International Masterclasses 2013 Farid Ould-Saada On behalf of IMC steering group & authors of the material presented

International Masterclasses – institutes, 163 Masterclasses (2012: 117 / 143) 37 video conferences (mostly 4-5 institutes) –12 on ATLAS Z (57 institutes) –12 on ATLAS W (55 institutes) –10 on CMS (40 institutes) –3 on ALICE (10 institutes) 25 moderators at CERN php?cat=schedule#moderators php?cat=schedule#moderators –Moderators training on Feb 18 + separate Masterclasses + Teacher Days +US Masterclasses – s_2013 –7 on CMS (21 institutes) –5 on ATLAS Z (13 institutes)

IMC 2013 Running in 37 Countries New countries: Romania (Bukarest) Turkey (Ankara, METU) Cyprus (Nicosia) Palestine (Birzeit) Egypt (Alexandria) Rejoiner: Südafrika (Durban, Cape Town)

New ATLAS Zpath Master the invariant mass technique –to study and measure the Z boson and other resonances (J/  ) decaying to l + l - –to search for new physics (Z’) –to search for the Higgs boson in  and l + l - l + l - HYPATIA event display  Data from 2011 –13000 events ~2.5 GB (password protected, 100 free) –13 directories, 20 groups (A-T), and 50 events/mixed sample/2 students –50% Z, 30%  10% (J/ , 5% Z', 5% l + l - l + l - –Higgs candidate events: –1 fb -1 according to ATLAS publication –125 GeV Higgs MC signals ready to upload (1fb -1, 10fb -1,25fb -1 ) M(  )=125 GeV M(ee  )=123 GeV 4

New ATLAS Zpath tests OPloT: –M ll and/or M  and/or M llll to be discussed locally –Moderator: 1 slide with 3 invariant masses; Invariant mass as a tool to identify particles, to discover new particles, and to search for exotic particles Web pages updated and measurement ready – es.org/exercises/ATLAS- 2013/en/zpath.htmhttp:// es.org/exercises/ATLAS- 2013/en/zpath.htm –Introduced Higgs –Described new measurements –Prepared material for instructors, moderators, for discussions, … 5

OPloT Tests 2013 Higgs comments –4l provided without requiring 2l from Z, with lower cut on other pair –  provide MC with 125 Higgs and background –Upload 125 Higgs MC ((1)&10 & 25 fb -1 ) 6

 or e + e - ? Left: p T >1GeV; right p T >5 GeV – 2 apparent tracks pointing to 2 calorimeter objects Zoom reveals 2-pairs e + e - – Left pair disappears if at least 2 pixel hits are required (bottom) – Each pair has an invariant mass of ~0.1 GeV, i.e. consistent with a photon conversion! (circle) – We are in presence of 2- photons, both converted. – The invariant mass of the 4 electrons is ~134 GeV [square] Calorimeter object information The conclusion is that the 2 calorimeter objects correspond to 2 photons, which have converted and lead to 4 tracks; the tracks from one pair had less than 3 pixel hits So, to be classified and entered as  7

Measurements –W  l –W+/W- ratio –Angular distribution between leptons in WW events MINERVA event display Improvements –2011 real data: 693 WW/Higgs candidates mixed with 5307 W and other background events –Histogram tool has been improved –spreadsheet and histogram websites connected with database New measurement tested New ATLAS W-path with real WW (+H) events 8

New ATLAS W-path 9

Measurements J/  for schools, workshops W/Z for IMC Improvements Better transfer of results Now in 11 languages Add a small number of Higgs candidates (4 leptons only). New Masterclass on the road Tested improvements in Beijing Close to ready for IMC 2013 CMS measurements 10

Measurement Option 1 – Strangeness: decay patterns of V 0 s: K 0 s, Λ, anti- Λ from p-p collisions Option 2 – Measure nuclear suppression factor R AA New and noteworthy visual analysis: – 30 events (2012), 15 events (2013) Samples – Small p-p at 7 TeV – large pb-pb at 2.76 TeV p-Pb collisions in 2012 – show different result from Pb-Pb samples: evidence of hot plasma? ALICE measurements 11

D 0  K  –2010 minimum bias data Usual kinematic/geometric/PID/event variables available in ntuple 1.fitting mass distribution 2.obtaining signal variable distributions 3.reducing background contamination 4.measuring the D 0 lifetime No event display  Targeted at undergrads or summer school students from other experiments,  Being adopted/simplified for a Masterclass  Some work needed before …  Possible pilot run with a few institutes in 2013  Aim at deployment for IMC 201 LHCb – lifetime of D o 12

IMC coordination IMC Coordination –Dresden just signed a contract with the CERN DG, which assures the –Financing of Uta Bilow (Dresden) for the next years as IMC coordinator –Includes Europe / Middle East / Africa –America / Far East / Australia coordinated by Ken Cecire (Notre Dame) and supported by Quarknet IMC steering group and the IPPOG co-chairs –working to establish a document: mandate of group, membership, quality assurance, procedure for new measurements, … Currently measurements from ALICE, ATLAS, CMS –LHCb measurements expected in 2014; working on pilot tes with a few institute in