The Role of Collinear Photons in the Rare Decay anti-B --> X(s) l+ l-

Understand

We review the phenomenology of the rare decay \bar B -> X_s l+ l-.

• We present the results of a detailed phenomenological analysis and discuss the role of the decay in the search for new physics at present and future colliders.
• Moreover, we extensively elaborate on the size of electromagnetic logarithms ln(m_b^2/m_l^2) in view of experimental cuts.
• We point out the differences in the analyses of BaBar and Belle and give suggestions on how to treat collinear photons in the experimental analyses.