/ 99 12 39 2 v 1 1 7 D ec 1 99 9 A QED Shower Including the Next - to - leading Logarithm

We develop an event generator, NLL-QEDPS, based on the QED shower including the next-to-leading logarithm correction in the e + e − annihilation. The shower model is the Monte Carlo technique to solve the renormalization group equation so that they can calculate contributions of α m log n (S/m 2 e) for any m and n systematically. Here α is the QED coupling, m e is the mass of electron and S is the square of the total energy in the e + e − system. While the previous QEDPS is limited to the leading logarithm approximation which includes only contributions of (α log(S/m 2 e)) n , the model developed here contains terms of α(α log(S/m 2 e)) n , the the next-to-leading logarithm correction. The shower model is formulated for the initial radiation in the e + e − annihilation. The generator based on it gives us events with q 2 , which is a virtual mass squared of the virtual photon and/or Z-boson, in accuracy of 0.04%, except for small q 2 /S.