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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 JINR University of Ljubljana “Jožef Stefan” Institute
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Outline Beauty Lecture 1 leptonic Lecture 2 semileptonic
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 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 ( ) Part of B-factories lectures with A.J. Bevan; division by topics, not by experiments
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Introduction Experiments continuum production g* c
very diverse exp. conditions We all live with the objective of being happy; our lives are all different and yet the same. on resonance production e+e- → U(4S) → B0B0, B+B- s(BB) 1.1 nb (~0.9x109 BB pairs) Anne Frank ( ) continuum production g* c s(c c) 1.3 nb (~109 XcYc pairs) 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
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B oscillations Time evolution
q1 q2 P0 P0 q2 q1 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: diagonal elem.: P0 P0 (including decays) non-diagonal elem.: P0 P0 more
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B oscillations Time evolution
D. Kirkby, Y. Nir, CPV in Meson Decays, in RPP 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
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B oscillations Time evolution more difficult to observe
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
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B oscillations Method l- similar to CPV, reconstruct
signal B oscillations Method similar to CPV, reconstruct flavor specific final states signal B0 or B0 m+ m- J/y fully reconstruct decay to flavor specific final state p- Bsig K*0 K+ tag flavor of other B from charges of typical decay products U(4S) l- K- Btag Dt=Dz/bgc determined B0(B0) determine time between decays
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B oscillations Method Method reconstructed flavour specific decays
Belle, PRD71, (2005), 140 fb-1 DE signal region Method reconstructed flavour specific decays measure Dt distribution Method Dt distribution Af=0, |y|<<1 more 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
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B oscillations Results flavour asymmetry Dmd=(0.511±0.005±0.006) ps-1
Belle, PRD71, (2005), 140 fb-1 Results flavour asymmetry Dmd=(0.511±0.005±0.006) ps-1 largest syst.: D** bkg. Dmd=(0.507±0.005) ps-1 x=DmdtBd= 0.776±0.008 HFAG,
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B oscillations Phenomenology P0-P0 transition →
P0: any pseudo-scalar meson; specific example of Bd0 Phenomenology (see also lectures by U. Nierste) P0-P0 transition → box diagram at quark level d b u, c, t W+ W- B0 Vid Vjd Vjb* Vib* d b u, c, t W+ W- B0 if mi = mj due to CKM unitarity: no mixing loop int., CKM unitarity considering CKM values and q masses: largest contribution from t quark more
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B oscillations Phenomenology calculate M12, G12 from
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/
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B oscillations Bs Dms /Dmd A amplitude method: instead of Dms
CDF, PRL97, (2006) 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=DmstBs= 25.5±0.6 Dms /Dmd uncertainties on (r2+h2): Dmd constraint ±13% Dmd ±1% fBdBBd ±12% Dms /Dmd constraint ±6% Dms /Dmd ±1.5% x ±5%
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Leptonic B decays l+ B → tn Method Q fP (H+) W+
G(B+ → t+n): G(B+ → m+n): G(B+ → e+n)= 1:4x10-3:10-7 fP → meas. VQq; H±; q VQq n 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
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Leptonic B decays Results BaBar: hadronic decays for Btag;
Belle, PRL97, (2006), 414 fb-1 Belle, ICHEP08, 600 fb-1 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, (2008), 346 fb-1 BaBar, PRD76, (2007), 346 fb-1 expected signal Br=3x10-3 HFAG, more
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Leptonic B decays t Phenomenology b H+ u n
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, (2005) b u B- t n H+ SuperB 50 ab-1 more
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Semileptonic B decays l+ P →Pln P →Vln H± exchange measurement
q1 q3 n l+ M1 q2 M2 skip W±, H± P →Pln 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 more H± exchange modified SM Br’s for t; in P→ V only helicity=0 V possible measurement challenging due to multiple n’s; more
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Semileptonic B decays B0 →D*-t+nt method: D* reconstruction;
Bsig e/p n Btag 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 excl. Btag reconstruction t →enn, mnn Bsig: D/D* and e/m mmis2=pmis2 t Belle, PRL99, (2007), 480 fb-1 Bsig →D*p MC data BaBar, PRL100, (2008), 209 fb-1 related to missing mass (>0 for several n); Evis < m(U(4S)) missing mass (>0 for several n);
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Semileptonic B decays B0 →D*-t+nt results bkg. from B0 →D*en (peaking)
Belle, PRL99, (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, (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
