1 / 58

Beauty and charm results from B factories

Beauty and charm results from B factories. B oštjan Golob University of Ljubljana , Jožef Stefan Institute & Belle Collaboration. Helmholtz International Summer School “Heavy Quark Physics” Bogoliubov Laboratory of Theoretical Physics, Dubna, Russia, August 11-21, 2008. “Jožef Stefan”

terrel
Download Presentation

Beauty and charm results from B factories

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Beauty and charm results from B factories Boštjan Golob University of Ljubljana, Jožef Stefan Institute & Belle Collaboration Helmholtz International Summer School “Heavy Quark Physics” Bogoliubov Laboratory of Theoretical Physics,Dubna, Russia, August 11-21, 2008 “Jožef Stefan” Institute University of Ljubljana JINR

  2. Lecture 1 • Beauty • Introduction • B Oscillations • (Mostly) rare B decays • leptonic • semileptonic • b →sg • b →sll • Lecture 2 • Charm and others • 4. D0 mixing and CPV • decays to CP states • WS decays • t-dependent Dalitz • 5. Ds leptonic decays • 6. Spectroscopy • exotic states Outline exp. results with some comments on phenomenology It is a curious fact that people are never so trivial as when they take themselves seriously. O. Wilde (1854 - 1900) Part of B-factories lectures with A.J. Bevan; division by topics, not by experiments

  3. Introduction Experiments very diverse exp. conditions We all live with the objective of being happy; our lives are all different and yet the same. Anne Frank (1929 -1945) on resonance production e+e-→ U(4S) → B0B0, B+B- s(BB)  1.1 nb (~0.9x109 BB pairs) continuum production s(c c)  1.3 nb (~109 XcYc pairs) c g* • e+e-→ y(3770) → D0D0, D+D- • (coherent C=-1 state); • ~800 pb-1 of data • available at y(3770); • 2.8x106 D0D0 3.5 fb-1 on tape s(D0; pt>5.5 GeV,|y|<1)≈ ≈13 mb 50x109 D0’s c

  4. q2 q1 diagonal elem.: P0 P0 (including decays) non-diagonal elem.: P0 P0 q2 q1 B oscillations P0 P0 Time evolution (also lectures by U. Nierste, A. Pivovarov) flavour states ≠ Heff eigenstates: (defined flavour) (defined m1,2 and G1,2) P0 = K0, Bd0, Bs0 and D0 eigenvalues: more

  5. D. Kirkby, Y. Nir, CPV in Meson Decays, in RPP B oscillations Time evolution P1,2 evolve in time according to m1,2 and G1,2: |P0(t)>, |P0(t)> decay rates: for easier notation: Gt → t U(4S) →B0B0: B meson pair in quantum coherent state; before 1st B decay: B0B0 1st B decay: tag B0/B0; mixing clock start, t →Dt Decay time distribution of experimentally accessible states P0, P0 sensitive to mixing parameters x and y, depending on final state more

  6. B oscillations Time evolution probab. to observe an initially produced X0 as X0 after time t probab. to observe an initially produced X0 as X0 after time t ~ Bs0 ~ D0 more difficult to observe oscillations within t visually unobservable deviation from pure exponential

  7. Btag B0 or B0 determined B0(B0) B oscillations signal Method similar to CPV, reconstruct flavor specific final states signal m+ m- fully reconstruct decay to flavor specificfinal state J/y p- Bsig K+ K*0 tag flavor of other B from charges of typical decay products l- U(4S) K- Dt=Dz/bgc determine time between decays

  8. Belle, PRD71, 072003 (2005), 140 fb-1 B oscillations DE signal region Method reconstructed flavour specific decays measure Dt distribution Method Dt distribution Af=0, |y|<<1 w: wrong tag probability (reduces ampl. of oscillations) R(Dt): resolution function - intrinsic detector resolution on position of both B vertices - smearing due to non-primary tracks - smearing due to B meson CMS momentum saver(Dt)=1.43 ps more more

