1 / 35

Das BELLE Experiment

Das BELLE Experiment. Mt. Tsukuba. KEKB. Belle. ~1 km in diameter. Gerhard LEDER Hephy ÖAW-Wien. KEK 　高エネルギ Tokyo 東京. Das Experiment. B-Physik. Überblick über neueste Resultate. BB threshold. L peak = 1.4 x10 34 cm -2 sec -1 design = 10 34 cm -2 sec. KEKB Collider. e -. e +.

haruko
Download Presentation

Das BELLE Experiment

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. Das BELLE Experiment Mt. Tsukuba KEKB Belle ~1 km in diameter Gerhard LEDER Hephy ÖAW-Wien KEK　高エネルギ Tokyo 東京 • DasExperiment • B-Physik • Überblick über neueste Resultate

  2. BB threshold Lpeak=1.4 x1034cm-2sec-1 design=1034cm-2sec KEKB Collider e- e+ 8GeV 3.5GeV = 0.425 bg B-Factory (on the 4s resonance) BB threshold

  3. Kontinuierliche Injection Kein Grund, Run zu unterbrechen Immer bei ~max. Strömen, Luminosität [CERN courier Jan/Feb 2004] both KEKB & PEP-II ~30% more L dt normal injection (old) continuous injection (new) HER current LER current Luminosity ~1 fb-1/day ! (~1x106 BB) - 0 12 24 Time

  4. SVD Der BELLE Detektor

  5. Unterschied SVD1.6 und SVD2.0 Rbeampipe 15 mm Rbeampipe 20 mm Rlayer 1 20 mm Rlayer 1 30 mm Routside 88 mm Routside 60 mm 8+10+14=32 Ladders 6+12+18+18=54 Ladders SVD1 SVD2

  6. Wiener R/O & Trigger Elektronik R-Z Trigger R-PHI Trigger 2 x 18 FADCTF 24 input OR and analog signal input from VATA

  7. * VudVub 2(a) * Vtd Vtb 3(g) 1(b) Vcd Vcb * B Zerfälle und das Standard Modell Quark level Electro-weak Hadrons QCD/Lattice New Resonances Final state b-quark: Heavy  variety of decay modes Reiches Feld für fundamentale SM Parameter

  8. b b W x t s,d s,d g,g,Z B Zerfälle und “Neue” Physik Experimental measurements agree? SM predictions Yes No Deeper understanding New Physics ? Key point:ANP ~ ASM(small/forbidden) Penguin + New particle, Phase

  9. Prozedur, um B Signal zu extrahieren Verwende spezielle Kinematik des Y(4S) Two almost independent variables MB and DE can be used to select B meson signal: * MB = (Ebeam)2 – (S Pi)2 DE = SEi - Ebeam * Methods to extract B signal yield: 1) Cut on MB and fit to DE 2) Cut on DE and fit to MB 3) Double dimensional fit to MB and DE distribution 4) If B->P1P2P3: cut DEand MB box and look at resonant structures in M(P1P2) mass distribution.

  10. qq e- e+ Other B continuum Y (4S) e+ e- - BB Signal B Continuums Unterdrückung Dominanter Untergrund für seltene Zerfälle: Continuum e+e-qq “continuum” (~3x BB) Jet-like To suppress: use event shape variables BB sphärisch

  11. Continuums Unterdrückung • To separate spherical BB events from jet-like continuum events, topological variables are used: • Second Fox-Wolfram moment • Super Fox-Wolfram • (six modified Fox-Wolfram moments, Fisher discriminant) • 3) Angle between B meson and • beam axis direction • 4) Angle between thrusts of • selected B meson particles and all other particles in event • Likelihood ratio includes all info.

  12. Die Standard Modell Physik bei BELLE dsb u Vud Vus Vub c Vcd Vcs Vcb t Vtd Vts Vtb B0->ππ B0->rπ B0->J/Ks B0->fKs B0->D(*) D(*) B0-> D*π B0->D*r B->DCPK CKM-Matrix {i=1,k=3}: Vub*Vud+Vcb*Vcd+Vtb*Vtd = 0 Vub*Vud Vcb*Vcd Vtb*Vtd Vcb*Vcd  + 1 + = 0 -(rih) -(1-rih) selbstkonsistent falls SM korrekt rih Unitaritäts Dreieck rih Vtb*Vtd Vcb*Vcd f2 Vub*Vud Vcb*Vcd (a) f3 f1 1 (g) (b) 0

  13. Direkte CP-Verletzung:B  Kp/pp W _ _ s/d Vtb t K/p+ W u s/d g K/p+ u u Vub 0 d B _ _ G(Bf ) - G(Bf ) p- p- d d u d d _ _ G(Bf ) + G(Bf ) ACP = 0 d B b b Vus/d Vts/d   Tree Penguin • Simplest charmless rare decay modes • Tree - Penguin interferenceDirect CP Violation Key prediction of Kobayashi-Maskawa model Understanding of Penguin Anomaly (New Physics)