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Semileptonic B decays B →D(*)tn phenomenology limits on H±;
M. Tanaka, Z.Phys.C67, 321 (1995) B →D(*)tn phenomenology limits on H±; inclusive B →Xctn predicted Br: (2.30 ±0.25)% sum of D*tn, Dtn: (2.59 ±0.39)% G(B →D*long.tn) G(B →D*mn)|SM Ba/lle average (assuming no correl. and 100% long. polariz.) A.F.Falk et al., PLB326, 145 (1994) BaBar more
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b → sg Motivation Difficulties FCNC process; theory:
W± u, c, t Vqb Vqs g b s u, c, t X Y H± g Motivation FCNC process; sensitive to NP in loop; parton level: Eg ≈ mb/2; determ. of mb, Fermi motion → needed for Vub determ. from inclusive semil. B decays; Difficulties theory: parameter extraction from partial Br(Eg>Ecut) → extrapolation needed; experiment: measure low Eg huge bkg. c± b s X Y g more signal continuum p0 Your background and environment is with you for life. No question about that. S. Connery (1930)
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b → sg Inclusive measurement (see also lectures by U. Heisch)
off on 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: , 605 fb-1 subtracted more 80% of remaining bkg. from p0, h → gg after vetoing p0, h → gg
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b → sg Inclusive measurement Eg spectrum Br(B →Xsg)
Belle, arXiv: ,605 fb-1 consistent with 0 above B decay threshold Inclusive measurement Eg spectrum Br(B →Xsg) deconvolution of Eg (Egmeas → Egtrue; using radiative di-muon evts); 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)
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b → sg Seminclusive measurement B reconstructed;
BaBar, PRD72, , 82 fb-1 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 K-(0)+h+(0-2)p K-(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
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b → sg Seminclusive measurement fit in bins of M(Xs) Br(M(Xs));
BaBar, PRD72, , 82 fb-1 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,
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b → sg Phenomenology average of results: comparison with limits from
M. Misiak et al., PRL98, (2007) Phenomenology average of results: comparison with limits from B →tn: HFAG, winter 08, 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, (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 ( )
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b → sll Motivation FCNC process; (see also lectures by E. Lunghi)
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 b s W± u, c, t Vqb Vqs g =VqbV*qs C7 x = perturbative (dependence on MW, mt, MNP) non-perturbative more
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b → sll l+l- l+ l- exclusive B →K*ll qK distrib. fraction
p K* K qK exclusive B →K*ll qK distrib. fraction of long. polarized K* (FL); ql distrib. lepton forward-backward asymmetry (AFB); prediction for AFB: q2=m2(l+l-) B l- K* ql l+ veto veto low q2 high q2 SM C7 = -C7SM C9 C10 = -C9SM C10SM C7 = -C7SM C9 C10 = -C9SM C10SM q2
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b → sll reconstruction e+e-, m+m-; K* →Kp, Kp0, Ksp; Mbc fit
BaBar, arXiv: , 350 fb-1 low q2 high q2 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
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b → sll results FL; consistent with SM and -C7SM; AFB;
q2 average over interval SM results FL; consistent with SM and -C7SM; AFB; -C9SM C10SM disfavored (>3 s); stronger constraints; C7 = -C7SM BaBar, arXiv: , 350 fb-1 Belle, PRL96, (2006), 357 fb-1 Belle, ICHEP08, 600 fb-1 SM C7 = -C7SM C9 C10 = -C9SM C10SM C7 = -C7SM C9 C10 = -C9SM C10SM more
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b → sll semi-inclusive similar as b →sg; e+e-, m+m-; K-/Ks+(0-4)p;
Nsig=68 ±14 5.4 s signif. (-2lnL0/Lmax) Belle PRD72, (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) Belle PRD72, (2005), 140 fb-1 BaBar PRL93, (2004), 82 fb-1 dC9 dC10 J. Kamenik, arXiv: dC7 dC9
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B oscillations more Time evolution
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
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B oscillations more Time evolution eigenvalues:
diagonal elem.: P0 P0 (including decays) non-diagonal elem.: P0 P0 P1,2 evolve in time according to m1,2 and G1,2:
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B oscillations more Time evolution eigenvalues:
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B oscillations more Time evolution eigenvalues: back
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B oscillations more Time evolution taking into account
we arrive at time evolution of P0, P0: back
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B oscillations more Time evolution decay rates:
for CP conjugated states: Af → Af, Af → Af
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B oscillations more CPV |p/q|=1, y<<1 (well fulfilled for Bd)
|Af/Af|≠1 CPV in decay |q/p| ≠1 CPV in mixing I(lf) ≠ 0 CPV in interf. back
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B oscillations more Method reconstructed flavour specific decays; D*ln
Belle, PRD71, (2005), 140 fb-1 Method reconstructed flavour specific decays; D*ln = known meas known meas known meas. meas. total bkg D** bkg. back
