Related papers: The quest for light multineutron systems
Theoretical and experimental situation in physics of heavy neutrinos $(M_N>M_Z)$ is briefly presented. Various experimental bounds on heavy neutrino masses and mixings are shortly reviewed. Special attention is paid to possibility of…
We consider lepton-neutron (and lepton-antineutron) bound states and resonances which appear due to spin-spin, spin-orbital interactions,neutron polarization by muon. Our analis is also true for any system which include one charge and one…
The problem of nucleon resonances N' with masses below the Delta is considered. We derive bounds for the properties of such states. Some of these are new, while others improve upon existing limits. We discuss the nature of N' states, and…
A short discussion on possible multineutron resonances.
Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of…
We review ideas and speculations concerning possible bound states or resonances of the nucleon--antinucleon system.
Following recent work in which events which may correspond to a bound tetraneutron ($^4$n) were observed, it is pointed out that from the theoretical perspective the two-body nucleon-nucleon (NN) force cannot by itself bind four neutrons,…
Bound states in the continuum provide a remarkable example of how a simple problem solved about a century ago in quantum mechanics can drive the research on a whole spectrum of resonant phenomena in wave physics. Due to their huge radiative…
The forward neutrino program at the Large Hadron Collider has entered the era of providing the first measurements and observations. As it has notable connections to astrophysics and will complement the results and projections of key…
Despite significant experimental sensitivity to point-like, weakly interacting particles at the electroweak mass scale, dark matter has not been found yet. This could hint at a more complex dark sector with multiple states or composite dark…
Short history of ideas concerning a possible existence of bound states of the $\eta$-meson and a nucleus is considered. First experiments at BNL and LAMPF on searching for these states are discussed. Another recent experiment using the…
In light of a new experiment which claims a positive identification, we discuss the possible existence of the tetraneutron. We explore a novel model based on a dineutron-dineutron molecule. We show that this model is not able to explain the…
Symmetry has imposed very strong constraints on the structures of internal wave functions and on the accessibility of outgoing channels. Based on symmetry consideration, the existence of a number of bound excited states and low-lying…
We review the chromoelectric and chromomagnetic mechanisms that tentatively lead to stable or metastable multiquark configurations. An alternative interpretation of the dynamics is the quark interchange between hadrons, as illustrated in…
The four-neutron system is studied using exact continuum equations for transition operators and solving them in the momentum-space framework. A resonant behavior is found for strongly enhanced interaction but not a the physical strength,…
We describe the recent experiments which claimed an observation of a tetra-neutron signal. Production reactions like transfer, knockout, fragmentation or photodisintegration have been used at very different experiments and facilities to…
The paper summarizes elements of theories and computational methods that we have constructed and applied over the years for the nonperturbative solution of many electron problems, in the absence or presence of strong external fields,…
We study the existence of bound states in the continuum for a system of n two-level quantum emitters, coupled with a one-dimensional boson field, in which a single excitation is shared among different components of the system. The emitters…
We review the status as regards the existence of three- and four-body bound states made of neutrons and $\Lambda$ hyperons. For interesting cases, the coupling to neutral baryonic systems made of charged particles of different strangeness…
Our present knowledge of neutrinos can be summarized in terms of the "standard neutrino scenario". Phenomenology of this scenario as well as attempts to uncover physics behind neutrino mass and mixing are described. Goals of future studies…