btev physics reach lhc 2003 symposium k. honscheid ohio state university
DESCRIPTION
BTeV Physics Reach LHC 2003 Symposium K. Honscheid Ohio State University. B Physics Today. CKM Picture okay CP Violation observed No conflict with SM. sin(2 b ) = 0.734 +/- 0.054. Surprising B Physics. >10 11 b hadrons (including B s ). B Physics at Hadron Colliders. - PowerPoint PPT PresentationTRANSCRIPT
LHC2003K. HonscheidOhio State
BTeV Physics Reach
LHC 2003 SymposiumK. Honscheid
Ohio State University
LHC2003K. HonscheidOhio State
B Physics Today
CKM Picture okay
CP Violation observed
No conflict with SM
Vud Vus Vub
VCKM = Vcd Vcs Vcb
Vtd Vts Vtb
sin(2) = 0.734 +/- 0.054
LHC2003K. HonscheidOhio State
Surprising B Physics
Year
Item Theory Prediction ~Value
# B’s
1983 bToo small to be observed ~ < 0.1ps 1 ps 2x104
1987 Bo-Bo mixing
Too small to see (~ < 1%) as mtop is believed to be ~30 GeV
20% 2x105
2001 sin(2) No direct prediction, but consistent with other measurements
3/4 107
>1011 b hadrons
(including Bs)
LHC2003K. HonscheidOhio State
B Physics at Hadron Colliders
The Tevatron as b (and c) sourceb cross section ~100 b, c cross section ~1000 bb fraction 2x10-3
Inst. Luminosity2x1032
Bunch spacing 132 ns (396 ns)Int./crossing <2> (<6>)Luminous region z = 30 cm
Forward Geometry
2x1011 b pairs/year
b production angle
b production angle
LHC2003K. HonscheidOhio State
The BTeV Detector
Beam Line
Pixel DetectorVacuum Vessel
• 60 pixel planes• inside magnet• = 5-10 m
Proper time resolution: 46 fs
RICH DetectorGas (C4F10) + Liquid Radiator (C5F12)
HPD + PMT read-out
/K/p separation up to 70 GeV/ce/ separation at low momenta
PbWO4 EM Calorimeter
CLEO/BaBar/BELLE-like performance in a hadron Collider environment!
~ 5 MeV
~ 3 MeV
10500 crystals220 mm long, 28x28 mm2
LHC2003K. HonscheidOhio State
Efficiencies and TaggingFor a requirement of at least 2 tracks detached by more than 6, we trigger on only 1% of the beam crossings and achieve the following trigger efficiencies for these states (<2> int. per crossing):
efficiency; D Dilution or (Nright-Nwrong)/(Nright+Nwrong)
Effective tagging efficiency D2
Extensive study for BTeV usesOpposite sign K±
Jet ChargeSame side ± (for Bo) or K± for (Bs)
LeptonsConclusion: D2 (Bo) = 0.10, D2 (Bs) = 0.13, difference due to same side tagging
Decay efficiency(%) Decay efficiency(%)
B +- 63 Bo K+- 63
Bs DsK 74 Bo J/ Ks 50
B- DoK- 70 Bs J/K* 68
B- Ks- 27 Bo K*
LHC2003K. HonscheidOhio State
The Physics Goals
There is New Physics out there: Baryon Asymmetry of Universe & by Dark MatterHierarchy problemPlethora of fundamental parameters…
BTeV is in a unique position to:Perform precision measurements of CKM Elements withsmall model dependence.Search for New Physics via CP phasesSearch for New Physics via Rare DecaysHelp 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 b
b & c quark ProductionStructure: B baryon statesBc decays
LHC2003K. HonscheidOhio State
Part 1: Is the CKM Picture correct?
Use different sets of measurements to define apex of triangle
(adopted from Peskin)
Also have K (CP in KL system)
Magnitudes
Bd mixing phase
Bs mixing phase
Can also measure via B-DoK-
LHC2003K. HonscheidOhio State
Measuring Using Bo
A Dalitz Plot analysis gives both sin(2) and cos(2)(Snyder & Quinn)
Measured branching ratios are:
(B = ~10-5
(B + = ~3x10-5
(B <0.5x10-5
Snyder & Quinn showed that 1000-2000 tagged events are sufficient
Not easy to measure0 reconstruction
Not easy to analyze9 parameter likelihood fit
Slow 0’s
Nearly empty( polarization)
Dalitz Plot for Bo
LHC2003K. HonscheidOhio State
Yields for BoBased 9.9x106 background events
Bo+-
5400 events, S/B = 4.1
Booo
780 events, S/B = 0.3
o
Background Signal
mB (GeV) mB (GeV)
Booo
LHC2003K. HonscheidOhio State
Our Estimate of Accuracy on
Geant simulation of Bo(for 1.4x107 s)
Example:1000 Bo signal + backgroundsWith input =77.3o
minimum 2
non-resonantnon- bkgrd
resonantnon- bkgrd
(gen)
Rres Rnon(recon)
77.3o 0.2 0.2 77.2o 1.6o
77.3o 0.4 0 77.1o 1.8o
93.0o 0.2 0.2 93.3o 1.9o
93.0o 0.4 0 93.3o 2.1o
111.0o 0.2 0.2 111.7o 3.9o
111.0o 0.4 0.2 110.4o 4.3o
LHC2003K. HonscheidOhio State
Bs Mixing (Vtd/Vts)
BTeV reaches sensitivity to xs of 80 in 3.2 years
6
5
4
3
2
1
LHC2003K. HonscheidOhio State
Measuring In the SM the phases and magnitudes are correlated:
|Vus| = 0.2205±0.0018
is the phase of Vts -> Bs Mixing
Good: Bs->J/ plus non-trivial angular analysisBetter: Bs -> CP eigenstate such as
BsJ/
2 sin sinsin
sin( + )
Silva & Wolfenstein (hep-ph/9610208)Aleksan, Kayser & London
LHC2003K. HonscheidOhio State
Measuring II
BTeV can reconstruct and ’
Yield in one yearBsJ/2,800 events with S/B = 15
BsJ/9,800 events with S/B = 30
Error on sin(2 = 0.024
With ~ 2o a precision measurement will require a few years.
