The BTe. V Experiment: Physics and Detector FPCP 2003 K. Honscheid Ohio State University FPCP 2003 K. Honscheid Ohio State More details can be found at www-physics. mps. ohio-state. edu/~klaus/research/cipanp. pdf and the BTe. V web site at fnal. gov
B Physics Today CKM Picture okay Vud Vub Vcd Vcs Vcb Vtd VCKM = Vus Vtb CP Violation observed sin(2 b) = 0. 734 +/- 0. 054 >1011 b hadrons No conflict with SM FPCP 2003 K. Honscheid Ohio State (including Bs)
B Physics at Hadron Colliders Tevatron Energy b cross section c cross section b fraction Inst. Luminosity Bunch spacing Int. /crossing Luminous region LHC 2 Te. V ~100 mb ~1000 mb 2 x 10 -3 2 x 1032 132 ns (396 ns) <2> (<6>) 30 cm 14 Te. V ~500 mb ~3500 mb 6 x 10 -3 >2 x 1032 25 ns <1> 5. 3 cm Large cross sections Triggering is an issue All b-hadrons produced (B, Bs, Bc, b-baryons) FPCP 2003 K. Honscheid Ohio State
Detector Requirements FPCP 2003 K. Honscheid Ohio State • Trigger, trigger • Vertex, decay distance • Momentum • PID • Neutrals (g, p 0) From F. Teubert
Forward vs. Central Geometry Multi-purpose experiments require large solid angle coverage. Central Geometry (CDF, D 0, Atlas, CMS) Dedicated B experiments can take advantage of Forward geometry (BTe. V, LHCb) 100 mb 230 mb bg bp rod FPCP 2003 K. Honscheid Ohio State uc tio na ng le ngle bp on a oducti r
The BTe. V Detector Beam Line FPCP 2003 K. Honscheid Ohio State
Pixel Vertex Detector Reasons for Pixel Detector: • Superior signal to noise • Excellent spatial resolution -- 5 -10 microns depending on angle, etc • Very Low occupancy • Very fast • Radiation hard Special features: • It is used directly in the L 1 trigger • Pulse height is measured on every channel with a 3 bit FADC • It is inside a dipole and gives a crude standalone momentum Doublet FPCP 2003 K. Honscheid Ohio State
The Pixel Detector II Vacuum System FPCP 2003 K. Honscheid Ohio State
Simulated B Bbar, Pixel Vertex Detector FPCP 2003 K. Honscheid Ohio State
Level 1 vertex trigger architecture 30 station pixel detector FPGA segment trackers Switch: sort by crossing number track/vertex farm (~2500 processors) Merge Trigger decision to Global Level 1 FPCP 2003 K. Honscheid Ohio State
L 1 vertex trigger algorithm Generate Level-1 accept if satisfy: “detached” tracks in the BTe. V pixel detector (Ge. V/c)2 cm FPCP 2003 K. Honscheid Ohio State
Efficiencies and Tagging Trigger Efficiency-Minimum Bias Events Trigger Efficiency. Bs Ds. K E E N=1 F F I N=2 74% I N=2 C C I N=3 E N N=1 F F N=4 I E N=3 N C C Y 1% N=4 Y Impact Parameter in units of s For a requirement of at least 2 tracks detached by more than 6 s, we trigger on only 1% of the beam crossings and achieve the following trigger efficiencies for these states (<2> int. per crossing): FPCP 2003 K. Honscheid Ohio State Decay efficiency(%) B p+ p 63 Bs Ds. K 74 B - Do K 70 B- Ksp 27 Decay efficiency(%) B o K+ p 63 Bo J/y Ks 50 Bs J/y. K* 68 B o K* g 40
The Physics Goals There is New Physics out there: Baryon Asymmetry of Universe & by Dark Matter Hierarchy problem Plethora of fundamental parameters … B Experiments at Hadron Colliders are well positioned to: Perform precision measurements of CKM Elements with small model dependence. Search for New Physics via CP phases Search for New Physics via Rare Decays Help interpret new results found elsewhere (LHC, neutrinos) Complete a broad program in heavy flavor physics Weak decay processes, B’s, polarization, Dalitz plots, QCD… Semileptonic decays including Lb b & c quark Production Structure: B(s) spetroscopy, b-baryon states Bc decays FPCP 2003 K. Honscheid Ohio State
