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DOE REVIEW

DOE REVIEW. Wisconsin at BaBar. Yibin Pan. For the Wisconsin Task H. May 15, 2007. Current Luminosities. As of April 2007, BaBar has collected 421 fb -1. Record Peak Luminosity 12.069 x 10 33 cm -2 s -1 (Aug 16, 2006). B 0  p + p - ,r + r - , r + p - , ….

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DOE REVIEW

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  1. DOE REVIEW Wisconsin at BaBar Yibin Pan For the Wisconsin Task H May 15, 2007

  2. Current Luminosities As of April 2007, BaBar has collected 421 fb-1 Record Peak Luminosity 12.069 x 1033 cm-2 s-1 (Aug 16, 2006)

  3. B0p+p-,r+r-, r+p-, … B0J/Y Ks, (f/h’/f0)Ks, … Physics At BaBar • Measure CP violation in the B meson system • Search for rare decay processes and new resonances. Our major contributions

  4. Our group contributes to the following 9 analyses/results in 2004-2007 • *Measurement of CKM angle α : • With B0→ ρ+ρ- decays • With B0→ ρ+π-decays using a Dalitz Plot Analysis *Probing new physics: 3. Measurement of CP violation (sin2β) in s-penguin dominated B0→K0decays 4. Measurement of CP violation (sin2β) in s-penguin dominated decays 5. Measurement of Branching Fraction and polarization in B0→ K*+ρ- 6. B0→K+π-π0 Dalitz Plot Analysis 7. *Search for B+→τ+υ 8. *Search for charmed pentaquarks in and 9. Search for resonances

  5. Highlights of Topics • Measurement of CP angle a: • Two complementary methods • B0 (rp)0 with time dependent Dalitz analysis • B rr with the help of isospin analysis • Measurement of CP angle b, probing new physics: • Sin2b with Charmonium (bccs) decays, precision measurement*. • Sin2b with s-Penguin (bsss) decays, probing new physics. • B0fKs • B0f0Ks • Rare decays and resonances: • B+t+n • Pentaquark • … * It should be noted that our group played a major role in the BaBar measurement of sin2b, especially in the area of tagging the flavor of the B0 Mesons. The flavor tagging algorithm we developed has been used in all CP measurements at BaBar

  6. 00 +– + Measurement of α in B0→(ρπ)0→π+π-π0with Time-Dependent Dalitz Analysis 345 fb-1 Preliminary a • Our group pioneered using time-dependent p+p-p0 Dalitz analysis to extract a. • The method is very powerful, yet very complicated. • Belle presented a similar analysis in August ’06. Three years after our 1st result.

  7. CKM indirect constraint fit: Measurement of a with Bρρ a=(92.0  19.5)o a (deg.) Our group is a major contributor to this result

  8. λ = CP violation parameter λ = ± 1 no CP violation λ≠ ± 1 CP violation η =±1, CP eigenvalue sin2β from s-Penguin – a Probe for New Physics In Standard Model, (sin 2β)K0 ~ (sin2β) ~ (sin2β) CP Violation from interference between tree amplitude and mixing B0→J/ψK0 sin2b=0.674 ± 0.026 (WA, ICHEP06) Tree: CP Violation from interference between s-penguin amplitude and mixing B0→K0, B0→f0K0 Penguin: New Physics? ?

  9. sin2β from s-Penguin – a Probe for New Physics Charmonium Our direct contributions s-penguin s-penguin average is 2.6σ lower than sin2β (charmonium) (was 3.7s in 2005)

  10. A Search for the Rare Leptonic Decay B++ Standard Model expectation BR(B++)=(9.3  3.9)10-5 New physics may enhance this BR • We pioneered methods of searching for B+t+n in the recoil of D0lX or D*0l. • Three BaBar papers have been published based on our analyses.  Our best limit is: BR(B+t+n) < 2.6x10-4 @ 90%C.L. • Last year, Belle, using a similar method on 414 fb-1 , reported an observation of B+t+n decays at 3.5s level. BR ~ (1.79 0.5)x10-4. • ICHEP 2006: BR(B+t+n) = (1.36 ± 0.48)x10-4 (Belle&BaBar, prelim.)

  11. CHARMED Pentaquark Search from the Exclusive B-decays (with BR Measurement) References Channel 1 Channel 2 R.Jaffe and F.Wilczek PRL 91(2003) S.Armstrong, B.Mellado and S.L.Wu hep-ph/0312344 (2003) J.Phys.G30: 1801, 2004 Channel 4 Channel 3 Include 3 D0 decays: Kp, Kpp0, Kppp

  12. Exotic states Interesting Channel : Phase Space Phase Space The distribution is clearly not phase-space, Needs further understanding. This result was published PRD-RC 74:051101(2006).

  13. BaBar Summary • Our Wisconsin group has played an important role in the BaBar experiment • We made important contributions to the construction, commissioning and software development of the Silicon Vertex Tracker (SVT). • We made major contribution to the BaBar’s first measurement of CP violation in the B decays • In the recent years, we made major or direct contribution to 9 analyses: • Measurements of CP angle a • Measurements of CP angle b in s-Penguin • Rare decays (Btn, pentaquark, …) • There have been 10 theses from our BaBar effort. • We feel sad that we have to reduce our BaBar efforts to concentrate on ALTAS due to funding reduction and in view of the imminent turn-on of the LHC.

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