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Contact interactions in D-brane models

I. Antoniadis·K. Benakli·A. Laugier
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Abstract

We compute the tree-level four-point scattering amplitudes in string models where matter fields live on D-brane intersections. Extracting the contribution of massless modes, we are left with dimension-six four-fermion operators which in general receive contributions from three different sources: exchange of massive Kaluza--Klein excitations, winding modes and string oscillator states. We compute their coefficients and extract new bounds on the string scale in the brane-world scenario. This is contrasted with the situation where matter fields arise from open strings with both ends confined on the same collection of D-branes, in which case the exchange of massive string modes leads to dimension-eight operators that have been studied in the past. When matter fields live on brane intersections, the presence of dimension-six operators increases the lower bound on the string scale to 2--3 TeV, independently of the number of large extra dimensions.

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I. Antoniadis, K. Benakli, A. Laugier. 2000-12-06. Contact interactions in D-brane models. https://doi.org/10.1088/1126-6708%2F2001%2F05%2F044

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