LHC2003K. HonscheidOhio State
Physics Reach (CKM) in 107 s Reaction B(B)
(x10-6)# of Events
S/B Parameter Error or (Value)
Bs Ds K- 300 7500 7 - 8o
Bs Ds- 3000 59,000 3 xs (75)
BoJ/KS J/+ - 445 168,000 10 sin(2) 0.017
BoJ/Ko, Ko 7 250 2.3 cos(2) ~0.5
B-Do (K+-) K- 0.17
170 1
B-Do (K+K-) K- 1.1 1,000 >10 13o
BsJ/ 330 2,800 15
BsJ/ 670 9,800 30 sin(2 0.024
Bo+- 28 5,400 4.1
Booo 5 780 0.3 ~4o Reaction B(B)
(x10-6)# of Events
S/B Parameter Error
B-KS -
12.1 4,600 1 <4o +
BoK+- 18.8
62,100 20 Theory err.
Bo+- 4.5 14,600 3 Asymmetry 0.030
BoK+ K- 17 18,900 6.6 Asymmetry 0.020
LHC2003K. HonscheidOhio State
Part II: Search for New Physics
For a nice overview see: S. Stone “BTeV Physics” athttp://doe-hep.hep.net/P5StoneMarch2003.pdf
LHC2003K. HonscheidOhio State
First Example: Supersymmetry
Supersymmetry: In general 80 constants & 43 phasesMSSM: 2 phases (Nir, hep-ph/9911321)
New Physics in Bo mixing: D , Bo decay: A, Do
mixing: K
Process Quantity SM New Physics
BoJ/Ks CP asym sin(2) sin2(D)
BoKs CP asym sin(2) sin2(DA)
DoK-+ CP asym 0 ~sin(K)
New Physics
Difference NP
LHC2003K. HonscheidOhio State
Rare b Decays Search for New Physics in Loop diagrams
New fermion like objects in addition to t, c or uNew Gauge-like objects in addition to W, Z or g
Inclusive Rare Decays including bs bd bs+
Exclusive Rare Decays such as BBK*+ Dalitz plot & polarization
+-
BoK*
LHC2003K. HonscheidOhio State
Yield, S/B for Rare b Decays
Reaction B (10-6) Signal S/B Physics
BoK*o+- 1.5 2530 11 Polarization; Rate
B-K-+- 0.4 1470 3.2 Rate
bs+- 5.7 4140 0.13 Rate; Wilson coefficents
LHC2003K. HonscheidOhio State
BTeV data compared to Burdman et al calculation
Dilepton invariant mass distributions,forward-backward asymmetrydiscriminate among the SM and various supersymmetric theories.(Ali, Lunghi, Greub & Hiller, hep-ph/0112300)
One year for K*+-, enough to determine if New Physics is present
Polarization in BoK*o+-
Ali et. al, hep-ph/9910221
LHC2003K. HonscheidOhio State
Second Example: Extra Dimensions
Aranda & Lorenzo Diaz-Cruz, “Flavor Symmetries in Extra Dimensions” (hep-ph/0207059) (Buras et al. hep-ph/0212143) Extra spatial dimension is compactified at scale 1/R = 250 GeV on upNo effect on |Vub/Vcb|, Md/Ms , sin(2)
–8%–100
+72%|Vtd|
Bs ->
LHC2003K. HonscheidOhio State
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 dependencediscover 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 BTeV with
an efficient, unbiased trigger and a high performance DAQa superb charged particle tracking systemgood particle identificationexcellent photon detection
LHC2003K. HonscheidOhio State
Changes wrt Proposal in Event Yields & Sensitivities
We lost one arm, factor = 0.5We gained on dileptons
From RICH IDin proposal we used only +-, now we include e+e-
factor = 2.4 (or 3.9), depending on whether analysis used single (dilepton) id
We gained on DAQ bandwidth, factor = 1.15Gained on D2 for Bs only, factor = 1.3
Mode Yieldproposal
Yield factor
Yieldone-arm
QuantityErr(prop) (D2)
QuantityErr(1arm) (D2)
BoJ/ Ks 80,500
0.5*3.9*1.15=2.24
168,000
sin(2) 0.025 (0.10)
sin(2)0.017 (0.10)
BsJ/() 9,940
0.5*2.4*1.15=1.38
12,600
sin(2)0.033 (0.10)
sin(2)0.024 (0.13)
Bs Ds K- 13,10
0 0.5*1.15 =0.58
7,500 6o (0.10)
8o (0.13)