Report International Masterclasses Michael Kobel TU Dresden ATLAS

Report International Masterclasses Michael Kobel, TU Dresden ATLAS week, Outreach Parallel Session CERN, 18. 02. 2015

Concept of IMC • High school students (15 – 19) are „scientists for one day“ • Get invited to a research institute or university • Introductory talks (standard model, detectors, accelerators) • 2 h measurement with LHC data (ATLAS W path / Z path) • International video conference ( 2 – 5 inst. + CERN/Fermilab)

International Masterclasses 2015 • Organized by IPPOG (International Particle Physics Outreach Group: independent group of outreach representatives from countries at CERN) • 25. 2. - 2. 4. 2015 • 42 countries involved Ecuador Coord. : Quark. Net / TU Dresden Ken Cecire / Uta Bilow • 39 institutes • 42 Masterclasses • 28 CMS • 14 ATLAS • 17 video conf. with Fermilab • 170 institutes • 225 Masterclasses • 129 ATLAS • 48 CMS • 28 LHCb • 20 ALICE • 51 video conf. with CERN • 18 moderators from ATLAS

ATLAS Masterclasses 2015 In 29 countries: • Austria • Brazil • Canada • Chile • Colombia • Czech Republic • Denmark • France • Germany • Greece • Ireland • Israel • Italy • Japan • Morocco • Netherlands • Norway • Palestine • Poland • Portugal • Sao Tomé and Principe • Slovakia • Spain • South Africa • Sweden • Switzerland • Turkey • U. K. • U. S. + Australia (outside period)

ATLAS W path http: //atlas. physicsmasterclasses. org/en/wpath. htm 2 1 6 Higgs signal accumulates at small angles 3 5 4 decay of W bosons structure ot the

Update 1: New Datasets • • total of 12. 000 events (old ones had 6. 000 events) • Composition: generated XMLs are tested via python program • 50% single W events more statistics for W+/W- measurement • follow old selections with two improvements: • single W events have less than two jets -> very clean signature -> easy to spot • leptons are well isolated (ptconerel 30 < 0. 2) • ~ 10% WW events: • selected about 1050 WW events from period J and K in 2011 • essentially same selection as before • less than two jets in selection • 40% Background events: • Z Background: 2 well isolated high-pt leptons, no jets, MET < 20 Ge. V • QCD Background: no isolated high-pt leptons, at least two high-pt jets • TTbar Background: 1 well isolated high-pt lepton, at least 4 jets, other top cuts • Backgrounds should be well discernible and orthogonal to signal W+/W- ratio in the 6 data packages: ~1. 4 to ~1. 6

Update 2: More information • • students sometimes have a hard time evaluating the events supply more info: show vertices, add isolation information • easier to tell whether tracks belong to the same vertex • showing vertices is standard in ATLANTIS -> enabled it via options file for MINERVA • isolation information replaces the fuzzy “lepton has to be well isolated” by introducing a clearly defined cut • Isolation is a relative track isolation with a cone of 0. 3

ATLAS Z path http: //atlas. physicsmasterclasses. org/en/zpath. htm

2015 Updates: nearly none, some minor Oplo. T fixes, some problematic events removed