We study a non-thermal scenario in a two-Higgs doublet extension of the standard model ( SM ) , augmented by an U ( 1 ) _ { B - L } gauge symmetry .
In this set up , it is shown that the decay product of a weakly coupled scalar field just above the electroweak scale can generate visible and dark matter ( DM ) simultaneously .
The DM is unstable because of the broken B - L symmetry .
The lifetime of DM ( \approx 5 \times 10 ^ { 25 } sec ) is found to be much longer than the age of the Universe , and its decay to the SM leptons at present epoch can explain the positron excess observed at the AMS-02 .
The relic abundance and the direct detection constraint from Xenon-100 can rule out a large parameter space just leaving the B - L breaking scale around \approx 2 - 4 TeV .