentials (nuclear Woods-Saxon, three-ion repulsive Coulomb, ion-Pd...
We shall introduce a nuclear interaction model with explicit mesons where the nucleons do not interact directly but rather emit and absorb mesons which are treated explicitly on equal footing with the nucleons.
We shall show that the model is able to i) provide a bound neutron-proton state, the deuteron~[1], and ii) adequately describe the threshold pion photo-production off...
We investigate $\phi$ photoproduction on the nucleon and on the ${}^4$He targets with a dynamical model approach by considering the Pomeron exchange, meson exchange, $\phi$ radiation, and nucleon resonance excitation mechanisms. The final $\phi N$ interactions are included and described by the gluon-exchange, direct $\phi N$ couplings, and the box diagrams arising from the couplings with $\pi...
Matter-wave interferometry with Bose-Einstein condensates (BECs) is a rapidly developing tool for precision measurements [1]. A crucial element of matter-wave interferometers is a beam-splitter that employs the interaction of atoms with laser beams and creates superposition of macroscopically occupied momentum states.
We consider the Bragg beam-splitting of an off-axis BEC with...
A hyperspherical cluster model has been developed to describe long-range behaviour of one particle removed from a few- or a many-body system. It has been applied to the ground and first excited states of helium drops with five, six, eight and ten atoms interacting via a two-body soft gaussian potential. Convergence of the hyperspherical cluster harmonics expansion is studied for binding...
The four quark covariant equations are presented which are adjusted to the description of tetraquarks in terms of an admixture of two-body diquark-antidiquark and two meson states. These equations unify seemingly unrelated the most developed models of the tetraquark where the diquark-antidiquark and meson-meson interactions are realised via quark exchange mechanism in one of them and via...
During the last few years, our understanding of the proton size has increased tremendously thanks to efforts from theorists as well as dedicated experiments. Recent progress for the neutron triggers the question: What is the role of flavor in the strong interaction dynamics, that governs the femtometer structure of hadrons? With their strange quark content, the hyperons offer the perfect...
In this contribution we present a rather personal overview of the most important results regarding the stability and general properties of states formed by two quarks and two antiquarks from the perspective of the constituent quark model (CQM). We will focus most part of the discussion on the different approaches that can be find in the literature for describing double-heavy four quark states,...
A consistent nonrelativistic Effective Field Theory exists for which the scattering length $a$ is large and the effective range $r_0$ is large in magnitude but negative. Such systems can for example be found in heavy mesons. Observables depend then only on the universal ratio $\xi=2r_0/a$, with $|r_0|$ fixing the overall distance scale. The two-body scattering amplitude displays two shallow...
In the present talk, we present a molecular nature of the charmed strange $D_{s0}^*(2317)$ state. The $D_{s0}^*(2317)$ state has a mass approximately 40 MeV below the $D^0K^+$ threshold, and the upper limit of the width is known to be $3.8$ MeV. Its favorable spin-parity assignment is believed to be $J^P=0^+$, the parity conservation being assumed. Since $D_{s0}^*(2317)$ only decays into the...
A general three-body interaction could be generated by the two-body linear and nonlinear interactions which could appear in the very short and in the long range regions, although the three-body Faddeev equation is written in terms of a two-body linear interaction.
However, in the very short range, many meson or multi quark/gluon exchanges may take place which are taken into account by a...
Fatima Benrachi and Nadjet Laouet
LPMPS Laboratory, Frères Mentouri Constantine-1 University, Constantine (Algeria)
email: fatima.benrachi@umc.edu.dz
With their few proton and neutron particles, the A=80 isobars, numbering about twelve nuclei distributed from the proton-rich side to the neutron-rich one, are of a great importance in nuclear structure studies. These nuclides are found...
Low-energy antiprotons are known to be promising tools to probe the nuclear structure [1]. In particular, the measurement of antiprotonic atom decays and nucleon-antinucleon annihilation products is expected to provide reliable data to study the tail of nuclear densities, which has motivated the antiProton Unstable Matter Annihilation (PUMA) project [2] at CERN. Although a qualitative picture...
Despite a century after the discovery of neutrons by E. Rutherford, few details are known for sure about this particle. For example, neutron halos, prototypical examples of the quantum realm, were discovered a few decades ago from indirect measurements. In an ambitious attempt, the PUMA experiment at CERN [1] will use the antiproton's unique property, i.e., the annihilation process's...
In this work, we investigate elastic neutron scattering on $^4$He within the context of baryonic effective field theory, specifically focusing on the $J^\pi = \frac{1}{2}^+$ channel. By employing the stochastic variational method, we solve the 5-body problem without making any prior assumptions about system clusterization. Our calculated scattering length and effective range exhibit excellent...
