Early Physics Prospects at CMS

1. Early Physics Prospects at CMS Jeffrey Berryhill/FNAL CMS Center Beyond the Standard Model: from the Tevatron to the LHC Sept. 17 2008

2. What happened September 10th? CERN celebrates first complete proton beam circulation in LHC Both beam lines sustained for minutes at a time CMS, ATLAS, LHCb and ALICE all report beam halo events Fermilab/USCMS celebrates with all-night “pajama party” CMS beam halo observed in the remote operations center Worldwide press and live BBC coverage 2008 BSM – Jeffrey Berryhill

3. Possible 2008 Run Plan • Establish collisions at 900 GeV this month • Establish 10 TeV collisions within 30 days • ~30 days of physics delivering ~10 pb-1 to detectors • Coasting for one month in most advanced mode (1% of design lumi) delivers ~40 pb-1 • Retrain the quenching dipoles during winter shutdown to allow 14 TeV collisions in 2009 Mid- Oct. 2008 BSM – Jeffrey Berryhill

4. 10 TeV vs. 14 TeV 10 TeV operations is a temporary measure to minimize dipole quenches seen at 14 TeV (limited to a specific manufacturer). Dipoles to be “re-trained” to restore response “forgotten” from surface tests, in time for 2009 run Running at 10 TeV instead of 14 TeV degrades cross sections of processes far from the LHC kinematic limit by about a factor 2 Discovery potential is largely maintained even with a (unanticipated) prolonged running period at 10 TeV 2 10 14 2008 BSM – Jeffrey Berryhill

5. 2009 Run Plan and Beyond Commission beams for 14 TeV collisions Plan for 150 days of pp physics running, w/efficiency for physics 40% Phase B: 1-10% of design lumi, ~few 100 pb-1 Phase C: 10-20% of design lumi, minimum bunch spacing, ~few fb-1 >=2010: attain 1034 design lumi, collect up to 60 fb-1/year, collect 300 fb-1 SuperLHC: IR+detector upgrades, 1035 lumi, 600 fb-1/year, collect 3 ab-1 2009 B C No beam Beam 2008 BSM – Jeffrey Berryhill

6. CMS Status • All subdetectors have been installed and have • recorded cosmic ray data with central trigger/DAQ • Growing pains: • ECAL endcaps all made it in at the last minute, however trigger • electronics there is arriving late (Nov.) for 2008 run* *No electron or photon trigger for |eta| > 1.5 BUT readout is operational for otherwise-accepted events • 3.8T solenoid cavern-tested • only 10 days ago, understanding • fringe field and mechanical(!) • impact on rest of CMS • Troubleshooting front-end • electronics noise 2008 BSM – Jeffrey Berryhill

7. CMS Physics Program Characterized roughly by epochs of log10(Integrated luminosity): 2008: 0-1 pb-1Channel-level detector calibration & alignment. Measurements of minimum bias pp and low PT leptons and jets. Modest W and Z signals possibly observable. 2008?2009? 1-10 pb-1Commissioning of high PT electrons, muons, and jets. Thousands of Z to dileptons, 10X more W to leptons Plentiful high-PT jet sample, small top signal possible 2009: 10-100 pb-1Re-discovery of the Standard Model. Precision W/Z/top cross sections, diboson production + discovery potential in some channels (jets, CMSSM SUSY, TeV Z’). b-jet commissioning. Usable missing ET resolution and jet energy scale. 2008 BSM – Jeffrey Berryhill

8. CMS Physics Program 2009?2010? 0.1-1 fb-1“Gold rush” phase begins: usable calibration and commissioning for all high PT physics objects (taus). Tevatron sensitivity usurped over a broad range of channels. SM Higgs evidence from 160 to 400 GeV. 2010 and beyond 1-10 fb-1SM Higgs discovery, high-mass BSM discovery 10-100 fb-1precision BSM, or evidence for stingier scenarios (VBF) It is a prerequisite to almost any search or discovery to successfully complete the 1/10/100 pb-1 commissioning and SM re-discovery program 2008 BSM – Jeffrey Berryhill

9. CMS Physics Program 0-1 pb-1 calibration, alignment. Measurements of minimum bias pp and low PT leptons and jets. Very low lumi, very open trigger. In-situ ECAL and HCAL response calibration (phi symmetry et al.) Tracking/muon chamber efficiency of muons w/ J/y and Upsilon Underlying event measurement at 10-14 TeV Low PT electron, photon, and conversion studies First look at jets Track multiplicity in minbias @ 1pb-1 p0 calibration of ECAL 2008 BSM – Jeffrey Berryhill

10. CMS Physics Program 1-10 pb-1Commissioning of high PT electrons, muons, and jets. thousands of electron and muon pairs from Z’s essential for optimizing lepton triggering, reconstruction, and ID Usability of missing ET diagnosed with large (10^5) W sample EWK xsecs and ratios are first precision tests of CMS analysis capability Z →ee signal @10 pb-1 W →mn signal @10 pb-1 2008 BSM – Jeffrey Berryhill

