Leah Welty Indiana University BEACH 2006 7706 BEACH

Leah Welty Indiana University BEACH 2006 7/7/06 BEACH Conference 2006

Outline : Movin’ On In • • • Tevatron D 0 Detector - unwrap it onion style Tracking improvements Trigger discussion Conclusions BEACH Conference 2006

Fermilab BEACH Conference 2006

Fermilab DZERO BEACH Conference 2006

D-Zero : Detector • • • Muon Detectors Calorimeter Central Fiber Tracker Silicon Detector NEW Layer 0 =0 =1 =2 =3 BEACH Conference 2006

D-Zero : Muon Detectors • Tracking Detectors – Drift Tubes (Mini & Proportional) – Fine segmentation – Slow readout • Trigger Detectors – 3 layers scintillators – Course segmentation – Fast readout • Muon Toroid – Allows for stand alone momentum measurement Source of much BEACH Conference 2006 of our power

D-Zero : Muon Detectors • Cosmic ray rejections – Scintilator timing Large | | coverage! Very Beneficial • Very low punch through – 14 interaction lengths – Have to get through toroid • Solenoid & Toroid – Polarities reversed roughly every week – 4 combinations of S&T combinations exposed to ~equal integrated luminosity – Good for systematic studies Triggered and reconstructed BEACH Conference 2006 Muons (semileptonic b decay)

Muon Detectors in Action • CP Violation of B 0 mixing and decay result • Took advantage : – solenoid and toroid reversals – Muon trackers and triggers • Reducing cosmics • Large coverage • Resulting in a world’s best measurement BEACH Conference 2006

D-Zero : Calorimeter BEACH Conference 2006

D-Zero : Calorimeter Designed for high p. T physics Help in B-Physics? • “Road Electrons” - Energy associated with central track p. T>2 Ge. V • “Calorimeter Muons” - MIP in calorimeter for ID Tagging preformance D 2( )=1. 48% D 2(e-)=0. 21% ~10% increase in signal J/ BEACH Conference 2006

D-Zero : Trackers BEACH Conference 2006

D-Zero : Fiber Tracker • • Radius : 20 cm - 52 cm Fibers used for best resolution for our tracking volume Covers central pseudo rapidity region | |<2 Reconstruct tracks + measure momentum of charged particles BEACH Conference 2006

D-Zero : SMT • 6 Central Barrels – 8 Layers of Ladders – Inner 4 barrels • All double-sided for 3 D reconstruction – Outer 2 barrels • Half of the layers double-sided • 12 Central ‘F’ Disks – Double-sided – Radius : 2. 6 cm -10. 0 cm • 4 Forward ‘H’ Disks – Single-sided – Radius : 9. 5 cm - 26 cm – Tracking out to ~ =3 BEACH Conference 2006

D-Zero : Layer 0 Beam Pipe Fits around the beam pipe and inside current silicon detector Radius : 16 mm Provide more robust tracking power and help with pattern recognition at higher luminosities BEACH Conference 2006 ~6/21/06 Installed over shutdown (~2/23/06 ~ 6/4/06)

Tracking in Action • Bs lifetime result • Importance still on the muon detector • Takes advantage of tracking also – Signed decay length – Primary & decay vertex • Resulting in a world’s best measurement BEACH Conference 2006

Tracking Corrections • Motivation – The masses of many particles at D 0 were being measured, however they were slightly off of the PDG value. – To combat this problem we looked at two sources: • Missing material in our reconstruction code • Variations in the magnetic field BEACH Conference 2006

Tracking Corrections • Used a Bethe-Bloch inspired correction to account for missing material • Used simple scale factor to take care of extra difference (B-Field Correction) BEACH Conference 2006

