Nucleon-antinucleon quasi-bound states, or states coupled to these, were searched for in the days of LEAR at CERN. Nothing has been found, but broad states or states close to the threshold were not excluded. Recent indications of the existence of quasi-bound states in the N$\overline N$ system will be presented. The BES collaboration has discovered a broad enhancement close to the p$\overline p$ threshold in the S wave, isospin 0 state formed in radiative decays of J$\psi$. Another enhancement located about 50 MeV below the threshold was found in mesonic decays of J$\psi$. In terms of the Paris potential model these findings are likely to be due to the same state. Antiprotonic atomic data provide some support for this interpretation and indicate existence of another fairly narrow quasi-bound state in a P wave. Few clarifying experiments will be indicated.

Read More »# Tag Archives: Evento scientifico

## On nuclear states of mesons

The existence of nuclear states of $\bar K$ mesons and $\eta$ mesons has been expected for about thirty years. The physical interest of this field is related to a new mechanism of nuclear binding generated by excitations of the internal nucleon structure. Despite being short lived such states might offer a new and interesting nuclear spectroscopy. Despite long and extensive experimental search, the existence and properties of such states are still elusive. Some similarities and related questions of the $\eta$ and $\bar K$ cases will be shown. Possible origin of the experimental difficulties related to weak production rate and large widths of such states will be discussed. I will try to indicate usefulness of the recent AMADEUS/KLOE measurements.

Read More »## “What Next at LNF: scienze dei materiali”

The workshop is intended to discuss the potentials for the future of the LNF infrastructures in the fields of Material Science and Applied Physics

Read More »## The quantum effects on all Lagrangian points and prospects to measure the effects in the Earth-Moon system.

The leading long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., at the Lagrangian libration points of stable equilibrium the planetoid is not exactly at equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. We show that such a theoretical calculation is governed by a couple of quintic algebraic equation, whereas coordinates of collinear Lagrangian points are given in terms of the solution of an algebraic equation of ninth degree. We also discuss the prospects to measure, with the help of laser ranging, the above departure from the equilateral triangle picture, which is a challenging task. On the other hand, a modern version of the planetoid is the solar sail, and much progress has been made, in recent years, on the displaced periodic orbits of solar sails at all libration points, both stable and unstable. By taking into account the quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist.

Read More »## The current landscape of neutrino physics

After a brief review of the status of neutrino oscillation physics I discuss some phenomenological implications of neutrino mass in astroparticle setups as well as at the LHC and in cosmological missions.

Read More »## Supersymmetry Breaking and Born-Infeld Actions

We review the partial breaking of N=2 rigid Supersymmetry and present new results for mass generation in the SuperHiggs phase. Special Geometry,underlying the dynamics of vector multiplets and the symplectic Structure of electric-magnetic duality play an important role in this context

Read More »## Workshop on New Trends in Algebraic Quantum Field Theory

The New Trends in Algebraic Quantum Field Theory (AQFT2015) will be held in Frascati. INFN – LNF on 11 -13 February 2015. The workshop is the third in a series aimed at intensifying the exchange and the collaboration between Italian and international research groups active in the context of rigorous approaches to quantum field theory, with particular regard to the interfaces with the theory of operator algebras and non-commutative geometry. The purpose of the workshop, and the series, is also to provide graduate students and post-docs the opportunity to communicate their findings and discuss with experienced researchers. The workshop is an activity that fits within the convention between the INFN and the Centre for Mathematics and Theoretical Physics (CMTP), University of Rome Tor Vergata, and is also financed by the PRIN 2010 “Operator Algebras, Noncommutative Geometry and Applications” (P.I. Roberto Longo), and by the INdAM-GNAMPA. Invited speakers: R. Brunetti, D. Buchholz, C. Dappiaggi, S. Doplicher, C. Fewster, F. Fidaleo, K. Fredenhagen, S. Hollands, G. Lechner, N.Pinamonti, A. Pizzo, K.H. Rehren, Y. Tanimoto Organizing Committee: G. Morsella, G. Ruzzi

Read More »## Secrets of the Higgs Boson

In two and a half years since the discovery of the Higgs boson, many particle physicists have gone the whole route from skepticism about the existence of this particle to contentment with its Standard-Model-like properties. In reality, we have hardly begun to explore the secrets of the Higgs boson. In this lecture, I will discuss open questions about the Higgs boson and the prospects that we can find the answers.

Read More »## Topical Workshop: Rethinking Naturalness

Aim of the workshop: We are all aware that the so-longed discovery of some kind of physics beyond the standard model that could be responsible for stabilizing the electroweak scale has so far escaped all experimental efforts (LHC Run 1, B-factories, EDM searches, etc.). As we know, the expectation that new physics should show up around the electroweak scale has been mainly motivated by naturalness arguments. Therefore, while all our community is eagerly awaiting the results of LHC Run 2, we believe that an unbiased scientific attitude should also reconsider issues related to the naturalness paradigm. During this 3-day workshop, we plan to have only three or four talks each day, and plenty of time to discuss and reanalyze jointly issues like: the naturalness paradigm, its predictivity, its survival chances, possible alternatives and time scales for crucial tests. Confirmed Speakers: Alberto Casas (IFT-UAM/CSIC, Madrid) André de Gouvêa (Northwestern U., USA) Jose Ramon Espinosa (IFAE & ICREA, Barcelona) Manfred Lindner (Heidelberg, Max Planck Institute) Duccio Pappadopulo (California U., Berkeley, USA) Martti Raidal (Tartu U. & NICPB, Tallinn) Francesco Sannino (Danish IAS, U. Southern Denmark) Mikhail Shaposhnikov (ITPP, Lausanne) Alessandro Strumia (Pisa U. & NICPB, Tallinn)

Read More »