The massive O(N) non-linear sigma model at high orders

• We extend our earlier work on the massive O(N) non-linear sigma model to other observables. We derive expressions at leading order in the large N expansion at all orders in the loop expansion for the decay constant, vacuum expectation value, meson meson scattering and the scalar and vector form factors. This is done using cactus diagram resummation using a generalized gap equation and other recursion relations. For general N we derive the expressions for the n-th-loop-order leading logarithms (M-2/F-2 log(mu(2)/M-2))(n), up to five loops for the decay constant and vacuum expectation value (VEV) and up to four loops for meson-meson scattering, the scalar and vector form factors. We also quote our earlier result for the mass. The large N results do not give a good approximation for the case N = 3. We use our results to study the convergence of the perturbative series and compare with elastic unitarity. (C) 2010 Elsevier B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Nyckelord

Spontaneous and radiative

1/N expansions)

numbers of components (e.g.

Renormalization group evolution of parameters

Expansions for large

symmetry breaking

Chiral Lagrangians

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