Few-Body Problems in Hadron Spectroscopy

Some rigorous results can be derived using a very simple approach to hadron spectroscopy, in which a static potential is associated with non-relativistic kinematics. Several regularities of the experimental spectrum are explained by such models. It is underlined that certain methods developed for hadronic physics have found applications in other fields, in particular atomic physics. A few results can be extended to cases involving spin-dependent forces or relativistic kinematics.Comment: Latex with espcrc1, Invited Talk at the 17th European Conference on Few-Body Physics, 11--16 September 2000, Evora, Portugal, to appear in Nuclear Physics A. Misprint corrected p.2, thanks to A. Ga

Borromean binding

A review is first presented of the Hall--Post inequalities relating $N$-body to $(N-1)$-body energies of quantum bound states. These inequalities are then applied to delimit, in the space of coupling constants, the domain of Borromean binding where a composite system is bound while smaller subsystems are unbound.Comment: 5 pages, Dedicated to V.B. Belyaev for his 70th birthday, to be included in a jubilee volume, edited by A.K.Motovilov and F.M.Pen'ko

Hadrons with Two Heavy Quarks

We review the spectroscopy and some properties of hadrons containing two charmed quarks, or more generally, two heavy quarks. This includes heavy baryons such as $(bcu)$, and possible exotic multiquark states.Comment: Talk given at the CHARM 2000 Workshop, Fermilab, June 1994 to appear in the Proceedings Latex, style file "charm2000" appende

Borromean molecules

For some values of the constituent masses m_i, the hydrogen-like molecule (m_1^+,m_2^+,m_3^-,m_4^-) is stable with respect to spontaneous dissociation into two neutral atoms, while none of its three-body subsystems such as (m_1^+,m_2^+,m_3^-) is stable. This occurs in particular in the neighbourhood of the (M^+,m^+,M^-,m^-) configuration with M/m=2, as for instance for the molecule (p,d,\bar{p},\bar{d}) involving an antiproton and an antideuteron.Comment: 3 pages, Talk given at the XVIII European Few-Body Conference, Bled, Slovenia, September 2002, to app. in Few-Body Sys. Supp

Steiner-tree confinement and tetraquarks

The linear confinement in quarkonium is generalised as a minimal tree, with interesting geometrical properties. This model binds tetraquarks more easily than the additive model used in earlier investigations.Comment: 6 pages, 1 fig., Contr. "Excited QCD", Zakopane, Poland, Proc. to be published in Acta Physica Polonic

The Role of Flavor in Multiquark Spectroscopy

In several mechanisms proposed for multiquark binding, the flavor content of the quark configuration plays a very important role. We shall review some past or recent results on multiquarks dealing with the chromomagnetic interaction and with the spin-independent potential among quarks.Comment: 6 pages, 1 figures, pdflatex, Presented at the International Workshop on Strangeness Nuclear Physics (SNP12), August 27 - 29, 2012, Neyagawa, Osaka, Japa

Stability of the Hydrogen and Hydrogen-like Molecules

We present a simple proof of the stability of the hydrogen molecule $(M^+M^+m^-m^-)$. It does not rely on the proton-to-electron mass ratio $M/m$ being very large, and actually holds for arbitrary values of $M/m$. Some asymmetric molecules of the type $(m_1^+m_2^+m_3^-m_4^-)$ are also stable. Possible applications to molecules containing antiparticles and to exotic hadrons in the quark model are briefly outlined. Revtex Version 3.0, 4 Figures available on request by Fax or Mail

Baryon spectroscopy and heavy quarks

Two topics are briefly reviewed in this talk: the decay of flavored hadrons or quarkonium states involving a baryon--antibaryon pair, and the spectroscopy of heavy baryons containing one, two or three heavy quarks. Some prospects for exotic heavy baryons are also discussed.Comment: 5 pages, 2 figures, Invited talk at "Charm 2010", 4th Int. Workshop on Charm Physics, Oct. 21-24, 2010, IHEP, Beijing, China, to appear in the Proceedings, ed.\ Hai-Bo Li et al., to be published in IJMPC

Spin and Flavour: Concluding Remarks

Summmary talk at the Workshop on Sin and Flavour in Hadronic and Electromagnetic Interactions, Turin (Italy), september 1992, to appear in the Proceedings,Comment: 13pages, ISN 93-1

Scalar Quarks at the Large Hadron Collider

The properties of scalar quarks are studied, especially the formation of fermionic mesons with an anti-quark. On the basis of this theoretical investigation together with the experimental data, both from last year and from this year, of the ATLAS Collaboration and the CMS Collaboration at the Large Hadron Collider, it is proposed that the standard model of Glashow, Weinberg, and Salam should be augmented by scalar quarks, scalar leptons, and additional fermions. If these scalar quarks and scalar leptons are in one-to-one correspondence with the ordinary quarks and ordinary leptons, either in number or in the degrees of freedom, then there may be a fermion-boson symmetry. The fermion-boson symmetry obtained this way is of a different nature from that of supersymmetry.Comment: 7 pages, 1 figur