BTeV Physics Reach LHC 2003 Symposium K. Honscheid Ohio State University

LHC2003K. HonscheidOhio State

BTeV Physics Reach

LHC 2003 SymposiumK. Honscheid

Ohio State University


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


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)


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


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


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*


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


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-


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


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


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


Bs Mixing (Vtd/Vts)

BTeV reaches sensitivity to xs of 80 in 3.2 years

6

5

4

3

2

1


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


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.


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


Part II: Search for New Physics

For a nice overview see: S. Stone “BTeV Physics” athttp://doe-hep.hep.net/P5StoneMarch2003.pdf


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


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*


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


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


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 ->


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


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)

BTeV Physics Reach LHC 2003 Symposium K. Honscheid Ohio State University

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