Scalar QED, NLO and PHOTOS Monte Carlo
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Recently, QED bremsstrahlung in B meson decays into pair of scalars (πs and/or Ks) has become of interest. If experimental acceptance must be taken into account, the PHOTOS Monte Carlo technique is often used in experimental simulations. We will use scalar QED to benchmark PHOTOS, even though this theory is of limited use for complex objects. We present the analytical form of the kernel used in the older versions of PHOTOS, and the new, exact (scalar QED) one. Matrix element and phase-space Jacobians are separated in the final weight, and future extensions based on measurable electromagnetic form-factors are thus possible. The massive phase-space is controlled in the program with no approximations. Thanks to the iterative solution, all leading and next to leading logarithmic terms are properly reproduced by the Monte Carlo simulation. Simultaneously, full differential distributions over the complete multiple-body phase-space are provided. An agreement of better than 0.01% with independent calculations of scalar QED is demonstrated.
KeywordsMatrix Element Invariant Mass Rest Frame Decay Product Total Decay Width
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- 3.M. A. Dobbs et al., hep-ph/0403045Google Scholar
- 9.Belle Collaboration, A. Limosani et al., hep-ex/0504046Google Scholar
- 11.FOCUS Collaboration, J.M. Link et al., hep-ex/0412034Google Scholar
- 12.P. Golonka, Z. Was, hep-ph/0508015Google Scholar
- 14.P. Golonka, Z. Was, hep-ph/0604232Google Scholar
- 16.F. James, FOWL – a General Monte Carlo Phase Space Program, 1977, CERN Computer Centre Program Library, Long Writeup W505Google Scholar
- 20.Z. Was, Written on the basis of lectures given at the 1993 European School of High Energy Physics, Zakopane, Poland, 12–25 September 1993Google Scholar