• V S Bhasin

      Articles written in Pramana – Journal of Physics

    • Three-body analysis of11Li and itsβ-decay to deuteron channel and to halo analog state11Be* (18.3 MeV)

      S Kumar V S Bhasin

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      The ground state wave function of11Li obtained in a three-body model proposed earlier (S Kumar and V S Bhasin,Phys. Rev.C65, 034007 (2002)) has been employed to study the probability distributions, momentum distributions and n−n correlation. Complex scaling method has been used to find the energy positions and widths of the three resonant states of11Li above the breakup threshold. The formalism is extended further to study the β-decay of11Li to two channels. One is the β-transition of11Li into a high lying excited state of11Be at 18.3 MeV, i.e.,11Be* and the second is the decay to deuteron +9Li channel. The11Be* state has been considered as a halo analog state identified as a bound three-body (9Li + n + p) system. The n-9Li interaction incorporates both the virtual state and the p-wave resonance observed experimentally. For p-9Li interaction, a Coulomb corrected separable interaction is constructed using charge indepedendence for strong interaction part. The n-p interaction is operative only in3S1 state corresponding to the isotopic spin Th =0. As a result the11Be* state has the same isotopic spin as that of9Li core, i.e.,T = 3/2. Using these realistic parameters as input and without invoking any other free parameter, the model has been used to predict the strength of the Gamow-Teller β-decay of11Li to11Be*, i.e.,Bgt = 1.5 and the value of the branching ratio to9Li + deuteron channel to be 1.3 × 10-4. These results are found to be in rather good agreement with the recent experimental findings.

    • On diquark clustering in quark—gluon plasma

      A K Sisodiya V S Bhasin R S Kaushal

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      The possibility that pairs of quarks will form diquark clusters in the regime above deconfinement transition for hadron matter at finite density is revisited. Here we present the results on the diquark-diquark (dq-dq) interaction in the framework of constituent quark model taking account of spin, isospin and color degrees of freedom in the spirit of generalized Pauli principle. By constructing the appropriate spin and color states of the dq-dq clusters we compute the expectation values of the interaction Hamiltonian involving pairwise quark—quark interaction. We find that the effective interaction between two diquark clusters is quite sensitive to different configurations characterized by color and spin states, obtained after the coupling of two diquark states. The value of the coupling parameter for a particular color—spin state, i.e., -3, 1 is compared to the one obtained earlier by Donoghue and Sateesh,Phys. Rev.D38, 360 (1988) based on the effective Φ4-theory. This new value of λ derived for different color-spin dq-dq states, may lead to several important implications in the studies of diquark star and diquark gas.

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