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B Physics at CDFB Physics at CDF

Junji Naganoma

University of Tsukuba

“New Developments of Flavor Physics“ Workshop2009/03/09 @ Tennomaru, Aichi, Japan

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B Physics at the TevatronB Physics at the Tevatron• Complements excellent programs at B-factories• Pros

• Large production cross section: • All bottom hadrons are produced

• B+, B0, Bs, Bc+, b, …

• Cons• Large combinatorics and messy events

• Difficult to detect low pT and 0’s from B decays• Inelastic cross section is a factor of 103 larger with roughly the same pT spectrum

• Difficult to trigger on B’s

Phys. Rev. D 71, 032001 (2005)Measured in inclusive J/ events = 17.60.4(stat)+2.5-2.3 (syst.) b

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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B Physics Results Discussed TodayB Physics Results Discussed Today

New results since last year’s workshop

• Production: X(3872)

• Lifetime: Bc, Bs, b

• Rare Decay: Bs e+-

• CP Violation: Bs J/

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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X(3872)X(3872)

• First observed by Belle collaboration in 2003• Confirmed by CDF, D0, and BaBar soon after

• Observed in decay X(3872)J/+-

• Nature of particle is still unknown• D*D “molecule”? 4-quark state? …

• Precise mass measurement can provide clues• Observation of mass splitting offers evidence of tetra-quark state• Absolute mass checks possibility of a D*D bound-state

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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X(3872) MassX(3872) Mass

• M(X) = 3871.61 0.16(stat) 0.19(syst) MeV/c2

• Result consistent with no mass splitting• Assign upper limit: m(X(3872)) < 3.6 MeV/c2 @ 95% C.L.

World best measurement

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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Interests in B Hadron LifetimesInterests in B Hadron Lifetimes• Test Heavy Quark Effective Theory (HQET) predictions

• Have previously seen 1-2 discrepancies between lifetime predictions and measurements in Bs and b

• Expect (B+) > (B0) (Bs) > (b) >> (Bc)• Shorter lifetimes indicate additional (non-SM) decay processes

HFAG 2006

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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BBss Lifetime Now Agrees with HQET Lifetime Now Agrees with HQET• L=1.3 fb-1

• displaced vertex trigger• ~1100 fully reconstructed Bs Ds

-(-)+

• ~2000 partially reconstructed BsDs

-(0+): 0 not reconstructed• Sample composition by mass fit

(Bs) = 1.518 0.041 (stat) 0.025 (syst) ps

Bs

K

K

Ds

HQET prediction with (B0) ~ (Bs): (B0) = 1.530 0.009 ps

World best measurement: consistent with theoretical prediction

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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BBcc++ Lifetime Lifetime

Bc

(e)

J/

• L=1.0 fb-1• di-muon trigger• Shorter lifetime than light B mesons

• via weak decays of b or c quark or via weak annihilation• Bc = b(~25%) + c(~65%) + W

• Fit e, channel separately, then combined

(Bc) = 0.475 +0.052 -0.049 (stat) 0.025 (syst) ps

Theory: (Bc) = 0.47 0.59 ps

consistent with theoretical prediction

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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bb Lifetime Lifetime

b

p

K

c

• 1.1 fb-1

• displaced vertex trigger• No helicity suppression• b c

+- decay• Sample composition from mass fit

(b) = 1.410 0.046 (stat) 0.029 (syst) ps

Theory: (b) = 1.346 0.077 ps

World best measurement: consistent with prediction

b(bud)

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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Rare DecaysRare Decays

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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BBs(d) s(d) e e++--, e, e++ee-- Search Search

• Bs(d) e forbidden in SM• Possible with R-parity violating SUSY, ED, or Lepto-quarks

• BR(B ee) ~10-15 in SM

• Most of direct searches for LQ set limits in the order of MLQ > 200-300 GeV/c2

Pati-Salam model allowsfor cross-generation couplings

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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BBs(d)s(d) ee, ee Search Results, ee Search Results

Nb

kg =

0.8

1

0.6

3

Nb

kg =

0.9

4

0.6

3

Nb

kg =

2.6

6

1.8

0

Nb

kg =

2.6

6

1.8

0

95% C.L. limits:Br(Bse) < 2.6 10-7, MLQ > 45 TeV/c2

Br(Bde) < 7.9 10-7, MLQ > 56 TeV/c2

95% C.L. limits:Br(Bsee) < 3.7 10-7

Br(Bdee) < 10.6 10-7

All limits are world best1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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CP ViolationCP Violation

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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CP Violation in BCP Violation in Bss J/ J/ Decays Decays

- CP violation phase s in SM is predicted to be very small O(λ2) : =0.23→ Any large CP phase is a clear sign of new physics

+

dominant contributionfrom top quark

- Analogously to the neutral B0 system, CP violation in Bs system occurs through interference of decays with and without mixing:

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

~ 2

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Results in Flavor-Tagged BResults in Flavor-Tagged Bss J/ J/

• 1.5 discrepancy with SM at L=1.35 fb-1

• Updated results have 1.8 discrepancy with SM s prediction.

Assuming no CP violation (s=0)

mean lifetime: (Bs) = 1.53 ±0.04 (stat) ±0.01 (syst) ps = 0.02 0.05 (stat) 0.01 (syst) ps-1

CP-even

CP-odd

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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CDF and D0 Combined ResultsCDF and D0 Combined Results• D0 result is very similar to CDF’s! (1.7 discrepancy with SM)• Updated CDF result is not included.

arXiv:0808.1297

G. Hou et al. suggest thatdiscrepancy might due tot’ quark with mass~300 GeV/c2 – 1 TeV/c2

(arXiv:0803.1234)

t’ search in CDF

M(t’) > 311 GeV/c2 @ 95%C.L.= -2s

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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ProspectsProspects

• Tevatron can search for large value of s, before LHC starts• 6/8 fb-1 expected at the end of 2009/2010

If s is indeed large, combined CDF and DØ results have good chance to prove it

Pro

babi

lity

of 5

σ o

bser

vatio

n

CDF only 8 fb-1

6 fb-1

s (radians) s (radians)

CDF+DØ

(assume twice CDF)

currentcentral value

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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SummarySummary

ProspectsProspects

CDF has a rich B-Physics program, complementary to B-factories.Recent results (L<2.8 fb-1) include :

• Lifetime measurements Uncertainties are still dominated by statistics.• s measurent 1.8 discrepancy with SM• Rare decay Bs e searches

• 5 fb-1 on tape and collecting ~50 pb-1/week• New s results expected this summer• Lifetime measurements with more than twice of data• New Bs results• And much more...

• Higher precision measurements could give us a stronger hint before the LHC turns on.

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary

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BackupBackup

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D0-> mumu

World best limitBr(D0) < 5.3 10-7 @ 95% C.L.21k22k < 9.8 10-4

SUSY with R-parity violation

• SM Prediction:Br(D0) 410-13• R-parity violating SUSY allows enhancements up to 3.510-6

• L = 360 pb-1• Branching ratio relative to D0+-• No excess observed

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ss Phase and the CKM Matrix Phase and the CKM Matrix- CKM matrix connects mass and weak quark eigenstates- Expand CKM matrix in λ = sin(Cabibbo) ≈ 0.23

- To conserve probability CKM matrix must be unitary → Unitary relations can be represented as “unitarity triangles”

unitarity relations:

unitarity triangles:

very small CPV phase s of order 2

accessible in Bs decays

≈

~1

2 ~ =1

1,Introduction 2,Production 3, Lifetime 4, Rare decay 5, CP Violation 6, Summary