Recent progress in the Physics area

1. Recent progress in the Physics area • current focus: move towards full MC and reconstruction • GRID registration, setting up working software frameworks at the different institutes • ensuring all tools are available for performing physics studies and studying detector effects • learning how to use the different packages • increased level of communication with experts from other groups • since June collaboration meeting, progress has been made on: • vertex package: diagnostic plots added (VM)  7/Aug/07, vertex charge reconstruction (ED)  17/July/07, Kalman filter for vertex fit (TL) • GEAR: MOKKA-, MarlinReco extended to automatically write out all GEAR parameters needed (KH, TPJ, CL)  slides 10/July/07, 7/Aug/07, mtg notes 31/July/07 • Damien Grandjean to provide information on flexible vertex detector geometry  10/July/07 • initial exploration of “data mining” approaches for flavour tag (Montenegro U, TL)  3/July/07 • event generation for anomalous Wtb coupling (ED)  17/July/07 • SUSY study: soft b-jets in sbottom decays (Montenegro U, A Belyaev, AN, TL)  7/Aug/07 • ZHH study initially using fast MC LCIO files provided by Tim Barklow (TL, AN)

2. Vertex package extensions / improvements • Victoria is working on implementation of • a new module LCFIAIDAPlot providing • a standard set of diagnostic plots for the • vertex package (tagging inputs, outputs, …); • framework based on earlier work by Mark • Vertex charge performance in released version is less good than it used to be in SGV • Erik and Sonja identified the reason: obsolete algorithm was implemented • Erik has been working on code for the up-to-date algorithm, and on tools needed to check it such as “MC true quark charge sign”; • doing so, Erik found MOKKA-”feature” in how the charge of MC particles is filled • has been reported to the developers who modified this for the next version • Tomas working on interfacing Kalman filter for vertex fitting with our package • developed by Darmstadt group (ALICE)

3. MOKKA-, MarlinReco interfaces to GEAR • Purpose: • MOKKA detector simulation based on MySQL database for detailed geometry description • reconstruction stage needs some information about detector geometry, but less detailed • this information is transferred via GEAR: MOKKA writes out GEAR file, read in by MarlinReco • problem: GEAR files used to be incomplete, edited by hand  easily creates confusion • aim: add missing parameters, so required parameters can be written fully automatically • Kristian / Talini have extended MOKKA by additional parameters for TPC and vertex detector • resulting parameters checked and give good agreement with previous manually provided ones • Paulo Mora de Freitas (MOKKA development team) was contacted and will cross-check and • submit extensions to CVS • Clare is taking care of the parameters that are first used by MarlinReco (e.g. resolutions), • and should therefore be written out only at that stage (NB: GEAR files so far read-only in Marlin)

4. Realistic vertex detector description • so far using a simplified vertex detector description, consisting of sensitive cylinders • Damien Grandjean (Strasbourg) has developed a more realistic vertex detector • description, which has some built-in flexibility, and is available in MOKKA, in the • detector model LDC01_02Sc • Model parameters can be changed by simple commands in the MOKKA initialisation: • /Mokka/init/globalModelParameter VXD_end_electronics_thickness 0.05 • (default value 0.19656) – see Mokka v05-02 release notes for a list of parameters • As next step of realistic performance study, suggest using LDC01_02Sc • this could be followed by a study of different detector options, varying the • available parameters • D. Grandjean has been contacted to obtain further information on what is available • and on future plans

5. Jet Tagging Algorithms Study • A group from University of Montenegro recently joined LCFI • this particular topic: Savo Tomović supervised by Goran Suković. • Current aim • Investigate various data mining and classification methods to evaluate their potential in the jet flavor tagging. • Understand classification inputs in terms of their influence on the tagging results. • TMVA(part of ROOT distribution, thanks to Erik for pointing this package out) and FANN(Fast Artificial Neural Networks) packages employed. • Data used so far • text file from Tim and Sonja (3732 b-jets, 3020 c-jets, 10042 light jets) • Z-peak data with TPC • Older version of tracking code (April) Tomáš Laštovička, 3/July/2007

6. Anomalous Wtb study • initial step: set up working chain of event generator, det’ simulation, reconstruction • to generate events, plan is to use CompHEP, interfaced to PYTHIA (hadronisation) • advantage: synergy with work by E. Boos et al for LHC • to check his setup, Erik looked at forward backward asymmetry for inclusive process e+e-  W+W- b bbar: 0.242, in reasonable agreement with expectation for leptonic W decay with muon in the final state (0.279)  confident set-up works

7. Soft b-jets in sbottom decays • Motivation: strong cosmological constraints on SUSY parameter space • some MSSM scenarios could favour light sbottom, decaying to produce low momentum b-jet •  sensitivity to material amount in the vertex detector • Generator: CALCHEP set up with MSSM model, to be interfaced to PYTHIA 8 via LHA interface, • set up ROOT histogramming at generator level • Future plans: • study which SUSY parameters correspond to small sbottom neutralino mass splitting • (A Belyaev) • use GEANT-based detector description to study • material effects, and with realistic tracking and • vertexing to determine sensitivity of ILC to the process • Timescale: approximately one year, • will for diploma topic of Marija Kovacevic (Montenegro U) sqrt(s) = 500 GeV