The double hypernuclei$$ \wedge \wedge He^6 $$ and$$ \wedge \wedge Be^{10} $$ have been analysed using purely attractive nonlocal separable potential. These double hypernuclei have been considered as three body (Λ+Λ+α) and four body (Λ+Λ+α+α) systems respectively. A consistent description of both the systems has been obtained for an intrinsic rangeb=1.5 fm of the ΛΛ interaction in the¹S₀ state. For the purely attractive Yukawa potential this corresponds to the two pion exchange range. The strength of the ΛΛ interaction deduced from the double hypernuclei was found insufficient to bind the two body ΛΛ system. The lightest double hypernucleus that is expected to be bound is$$ \wedge \wedge He^5 $$. The heavier double hypernuclei$$ \wedge \wedge C^{14} $$ and$$ \wedge \wedge O^{18} $$ have also been analysed. The binding energies obtained are in reasonable agreement with those of earlier workers.

Using the consistency requirements arising from the Coleman-Glashow null result for ‘tadpole’-type symmetry-breaking, we obtain a simple method of accounting for the SU(3) symmetry-breaking at theBBP-vertex, without introducing any new parameters. The results obtained are in excellent agreement with the available numbers. We extend the analysis to the charmed baryon couplings in order to accommodate SU(4)-breaking.

The possible existence of charmed analogues of the YN and light hypernuclear systems are investigated using phenomenological one-boson-exchange potential and the SU(4) symmetry. Bound light supernuclei such as C₁N (I=3/2, J=0) and C₁NN(I=2, J=1/2) C₀NN (I=1, J=1/2, and I=0, J=1/2 or 3/2) are predicted with reasonable binding energies using Faddeev formalism for the three body systems.

The possible existence of charmed multiquark hadrons are investigated using phenomenologicalmit bag model and the SU(4) flavour symmetry. The masses of 6q, 9q and 15q systems having the same quantum numbers as the physically interesting ordinary nuclei, hypernuclei and supernuclei are estimated. We find that several new states with distinct signatures are predicted.