  9. Belle, PRD71, 072003 (2005), 140 fb-1 B oscillations Results flavour asymmetry Dmd=(0.511±0.005±0.006) ps-1 largest syst.: D** bkg. Dmd=(0.507±0.005) ps-1 x=DmdtBd= 0.776±0.008 HFAG, http://www.slac.stanford.edu/xorg/hfag/

  10. Vjb* Vid Vjd Vib* b d W+ b d B0 B0 u, c, t u, c, t u, c, t u, c, t B0 W- W+ B0 W- d b b d B oscillations P0: any pseudo-scalar meson; specific example of Bd0 Phenomenology (see also lectures by U. Nierste) P0-P0 transition → box diagram at quark level if mi = mj  due to CKM unitarity: no mixing loop int., CKM unitarity  more considering CKM values and q masses: largest contribution from t quark

  11. B oscillations A.J. Buras et al., Nucl.Phys.B245, 369 (1984) Phenomenology calculate M12, G12 from box diagram; from that calculate Dm, DG must be calculated to determine Vij; theor. uncertainty (LQCD) q: d (Bd) or s (Bs); and Dms also measured... BBq: bag parameter, <Bq0|bgm(1-g5)q|Bq0> fBq: decay constant hB(‘): QCD corr. O(1) S0(xt): known kinematic function reduced theor. uncertainty in ratio x2 M. Okamoto, hep-lat/0510113

  12. CDF, PRL97, 242003 (2006) B oscillations A Bs amplitude method: instead of Dms fit A at different values of Dms; A=1  oscillations at this Dms value Dms=(17.77±0.10±0.07) ps-1 x=DmstBs= 25.5±0.6 Dms/Dmd uncertainties on (r2+h2): Dmd constraint ±13% Dmd±1% fBdBBd ±12% Dms/Dmd constraint ±6% Dms /Dmd ±1.5% x ±5%

  13. Q fP Leptonic B decays l+ (H+) P+ B → tn W+ G(B+→ t+n): G(B+→ m+n): G(B+→e+n)= 1:4x10-3:10-7 fP→ meas. VQq; H±; VQq n q Method fully reconstruct Btag in hadronic decays (K+p-p+p-p+); search for 1/3 tracks from Bsig→tn (e-); no additional energy in EM calorim. (from p0, g, ...); signal at EECL~0 EM calorim. B → tn candidate event

  14. Belle, PRL97, 251802 (2006), 414 fb-1 Belle, ICHEP08, 600 fb-1 Leptonic B decays Results largest syst. from signal and bkg. shape semileptonic tag added BaBar: hadronic decays for Btag; combined with semil. decays: bkg. Nsig=17 ± 5 3.5 s signif. (-2lnL0/Lmax) signal BaBar, PRD77, 011107 (2008), 346 fb-1 BaBar, PRD76, 052002 (2007), 346 fb-1 expected signal Br=3x10-3 HFAG, http://www.slac.stanford.edu/xorg/hfag/ more

  15. Leptonic B decays Phenomenology using fB=(216 ± 22) MeV, |Vub|=(3.9 ± 0.5)x10-3, tB  BrSM(B+→tn) = (1.25± 0.41)x10-4 new physics: to make predictions/measure |Vub| → fB (from LQCD) needed; validate LQCD in charm sector (better exp. precision) → to be addressed later; established method for decays with large Emiss; to be exploited at SuperB (B→Knn, dark matter) HPQCD, PRL95, 212001 (2005) u t b H+ B- n SuperB 50 ab-1 more

  16. l+ n q1 q3 M2 M1 q2 Semileptonic B decays W±, H± P →Pln q2 in G suppressed by ml2/mM12 negligible for e,m; not for t P →Vln 3 form f. for e,m; 4 for t HQS: relations among f.f.’s; can be tested; for suppressed f.f.’s only by t H± exchange modified SM Br’s for t; in P→ V only helicity=0 V possible measurement challenging due to multiple n’s; more more skip

