Future CDF and D0 B Physics

1
Future CDF and D0 B Physics
Kaon 2001 International
Conference in CP violation Pisa Italy June 12th
- 17th , 2001 Donatella
Lucchesi University and INFN of Padova
for CDF and D0 collaborations

• OUTLINE
• B physics at the Tevatron Run I experience
• Major upgrades (Tevatron and detectors
  )(skipped)
• Main b-physics prospects for Run II

2
B Physics at the Tevatron
1) Large cross section s(pp bb) 100 mb at
Ös 1.8 TeV s(ee- bb) 7 nb at Z0
s(ee- BB) 1 nb at (4S)
BUT inelastic cross sect. 103 times larger
Specialized trigger Run I (CDF and D0)
Run II - inclusive
leptons Run I -
di-leptons CDF
displaced tracks
D0 track trigger
3
B Physics at the Tevatron con't
2) All species, including Bs, Bc, b produced
Bc discovery
3) Precise measurements already done -
lifetimes (Bs,Bd,b) - B - B mixing - sin(2b)
4
Major Upgrades
Tevatron New Main Injector(more p ) and
Recycler Ring (reuse p)
D0
Time of flight
Layer 00
L00
5
Run II B Physics Goals

• In this talk
• Bs mixing
  
• CP violation and CKM angles
• - sin(2b)
• - sin(g )
• Non Standard Model CP
• violation in BsJ/??
• DG/G in Bs decays

• What is missing
• QCD tests
• Spectroscopy and lifetimes
• Rare and radiative decays
• Everything else

6
B Physics in the Standard Model
Weak eigenstates ¹ mass eigenstates

Cabibbo Kobayashi Maskawa matrix

h



Unitarity Þ VtbVtd VcbVcd VubVud 0
with l sin(qc ) measured to a few Vcb _at_
Vts
(r,h)
a
g
b
h¹0 Þ CP is violated
1
r
7
Analysis Requirements
?

• Mixing
• Reconstruct the decay time
• Tag the B flavor at production
• and decay time

Jet charge

• CP Violation
• Identify the decay channel
• reconstruct the decay time
• tag the B flavor at production

i.e. B0 ? J/?K0s A(t) Dsin(2b)sin(Dmt)
A(t)

• Tagging
• several methods
• figure of merit eD2
• e efficiency Ntag/Ntot
• Ddilution NR-NW/NRNW

8
Bs - Bs Oscillations
Bd mixing Dmd Bs mixing Dms measuring both Þ
Unique to hadron collider
xs Dmst Sig(xs) µ e-(xssctG)2/2 Þ need
fully reconstructed B
BsDsp BsDspp-p (100-300
events) (300-900 events) - Trigger
opposite side lepton initial flavor tag -
Final flavor tagged by Ds charge Bs J/yK
KKp- (300-1000 events) - Trigger on muons -
Initial flavor tag eD27, final eD290
Xs up to 20 -30
9
Bs - Bs Oscillations
Run I Dmsgt5.8 ps-1 _at_95 C.L. with BsDsln ?
ln X
Run II
BsDsp BsDspp-p 20,000 events trigger on
displaced tracks
Assumptions
flavor tag
eD2
11.3
st 45 fs
63 SN21
?
XsMAX

56 SN12
10
Bs - Bs Oscillations
Integrated Luminosity for a 5? measurement
Once oscillations are observed Xs will be
measured precisely
11
CP Violation sin(??)
Scale the error for Run II
Systematic error Run I eD2 (6.3 ? 1.7)
calibrated with B??J/?K? (statistically limited)
Run II eD2 9.1 ?
Statistical error Run I 198 ? 17 events
0.027
Systematic error scale with statistic
Assuming sin?? 1 ? ?(sin??) 0.072
If Nevents ? 28,000 (by increasing di-lepton
trigger
bandwidth )
Run II 10,000 events
?(sin??) 0.043
12
CP Violation sin(??)
Trigger single muons, di-muons ? 27
di-electrons ? 20
Reconstruction efficiency ? ?85 J/? ? ?27 Ks
Flavor tagging eD2 9.8 (MC CDF data)
S/N ? 0.75
?t ? 100 fs
Assuming luminosity 2 fb-1
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CP Violation B?hh-

• Four decays compete
• Tree dominant (BR?5x10-6)
• 1) Bd ? p p- 2) Bs ? K p-
• Penguin dominant (BR?5x10-5)
• 3) Bs ? K K- 4)Bd ? K p-

Bd ? p p- should measure sin2(bg) (sin2? if
??????) BUT penguin pollution could be
large
R. Fleisher (PLB459,306 (1999)) suggested to use
Bd ? p p and Bs ? K K- to measure g

• Four CP asymmetries
• Adir(p p-)f(sin(g),cos(g),d,?)
• Adir(K K-)f(sin(g),cos(g),d,?)
• Amix(K K-)f(sin(g),cos(g),d,?)
• Amix(p p-)f(sin2(bg),cos(g),sin2b,sin(2bg),d,?
  )

d penguins/tree ratio ? strong inter. phase
14
CP Violation B?hh-
Trigger lepton from the other B in the event
Ptgt 3 GeV 2 other tracks Ptgt 1.5
GeV ? between 0.25-0.5
Number of tagged events Bd ? p p- 300 - 600 Bs ?
K K- 650 - 1300 Bd ? K p- 1300 - 2600 Bs ? K
p- 150 300
15
CP Violation B?hh-
Trigger displaced tracksBd ? p p- 5k N
events per fb-1 Bs ? K K- 10k Bd ?
K p- 20k Bs ? K p- 2,5k
sA(K K-) 0.08 sA(p p-) 0.14

• Assuming
• flavor SU(3) symmetry
• dKK dpp ?KK ?pp
• sin(??) from J/?Ks
• S/B 1/2
• Xs 30
• ?(?) 10o (stat. ? syst.)

16
CP Violation g from Bs

• R. Aleksan, et al. Z.Phys. C54, 653 (1992)
  proposal
• Bs ? Ds-K Bs ? DsK- time dependent decay rate
  depends on
• sin(d?g), cos(d? g)
• Theoretically clean
• Reasonable branching ratio
• Background (Bs ? Dsp) separation difficult
• Need tagging
• Need time dependent analysis

Trigger displaced tracks N850 events/2
fb-1 S/B1/1(physics) S/B1/3
1/10(combinatorial) eD2 11.3
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Bs? J/?? DG/G CP beyond S.M.
DG/G DG/G 1/2(Gh - Gl)/(Gh Gl) DG/G
0.05 - 0.20 (S.M.) DG?Dm (within S. M.) Bs? J/??
CP mixed Run I CP even fraction
0.77?0.19 Run II No events 4,000 in 2 fb-1 Fit
decay time distribution s(DG/G) 0.05
CP violation is expected 3 If larger ? New
Physic Requirement of Xs Run II No events
4,000 in 2 fb-1 eD2 9.7
18
Conclusions

• Run II projections
• Constrain one side and 2 angles of Unitary
  Triangle
• Sin2b, g, Xs Unique to Hadron Collider
• Measure DG and compare to Dm
• Search for New Physics
• by measuring ACP in Bs? J/??
• By Summer 2002
• Expected 400 pb-1 by Spring 2002

1 yr data
From the new Run .
19
Conclusions cont
W ? e n cand.
Impact parameter distribution as seen by Silicon
Vertex Tracker in the first 36X36 collisions
SVT res.
Missing Et 38 GeV
s 66 mm
mm