1. (what are all those B factory talks really about ?)
Section 5:
B mesons
(what are all those B factory talks really about ?) :

2. Bo Bo systems Decays of Bo Bo are the same,
so lifetimes of B1 and B2 are similar
Two types of neutral B mesons:
Bd = (bd) ; Bd = (bd)
Bs = (bs) ; Bs = (bs)
Difference in B1 and B2 lifetimes is small
Difference in B1 and B2 masses is large
Oscillation parameter o o

3. Mixing - B0 B0 Dominated by top quark contribution
(and similarly for Bs) o b d W-
u, c, t
u, c, t _ _ W+ d b - B0 B0 d b
u, c, t W- _ _ _ W+ _ _
u, c, t d b
Dominated by top quark contribution
For Bo
For Bo s

4. Bd Mixing EPS,2005 BELLE 152 106 BB . Full B reconstruction
Time-dependent probability for a at t=0
to be observed as or at time t
BELLE BB . Full B reconstruction
Asymmetry  cos(Dmdt)
|Dt| (ps)
Dmd : a high precision measurement (~1%) dominated by B factories results
Dmd = 0.5090.005 ps-1

5. Amplitude method search:
ms
EPS 2005
68%CL
95%CL
Dms= 22.2 3.1 ps-1
Dms > 14.4 ps-1 at 95%CL
Expectation from fits to the Unitarity Triangle
Amplitude method search:
LEP, SLD, Tevatron
( )

6. Bs Mixing - xs wtag backgroundst st = 43 fs s DMs= 8fs-1
CDF DMs/Gs = xs <60
SM 22< xs < 31
Si detector & disp. track trigger
combine with Bd mixing - xd
xs/xd a |Vts/Vtd| (s - theoretical unc.)
constrain side of CKM triangle
Flavour at Decay
Flavour at Production
- other B
proper time
wtag backgroundst
LHCb
st = 43 fs
s DMs=
8fs-1
DMs = 10 ps-1

8. CP Violation in B Decays
TYPES:
1) neutral to CP eigenstates
2) neutral to non-CP eigenstates
3) charged B-decays
CP Possibilities:
Mixing
Decay
Interference between mixing and decay
Channels:
Far too many to discuss!
A few well known ‘benchmark channels’

9. BdJ/Ks (CP=-1) J/ ( ) o c b c o o s K  K mixing s d d o
( )
BdJ/Ks (CP=-1) o c b
J/ c o o s K  K
mixing s d d o
Look at decay (l+l-)(+-), Br(BdJ/Ks) ~ 5x10-4
Minus for CP odd state

10. ( )
BdJ/Ks (CP=-1)
Asymmetry

11. B  charmonium EPS 2005 B0 tag _ B0 tag golden mode C=0 S=sin(2b)
B0  f
B0  B0  f
B  charmonium
(_)
B0 tag
B0 tag _
Dominant penguin contribution : same weak phase ( no direct CP violation)
The only diagram with a different weak phase is suppressed by O(l2) (+OZI)
golden mode
C=0
S=sin(2b)
New BELLE result for J/K0 ( BB)
EPS 2005

12. Discovery of Direct CP in B system
Look at B-> K+ -
Cf. anti-B->K- +
Tree and Penguin Diagrams
Contribute
Sign of Kaon Tags B
rather than anti-B meson

14. Sin(2a) from Bdgp+p- Penguin Pollution BR 5x10-6 Tree only:
Penguin
Pollution
BR 5x10-6
No sub-mass constraint
Other 2 body backgrounds
Tree only:
Due to Penguin:
a, d, |P/T|
Hard to interpret in terms of a
P in BgKp, or isospin Bgp0p0
Another possibility, clean theory, complex analysis
a from Bdgrpgp+p-p0

15. Benchmark g BdgD*-p+ BsgDsK+ - g-2dg 2b + g Tree only BR 10-3-
BdgD*-p+
BsgDsK+
2b + g
Tree only
Mixing and decay
BR 10-3
But bgu doubly cabibbo suppressed (~ 2% bgc)
Bs counterparts
g-2dg
Similar strength diagrams
Larger asymmetry
BS BR 10-4
Better Bet (if RICH)
Dsp background

