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Measurements of the angles of the Unitarity Triangle at B A B AR

PHENO06 Madison,15-18 May 2006. Measurements of the angles of the Unitarity Triangle at B A B AR. Francesco Polci Universita’ degli Studi di Roma “La Sapienza” & INFN Roma. On behalf of the BaBar Collaboration. The CKM matrix and the Unitarity Triangle.

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Measurements of the angles of the Unitarity Triangle at B A B AR

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  1. PHENO06 Madison,15-18 May 2006 Measurements of the angles of the Unitarity Triangle at BABAR Francesco Polci Universita’ degli Studi di Roma “La Sapienza” & INFN Roma On behalf of the BaBarCollaboration

  2. The CKM matrix and the Unitarity Triangle The Standard Model explains the CP violation through the matrix VCKM Unitarity of VCKM Unitarity Triangle 1 UT Angles Measurements at BaBar Francesco Polci

  3. Improvinga measurement Up to now the best channel for a determination is: 68% 90% BABAR [PRL95, 041805 (2005),232M BB] 2 UT Angles Measurements at BaBar Francesco Polci

  4. Measuring a in b → uud transitions is measured analyzing the decays: Penguin contribution cannot be neglected (see which is pure penguin). That is why what we measure isaeff ! • An isospin analysis allows to estimate the penguin contribution. • Recently a proposal of determination of penguin effect in from SU(3) related decay , which should reduce the theoretical error on a (hep-ph/0604005). 3 UT Angles Measurements at BaBar Francesco Polci

  5. The rr isospin analysis NEW • The decaysB r+r-, r+r0, r0r0are related by SU(2), thus we have isospin relations between amplitudes A+-, A+0, A00 • rrstates can have I = 2 or 0, but gluonic penguins only contribute to I = 0 (DI = ½rule). But r+r0 is pure I = 2, so only tree amplitude  |A+0| = |A-0| Gronau and London, Phys. Rev. Lett. 65, 3381 (1990) New measurement ofr+r0: ~100% longitudinally polarized: 4 UT Angles Measurements at BaBar Francesco Polci

  6. New approaches: a from a1? 9.2s Dp NEW NEW hep-ex/0603050 B0→ a1(1260)+p- Interesting by itself since: - Little is known about the a1 - Can test of factorization Signal has been observed! Search forB0→ a1(1260)+r- • Background torr • (in principle) sensitive toa 5 UT Angles Measurements at BaBar Francesco Polci

  7. Status of a Up to now, if we combine all world measurements (BaBar+Belle), we can determine the Standard Model solution for a like this: a = (99 +12 – 9)0 (direct measurement, HFAG) a = (91.9 ± 5.5)0 (indirect UTfit prediction from the other UT bounds) 6 UT Angles Measurements at BaBar Francesco Polci

  8. Measurements ofb Many modes to measure b : Charmonium: Charm (and charmonium): Penguin dominated: But B→J/y KSis the cleanest mode! Both theoretically: and experimentally (large branching ratio and clean signature). BABAR [PRL94, 161803 (2005),227M BB] 7 UT Angles Measurements at BaBar Francesco Polci

  9. The b→d penguin pollution UPDATE The b →d penguin has a different weak (and strong) phase respect to the tree. The color-suppressed tree has same weak phase asJ/yKS. • Penguin pollution causes deviations in the values of C and S parameters respect to J/yKs . • Also a way for a model independent constraint on the penguin dilution within charmonium modes. hep-ex/0603012 8 UT Angles Measurements at BaBar Francesco Polci

  10. The b→s penguins: sin2beff Dsin2b New Physics could contribute in the loop. They are small effects, here more easily detectable since Tree is missing or negligible. Look forDsin2b≠ 0in many modes: Theory prefers Dsin2b > 0 Examples of QCD factorization: Beneke - PL B620, 143 (2005) Cheng,chua,soni - PRD72, 094003 (2005) Experimental: penguin modes Experimental: J/y mode 9 UT Angles Measurements at BaBar Francesco Polci

  11. New results for sin2beffin b→s penguins B0 B0 NEW UPDATE NEW : first measurement ! Complicated analysis since: • f0/roverlap, BB background • Color-suppressed tree, butDsin2bexpected to be small Asymmetry Other searches: hep-ex/0603040 10 UT Angles Measurements at BaBar Francesco Polci