  17. Semileptonic B decays D* e/p • B0→D*-t+nt • method: • D* reconstruction; • t→enn, pn • Bsig: D* and e/p • Btag: rest of event • control sample: • Bsig→D*p , check Btag reconstruction • signal sample: • requirements on Xmis, Evis • method: • excl. Btag reconstruction • t→enn, mnn • Bsig: D/D* and e/m • mmis2=pmis2 t Bsig Btag Belle, PRL99, 191807 (2007), 480 fb-1 n n Bsig→D*p MC data BaBar, PRL100, 021801 (2008), 209 fb-1 related to missing mass (>0 for several n); Evis < m(U(4S)) missing mass (>0 for several n);

  18. Semileptonic B decays Belle, PRL99, 191807 (2007), 480 fb-1 • B0→D*-t+nt • results • bkg. from B0→D*en (peaking) • t→rn Nsig=60 ±12 6.7 s signif. (-2lnL0/Lmax) main systematics: from signal and bkg shape (MC) Btag reconstr. eff. (control sample) BaBar, PRL100, 021801 (2008), 209 fb-1 D*-l+n D*-t+nt last uncertainty: normaliz. modes (Dln , D*ln) main systematics: from signal and bkg shape (MC) D** contrib. D-l+n D-t+nt

  19. M. Tanaka, Z.Phys.C67, 321 (1995) Semileptonic B decays • B →D(*)tnphenomenology • limits on H±; • inclusive B →Xctn predicted Br: • (2.30 ±0.25)% • sum of D*tn, Dtn: • (2.59 ±0.39)% Ba/lle average (assuming no correl. and 100% long. polariz.) A.F.Falk et al., PLB326, 145 (1994) G(B →D*long.tn) G(B →D*mn)|SM BaBar more

  20. b → sg H± b s • Motivation • FCNC process; • sensitive to NP in loop; • parton level: Eg≈ mb/2; • determ. of mb, Fermi motion → • needed for Vubdeterm. from • inclusive semil. B decays; • Difficulties • theory: • parameter extraction from • partial Br(Eg>Ecut) → • extrapolation needed; • experiment: • measure low Eg • huge bkg. X Y W± u, c, t b s g c± Vqb Vqs b s u, c, t g X Y g continuum p0 Your background and environment is with you for life. No question about that. signal more S. Connery (1930)

  21. on off b → sg • Inclusive measurement • (see also lectures by U. Heisch) • only g reconstructed; • bkg. treatment • subtract lumin. scaled off-data • from on-data (continuum bkg.); • veto p0, h → gg; • rest bkg. from MC (control samples); • timing info for EM calorim. clusters • (overlapping evts.: hadronic + Bhabha) • inclusive B→p0X, hX samples • reconstructed in data • (off- data subtraction) and MC; • 5%-10% correction to MC bkg. normaliz. on scaled off Belle, arXiv:0804.1580, 605 fb-1 subtracted 80% of remaining bkg. from p0, h → gg after vetoing p0, h → gg more

  22. Belle, arXiv:0804.1580,605 fb-1 b → sg consistent with 0 above B decay threshold • Inclusive measurement • Eg spectrum • Br(B →Xsg) • deconvolution of Eg • (Egmeas→ Egtrue; using • radiativedi-muonevts); • boost to B rest frame; • b →dg contrib. (4%); mb1S/2~2.3 GeV last uncertainty due to boost; largest system.: corr. factors in off-data subtraction; bkg. g’s from B (other than p0, h)

  23. BaBar, PRD72, 052004, 82 fb-1 b → sg • Seminclusive measurement • B reconstructed; • (see also lectures by B. Pecjak) • sum of exclusive decay modes • Xs: no S-wave states in B→Xsg • 22 final states K-(0)+(1-4)p • 10 K-(0)+h+(0-2)p • 6 3K-(0)+(0-1)p • g + Xs B • (better resol.) • bgk.: p0, h veto, NN from topological • variables for continuum; • not all final states reconstructed • →corr. for missing fraction • (from MC, checked with data in various • final state categories) peaking bkg.: missing final states reconstructed as one of signal decays; signal decays with some particles exchanged with other B 25% at low M(Xs) from KL at high M(Xs) from K+ 5p