16. Brief Angles Prospects Summary
BdgJ/Ks Measured accurately by BaBar/Belle 
Bdgp+p-, with |P/T| knowledge.
Bdgrpgp+p-p0, time dep. Dalitz plot 
As BdgD*-p+ or BsgDsK+
Bdgp+p- - What is it good for ? Comparing with BsgK+K- 
BdgJ/, obtain CP eigenstates from angular correlations
Probe higher order unitarity r o o o o o - o o o

17. The Experiments B Factories (2000): TeVatron (2001 ):
BaBar, Belle
(also CLEO)
TeVatron (2001 ):
CDF, D0, (proposed BTev)
LHC (start 2007)
LHCb (also ATLAS,CMS)

18. Flavour Tagging B Signal B Other B use particles accompanying signal B
e – tagging efficiency
w – wrong tagging fraction
D=1-2w, Dilution
Identify other b hadron
- deduce initial flavour
Semileptonic decay bgl
kaon tag bgcgs
jet charge

19. Systematic Errors measure e,e w,w Precision 10-3 Untaggeda f+ / f-
Production Asymmetries
Initial fraction b , b
e , e
e.g. detector response
asymmetry
in magnetic field
w , w
Final State acceptance
Control Channels
e.g.
measure e,e w,w
Precision 10-3
Untaggeda f+ / f- + -

20. B Factories: BaBar/PEPII, Belle/KEKB
Asymmetric beams boosted B
Time difference between B decays  z
At decay time on b one bbar (c.f. EPR ‘Paradox’)

21. Why study CP at a hadron collider ?
e+ e-
(BaBar)
pp(bar)
(D0)
Rate
statistics limited channel
Clean environment
no additional tracks
Initial state
B0B0 or B+B-
B mesons ~ 20% stot
simpler triggering Bs
DMs Bs
Extracting g Bs
J/Yf

22. Hadronic b production h = - ln (tan (q/2))
LHC 1012 bb per year
h = - ln (tan (q/2))
2 < h<5 LHCb/BTeV
for larger |h | B boost bg increases rapidly
(B factories ~ 108)
B quark pair produced preferentially at small q
highly correlated

23. LHCb Detector Forward single arm spectrometer
Two RICH detectors for particle ID
Multi-level Trigger system, using displaced vertices
Precision Silicon Vertex Detector
40MHz beam crossing rate
Series of Discs
Detectors separated 6cm during injection

24. Bdgp+p- No identification Purity = 9.5% With pion identification
Purity = 85%, Eff. =90%

25. Remarks on CP Violation
Section 6:
Concluding
Remarks on CP Violation :

26. CKM triangle status, ICHEP 2004
Compatibility obtained between all constraints
2002: first non-trivial compatibility test for CKM triangle
Next step to measure alpha and beta angles

28. Final Comments CP violation: a fundamental symmetry broken Next Decade
Good reasons to believe SM is not final answer
Sensitive to new physics
Next Decade
Promises to be v. exciting for CP studies
BaBar/Belle , TeVatron, LHC
Overconstrain CKM triangle

29. Not the whole picture…. Do mixing CP violation in the lepton sector
Not yet observed
Slow oscillations x< 0.01
Sensitive to new physics
CP violation in the lepton sector
Massive neutrinos 
Neutrino mixing between flavour eigenstates to produce mass eigenstates
Neutrino Oscillations between 3 famillies and CP phase.
Neutrino Factory would produce enough neutrinos for CP violation test.
See Paul’s neutrino course

30. Further Reading SLAC-R-504 The BaBar Physics Book,
Chapter 1, A CP Violation Primer
CP Violation, Bigi & Sanda, Cambridge University Press, 2000
FERMILAB-Pub-01/197 B Physics at the Tevatron: Run II and Beyond
CERN Proceedings of the workshop on Standard Model Physics (and more) at the LHC
B Decays Chapter
Hep-ph/ , Y. Nir, Lectures at the SLAC Summer Institute (1999)