Search for exotic charmonium states

One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. The $BABAR$ and Belle experiments have extensively studied those in B meson decays, initial state radiation processes and two photon reactions. We can question what we have understood after 11 year search in this field, and try to combine results to conclude on what these new unpredicted resonant states are, and how they can be accommodated in the theory. Big effort has been made from theoretical and experimental point of view, as the potential models unlikely explain the presence of so many enhancements, for mass values above the $D \bar D$ threshold. In this report the $BABAR$ and Belle results of the two invariant mass systems of $J/\psi \phi$ and $J/\psi \omega$ are put in comparison in a search for non-conventional charmonium states. This involves the study of the systems of $J/\psi K^+ K^-$ and $J/\psi \pi^+ \pi^- \pi^0$, respectively. There are strong theoretical arguments in favor of the presence of hybrids or exotic states, in those invariant mass distributions. Remarks on these data analyses are given, based on the $BABAR$ and Belle experimental results.Comment: 8 pages, 21 figures, Proceedings of a plenary talk on behalf of the BaBar and the Belle Collaborations, at the Conference HQL 2014. Submitted at Pos - Proceedings of Science. arXiv admin note: substantial text overlap with arXiv:1410.565

Exotics at Belle and perspectives at Belle II

The search for multi-quark states beyond the constituent quark model (CQM) has resulted in the discovery of many new exotic states, starting with the observation of the X(3872), discovered by Belle in 2003. Also in the sector of charm-strange physics the CQM does not seem to describe properly all spectrum, despite of theoretical expectations. These new forms of quark bounds clearly show that mesons and baryons are not the only possibilities to be considered. We shortly report in this paper selected recent results on searching for such states at Belle, with the perspectives in the hadron physics program at the Belle II experiment.Comment: 8 pages, 3 figures, proceedings written for the "Excited QCD Workshop 2018", Kopaonik (Serbia

Search for exotics in the rare decay B→J/ψKKKB \rightarrow J/\psi K K K at BABARBABAR

One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. Over the years, the experiment $BABAR$ has extensively studied those in B meson decays, initial state radiation processes and two photon reactions. We report in this paper a new study on some of those states, performed using the entire data sample collected by $BABAR$ in $e^+e^-$ collisions, at center of mass energies near 10.58 GeV/c$^2$. The study of the process $B \rightarrow J/\psi \phi K$ will be presented, and the search for the resonant states X(4140) and X(4270) in their decays to $J/\psi \phi$, will be highlighted.Comment: 5 pages, 16 figures; Proceedings written for a poster at the International Conference of New Frontiers in Physics, ICNFP 2014; submitted at EPJ Web of Conference

Search for exotics in the rare decayB→J/ψKKKatBABAR

One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. Over the years, the experiment BABAR has extensively studied those in B meson decays, initial state radiation processes and two photon reactions. We report in this paper a new study on some of those states, performed using the entire data sample collected by BABAR in e+e− collisions, at center of mass energies near 10.58 GeV/c2. The study of the process B → J/ψϕK will be presented, and the search for the resonant states X(4140) and X(4270) in their decays to J/ψϕ, will be highlighted

Perspectives of Open Charm Physics at PˉANDA\bar PANDA

The $\bar PANDA$ experiment at FAIR (Facility for Antiproton and Ion Research) in Darmstadt (Germany) is designed for $\bar p p$ annihilation studies and it will investigate fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei. Gluonic excitations and the physics of hadrons with strange and charm quarks will be accessible with unprecedented accuracy, thereby allowing high precision tests of the strong interactions. In particular, the $D_{s0}^*(2317)^+$ and $D_{s1}(2460)^+$ are still of high interest 11 years after their discovery, because they can not be simply understood in term of potential models. The available statistics and resolution of the past experiments did not allow to clarify their nature. Recently LHCb at CERN has made progresses in this respect, but still not at the level of precision required in order to clarify the puzzle of the $cs$-spectrum. $\bar PANDA$ will be able to achieve a factor 20 higher mass resolution than attained at the B-factories, which is expected to be decisive on these and second-order open questions. The technique to evaluate the width from the excitation function of the cross section of the $D_s$ mesons will be presented, and ongoing simulations performed with $PandaRoot$ will be shown.Comment: 8 pages, 21 figures, Proceedings of a talk given at the International Conference of New Frontiers in Physics, ICNFP 2014; submitted at EPJ Web of Conferences. arXiv admin note: text overlap with arXiv:1410.520

Search for exotics at BABARBABAR

One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. The $BABAR$ experiment has extensively studied those in B meson decays, initial state radiation processes and two photon reactions. The study of the process $B \rightarrow J/\psi \phi K$, with a search for the resonant states X(4140) and X(4270) in their decays to $J/\psi \phi$, will be highlighted. The recent results of the Dalitz analysis of $\eta_c$ to 3 pseudoscalar mesons, via 2-photon interactions, will be presented in this reportComment: 4 pages, 9 figures, Proceedings written for the conference PANIC2014, submitted at DESY-PROC-2014. arXiv admin note: substantial text overlap with arXiv:1410.565

X, Y, Z Search at Belle II

Search for exotics has increased importance since the observation of the X(3872), 13 years ago, announced by the Belle Collaboration. The observation of pentaquark states by LHCb, and the Z-charged states observed at Belle and BES III have raised even more the attention to the field. Presently several states are observed that do not fit potential models, and looking for them in different production mechanisms and search for their decay modes it is important, as well as to do precise measurement of their mass, width, lineshape. We shortly report in this note about the plan in searching for exotics at Belle II at KEK (Tsukuba, Japan), that just ended the Phase-II running period, and show the first re-discovery results using 5 pb$^{-1}$ integrated luminosity.Comment: 6 pages, 2 figures. Proceedings of the CHARM2018 conference, on behalf of the Belle II collaboration. arXiv admin note: text overlap with arXiv:1806.1093