Importance of Particle Identification BTe. V RICH Detector Liquid Gas
Measuring a Using Bo rp p+p-po A Dalitz Plot analysis gives both sin(2 a) and cos(2 a) (Snyder & Quinn) Measured branching ratios are: B(B- rop-) Nearly empty (r polarization) ~10 -5 = B(Bo r-p+ + r+p-) = ~3 x 10 -5 B(Bo ropo) <0. 5 x 10 -5 Snyder & Quinn showed that 1000 -2000 tagged events are sufficient Not easy to measure p 0 reconstruction Not easy to analyze 9 parameter likelihood fit FPCP 2003 K. Honscheid Ohio State Slow p 0’s Dalitz Plot for Bo rp
Yields for Bo rp Based 9. 9 x 106 background events Bo r+p 5400 events, S/B = 4. 1 Bo ropo 780 events, S/B = 0. 3 Background po FPCP 2003 K. Honscheid Ohio State g Bo ropo Signal g m. B (Ge. V)
Our Estimate of Accuracy on a Geant simulation of Bo rp, (for 1. 4 x 107 s) a (gen) Rres Rnon a (recon) Da 77. 3 o 0. 2 77. 2 o 1. 6 o 77. 3 o 0. 4 0 77. 1 o 1. 8 o 93. 0 o 0. 2 93. 3 o 1. 9 o 93. 0 o 0. 4 0 93. 3 o 2. 1 o 111. 0 o 0. 2 111. 7 o 3. 9 o 111. 0 o 0. 4 0. 2 110. 4 o 4. 3 o minimum c 2 Example: 1000 Bo rp signal + backgrounds With input a=77. 3 o FPCP 2003 K. Honscheid Ohio State non-resonant non-rp bkgrd
Electromagnetic Calorimeter The main challenges include • Can the detector survive the high radiation environment ? • Can the detector handle the rate and occupancy ? • Can the detector achieve adequate angle and energy resolution ? BTe. V will have a high resolution Pb. WO 4 calorimeter • Developed by CMS for use at the LHC • Large granularity Block size 2. 7 x 22 cm 3 (25 Xo) ~11000 crystals • Photomultiplier readout (no magnetic field) • Pre-amp based on QIE chip (KTe. V) • Energy resolution Stochastic term 1. 8% Constant term 0. 55% • Position resolution FPCP 2003 K. Honscheid Ohio State
Electromagnetic Calorimeter Tests Block from China’s Shanghai Institute • Resolution (energy and position) close to expectations • This system can achieve CLEO/Ba. Bar/BELLE-like performance in a hadron Collider environment! FPCP 2003 K. Honscheid Ohio State
Rare b Decays Search for New Physics in Loop diagrams New fermion like objects in addition to t, c or u New Gauge-like objects in addition to W, Z or g Inclusive Rare Decays including g, l+l- b sg b dg b sl+l- Exclusive Rare Decays such as B rg, K*g B K*l+l. Dalitz plot & polarization FPCP 2003 K. Honscheid Ohio State Bo K*g
Polarization in Bo K*om+m. BTe. V data compared to Burdman et al calculation Dilepton invariant mass distributions, forward-backward asymmetry discriminate among the SM and various supersymmetric theories. Ali et. al, hep-ph/9910221 (Ali, Lunghi, Greub & Hiller, hep-ph/0112300) FPCP 2003 K. Honscheid Ohio State One year for K*l+l-, enough to determine if New Physics is present
Muon System Provides Muon ID and Trigger for interesting physics states Check/debug pixel trigger fine-grained tracking + toroid Stand-alone mom. /mass trig. Momentum “confirmation” Basic building block: Proportional tube “Planks” ~3 m toroid(s) / iron track from IP FPCP 2003 K. Honscheid Ohio State 2. 4 m half height