11. CMS Physics Program 10-100 pb-1Re-discovery of the Standard Model. Precision W/Z/top cross sections, diboson production + discovery potential in some channels (jets, CMSSM SUSY, TeV Z’). Usable missing ET resolution and jet energy scale. Multi-TeV q/g compositeness sensitivity once JES is known Top dilepton signal @100 pb-1 with commissioned MET, btagging, JES. Top lepton+jets can ultimately be a calibration sample for them! 2008 BSM – Jeffrey Berryhill

12. CMS Discovery Phase MSSM gluino/squark 5s discovery @ 1fb-1 M(1/2) < 650 GeV, M(0) < 1.5 TeV LM1 discovery with < 10 pb-1 (if you understand jets and MET… but that will take ~10-100 pb-1) Light SM Higgs discovery @ 10 fb-1 Heavy SM Higgs discovery @ 5 fb-1 2008 BSM – Jeffrey Berryhill

13. CMS vs. ATLAS ATLAS has better: HAD calorimetry, ~6 months head start in commissioning CMS has better: ECAL E resolution Track/muon P res. 2008 BSM – Jeffrey Berryhill

14. CMS vs. CDF/D0 Advantages for CMS: ECAL granularity and resolution is excellent Tracking, ECAL and muon acceptance lead to good lepton trigger and ID out to eta of 2.5 3.8T magnet plus 200 m^2 of silicon lead to better IP and momentum resolution Muons are everywhere redundantly triggered and tracked with RPCs 2008 BSM – Jeffrey Berryhill

15. CMS vs. CDF/D0 BUT Even at 1% design lumi, CMS trigger is much more selective/less efficient. No inner tracking in the low-level trigger (bad for b,t). The high mass tracker causes electron, photons, and pions to shower! S/B often worse at 14 TeV: “signal” xsecs are 10X but tt, bb, multijet, and V+jet background xsecs are typically >10X Biggest Tevatron edge by far is detector and analysis experience, they will have better sensitivity per/event produced, so they will have unique results for medium x searches (read: Higgs) some time after the “crossover point” of ~100pb-1@LHC Once the LHC enters the fb-1 epoch, brute force wins the day….and the experience gap will close in time as well 2008 BSM – Jeffrey Berryhill

16. Caveats for BSM • Missing ET commissioning will be a rocky road as we • characterize and eliminate all the unsimulated instrumental backgrounds • Signatures resulting in only b or tau particles will be difficult to • trigger on. Needs an e, mu, photon or something else to improve • “level 1” efficiency. • Lower ET and non-isolated object topologies will be prescaled away • as lumi grows Need to understand MET from collisions (pileup) MET from LHC (halo) MET from CMS (noise) Before MET for physics is usable Run II V. Shary CALOR04 D0 raw missing ET in Run II 2008 BSM – Jeffrey Berryhill

17. Caveats for BSM • Signatures somewhat out of time (<10 ns) will have some • sensitivity: ECAL has ~ns time resolution with high granularity so “non-pointing” photons (from GMSB) can be reconstructed • Signatures with way out-of-time (> ~10ns) particles will have • triggering problems (25 ns bunch crossing timing requirements • for the trigger, “trigger rules” prohibiting consecutive bunches to • trigger, limited time sampling of readout) • Very non-prompt (many cm) or kinked track signatures may also • be difficult to distinguish from tracker conversions/interactions 2008 BSM – Jeffrey Berryhill

18. Caveats for BSM Non-”Vanilla” physics objects will require a good deal of foresight to detect (reconstruction software and triggering). Ask experimenters to get started now! Even seemingly vanilla signatures may not survive trigger evolution to higher lumi. Talk to your experimenter friends often about the trigger menu. Although on paper discovery should be “instantaneous” in some BSM scenarios, there will be a protracted period of debugging and commissioning through the first 100 pb-1 which must occur to make any discovery a sound one. These are exciting times! 2008 BSM – Jeffrey Berryhill

19. Backups 2008 BSM – Jeffrey Berryhill

20. MET Plans:From 1023 to 1027 /(cm2sec) – 14 TeV From Dan Green 2008 BSM – Jeffrey Berryhill

21. Rough Plan for Taus 0-0.1 pb-1 • Establishing basic trigger functionality: • Tuning initial L1 tau definition and veto bits • Tau trigger efficiency measurement using offline electrons and jets: • Trigger efficiency measurements without real taus: • Measurement using offline electrons: • Measurement with tight offline “taus” (fakes): • Final validation will need clean tau samples • Re-measure efficiencies using clean Z→mt(et) • Use inclusive m(e) triggers • Establishing basic functionality: • Offline efficiency measurement using high quality electrons: • Basic understanding of conversion finding: • Further progress requires clean tau samples: • Measure “other” ID efficiencies, energy calibration etc • Use Z→mt(et) using inclusive m(e) trigger • Bottom Line: • Taus will be the last object to commission 1-10 pb-1 10-100 pb-1 ? 100-500 pb-1 ? 10-100 pb-1 ? 100-500 pb-1 ? 2008 BSM – Jeffrey Berryhill