Extensive research has been conducted in recent years to determine the accurate atomic data and uncertainties associated, as they are crucial for interpreting a large amount of high-resolution data obtained by astrophysicists. In other way, the need for this research is primarily due to the upcoming ITER project (International Thermonuclear Experimental Reactor), which requires precise and...
Chiral effective field theory ($\chi$EFT) is an approach to describe the force between nucleons as arising from the more fundamental principles of quantum chromodynamics. A vital part is to have a power counting (PC) that describes the relative importance of the EFT order-by-order contributions to nuclear observables. The definition of the PC is not unique, and the fact that nuclear systems...
The generalized contact formalism is an effective tool for describing short range correlations in the atomic nucleus and their impact of different observables. Working within the equal time formalism, in this contribution we examine the impact of Lorentz boost on the predictive power of the theory.
We explore the Borromean states of a one-dimensional quantum three-body system composed of two identical heavy particles and a different particle of smaller mass. There is no heavy-heavy interaction potential and no bound state supported by the heavy-light one. The three-body spectrum and corresponding wave-functions are calculated numerically within the Faddeev approach. In addition, we have...
We present the study of the inclusive photo-disintegration reaction $\gamma + {}^{9}\mathrm{Be} \to \alpha + \alpha + n$ at low-energy regime, including calculations of the $\alpha\alpha n$ three-body binding energy of $^9\textrm{Be}$ and the reaction cross section. The inverse process of the ${}^{9}\mathrm{Be}$ photo-disintegration, including both sequential and direct reactions combining...
Recent global analysis of Fermi decays within a dispersion relation framework and the corresponding $V_{ud}$ determination have revealed tension with the Standard Model (SM) expectation of Cabibbo-Kobayashi-Maskawa (CKM) matrix unitarity, theoretical confirmation of which would indicate a deficiency within the SM weak sector. Extracting $V_{ud}$ requires electroweak radiative corrections...
In previous works, the two-nucleon potential has been successfully determined to a high-precision level in the framework of chiral effective field theory. Nonetheless, there are still some free parameters of this potential, which cannot be extracted from two-nucleon data. The goal of the work presented in this talk is to adjust these parameters using three-nucleon data. Because of the high...
Neutron stars are among the most exotic and extreme objects in the universe, consisting primarily of neutrons packed together at incredibly high densities. In the inner crust of these stars, the neutrons are believed to form a superfluid. In this superfluid, the nuclei (clusters of protons and neutrons) are thought to be immersed and interact with the surrounding neutrons. The study of these...
A topic of high interest in the field of cold atoms and molecules is the crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid with loosely bound Cooper pairs to a Bose-Einstein condensate (BEC) of tightly bound dimers (molecules). While the crossover can be investigated experimentally near Feshbach resonances, there is a lack of analytical solutions providing insights into the crossover...
We investigate the spin-entanglement in few-particle scattering following the analysis carried out by Beane et al. [Phys. Rev. Lett. 122, 102001 (2019)]. Our calculations are focused on the entanglement entropies of scattering processes involving Spin-1/2 and Spin-1 particles.
The entropies are evaluated using scattering data for neutron-proton and neutron-deuteron scattering and, taking into...
Proton-drip line nuclei offer significant information about nuclear structure and nucleon-nucleon interaction. Their positions, far from beta stability and close to the astrophysical rp-process path, give them a great importance in both theoretical and experimental studies. This provides the opportunity develop our knowledge about nuclear systems and lead to improve the theoretical nuclear...
Extensive and precise investigations have been conducted on lithium-like neon, iron, and krypton, focusing on the energy levels, wavelengths, weighted oscillator strengths, transition rates, line intensity ratios, and plasma parameters of their lowest 35 odd and even parity states arising from the $1s^2nl (n = 1−6,0 ≤ l ≤ n−1)$ configurations. Accurate atomic data determination is considered...
Lattice quantum chromodynamics (LQCD) calculations of few nucleon systems started a new era of ab-initio predictions in nuclear physics. To obtain physical quantities, the finite-volume LQCD numerical results have to be extrapolated to free space. This extrapolation is traditionally performed using the Lüscher formula for the two-body case and its generalizations to larger systems. Recently,...
Light nuclei at the driplines exhibit fascinating phenomena, such as the formation of diluted structures where a tightly-bound core is surrounded by a halo of one or more weakly-bound nucleons. Among them, $^8$He is the only four-neutron halo, and it is the most exotic nucleus on Earth, having the largest neutron-to-proton ratio in the nuclear chart (N/Z = 3). This makes it an interesting...
