Predictions are made for the structure of a second 2 ϩ resonance, the soft dipole mode and unnatural parity modes in the 6 He continuum. We use a structure model which describes the system as a three-body ␣ϩNϩN cluster structure, giving the experimentally known properties of 6 He and 6 Li, and use the distortedwave impulse approximation ͑DWIA͒ reaction theory appropriate for dilute matter. The presence of both resonant and nonresonant structures in the halo excitation continuum is shown to be manifest in chargeexchange reactions as well as inelastic scattering with single nucleons. ͓S0556-2813͑97͒50302-5͔PACS number͑s͒: 21.45.ϩv, 21.60.Gx, 24.30.Gd, 27.20.ϩn The known spectrum of 6 He contains only the 0 ϩ bound state and the well known 2 ϩ (E*ϭ1.8 MeV͒ three-body resonance, and then a desert in the three-body ␣ϩnϩn continuum up to the 3 H ϩ 3 H threshold at about 13 MeV ͓1͔. While for 11 Li a response ͑E1 strength͒ function has been reconstructed from exclusive experiments ͓2,3͔, such information is still lacking for 6 He. Except for momentum distributions from fragmentation experiments with 6 He beams ͓4-6͔, the only data are from charge-exchange reactions with 6 Li to the 6 He continuum, but with poor statistics and limited angles ͓7-9͔.The recent developments of radioactive nuclear beam techniques and of dynamic approaches to three-body continuum theory ͓10͔ make it possible to investigate to what extent our knowledge of the lightest Borromean halo nucleus 6 He is complete. What are the specific features of the continuum of a system with a halo ground state? Below we give predictions of a second 2 ϩ three-body resonance that may be accessible in experiment, and also ͑a much less pronounced͒ 1 ϩ resonance. The so-called ''soft dipole mode'' suggested in ͓11,12͔ still needs clarification ͓13͔. According to existing three-body models it is not a simple binary core -point dineutron resonance, neither in 11 Li nor probably in 6 He, but although this seems now widely accepted, further tests within these three-body models are desirable. It shows no three-body pole structure, as discussed, e.g., in ͓14͔, and therefore it is still an open question whether the ''soft dipole mode'' is just a dynamical enhancement arising from final state interactions in the direct excitation of the three-body continuum. It is now possible for experiments to tell whether the three-body frameworks are adequate, since these models are shown in the present paper to give rise to other soft modes of other multipolarities. Such modes were suggested in ͓15͔, but need both theoretical and experimental clarification. We believe that the predictions given below are reliable as guide for future experiments, and that the observation of the dipole and other modes predicted here would support the validity of three-body models and their representation of the ''soft dipole mode'' as not being a genuine three-body resonance.The nucleus 6 He has in past years been used as a reference case, with the most reliable information on the binary core-n interac...

Recent studies of lighter dripline nuclei have revealed dramatic deviations from the matter distribution of ordinary stable nuclei and shell model ordering. New stability patterns such as halo nuclei with co-existence of normal and low-density nucleonic matter have been discovered, the Borromean nuclei being the most outstanding. Lessons of the last decade which have led to enrichment of the nuclear paradigm are discussed.

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It is possible to make perfect conical carbon nanostructures fundamentally different from the other nanocarbon materials, notably buckyballs and nanotubes. Carbon cones are realized in five distinctly different forms. They consist of curved graphite sheets formed as open cones with one to five carbon pentagons at the tip with successively smaller cone angles, respectively. The nucleation and physics of nanocones has been relatively little explored until now. We present here the key facts and latest results on this “5’th form of carbon”.

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