Before & After M(J/ )PDG=3. 097 Ge. V UNCORR Mean 1=3. 075 Mean 2=3. 065 Uncorrected the mean of the narrow peak is 3. 075 Ge. V Corrected the mean of the narrow peak is 3. 098 Ge. V CORR Splitting between the narrow and wide Gaussian means is less after corrections. BEACH Conference 2006 Mean 1=3. 098 Mean 2=3. 093

Before & After Before the corrections the p. T distribution of the M(J/ ) has a large dependence. After corrections applied M(J/ ) is much flatter and distributed around the PDG value of the J/ mass. BEACH Conference 2006

Trigger System Crossing Frequency 1. 7 MHz p p Data Acquisition rate limited to average 55 Hz (up to 150 Hz) 3 Level Trigger System L 2 L 1 1. 7 MHz 4. 2 s 2. 5 k. Hz Hardware based Simple decisions 100 s 1 k. Hz Software + Firmware Physics Objects BEACHe, , jets, tracks Conference 2006 Inelastic xsection: 60 mb D+~4. 2 b & B+~3. 6 b L 3 50 ms 150 Hz (<55> Hz) Software based Simple versions of recon. algorithms

Trigger System Our superhero muon detector comes to the rescue! L 1 1. 7 MHz Muon + EM + Jets completely fills up L 1 NO ROOM for “track only” trigger D-Zero’s B physics program is therefore muon based 4. 2 s Hardware based Simple decisions This is the major difference between D 0 and CDF in the B-physics programs BEACH Conference 2006

Detector L 1 Trigger CAL L 1 CAL FPS CPS (track trigger) L 1 CTT L 2 Trigger L 2 CAL L 2 PS CFT SMT L 2 CFT (muon trigger) Muon L 1 Framework Towers, tracks, correlations L 1 Muon L 2 STT (IP Trigger) L 2 Muon BEACH Conference 2006 Global L 2 L 3 F A R M L 2 Framework Combined objects E, mu, jets

Di-Muon Triggers • Low Luminosity • High Luminosity – Muon system only trigger – Both muons | |<2 – 1 st muon • Required to hit all layers – 1 st muon • p. T>3 in central region | |<1. 5 • Central track match – 2 nd muon – p. T>3 • All layers – p. T>3 – 2 nd muon • One layer – p. T>1. 5 BEACH Conference 2006

Single Muon Triggers • Low Luminosity • High Luminosity – | |<1. 5, p. T>3 Ge. V • Muon + Trk match at Level 1 & muon at Level 2 • Unbiased – No IP cuts • Turned off >60 -100 e 30 • Medium – Impact Parameter requirements – Associated invariant mass – Track selections at Level 3 – Extra tracks BEACH Conference 2006

Level 3 • • • Fast track reconstruction High efficiency wrt recon Down to p. T>0. 5 | |<1. 5 Primary vertex & I. P. reconstruction • 2 tracks – p. T>1. 5 – IP sig>3 • Cuts on invariant mass , Ds • • # tracks >p. T cut # IP tracks Invariant mass Use all possible combinations to reject or keep event • Tuned on semileptonic Bs data BEACH Conference 2006

Trigger Plots Efficiency vs Rejection L 3 L 1 Rate vs Luminosity Phi Mass at L 3 BEACH Conference 2006

In the Life of Muon Triggers • ~200 -300 E 30 – p. T>5 -6 • 150 -200 E 30 – p. T>4 -5 • 100 -150 E 30 – p. T>3 Ge. V – Tight L 3 • <100 E 30 – p. T>3 Ge. V – Loose L 3 ~30 Hours BEACH Conference 2006

Conclusions • Strongest D 0 detector component for B-physics is our muon detector – Although can use all parts (Calorimeter + tracking) to aid in several other analysis • D-Zero has a strong B physics program – 9 publications on Run 2 a data – 3 currently submitted – 14 preliminary results • Rely on the detector & writing triggers which allow us to get the most out of the data flow. – Quick turnaround for analysis • Presented Bs mixing results a few months after data taking ended on a full 1 fb-1 data sample BEACH Conference 2006