Transcript Slide 1
Topics from the Tevatron: CDF and D0 at 1.96 TeV And A Christmas Wish List Henry Frisch Enrico Fermi Institute and Physics Dept, University of Chicago 2004 Annual Theory Meeting, Durham, UK Current Status of the Tevatron Complex, CDF and D0 Note `goals’ are `Delivered; data points are ‘Published’. Pbar-p Luminosity vsYear per expt. Note Chicago ! Recycler (2000-2004) is 8 GeV machine in Main Injector (1999) (foreground) – where electron cooling is now being installed. 7 accelerators used in pbarp. Run 2b silicon detector upgrades-critical for top, Higgs, b-physics, … (most everything) CDF SVX/ISL remains as is: D0 Si is less radhard; good for > 4 fb-1 ? add new Layer 0 for Run IIb Inclusive Jet Spectrum- excess at high Pt or PDF’s (or scale error)? Note reach: kinematic limit is 980 High Et jets- comparison to expectations IWish List Item: Answer to Q: Can one calibrate highest Et jets against sum of several lower Et jets? E.g. take events with only 1 jet in hemisphere and max jet in opp. hemisphere < 60% of 1st jet; balance sums in 2 hemispheres (i.e. a bootstrap calibration.) Measuring Jets Wish List Item: comparable plots from both experiments (!). Jet energy scale is critical to top mass measurement B-jets contribute most to mass (don’t have W mass constraint)… Promising Idea: Balance photon and b-jets to calibrate response Un-Ki Yang, Adam Gibson Wish List Item: Answer to Q: What are the theoretical limitations on the ratio of gamma-b(c)/gamma-jet balancing? The Top Mass and the W Mass : Two key precision measurements: calib.! Error on W mass has scaled inversely with sqrt of luminosity so far – now at 59 MeV. what are our expectations with 10-20X more data? Modelling requires NLO QCD and QED in same MC Underlying event is 30 MeV/interaction in CDFneed to get from data Recoil event modelling depends on W Pt at low Pt- also need to get response from data W Mass Measurement Limited by Theoretical Issues? Modelling requires NLO QCD and QED in same MC Recoil event modelling depends on W Pt at low Pt Underlying event (uev) is 30 MeV/tower/interaction in CDF- indicates scale of precision needed- must get all detector response to uev from data (i.e. not MC). Old idea (UA2, CDF Run 1a)- use Z sample to get detector response to recoil. E.g. (D. Saltzberg) for each W from MC use measured recoil from a Z with the same Pt. Limiting factor for using Z’s was factor of 10 smaller s X BR. Q: Will future require measuring W and Z mass simultaneously by same technique? If so, need QCD/QED NLO, Z/g int.., for Z. A. Focus on W and Z production and higher order differences Top Quark Mass Measurements Run 2 detectors still commissioning - not caught up to Run 1 despite more and better data. More sophisticated techniques- D0 DLM Run 1 reanalysis: 173.3 +/- 7.8 goes to 180.1 +/-5.3 GeV Advice- take 1-sigma on Mtop seriously! Sensitivity of EWK fits to top mass This change is due to the D0 remeasurement of the same data, same calibrations, different sample weighting- Xmass Wish list item: detailed explanation of what caused the shift in mtop- same events. SM Higgs Reworked Sensitivity Estimates (2003) Run 1- 100 pb-1, 1.8 TeV, 1 expt.- Eyeball estimator: scale this by expected luminosity in Run II Standard Model Higgs CDF+D0 initial Run 2 results Z-g Interference Run 1 CDF two highest mass events were `backwards’sensitive to highermass Z’s through interference. Lovely gamma-Z interference for QM class… Above the Poles: The W Width Direct Measurement Idea (HF, Sacha Kopp, J. Rosner)- Breit-Wigner should fall slower than resolution (power law vs Gaussian, hopefully)… Insensitive to radiative corrections- good place to look for new Jacobian peaks- see Rosner, Worah, and Takeuchi, PRD49,1363 (1994) (hep-ph/9309307) From D0- MC Above the Poles: The W Width Direct Measurement GW = 2.011+/- 0.142 Systematics are largely from the Z, World Average and SM hence statistics-limited: note Z/W is 1.25 at pt=100, 1.5 at pt=200 (Arnold Prediction and Reno, Nucl Phys B319, 37, 1989) W Asymmetry W Asymmetry CTEQ6 comparison with uncertainties Wish List Item: Answer to Q: is the ratio W e vs h, PT, (mass) Zo /g e sensitive to PDF’s in a different way? High Pt Photons as New Physics Signature: (e.g. CDF Run1 eegg, mmgg events) Are Run 1 anomalies real? Experiments see only upward fluctuations- can estimate factor of luminosity needed to get to the mean (though huge uncert.) High Pt Photons as New Physics Signature: `W-gamma’ (l-met-gamma): hmm Exact Repeat of CDF Run 1 cuts in progress (Andrei Loginov) High Pt Photons as New Physics Signature: `Zgamma’ (ee or mumu-gamma): (superset of CDF eegg mmgg events Need more luminosity- keep an eye on… Diphoton + Missing Et (met) Again signature includes dilepton-diphoton, one lepton-diphoton… `Top’ Dileptons- 2 e or mu, met, jets `Top’ Dileptons- 2 e or mu, met, jets `Top’ Dileptons- 2 e or mu, met, jets Also to watch- by eye LH looks like CDF Run 1 at large met? One of Hardest Problems is precise predictions of W,Z+Njets Each with at least on tag in this case- this from top crossection meas. One of Hardest Problems is precise predictions of W,Z+Njets L. Beitler from datasets with CKKW matching made by Steve Mrenna– see S. Mrenna and P. Richardson, hepph/0312274 One of Hardest Problems is precise predictions of W,Z+Njets Each with at least on tag in this case- this from top crossection meas. Conclusions and Wish List •With luck (truly) we have a shot at exploring LOTS of channels, topics, opportunities •a large region of unexplored kinematic and signature space. •Big effort now on machine performance •Detectors working well enough- detailed calibrations still in progress Wish List •Peace on Earth •Long life to the machine, CDF and D0, and a low scale for rich new physics --`all the above’-i.e. SUSY, ED, E(6),….. AcknowledgementsThanks to all the Beams Division, and the CDF and D0 physicists and staff. Thanks also to all the technical folks at other institutions and also those at Fermilab who make this all possible. Merry Xmas to all! The End