  12. b :other searches NEW NEW NEW Search for It is a penguin Allows to interpret and to put a bound on its DS. Search for hep-ex/0603054 Confirmed from Belle. No signal for (unexpected). Searches for hep-ex/0603013 • Can reduce theoretical uncertainty of Color Suppressed tree amplitudes for h’Ks decays in SU(3)-based analysis [Gronau,Rosner,Zupan PLB596,107(2004)] 11 UT Angles Measurements at BaBar Francesco Polci

  13. Measurements ofg Best method to g determination: BABAR [PRL95, 121802 (2005),227M BB] 12 UT Angles Measurements at BaBar Francesco Polci

  14. g from DK decays suppressed favored _ If common final state to D0 and D0 interference weak phase Critical parameter: A(b→u) strong phase A(b→c) Three methods: D0 to common flavor state (ADS) D0 Dalitz (GGSZ) D0 CP modes(GLW) (only2ambiguities) 13 UT Angles Measurements at BaBar Francesco Polci

  15. New results for the GLW Method NEW 4 observables (ACP+-,RCP+-) for three unknown (rB, g, dB): Some issues: • B → Dp background • D0CPhave small BRs • 8 ambiguities 131 CP+ New fromBaBar:added D0 KSw, KSf 148 CP- hep-ex/0512067 14 UT Angles Measurements at BaBar Francesco Polci

  16. sin(2b+g) from B→D(*)p(r) 68% CL 90% CL Frequentist confidence level UPDATE Small CP asymmetry (r~0.02)! Vcd V*ud Interference and B0 mixing V*ub Vcb Suppressed u,c,t Favored u,c,t hep-ex/0602049 |sin(2+)| > 0.64 (@ 68 % C.L.) |sin(2+)| > 0.42 (@ 90 % C.L.) To consider tag-side CP violation, fit for: a = 2r sin(2b+g) cos (d) c= cos(2b+g) [2r sin(d)+2r’sin(d’)] b = 2r’ sin(2b+g) cos (d’) Extract result from a, clep and: +30% theoretical error on r (Due to use of SU(3) simmetry and W-exchange neglection) r(D) = 0.019 ± 0.004 r(D*) = 0.015 ± 0.006 r(D) = 0.003 ± 0.006 15 UT Angles Measurements at BaBar Francesco Polci

  17. B0→Ds*p and B0→ Ds* K observations. First observations for 5 sigma 6 sigma NEW Decays proceeding through W-exchange diagrams. Allows a more precise estimation of the theoretical error on r from SU(3)-related decays Ds(*)p : hep-ex/0604012 But DsK smaller than before, so smaller rDp and less sensitivity! 16 UT Angles Measurements at BaBar Francesco Polci

  18. sin(2b+g) from B0→D(*)0K(*)0 Vub Vcb NEW NEW Charge correlation allows to tag the B0: You can distinguish Vub from Vcb and measure r! But no Vubobserved… r< 0.4 @90%CL hep-ex/0604016 17 UT Angles Measurements at BaBar Francesco Polci

  19. Two other approaches for g NEW NEW B  DKp hep-ex/0509036 - Self-tagging. - b  ucs decay includes color-allowed diagrams, so (possibly) large CP-violating effects. - Strong phase difference accessed through Dalitz plot, so 8-fold  2-fold ambiguity. Unfortunately, didn’t find b  u! B  D(*)a0(2) hep-ex/0512031 - Due to form-factor suppression in B  a0(2)X, favored and suppressed amplitudes become comparable. - First step: search for the (b  u) SU(3)-related decays Ds(*)a0(2) Again, Vub component is missing! 18 UT Angles Measurements at BaBar Francesco Polci

  20. Status of g Combining all direct world measurements (BaBar+Belle): g = (65 ± 20)o &g = (-115 ± 20)o 19 UT Angles Measurements at BaBar Francesco Polci

  21. Conclusions • Angles measurements are still being performed at BaBar both updatingold results to the full available dataset and exploring new methods. • Some satellites measurements have been performed, which provides a better understanding of old results. • This field is sensitive to new physics effects, expecially in the penguin diagrams • Measurements of the angles of the Unitarity Triangle contribute to the precise determination of the allowed region in the r-h plane. • More results are expected to come in the future. 20 UT Angles Measurements at BaBar Francesco Polci

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