1. B-physics group simulations: DC1-2 period & data preparation for Trigger TDR DC1 for B-physics: physics validations with 4.0.0 DC1-2: Generators/PythiaBModule &Py6 tunings Production for Trigger TDR

2. DC1 for B-physics: physics validations with 4.0.0 1.Institutes involved: Frascatti, Innsbruck, Lancaster, Moscow, Roma 2.Input from TDR Generator events – well understood 3.Aim of test: check atlsim-vs-atrecon & for the first time check impact of new geometry and solenoid field on B-physics parameters. 4.Previous test - Lund release: serious errors in atlsim-vs-atrecon 5.Current status: all events simulated, part reconstructed. 6.Preliminary: mass resolutions degraded by ~20-25% XKalman need more tuning, Vertex-fit code to be adopted for solenoid field. 7.But possibly the mass resolution will be degraded due to angular resolution – to be shown. Impact parameter and B-life-time resolutions – to be done.

3. DC1-2: Generators/PythiaBModule 1.New algorithm PythiaBModule: 3.2.0 – introduced, 4.3.0 –version for massive production. 2.Why dedicated code for B-events? 3.Pythia gg->bb with mass matrix element strongly contradicts CDF,D0 data. Simulation: as minbias and b-events (~1%) selected – time consuming. PythiaBModule – speed-up the process. 4. Other functions: production of just single exclusive B-decay, automatic selection cuts… All controlled by data cards. Manual available from B-production page.

4. DC1-2: Py6 tuning Py6 default:CTEQ5 CTEQ3

5. DC1-2: tuning NLOQCD

6. Production for Trigger TDR Detector simulation: moderate statistics Large bb->inclusive samples are : ~1-2 * 10 6 + many exclusive channels together: ~ 10 6 1event ~220 sec all detector, 20sec Inner detector only Generator events & atlfast Typically 10 times more events then detector time depends on channel B-simulation: medium time consuming Currently validation tests more important then massive production - however should go with 5.0.0