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B oscillations more Method tagging q=+(-)1 B0(B0) r: tag quality
H. Kakuno et al., NIM A533, 516 (2004) Method tagging q=+(-)1 B0(B0) r: tag quality
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B oscillations more Method tagging single r bin: two r bins:
H. Kakuno et al., NIM A533, 516 (2004) Method tagging single r bin: two r bins: back
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B oscillations more Method resolution function
H. Tajima et al., NIM A533, 370 (2004) Method resolution function Rful: vtx of fully reconstructed B meson Rasc: vtx of tagging B meson Rnp: non-primary tracks Rk: kinematic smearing back
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B oscillations more Phenomenology P0-P0 transition →
back P0: any pseudo-scalar meson; specific example of Bd0 Phenomenology P0-P0 transition → box diagram at quark level d b u, c, t W+ W- B0 Vid Vjd Vjb* Vib* d b u, c, t W+ W- B0 if mi = mj due to CKM unitarity: no mixing simplified treatment based on dimension: O. Nachtmann, Elem. Part. Phys., Springer-Verlag for serious treatment see e.g.: A.J. Buras et al., Nucl.Phys.B245, 369 (1984)
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Leptonic B decays more Systematic checks Bsig decay modes
Belle, PRL97, (2006), 414 fb-1 Systematic checks Bsig decay modes check of EECL, double tagged decays, Bsig- →D*0 l- n, D*0 →D0p0 back
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Leptonic B decays more Phenomenology additional Higgs doublet;
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) if Gmeas>GSM H± contribution dominant back
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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
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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
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Semileptonic B decays more
M. Tanaka, Z.Phys.C67, 321 (1995) B →D*tn phenomenology 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
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Semileptonic B decays more
U. Nierste et al., PRD78, (2008) B →Dtn phenomenology update of predictions: measurement BaBar, PRL100, (2008), 209 fb-1 mB2/mH2 tan2b (in 2HDM-II) back
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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
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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
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b → sg more off-data subtraction a: lumin. ratio;
ehadronic,B→XsgON,OFF: efficiency of hadronic, signal selection; FN,E: corr. factor due to lower mean E and multiplicity in off-data back
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b → sg more Eg resolution inclusive meas.: Eg measured in EM calorim.;
s(Eg;Eg=2 GeV) ~ 20 MeV; semi-inclusive meas.: Eg from s(Eg) ~ 1-5 MeV; back
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b → sll more OPE, Wilson coeff. example of b →cdu
BaBar Physics Book, SLAC-R-504 W b c u OPE, Wilson coeff. example of b →cdu almost point-like inter.: series: product of currents expressed as series of local operators (OPE); such expansion valid if q2/MW2<<1; in this range an effective theory can be constructed, valid up to a cut-off, in the above case up to MW; back
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b → sll more OPE, Wilson coeff. example of b →cdu
g d BaBar Physics Book, SLAC-R-504 W b c u OPE, Wilson coeff. example of b →cdu rad. corr. to lowest order: operators receive radiation corr. and must be renormalized; they become dependent on renormalization scale m; physics must be independent of m operators receive m dependent coefficients in order for Heff to satisfy: (i,j: color indices) back
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b → sll more OPE, Wilson coeff. example of b →cdu
g d BaBar Physics Book, SLAC-R-504 W b c u OPE, Wilson coeff. example of b →cdu under renormaliz. set of operators can be enlarged, for the example under consideration there is also Heff is thus Ci(m) are Wilson coeff., containing information on short distance physics down to (arbitrary) scale m; all heavy masses (M>>m) dependence (mt, MW, MNP) is contained in Ci(m) (changed color indices) back
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b → sll more OPE, Wilson coeff. once Oi(m) dependence is
calculated, Ci(m) follow from for b →cdu division of energy scales between Ci(m) and local operators <f|Oi(m)|B> can be schematically viewed as Wilson coeff. Ci(m) are independent of external states (f) <f|Oi(m)|B> Ci(m) back
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b → sll more OPE, Wilson coeff. Br(b → sll ): AFB, RPV SUSY contrib.:
P. Gambino et al., PRL94, (2005) OPE, Wilson coeff. Br(b → sll ): AFB, RPV SUSY contrib.: Y.-G. Xu et al., PRD74, (2006) |l1i3’l1i2’*|<4.7x10-5 back
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b → sll more SM C7 = -C7SM C9 C10 = -C9SM C10SM C7 = -C7SM
Belle, PRL96, (2006), 357 fb-1 SM C7 = -C7SM C9 C10 = -C9SM C10SM C7 = -C7SM C9 C10 = -C9SM C10SM back
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