  14. 275M BB Neu ACP(B0 K+p-) _ B0 K-p+ B0 K+p- Signal: 2139 53 [submitted to PRL] ACP = -0.101  0.025  0.005 3.9ssignificance [PID efficiency bias correction: dA = -0.01  0.004] Evidenz für DCPV bei Belle auch bei [A(p+p-) 3.2s]

  15. Time-Dependent CP Asymmetry • The CP violationmanifests itself inproper-time differencedistributionsof two B meson decays. • The time-dependent CP asymmetry ACPis: • Standard Model prediction:Sccs= sin2f1, Accs= 0Ssss= sin2f1, Asss= small

  16. Prinzip der Messung BCP e-: 8.0 GeV e+: 3.5 GeV e- e+ fCP (J/yK0) (4S) bg ~ 0.425 Btag DzcbgtB ~ 200 mm Flavor tag Dz • Rekonstruiere BJ/yK0 Zerfälle • Messe Eigenzeit Differenz: Dt • Bestimme flavor von Btag • Berechne CP Asymmetry aus beiden Dt Verteilungen

  17. Prinzip der f1-Messung mit B  J/y Ks Flavor-tag decay (B0 or B0 ?) J/ e fCP e t=0 KS z B - B B + B more B’s more B’s t z/(cβγ)

  18. sin2f1 mit 152106BB Paaren K. Abe et al. [Belle collaboration], BELLE-CONF-0436. 4347 signal events @ 152106BB poor flavor tag consistent with no direct CPV • Decay modes used: • J/yKS(p+p-), J/yKS(2p0), y(2S)KS, cc1KS, hcKS • J/yK*(KSp0) • J/yKL good flavor tag

  19. Lebensdauer und Mixing mit neuem Detektor Parameter fit results(with new detector only) Belle preliminary Belle preliminary [ps] Belle preliminary [ps] [ps-1] Previous data sets and fitting function for them are unchanged. New detector resolution is well understood. Belle preliminary

  20. Indirect CP Violation:Mixing und/oder • Tree - Penguin interference B0 J/y Vcb KS V*2 td B0 B0 V* J/y Vcb td Vtb KS V* Vtb td sin2f1(bgsqq) = 0.41  0.07 sin2f1(bgccs) = 0.726  0.037 CP violation “same” as J/Ks within the Standard Model (SM) Penguin~O(l2), Tree~O(l4) deviation = O(1)%

  21. 275M BB pB* B0f K0 [hep-ex/0409049] fKS Nsig=139 14 fKL purity 0.63 Nsig= 36 15 purity 0.17 Similar to J/yKL recon. + sophisticated continuum suppression includes Ks p0po (Nsig=13 5)

  22. 275M BB S = 0.736 fit B → fK0CPV Resultat [hep-ex/0409049] Poor tags Good tags fKS+fKL:S(fK0) = +0.06 ±0.33 ±0.09 A(fK0) = +0.08 ±0.22 ±0.09 “sin2f1”~2.2s away from SM

  23. BABAR Resultate für B0fK0 BABAR 227MBB pairs - BABAR-CONF 04/033

  24. S = 0.736 fit B0 → wKS & f0(980)KS New modes ! wKS f0(980)KS Nsig=31 7 purity 0.56 Nsig=102 18 purity 0.58 “sin2f1” Raw Asymmetry Good tags Good tags (~0s @SM) (~2.9s @SM) S = +0.75 0.64 -S = -0.47 0.41 0.08 A = +0.26 0.48 0.15 A = -0.39 0.27 0.08 0.13 0.16

  25. sin2f1 from bgs penguins at FPCP04 sin2f1(bgsqq) = 0.41  0.07 sin2f1(bgccs) = 0.726  0.037 CL = 0.00012 (3.8s)

  26. „Neue“ Physik bei B f K0 ? • B f Ks theoretisch verstanden • A = 0.08 ± 0.22 ± 0.09 • sin2f1eff= 0.06 ± 0.22 ±0.09 • 2,2 s Abweichung von „SM“ sin2f1(bgsqq) = 0.41  0.07 sin2f1(bgccs) = 0.726  0.037 CL = 0.00012 (3.8s) SM predicts same CPV in b ccs and sqq. New physics may deviate CPV in b ccs from sqq New process with different CP phase SM penguin f +

  27. ZukünftigeUntersuchungen: Radiative and EW Penguins b→sg, sl+l- decays proceed via FCNCBox and penguin diagrams b→sg • Br(b→sg) ≈ 3.5×10-4 • Br(b→sl+l-) ≈ aem×Br(b→sg) ≈ 10-6 • New particle (via loops) may make appreciable contribution to decay rates and/or asymmetries. • Good testing ground of SM and beyond SM. b→sl+l-