We report progress on calculations of the heavy-light baryons $\Sigma_c$ and $\Lambda_c$ and their excitations with $J^P=1/2^+$ and $3/2^+$ using functional methods. The three-quark Faddeev equations are reduced to two-body equations by employing a covariant quark-diquark approach. The interaction amounts to a quark exchange between quarks and effective diquarks, and the ingredients are...
In our contribution, we shall discuss our work at the interface of nuclear ab initio theory and nuclear density functional theory (DFT).
DFT is a powerful and versatile method in nuclear structure theory, with a wealth of application to ground state and collective excitations over the whole nuclear chart, as well as infinite nuclear matter [1].
The key object on which DFT is based on is...
We study the apparent disagreement between experimental measurement of three-body observables in ultracold lithium-7 and the predictions of universal theory, which has shown to be generally accurate in describing the other alkali-metals. For this purpose, we apply a sophisticated numerical approach based on an expansion and subsequent diagonalisation of the full three-body Hamiltonian in...
Spectroscopy experiments in muonic atoms allow for the extraction of the nuclear charge radii of the lightest nuclei with unprecedented precision. The measurement of the Lamb shift in muonic hydrogen [1] and the related emergence of the proton radius puzzle have motivated an experimental campaign devoted to other light muonic atoms, such as muonic deuterium [2] and helium [3]. For these...
It is well known that exactly solvable models play an extremely important role in many fields of quantum physics. After the discovery of graphene in 2004 the study of a few particle systems in novel 2D materials became very important [1]. We consider two particles problem in three-dimensional (3D) coordinates space that are exactly solvable for a given central two-particle interaction V(r)...
Halo nuclei are fascinating short-lived nuclear objects found near the dripline.
In standard reaction models, halo nuclei are usually described as an inert core with one or two weakly bound neutrons. However, some breakup data suggest that the excitation of the core to its excited states to have a significant influence in the dynamics of the reaction [1]. In order to shed more light on this...
An adequate probe to investigate detailed characteristics of the Three Nucleon Forces (3NFs) is few-nucleon scattering experiment. Comparison between high-precision data in few-nucleon scattering (differential cross sections, various spin observables) and theoretical predictions based on rigorous numerical calculations enable us to extract information within the nuclear force. From an...
The $d(\alpha,\gamma ){^6\textrm{Li}}$ reaction that produces ${^6\textrm{Li}}$ was the primitive reaction in the standard BBN framework. As a consequence of the importance of the reaction, we study the radiative capture process of deuteron on alpha through the cluster Effective Field Theory. In detail, we outline the calculation of the amplitude and S-factor of the capture process leading to...
In the consistent approach, total cross-sections and reaction rates of radiative neutron capture on lithium isotopes $^{6-8}$Li in the temperature range from 0.01 to 10 $T$$_9$ within the framework of the modified potential cluster model (MPCM) with forbidden states are considered [1-3]. These reactions are of significant astrophysical interest as a part of the chain of primordial...
Scattering length is one of the most useful parameters used to describe low-energy electron-atom and positron-atom collisions. It is defined as a radius of a hard sphere in the zero-energy total cross section, where the sign represents the type of interaction: it is positive for repulsion and negative for attraction. Such data is mainly used in low-temperature systems such as Bose-Einstein...
In the last decades, exotic few-body atoms, in which an electron is replaced by an exotic particle, have attracted great scientific interest. These systems are indeed very useful to determine accurately the properties of their constituting exotic particles (e.g. antiprotons or mesons). For instance, an antiproton can be captured by a helium atom in a high orbital momentum state (typically L =...
The gravitational form factors (GFFs) of the nucleon encode information on the structure of the mass, spin, and mechanical properties. In this talk, we present results from a recent investigation on the GFFs of the nucleon in flavor SU(3) symmetry, highlighting the flavor structure of the GFFs within the framework of the SU(3) pion mean-field approach. We show how much momentum fraction of the...
We study three-charge-particle low-energy elastic collision and particle-exchange reaction with special attention to the systems with Coulomb and an additional nuclear interaction employing a close-coupling expansion scheme to a set of coupled two-component few-body equations [1,2]. First we apply our formulation to compute low-energy elastic scattering phase shifts for the d+(t$\mu^-)_{1s}$...
In this talk, we present the results of a recent investigation on the behavior of the charge distributions of the $\Delta$ baryon,both unpolarized and transversely polarized, as a function of longitudinal momentum ($P_z$) in a Wigner phase-space perspective. Specifically, we examine how the charge distributions change as $P_z$ increases from 0 to $\infty$. We find that the charge...
