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CDF Overview

CDF Overview. Joseph Kroll Penn DOE Review 6 August 2007. TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: A A A A A A A. Faculty Joseph Kroll Nigel Lockyer (adjunct, not DOE) Evelyn Thomson Brig Williams Post-docs Anadi Canepa (not DOE)

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CDF Overview

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  1. CDF Overview Joseph Kroll Penn DOE Review 6 August 2007 TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAAA

  2. Faculty Joseph Kroll Nigel Lockyer (adjunct, not DOE) Evelyn Thomson Brig Williams Post-docs Anadi Canepa (not DOE) Aart Heijboer Chris Neu Graduate Students Justin Keung (20% DOE) Elizabetta Pianori Tatiana Rodriguez Yanjun Tu Instrumentation Group Joel Heinrich Walter Kononenko Personnel Advances in people’s careers: Kristian Hahn: MIT post-doc Aafke Kraan: Marie Curie EU Fellowship Daniel Whiteson: Assistant Professor UC Irvine

  3. Contributions to CDF Experiment/Operations • Major contributions of the past*** • COT front end electronics - ASDQ ASIC & daughter board (Lockyer) • TOF signal electronics (Jones, Oldeman, Chen, Usynin, Kroll) • Still carry TOF pager (Heijboer) • Trigger Level 2 upgrade • Run IIa upgrade (Hahn, Neu, Whiteson, Kroll, Wittich)*** • Run IIb Calorimeter + general expertise (Canepa – see talk today) • Calibration constants • 1st organized systematic calibration effort (Kraan) • Set up automatic calibration procedure for production (Whiteson) • Silicon tracking detector alignment (Heijboer) ***Critical contributions from Penn Instrumentation Specialists

  4. Physics • B Physics (this talk) • Primary participants in B0s flavor oscillations • Top Physics (see talk by E. Thomson) • Top cross-section • Top mass • Top decay properties (W helicity measurement) • SUSY (see talk by A. Canepa) • High mass dilepton pairs (e¹, e¿, ¹¿) • Standard Model Higgs (this talk & Thomson, Canepa) • Contributions in several areas – see details later in this presentation

  5. Publications • Authors of 12 publications from CDF Run II in PRL or PRD including • 1st Tevatron Run II PRL (Charm cross-section, C. Chen thesis) • 1st Tevatron Run II High-pT PRL (top dilepton cross-section) • This past year we authored 5 publications

  6. Penn played major leadership role Began in Run I Development of flavor tagging B0 oscillation measurements Sin2¯ analysis TOF prototype Run II Highlights TOF critical for observation Co-leader of analysis (Kroll) 1st measurement of excess of kaons around B0s (Usynin) Proposed & executed method to determine significance (Heijboer) Critical innovations to sped up likelihood fit (Heijboer) Primary authors of both PRLs Observation of B0s Oscillations

  7. Conference Presentations by Penn People

  8. Plans for the Coming Year Tevatron and CDF CDF: > 2.6 fb-1 80% eff. are both running extremely well The most exciting results are still to come from these data

  9. Largest production cross-section Instead search for But QCD background overwhelms at low mass For low mass Higgs Use associated production Leptonic W & Z easily identified Search for SM Higgs at Tevatron

  10. Penn Contributions to Higgs Search • New trigger capabilities (see talk by A. Canepa) • L2 upgrade • Studies of trigger algorithms (Higgs trigger task force, ¿ triggers) • Increase trigger efficiency – especially as inst. L increases • Understand backgrounds (see talk by E. Thomson) • Measure Wbb cross-section (see talk by E. Thomson) • Measure WZ, ZZ production • Increase signal sensitivity (see talk by E. Thomson) • Z! bb for b-jet energy calibration • b tagging studies • Add new signal paths • Build on ¿ id developed for dilepton SUSY search (A. Canepa talk) • Add W!¿º¿ to WH channel • Use W!¿º in H! WW • Use W,Z! qq0 in WH, ZH (discussed here) • Exploit experience with Matrix Element tech. used in top mass meas.

  11. q q Motivation W decay modes Z decay modes b ene _ H nn b mnm ee mm tt tnt V (= W or Z) _ _ _ qq=70% qq=68% CDF Run IPRL 95, 051801(2005)‏ • All-hadronic channel has largest signalyield of all channels (Br W/Z ! qq ≈ 68%) • Challenge: Large QCD bbqq background • Run I result was comparable with leptonicchannels: as good as Wln and Zl+l- • Not yet investigated in Tevatron Run II.Will add new events to ongoing searches. • Data collected with multi-jet trigger originallyintended for all-hadronic ttbar. _ _ _ Initiated by A. Heijboer + D. Whiteson. Joined up with parallel initiative by group from Academia Sinica (Taiwan).

  12. Modeling the QCD background • idea: look in background-enriched 1-b tagsample to estimate the number of 2-b tag signal events. • Determine the Tag Rate Fraction (TRF) in a region without VH signal. • Backgrounds with real Z/W (e.g. ttbar) will be modeled by MC TRF prediction data _ qq sideband: use to measure TRF Tag rate function predicts #events in signal region. Mqq 'signal' region VH signal _ qq sideband: use to measure TRF Mbb (GeV)‏ Mbb

  13. data (QCD)‏ Higgs signal MC ( P(x|WH) + P(x|ZH) P(x|WH) + P(x|ZH) + P(x|QCD) ) log Separating signal and background Discriminate between data and background using Likelihood computedusing Matrix Elements. The probability of seeing event x is: integrate over unknown parton momenta matrix element describes parton level physics jet transfer functions describes the detector response to partons Likelihood ratio to discriminate signal and bg. QCD normalized to signal MC • particular for this analysis: O(100k) events to analyze. Execution speed had to be drastically improved (from 15 min ! 10 sec). • S/B separation compares favorably to alternatives (NN, DBT)

  14. ( P(x|WH) + P(x|ZH) P(x|WH) + P(x|ZH) + P(x|QCD) ) log Separating signal and background Discriminate between data and background using Likelihood computedusing Matrix Elements. The probability of seeing event x is: integrate over unknown parton momenta matrix element describes parton level physics jet transfer functions describes the detector response to partons Likelihood ratio to discriminate signal and bg. • particular for this analysis: O(100k) events to analyze. Execution speed had to be drastically improved (from 15 min ! 10 sec). • S/B separation compares favorably to alternatives (NN, DBT)

  15. Plan • First estimate of expected sensitivity expect limit around s/ssm=15 for low MH • Comparable to other analyses • Good prospect for adding significantlyto combined Tevatron limit. • Goal: Complete a ~2 fb-1 analysis by the end of the year. sensitivity estimate for 1.7 fb-1 (no systematics included)‏ exluded by LEP • Possible improvements: • Add other trigger paths potentially factor ~2 more data • Analyze events with 1 b-tagequivalent to adding ~50% statistics • Use advances b-tagging algorithms • Add Vector Boson Fusion channel(initial studies being done by P. Methala, Univ. Helsinki).

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