  24. BaBar, PRD72, 052004, 82 fb-1 b → sg Seminclusive measurement fit in bins of M(Xs) Br(M(Xs)); Eg spectrum (Eg>1.9 GeV); moments of dG/dEg also determined; mb (and other QCD parameters) determined for use in b →uln; e.g. main systematics: from missing final states K*(892) more more details at HFAG, http://www.slac.stanford.edu/xorg/hfag/

  25. M. Misiak et al., PRL98, 022002 (2007) b → sg Phenomenology average of results: comparison with limits from B →tn: HFAG, winter 08, http://www.slac.stanford.edu/xorg/hfag/ 95% C.L. lower limit on m(H±), all tanb first error: stat.+syst. second error: Eg spectrum (extrapol.) m(H±)=300 GeV Belle, PRL97, 251802 (2006), 414 fb-1 For my part I know nothing with any certainty, but the sight of the stars makes me dream. V. van Gogh (1853 - 1890)

  26. b → sll Motivation (see also lectures by E. Lunghi) FCNC process; M expressed in terms C7,9,10; Wilson coeff.’s NP modifies C7,9,10 or/and adds new operators Wilson coeff.’s independent of final state (C7 same for b→sg and b→sll); |C7 |2 constrained by Br(B→Xsg); sign not known; b→sll: interference of amplitudes additional information (also sign) on C7,9,10 W± b s Vqb Vqs u, c, t g = perturbative (dependence on MW, mt, MNP) non-perturbative b s =VqbV*qs C7x g more

  27. b → sll exclusive B →K*ll qKdistrib.  fraction of long. polarized K* (FL); qldistrib.  lepton forward-backward asymmetry (AFB); prediction for AFB: q2=m2(l+l-) l+ ql K* B l- veto veto high q2 low q2 SM K C7 = -C7SM qK l+l- K* B C9 C10 = -C9SM C10SM C7 = -C7SM C9 C10 = -C9SM C10SM p q2

  28. BaBar, arXiv:0804.4412, 350 fb-1 high q2 low q2 b → sll Ns=27.2 ±6.3 • reconstruction • e+e-, m+m-; K* →Kp, Kp0, Ksp; • Mbc fit • combinatorial bkg.: e+m-; • misid. hadrons: h+m-; • peaking bkg.: D(→K*p)p • (mm sample only, • veto on m(K*p)); • signal fraction • qK fit • FL free parameter; • ql fit • AFB free parameter; Ns=36.6 ±9.6

  29. b → sll average over interval SM results FL; consistent with SM and -C7SM; AFB; -C9SM C10SM disfavored (>3 s); stronger constraints; C7 = -C7SM BaBar, arXiv:0804.4412, 350 fb-1 q2 Belle, PRL96, 251801 (2006), 357 fb-1 Belle, ICHEP08, 600 fb-1 SM C7 = -C7SM C9 C10 = -C9SM C10SM C7 = -C7SM C9 C10 = -C9SM C10SM more

  30. b → sll Belle PRD72, 092005 (2005), 140 fb-1 semi-inclusive similar as b →sg; e+e-, m+m-; K-/Ks+(0-4)p; ~30% missing modes; charmonium sample provides cross-check of bkg.; constraints on NP in Ci Br(B →Xsg), Br(B →Xsll), Br(K →pnn ) Br(Bs→mm), no Br(B →K*ll ) (large th. uncertainty) Nsig=68 ±14 5.4 s signif. (-2lnL0/Lmax) Belle PRD72, 092005 (2005), 140 fb-1 BaBar PRL93, 081802 (2004), 82 fb-1 dC10 dC9 J. Kamenik, arXiv:0805.2363 dC9 dC7

  31. B oscillations more D. Kirkby, Y. Nir, CPV in Meson Decays, in RPP Time evolution state initially produced as superposition (n.b.: a(0)/b(0) can be 0) will evolve in time as if interested in a(t), b(t): effective Hamiltonian and t-dependent Schrödinger eq.: eigenstates: (well defined m1,2 and G1,2) back

  32. diagonal elem.: P0 P0 (including decays) non-diagonal elem.: P0 P0 B oscillations more Time evolution eigenvalues: P1,2 evolve in time according to m1,2 and G1,2:

