BTeV Physics Reach
LHC 2003 Symposium
K. Honscheid
Ohio State University
LHC2003
K. Honscheid
Ohio State
B Physics Today
CKM Picture okay
VCKM =
Vud
Vus
Vub
Vcd
Vcs
Vcb
Vtd
Vts
Vtb
CP Violation observed
sin(2b) = 0.734 +/- 0.054
No conflict with SM
LHC2003
K. Honscheid
Ohio State
Surprising B Physics
Year
Item
1983
tb
1987
2001
Theory Prediction
~Value
# B’s
Too small to be observed ~ < 0.1ps
1 ps
2x104
Bo-Bo
mixing
Too small to see (~ < 1%) as mtop is
believed to be ~30 GeV
20%
2x105
sin(2b)
No direct prediction, but consistent
with other measurements
3/4
107
a,b,g
>1011 b hadrons
(including Bs)
LHC2003
K. Honscheid
Ohio State
B Physics at Hadron Colliders
The Tevatron as b (and c) source
b cross section
b fraction
Inst. Luminosity
Bunch spacing
Int./crossing
Luminous region
~100 mb, c cross section ~1000 mb
2x10-3
2x1032
2x1011 b pairs/year
132 ns (396 ns)
<2> (<6>)
sz = 30 cm
Forward Geometry
bg
LHC2003
K. Honscheid
Ohio State
The BTeV Detector
RICH Detector
Pixel Detector
Gas (C4F10) + Liquid Radiator (C5F12) Vacuum Vessel
PbWO4 EM Calorimeter
HPD + PMT read-out
10500 crystals
220 mm long, 28x28 mm2
Beam Line
p/K/p separation up to 70 GeV/c
s(h->gg) ~ 5 MeV
e/m separation at low momenta
Proper time resolution: 46 fs
s(p->gg) ~ 3 MeV
CLEO/BaBar/BELLE-like performance
in a hadron Collider environment!
LHC2003
K. Honscheid
Ohio State
• 60 pixel planes
• inside magnet
• s = 5-10 mm
Efficiencies and Tagging
For a requirement of at least 2 tracks detached by more than 6s, we
trigger on only 1% of the beam crossings and achieve the following
trigger efficiencies for these states (<2> int. per crossing):
Decay
efficiency(%)
B  p+p63
Bs  DsK
74
B-  DoK70
B-  Ksp27
LHC2003
K. Honscheid
Ohio State
Decay efficiency(%)
Bo  K+p63
Bo  J/y Ks
50
Bs  J/yK*
68
Bo  K*g
40
e  efficiency; D  Dilution or (Nright-Nwrong)/(Nright+Nwrong)
Effective tagging efficiency  eD2
Extensive study for BTeV uses
Opposite sign K±
Jet Charge
Same side p± (for Bo) or K± for (Bs)
Leptons
Conclusion: eD2 (Bo) = 0.10, eD2 (Bs) = 0.13, difference due to same side
tagging
The Physics Goals
There is New Physics out there:
Baryon Asymmetry of Universe & by Dark Matter
Hierarchy problem
Plethora of fundamental parameters
…
BTeV is in a unique position 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 baryon states
Bc decays
LHC2003
K. Honscheid
Ohio State
Part 1: Is the CKM Picture correct?
Use different sets of measurements to define apex of triangle
(adopted from Peskin)
Also have eK (CP in KL system)
Bd mixing phase
Magnitudes
Bs mixing phase
Can also measure g
via B-DoK-
LHC2003
K. Honscheid
Ohio State
Measuring a Using Borp  p+p-po
A Dalitz Plot analysis gives
both sin(2a) and cos(2a)
(Snyder & Quinn)
Measured branching ratios are:
B(B-rop-)
Nearly empty
(r polarization)
~10-5
=
B(Bor-p+ + r+p-) = ~3x10-5
B(Boropo) <0.5x10-5
Snyder & Quinn showed that
1000-2000 tagged events are
sufficient
Not easy to measure
p0 reconstruction
Not easy to analyze
9 parameter likelihood fit
LHC2003
K. Honscheid
Ohio State
Slow p0’s
Dalitz Plot for Borp
Yields for Borp
Based 9.9x106 background events
Bor+p5400 events, S/B = 4.1
Boropo
780 events, S/B = 0.3
Background
p
o
LHC2003
K. Honscheid
Ohio State
g
Boropo
Signal
g
mB (GeV)
mB (GeV)
Our Estimate of Accuracy on a
Geant simulation of Borp, (for 1.4x107 s)
a (gen)
Rres
Rnon
a (recon)
Da
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
minimum c2
Example:
1000 Borp signal + backgrounds
With input a=77.3o
LHC2003
K. Honscheid
Ohio State
non-resonant
non-rp bkgrd
resonant
non-rp bkgrd
Bs Mixing (Vtd/Vts)
BTeV reaches sensitivity to xs of 80 in 3.2 years
6
5
4
3
2
1
LHC2003
K. Honscheid
Ohio State
Measuring c
In the SM the phases and magnitudes are correlated:
sinb sing
sin c = l
sin(b+g )
2
Silva & Wolfenstein (hep-ph/9610208)
Aleksan, Kayser & London
l = |Vus| = 0.2205±0.0018
c is the phase of Vts -> Bs Mixing
Good: Bs->J/yf plus non-trivial angular analysis
Better: Bs -> CP eigenstate such as
BsJ/yh() , hgg, hrg
LHC2003
K. Honscheid
Ohio State
Measuring c II
BTeV can reconstruct h and h’
Yield in one year
BsJ/y h: 2,800 events with S/B = 15
BsJ/y h: 9,800 events with S/B = 30
Error on sin(2c) = 0.024
With c ~ 2o a precision measurement will require a few years.
