Bootstrap equations in effective theories

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Cross Section and Single Transverse Target Spin Asymmetry for backward Pion Electroproduction.

Nucleon to meson transition distribution amplitudes (TDAs), non-diagonal matrix elements of nonlocal three quark operators between a nucleon and a meson states, arise within the collinear factorized description of hard exclusive electroproduction of mesons off nucleons in the backward direction. Below we address the problem of modelling pion to nucleon TDAs. We suggest a factorized Ansatz for quadruple distributions with input from the soft pion theorem for pi N TDAs. In order to satisfy the polynomiality property in its full form the spectral representation is complemented with a D-term like contribution from the nucleon exchange in the u-channel of the reaction. We present our estimates for the backward pion electroproduction unpolarized cross section and its transverse target single spin asymmetry within our composite model for pi N TDAs.Comment: 6 pages, 3 figures, proceedings of the XIV Advanced Research Workshop on High Energy Spin Physics, Dubna, sept.20-24, 2011 (DSPIN-11

Testing the bootstrap constraints in the strange sector

In this paper the bootstrap conditions that follow from the general postulates of effective scattering theory (EST) are checked in the strange sector. We construct the system of tree level bootstrap constraints for the renormalization prescriptions fixing the physical content of the theory. Then we perform the numerical testing of corresponding sum rules for the parameters of strange resonances. It is shown that, generally, the bootstrap constraints turn out consistent with presently known data on the strange resonance parameters. At the same time we point out few sum rules which cannot be saturated with modern data and discuss the possible reasons for such discrepancies

Renormalization prescriptions and bootstrap in effective theories

We discuss the peculiar features of the renormalization procedure in the case of infinite-component effective theory. It is shown that in the case of physically interesting theories (namely, those leading to the amplitudes with asymptotic behavior governed by known Regge intercepts) the full system of required renormalization prescriptions only contains those needed to fix the minimal counterterm vertices with one, two, three and (in some cases) four lines. There is no necessity in imposing the prescriptions for n-leg counterterm vertices with (n > 4). Moreover, the prescriptions for n =< 4 cannot be taken arbitrary: an infinite system of bootstrap constraints must be taken into account. The general method allowing one to write down the explicit form of this system is explained and illustrated by the example of elastic scattering process

pi N transition distribution amplitudes: Their symmetries and constraints from chiral dynamics

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