BLIND SUSY ANALYSIS REPORT ON THE LYON WORKSHOP

BLIND SUSY ANALYSIS REPORT ON THE LYON WORKSHOP • OUTLINE • Introduction • Updates • First public results • Conclusions and Outlook 1 S. Muanza, CPPM Marseille

Introduction- Reminders - • The « SUSY Blind Analysis » is a SUSY challenge that was coocked • ~2 years ago in the SUSY GDR and proposed to SUSY hunters • communities (LH 2007) • The aim was to test our methods and strategies to: • assess a SUSY signal at the LHC • measure some observables (end-points, thresholds, s, BR ratios,…) • constrain or determine the underlying model parameters • all of this in aBLIND ANALYSIS 2

Introduction- Cookbook - • A SUSY point was chosen in a model to be determined • All the SUSY & Higgs processes were produced simultaneously and mixed • with the SM background (MC truth infos removed) • CoM energy: 14 TeV, L=100 pb-1 • Individual SM background samples were also made available • Format: simple root-tuples available at CCIN2P3 in HPSS, also made • available elsewhere using SRB • Website:http://www-clued0.fnal.gov/~muanza/Blind_SUSY_Analysis.html 3

Introduction- Lyon Workshop - • Very few people dared to try & solve this SUSY challenge • The Lyon workshop was proposed to revive this project within the GDR • and to make myself available to answer any technical questions while some • analyzers were actually « getting their hands dirty » with the challenge • Place: IPN Lyon • Date: 25-27 march 2009 • Low attendance: • 2 post-docs from Lyon => very informal workshop • 3 people based at CERN expressed interest but finally did not have • time to try the challenge at the time of the workshop 4

Updates- Technicalities - • At CCIN2P3 the Linux platforms have evolved: • at the time I produced the samples: • ROOT v5.14, SL v3, gcc v3.2.3, 32-bits • currently: • ROOT v5.14, SL v4, gcc v3.4.6, 64-bits platform (supports 32-bits) • h2root does not work anymore! • solution connect to ccalisl432.in2p3.fr : • works interactively • no batch support for 32-bits code 5

Updates- Revealing a Clue - • Here’s the main experimental trick I introduced to differentiate the • pseudo-data sample from the SM background samples: • PsD1: was produced using the option KEYLUM=2 (high lumi) • BKGD: was produced using the option KEYLUM=1 (low lumi) • effects: • I chose not to change the trigger nor the jets thresholds • the only effects are different resolutions • can find it in the code (tarball on the webpage): • atlfast-00-02-22/atlfast/atlfast.F • FUNCTIONS: RESHAD, RESEL, RESPHO 6

Updates- Revealing a Clue - • This is propagate to the mET calculation: • SUBROUTINE: MAKMIS • Example: Jet Resolutions • |h|<3.0: • |h|>3.0: • for DR=0.4, Epile-up=7.5 GeV 7

Updates- New Analysis Code - • I updated the proposed analysis code: • a bug fix on a Z(qq)+jets cross section (thanks to Patrice Verdier) • slightly different access to the sub-processes root-tuples: • each sub-process in its own sub-dir • the analysis code automatically makes TChain w/ all the root-tuples • in there • it does not depend on a specific root-tuple name anymore • the user will have to copy the sub-dir tree in his/her working area • the code is set to analyze the skimmed (mET > 150 GeV) root-tuples • the code can perform further skimmings 8

Updates- New Analysis Code: Outputs - • Arbitrary Cuts: • Trigger OR • mET > 250 GeV • Njets > 3 9

First Public Results- P. Verdier - 10

Conclusions & Outlook • Apologies I did not find the time to update the website (end of this week) • I encourage all of you to try this SUSY challenge • Especially to measure some features of the SUSY+Higgs excess • And to hand it over to SUSY fitters (Sfitter, Fittino, OSET methods,…) • I’ll « open the box » at the time of the Les Houches 2009 meeting • And give the bottle champagne to the author of the • closest answer! 11

BLIND SUSY ANALYSIS REPORT ON THE LYON WORKSHOP