  33. B oscillations more Time evolution eigenvalues:

  34. B oscillations more Time evolution eigenvalues: back

  35. B oscillations more Time evolution taking into account we arrive at time evolution of P0, P0: back

  36. B oscillations more Time evolution decay rates: for CP conjugated states: Af → Af, Af→ Af

  37. B oscillations more CPV |p/q|=1, y<<1  (well fulfilled for Bd) |lf|≠1 |Af/Af|≠1 CPV in decay |q/p| ≠1 CPV in mixing I(lf) ≠ 0 CPV in interf. back

  38. Belle, PRD71, 072003 (2005), 140 fb-1 B oscillations more Method reconstructed flavour specific decays; D*ln =0 known meas. known meas. known meas. meas. total bkg D** bkg. back

  39. H. Kakuno et al., NIM A533, 516 (2004) B oscillations more Method tagging q=+(-)1 B0(B0) r: tag quality

  40. H. Kakuno et al., NIM A533, 516 (2004) B oscillations more Method tagging single r bin: two r bins: back

  41. H. Tajima et al., NIM A533, 370 (2004) B oscillations more Method resolution function Rful: vtx of fully reconstructed B meson Rasc: vtx of tagging B meson Rnp: non-primary tracks Rk: kinematic smearing back

  42. Vjb* Vid Vjd Vib* b d W+ b d B0 B0 u, c, t u, c, t u, c, t u, c, t B0 W- W+ B0 W- b d d b B oscillations more P0: any pseudo-scalar meson; specific example of Bd0 Phenomenology P0-P0 transition → box diagram at quark level if mi = mj  due to CKM unitarity: no mixing simplified treatment based on dimension: O. Nachtmann, Elem. Part. Phys., Springer-Verlag back for serious treatment see e.g.: A.J. Buras et al., Nucl.Phys.B245, 369 (1984)

  43. Belle, PRL97, 251802 (2006), 414 fb-1 Leptonic B decays more Systematic checks Bsigdecay modes check of EECL, double tagged decays, Bsig-→D*0l-n, D*0→D0p0 back

  44. Leptonic B decays more Type II Two Higgs Doublets Models (f1 gives masses to d-type and charged l; f2 gives masses to u-type; in Type I models f1 is decoupled and f2 generates all masses) Phenomenology additional Higgs doublet; tanb=v1/v2, ratio of vacuum expectation values; H± coupling  ml same factor as helicity SM suppression ratio independent of H ± contribution: W.S.Hou, PRD48, 2342 (1993) back if Gmeas>GSM H± contribution dominant

  45. Semileptonic B decays more Form factors P→P: B(v) → B(v’): for mb→  amplitude can only depend on g= v·v’; for v = v’ nothing happens, z(1)=1; B(v) → D(v’): for mb, mc→  same (HQS) z(v·v’): Isgur-Wise function relates two in principle independent form factors for P → P transition back

  46. Semileptonic B decays more Form factors P→V: q2 one more f.f. if ml not small; HQS: relations among f.f.’s for P→ P and P →V back

  47. M. Tanaka, Z.Phys.C67, 321 (1995) Semileptonic B decays more B →D*tnphenomenology amplitude for W exchange: lM=±,0; lt=±; lW=±,0; D*, t, W helicity amplitude for H± exchange: relation among H ±, W exchange amplitudes: H ± : no contribution of transversely polarized D* (HR,L±=0) back

  48. U. Nierste et al., PRD78, 015006 (2008) Semileptonic B decays more B →Dtnphenomenology update of predictions: measurement BaBar, PRL100, 021801 (2008), 209 fb-1 mB2/mH2 tan2b (in 2HDM-II) back

  49. b → sg more inclusive semil. B decays semil. width: Operator Product Expansion to O(1/mb2): two parameters, l1, l2: average p2 of b in B hyperfine interaction back

  50. b → sg more inclusive semil. B decays Fermi motion: new parameter L same parameters governing moments of various distributions, e.g. mass of hadronic system in semil. decays: or Eg moments in b →s g: A.F.Falk, M.E.Luke, PRD57, 424 (1998) A.Kapustin, Z. Ligeti PLB355, 318 (1995) back

More Related