LHC2003
K. Honscheid
Ohio State
Physics Reach (CKM) in 107 s
Reaction
B(B)
(x10-6)
S/B
Parameter
Error or
(Value)
Bs Ds K-
300
7500
7
g - 2c
8o
Bs 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
15
BsJ/y h
670
9,800
30
Bor+p-
28
5,400
4.1
Boropo
5
780
0.3
Reaction
B(B)
(x10-6)
LHC2003
K. Honscheid
Ohio State
# of
Events
# of
Events
S/B
sin(2b)
0.017
cos(2b)
~0.5
13o
g
sin(2c)
0.024
a
~4o
Parameter
Error
B-KS p-
12.1
4,600
1
BoK+p-
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
<4o +
g
Theory err.
Part II: Search for New Physics
LHC2003
K. Honscheid
Ohio State
For a nice overview see: S. Stone “BTeV Physics” at
http://doe-hep.hep.net/P5StoneMarch2003.pdf
First Example: Supersymmetry
Supersymmetry: In general 80 constants & 43 phases
MSSM: 2 phases (Nir, hep-ph/9911321)
New Physics in Bo mixing: qD , Bo decay: qA, Do mixing: fKp
Process
Quantity
SM
New Physics
BoJ/yKs
CP asym
sin(2b)
sin2(b+qD)
BofKs
CP asym
sin(2b)
sin2(b+qD+qA)
DoK-p+
CP asym
0
~sin(fKp)
New Physics
LHC2003
K. Honscheid
Ohio State
Difference
 NP
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+lDalitz plot & polarization
LHC2003
K. Honscheid
Ohio State
BoK*g
Yield, S/B for Rare b Decays
Reaction
LHC2003
K. Honscheid
Ohio State
B (10-6)
Signal
S/B
11
BoK*om+m-
1.5
2530
B-K-m+m-
0.4
1470
3.2
bsm+m-
5.7
4140
0.13
Physics
Polarization; Rate
Rate
Rate;
Wilson coefficents
Polarization in BoK*om+mBTeV 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)
LHC2003
K. Honscheid
Ohio State
One year for K*l+l-, enough to determine if New Physics is present
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
up
No effect on |Vub/Vcb|, DMd/DMs , sin(2b)
Bs -> mm
–8%
|Vtd|
LHC2003
K. Honscheid
Ohio State
–100
g
+72%
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
BTeV with
an efficient, unbiased trigger and a high performance DAQ
a superb charged particle tracking system
good particle identification
excellent photon detection
LHC2003
K. Honscheid
Ohio State
Changes wrt Proposal in Event Yields & Sensitivities
We lost one arm, factor = 0.5
We gained on dileptons
From RICH ID
in proposal we used only m+m-, now we include e+efactor = 2.4 (or 3.9), depending on whether analysis used single (dilepton) id
We gained on DAQ bandwidth, factor = 1.15
Gained on eD2 for Bs only, factor = 1.3
LHC2003
K. Honscheid
Ohio State
Mode
Yield
proposal
BoJ/y Ks
80,500
BsJ/yh()
9,940
Bs Ds K-
13,100
Yield
factor
Yield
one-arm
Quantity
Err(prop) (eD2)
Quantity
Err(1arm) (eD2)
0.5*3.9*
1.15=2.24
168,000
sin(2b)
0.025 (0.10)
sin(2b)
0.017 (0.10)
0.5*2.4*
1.15=1.38
12,600
sin(2c)
0.033 (0.10)
sin(2c)
0.024 (0.13)
0.5*1.15
=0.58
7,500
g
6o (0.10)
g
8o (0.13)