Ananthanarayan, B (1999) Effective Lagrangians in $2 + \epsilon$ Dimensions. [Preprint]
The failure of the the loop expansion and effective lagrangians in two dimensions, which traditionally hinges on a power counting argument is considered. We establish that the book keeping device for the loop expansion, a role played by (the reciprocal of) the pion-decay constant itself vanishes for $d=2$, thereby going beyond the power counting argument. We point the connection of our results to the distinct phases of the candidate for the effective lagrangians, the non-linear sigma model, in $d=2+\epsilon$, and eventually for $d=2$. In light of our results, we recall some of the relavant features of the multi-flavor Schwinger and large $N_f$ $QCD_2$ as candidates for the underlying theory in $d=2$.
|Additional Information:||Phys.Rev. D61 (2000) 076001|
|Department/Centre:||Division of Physical & Mathematical Sciences > Centre for Theoretical Studies|
|Date Deposited:||30 Jul 2004|
|Last Modified:||19 Sep 2010 04:13|
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