1. Download the Minerva software at http://atlas-minerva.web.cern.ch/atlas-minerva Read through the introduction and, using the Minerva help and instructions pdf, work through the 5 tutorial examples.

2. Strange Particle event files There are four type of event files for the Strange Particle explorations on the Minerva event location : K 0 and Lambda (  0 ) event files – K 0 0.9 TeV (collision data) 10 files with 25 events in each file 1 file with 25 very selected events – Lambda 0.9 TeV (collision data) 10 files with 25 events in each file 1 file with 25 very selected events 2

3. Exploration hints Preparation of the event display (Note that Data tab, InDet tab and Cuts tab might already be properly set at start- up, but if not follow the instructions.) – “Data” tab – Click “Data” tab under “Status”, then “InDet” and tick “Track Collection”, “Space Point” and “RecVertex”. – “InDet” tab – Make the collision point (primary vertex) and the decay points (secondary vertices) well visible by clicking on “InDet” tab, then “RecVertex” and set the “Symbol size” to 7. Tick “Force symb” to see vertex also on top display. 3

4. Exploration hints cont. “Cuts” tab – Set pT to > 0.5 GeV (pT is the momentum in the direction at right angle to the colliding beams). Tick the box, and highlight the number. Enter the new number and do “Return”. This selection removes quite a few tracks and makes it easier to explore the event. – Set z0 < 20 cm (z0 is the z coordinate of the primary vertex and should be rather close to 0) and d0Loose to < 4 cm (d0 is the distance the track misses the primary vertex) – The d0 cut can be used during the exploration of the event. Normally require d0> 0.5 mm. This focuses the interest on the particles from secondary vertices. Note that this cut can sometimes also remove a track from the secondary vertex. By removing the cut, all the tracks from the primary vertex are also seen. 4

5. Exploration hints cont. Exploration – Use both display projections to inspect primary and secondary vertices close to the collision point, typically within 40 cm from the collision point. Use the zoom facility to focus on that part of the detector. Use the information from both views as some tracks and vertices are easier to observe in one of the views. Sometimes the vertices are somewhat displaced from the real vertex. The best is to complement the display with your own pattern recognition capacity During the exploration of the event, it is useful to switch between having no d0 cut and including the cu in order to see all the tracks (no d0 cut) and focusing on tracks coming mainly from the secondary vertex (with d0 cut). 5