Using our present knowledge on effective hadronic theories, short-distance QCD information, the 1/N C expansion, analyticity and unitarity, we derive an expression for the pion form factor, in terms of m π , m K , M ρ and f π . This parameter-free prediction provides a surprisingly good description of the experimental data up to energies of the order of 1 GeV.

We have calculated the KK → KK scattering amplitude to next to leading order in Chiral Perturbation Theory. Then, making use of a unitarization procedure with one or several coupled channels (ππ,KK in our case) we have calculated the ππ → ππ, ππ → KK and KK → KK S and P waves in good agreement with the experiment up to √ s ≃ 1.2 GeV. The ππ scattering lengths with isospin and spin (I,J) equal to (0,0), (1,1) and (2,0) are also calculated in agreement with experiment and former Chiral Perturbation Theory calculations.Finally we have employed these amplitudes, making use of an Omnès representation, to calculate the scalar and the vector pion form factors, obtaining a good agreement with the available experimental data.

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Background:There are many models that study different aspects concerning smoking habits: influence of price, tax, relapse time, the effects of prohibition, etc. There are also studies on the effect of the Spanish smoke-free law, but from a statistical point of view, not from a dynamic point of view. We wanted to build a model able to separate the effect of the law from the pre-law evolution of smoking habits.

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