1. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 0 WP 1 – Simulation and Physics Studies Overview of recent progress LCFI Collaboration Meeting, RAL, 6 th March 2007 Sonja Hillert (Oxford)  Introduction (Sonja)  Update on the LCFI Vertex Package (Sonja, Ben, Erik)  Plans for studying the Wtb coupling in e + e -  t tbar (Erik)

2. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 1 Current Status of Physics work Tool development – the LCFI Vertex Package  since December found a few issues, mainly concerned with features of the software framework into which the code will be embedded, which have delayed the release  concerted effort in collaboration with other groups (MPI Munich, DESY) has allowed us to make fast progress in these areas  1 st release will hopefully be possible later this month  development of the Vertex Package will continue beyond the 1 st release, driven by new members of the physics group; detailed plans for who will work on what to be discussed in the immediate future Study of benchmark physics processes: 3 studies to start immediately after the release:  Higgs branching ratios  e + e -  b bbar  sensitivity of Wtb coupling to new physics in e + e -  t tbar (see Erik’s talk in this meeting)

3. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 2 Tool development beyond the release  more detailed comparisons with performance obtained when using MarlinReco – the Vertex Package System Test with MarlinReco event reconstruction is based on a simplified vertex detector geometry and relies on track cheater (no pattern recognition); after release, will make the transition to more realistic detector description and reconstruction: replace track cheater by 1 st : SiliconTracking: performs pattern recognition only in Silicon detectors (VTX, SIT, FTD) without TPC, and fits reconstructed tracks 2 nd : full tracking in the LDC detector, including TPC (Marlin processors for both options developed by Alexei Raspereza, MPI Munich) replace simplified vertex detector geometry (cylinders) by proper one (ladders)  explore and quantify what can be gained for flavour tag and vertex charge determination when using the ghost track (ZVKIN) algorithm should feed into future update, so the community can profit from our studies

4. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 3 Physics-related meetings Internal meetings:  LCFI Physics Meetings every two weeks on Tue, 1pm, by phone; beginning in May, we will have two series of presentations by Ben, Mark and Erik: tutorials on the Vertex Package (technical introduction, mainly for the new group members) introductions to the three benchmark studies External meetings:  ECFA simulation and physics meetings (~ once monthly, usually by phone) last reported on Vertex Package on 7 th February 2007 next presentation planned shortly after the release ‘ILC software workshop’ 2 nd – 4 th May at LAL Orsay  IoP meeting, University of Surrey, 3 rd – 5 th April 2007  after release, further presentations on Vertex Package envisaged in the software meetings in the US (ALCPG group) and Asia

5. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 4 Update on the LCFI Vertex Package

6. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 5 interface SGV to internal format interface LCIO to internal format input to LCFI Vertex Package output of LCFI Vertex Package interface internal format to SGV interface internal format to LCIO ZVRESZVKIN ZVTOP: vertex information track attachment assuming c jet track attachment assuming b jet track attachment for flavour tag find vertex- dependent flavour tag inputs find vertex charge find vertex- independent flavour tag inputs neural net flavour tag

7. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 6  Package will be interfaced to MarlinReco reconstruction framework, based on Marlin (Modular Analysis & Reconstruction for the LINear collider) software modules called processors; each can be enabled & configured in XML steering file steering file replaces ‘main’ program and is hence integral part of the code  easy to exchange modules and run with different parameters without recompiling  MARLIN processors to be provided and their status of development / testing: processor implementing track selection cuts for ZVTOP & flavour tag / vertex charge ( ) ( ) ZVRES processor (classical branch of ZVTOP) ZVKIN processor (ghost track algorithm) determine jet flavour MC truth information calculating NN input variables and vertex charge from input tracks & ZVTOP output training neural nets for flavour tag obtain NN outputs for pre-trained nets PlotProcessor to calculate and plot flavour tag purity versus efficiency = implemented = tested (standalone)                MARLIN processors – status of December 2006

8. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 7  MARLIN processors to be provided and their status of development / testing: processor implementing track selection cuts for ZVTOP & flavour tag / vertex charge ZVRES processor (classical branch of ZVTOP) ZVKIN processor (ghost track algorithm) determine jet flavour MC truth information (see Erik’s part of the presentation) calculating NN input variables and vertex charge from input tracks & ZVTOP output training neural nets for flavour tag obtain NN outputs for pre-trained nets PlotProcessor to calculate and plot flavour tag purity versus efficiency IP-fit processor = implemented = tested (standalone)                MARLIN processors – current status   

9. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 8 System Test with SGV input  fast MC simulation SGV, interfaced to the PYTHIA event generator, has been used throughout the software development to provide input for validation and comparison to old FORTRAN code  for System Test = ZVRES + flavour tag input calculation + NN flavour tag + vertex charge FORTRAN-to-LCIO interface from LCIO web site was used to output SGV-jets in LCIO format read in by MARLIN processors under test LCIO output from MARLIN processors converted into root-ntuple fed into old analysis code  permitted passing identical input events through FORTRAN & MARLIN and analysing them with identical already existing program  previously, performance of MARLIN did fall short of FORTRAN performance; in addition, many changes in the code since December  needed to re-run test

10. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 9 System Test with SGV input: Current Status  Recent problem: inconsistency between results from Ben’s and Sonja’s test systems to compare SGV and MARLIN  difference found to be introduced in the flavour tag part of the code Ben’s system, using Marlin flavour tag processor, gives poorer performance for both SGV- and Marlin flavour tag inputs (and similar performance for MARLIN & SGV)  Sonja’s system, using a standalone flavour tag implementation gives better performance for both  in both systems, Marlin performs better than SGV (Z-peak)  at the time of last physics meeting, it looked as if the problem was in the NN area  last week-end, made detailed comparisons of the inputs and outputs to the NN and found that not to be the case – after correcting a bug in the code, 100% agreement of the NN outputs – should now obtain performance similar to the one shown so far for SGV, from both systems

11. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 10 System Test with SGV input: Current Status current result (extremely low statistics – 400 jets, corresponding to 1/50 of full sample) c c (b-bkgr) b open: SGV full: MARLIN

12. LCFI Collaboration Meeting, RAL, 6 th March 2007Sonja Hillert (Oxford)p. 11 System Test with input from MarlinReco event rec´n  System Test will be repeated with events from full detector simulation MOKKA, reconstructed using the MarlinReco analysis framework; procedure: PYTHIA interfaced to SGV was used to generate the input STDHEP files advantage: can again use the same input events as in the previous system test Dennis Martsch (DESY) is working on passing these events through the GEANT4-based detector simulation MOKKA on the GRID – will take 1 week, once the setup is working a simplified vertex detector geometry is used (no sensors, just cylinders) advantage: similar to detector description used in SGV we will run MarlinReco event reconstruction on these events using track cheaters  Surprises encountered while preparing for this test: TrackCheater processor did not provide covariance matrices, number of hits in subdetectors; responding to our request, Alexei Raspereza has fixed these problems on a very short timescale running MOKKA more complicated – even for experts – than envisaged: 1 st run with one test file showed bug in MOKKA version used  switched to older version output file from 2 nd run also has some deficiencies, being investigated at DESY (see Ben‘s talk)