  28. X(3872) Produktion in B Zerfällen Recently, Belle observed the X(3872) in B+->X(3872) K+ decay, with X(3872)->J/Y p+p- (confirmed by CDF, D0 and BaBar). Br(B-K-X3872) Br(X3872p+p-J/y) = 0.063 ± 0.012 ± 0.007 Br(B-K-y’) Br(y’p+p-J/y) 35±7 events M=3872.0±0.8 MeV G<2.3MeV (90%) Y ’ M(J/Yp+p-) X(3872) M(J/Y p+p-) – M(J/Y)

  29. Charmonium Spektroskopie cc1’ hc2Y2 Y3 hc’ cc2 cc1 cc0 Decay to J/Yp+p- Isospin 0++ allowed J/Y Isospin 1-- violating hc < 1 MeV/c2 hc’’ X(3872) MD*+MD 2MD Y’ hc

  30. Studie der X(3872) Produktion in B Zerfällen • Search for B gX(3872)K decay, with X(3872)gcc2g. MB DE 152x106 BB pairs G (Xgcc2g) = 0.42 ± 0.45 ± 0.23 <1.1 (90%CL) G(XgJ/Yp+p-) • Search for B gX(3872)K decay, with X(3872)gJ/Y g. MB MX DE G (XgJ/Y g) = G(XgJ/Yp+p-) 0.22 ± 0.12 ± 0.06 <0.40 (90%CL) |cos q| nHelicity angle: if Jp=1+- (hc’), sin2q angular distribution is expected. g ruled out by data. X

  31. events with M(3p)>0.75 GeV These events are almost pure signal Nevt=10.0 ± 3.6 S/N = 5/1 Signif = 5.8s Studie vom B+ X(3872) K+ Zerfall, X(3872)J/Y p+p-p0 274x106 BB pairs Events within B signal region and mass interval: | M(J/Y p+p-p0) – 3872. | < 12 MeV/c2 Assuming events with M(3p) > 0.75 as J/Yw : G (XgJ/Yw) = 0.8 ± 0.3 (stat) ± 0.1(syst) G(XgJ/Yp+p-) It provides support for DD* molecular interpretation of X(3872).

  32. M too low and G too small angular dist’n rules out 1+- G(gJ/y) way too small G(gcc1) too small; (PRL 93, 2003) pp hc should dominate ppJ/y G( gcc2 & DD) too small Welcher Zustand ist X(3872)? _ Keine guten cc Kandidaten für X(3872): hc” hc’ cc1’ y2 hc2 y3 - Isospin violating decays to J/Yp+p-

  33. q q Neue Charmonium Resonanz ? • Interpretation: • Masse gerade an der D0D*0 Schwelle • lose gebundenes “molecular charmonium”, oder ein Y(13D2) Zustand? • Ersteres in der Literatur diskutiert seit 1975: • ausgelöst durch komplizierte Struktur vons(e+e- ->hadrons) bei SPEAR • M. Bander, G.L. Shaw, P. Thomas, PRL 36, 695 (1976) • M.B. Voloshin, L.B. Okun JETP Lett. 23, (1976), Pisma Zh.Eksp.Teor.Fiz.23, 369 (1976) • A.De Rujula, H.Georgi, S.L.Glashow, PRL 38 (1977) • WW beschrieben durch p-Austausch gibt attraktive Kraft für DD*, BB* • N.A. Tornqvist, PRL 67, 556 (1991), Z.Phys. C61, 525(1994) • A.V. Manohar, M.B. Wise,Nucl.Phys. B339, 17(1993) D0D*0 Molekül q Ältere Ideen: q Q Q Q Q Stärkere Bindung Lose Bindung Decays to (QQ)+(light mesons) via quark rearrangement which suppresses the width. Diquark Model (Qq) are colored sin2f1 (NEW World Av.) =0.736±0.049

  34. Zusammenfassung (1) SM bisher überraschend selbst in Details erfüllt! Bestimmung der CKM-Matrix-Elemente im SM Indirekte CP-Verletzung A(t) bestimmt mit hoher Präzision sin2f1(bgccs) = 0.726  0.037 Grosse Anstrengung auch die beiden anderen Winkel zu messen (f2 und f3) Außerdem „Seitenlängen“ des Dreiecks: Dmd und Dms, sowie Vub/Vcb etc. sin2f1(bgsqq) = 0.41  0.07 Bedeutet anderer Wert (3.8 s) schon „neue Physik“ oder „nur“ Penguin-Beitrag ?

  35. Zusammenfassung (2) Beträchtliche Direkte CP-Verletzung (3.9 s ) ACP (B0 K+p -) = -0.101  0.025  0.005 Asymmetrie Materie-Antimaterie im Universum ? Molekül D*0D0 = 4 Quarkzustand oder konventionelle Erklärung? Neues Gebiet: Ds- Spektroskopie etc. BELLE ist bei vielen Gebieten an vorderster Front: SUPERBELLE mit höherer Luminosität

More Related