Summary Heavy quark physics at hadron colliders provides a unique opportunity to measure fundamental parameters of the Standard Model with no or only small model dependence discover new physics in CP violating amplitudes or rare decays. interpret new phenomena found elsewhere (e. g. LHC) Some scenarios are clear others will be a surprise This program requires a general purpose detector like BTe. V with an efficient, unbiased trigger and a high performance DAQ a superb charged particle tracking system good particle identification excellent photon detection FPCP 2003 K. Honscheid Ohio State
Additional Transparencies FPCP 2003 K. Honscheid Ohio State
Physics Reach (CKM) in 107 s Reaction B(B) (x 10 -6) # of Events S/B Parameter Error or (Value) B s Ds K - 300 7500 7 g - 2 c 8 o B s Ds p - 3000 59, 000 3 xs (75) 445 168, 000 10 7 250 2. 3 B- Do (K+p-) K- 0. 17 170 1 B- Do (K+K-) K- 1. 1 1, 000 >10 Bo J/y KS J/y l+ l - Bo J/y Ko, Ko p l n Bs J/y h, 330 2, 800 670 9, 800 30 Bo r+p- 28 5, 400 5 780 0. 3 cos(2 b) ~0. 5 13 o g 4. 1 Bo ropo 0. 017 15 Bs J/y h sin(2 b) Reaction B(B) (x 10 -6) # of Events S/B sin(2 c) 0. 024 a ~4 o Parameter Error B- KS p- 4, 600 1 Bo K+p. FPCP 2003 K. Honscheid Ohio State 12. 1 18. 8 62, 100 20 Bo p+p- 4. 5 14, 600 3 Asymmetry 0. 030 Bo K+ K- 17 18, 900 6. 6 Asymmetry 0. 020 <4 o + g Theory err.
A simplified trigger comparison FPCP 2003 K. Honscheid Ohio State From U. Egede
Unitarity Triangles Bd 0 p+ p. Bd 0 r p B S 0 DS p Bd 0 DK*0 B S 0 DS K Bd 0 D* p, 3 p Bd 0 J/y KS 0 dg = c FPCP 2003 K. Honscheid Ohio State BS 0 J/y f From N. Harnew
Pixel Test Beam Results No change after 33 Mrad (10 years, worst case, BTe. V) Track angle (mr) FPCP 2003 K. Honscheid Ohio State Analog output of pixel amplifier before and after 33 Mrad irradiation. 0. 25 CMOS design verified radiation hard with both g and protons.
Forward Tracker Prototype Straw tracker being constructed for FNAL beam test summer/fall 2002 FPCP 2003 K. Honscheid Ohio State Predicted performance Momentum resolution is better than 1% over full momentum and angle range Drawing Of forward Microstrip tracker
HPD Schematic for BTe. V RICH HPD Tube HPD Pixel array HPD Pinout Pulse Height from 163 pixel prototype HPD. Note pedestal, 1, 2, 3 pe peaks FPCP 2003 K. Honscheid Ohio State
Prop Tube Planks Basic Building Block: Proportional Tube “Planks” 3/8” diameter Stainless steel tubes (0. 01” walls) “picket fence” design 30 (diameter) gold-plated tungsten wire Manifolds are brass soldered to tubes (RF sheilding important!) Front-end electronics: use Penn ASDQ chips, modified CDF COT card Try “D 0 fast gas” 88% Ar 10% CF 4 - CO 2 or 50% Ar – 50% Eth. FPCP 2003 K. Honscheid Ohio State
Plank Cosmic Ray Tests Cosmic Ray Test Stand FPCP 2003 K. Honscheid Ohio State
BTe. V Data Acquisition Architecture 7. 6 MHz 800 GB/s L 1 rate reduction: ~1/100 L 2/3 rate reduction: ~1/20 4 KHz FPCP 2003 K. Honscheid Ohio State 200 MB/s
Pb. WO 4 Calorimeter Properties Property Density(gm/cm 2) Radiation Length(cm) Interaction Length(cm) Light Decay time(ns) (3 components) Value 8. 28 0. 89 22. 4 5(39%) 15(60%) 100(1%) Refractive index 2. 30 Max of light emission 440 nm Temperature Coefficient (%/o. C) -2 Light output/Na(Tl)(%) 1. 3 Light output(pe/Me. V) into 2” PMT 10 FPCP 2003 K. Honscheid Ohio State Property Transverse block size Block Length Radiation Length Front end Electronics Inner dimension Energy Resolution: Stochastic term Constant term Spatial Resolution: Outer Radius Total Blocks/arm Value 2. 7 cm X 2. 7 cm 22 cm 25 PMT +/-9. 8 cm (X, Y) 1. 8% (2. 3%) 0. 55% 140 cm--215 cm $ driven 11, 500
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