Projektbericht BELLE Vorstandssitzung 8 Juni 2006 Projektbericht BELLE

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Projektbericht BELLE KEK 高エネルギ, Collaboration • Rekordluminosität • Neue wichtige Resultate • HEPHY Physik-Analysen • SVD Upgrade bei BELLE

Projektbericht BELLE KEKB Collider Vorstandssitzung 8. Juni 2006 1034 cm-2 sec-1 Lpeak=1. 62 × design=1034 cm-2 sec e 8 Ge. V e+ 3. 5 Ge. V bg = 0. 425 B-Factory (on the 4 s resonance) BB threshold

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 BELLE-Detector ECL CDC SVD KLM

Projektbericht BELLE • Pure leptonic decay Vorstandssitzung 8. Juni 2006 2. 05+0. 65 -0. 55(stat) Signal Remaining energy of signal B in ECL Ikado et al hep-ex/0604018 4. 0 s One B (tag) fully reconstructed

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 10. 75 0. 245

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 First Observation of b d Mohapatra. Nakao, Nishida et al hep-ex/0506079 signal qq CDF _ Addresses the same physics issue as Bs- Bs mixing K*g other B CDF

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Additional Constraints for Unitary Triangle

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Current status Constraints from “Loop” CPV angles only: η=0. 321± 0. 027 =0. 193± 0. 57 sides only: η=0. 342± 0. 02 =0. 216± 0. 06 Constraints from tree

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 HEPHY Physik-Analysen Christoph Schwanda: B p l n / B r l n / B w l n Vub Laurenz Widhalm: Formfaktoren semileptonischer D° Zerfälle Franz Mandl+G. L+H. D: BRs der inklusive Zerfälle D° KK (F) X Gerhard Leder + L. W. : BRs der inklusive Zerfälle Ds Gerald Richter: Dekohärenz Modelle verschränkter Winfried Mitaroff: Y(5 S) Bs(*)[ D 0 K 0 s] B-Paare

Projektbericht BELLE Vorstandssitzung 8. Juni 2006

Projektbericht BELLE • Semileptonic Formfactors Vorstandssitzung 8. Juni 2006 Method of Reconstruction (Event Topology) additional primary mesons IP 3. 5 Ge. V e+ e- 8 Ge. V p D*- g D Ktag p K pslow mass-constrained vertex fits p tag side D 0 note: • all possible combinations tried in parallel + e/µK/p • pcuts after complete reconstruction • equal weight for remaining combinations no event loss due to particle signal exchanges! „inverse“ fit n side K p

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Summary of Signal / Background Decomposition D 0 Ken D 0 Kmn Results (282 fb -1 data remaining signal data fake-D 0 bkg data hadronic bkg data Kln bkg MC K*/rln bkg D 0 pen D 0 pmn mn² / Ge. V² of BELLE data) signal events fake D 0 bkg semileptonic bkg* hadronic bkg** Ken Kmn pen pmn 1318 1249 126 ± 37 stat ± 7 syst ± 37 stat ± 25 syst ± 12 stat ± 3 syst 12. 6 ± 2. 2 12. 2 ± 4. 8 12. 3 ± 2. 2 12. 5 ± 4. 5 6. 7 ± 2. 6 10. 0 ± 2. 5 11. 7 ± 1. 2 12. 6 ± 1. 9 11. 9 ± 5. 6 62. 1 ± 23. 9 1. 8 ± 0. 7 9. 7 ± 3. 7 • *error dominated by MC statistics • ** error dominated by fit errors & bias special bkgsample 106 ± 12 stat ± 6 syst

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Absolute Branching Ratios • ratio to total number of recoil D 0 tags • efficiency correction • corrected for bias due to differences data/MC (1. 9%± 3. 9%) BRs (%) this analysis PDG CLEO-c (2005) (hep-ex/0505035) K - e+ n 3. 45 ± 0. 10 stat ± 0. 19 syst 3. 62 ± 0. 16 K - m+ n 3. 45 ± 0. 10 stat ± 0. 21 syst 3. 20 ± 0. 17 p - e+ n 0. 279 ± 0. 027 stat ± 0. 016 syst 0. 311 ± 0. 030 p - m+ n 0. 231 ± 0. 026 stat ± 0. 019 syst 0. 24 ± 0. 04 3. 44 ± 0. 10 stat ± 0. 10 syst 0. 262 ± 0. 025 stat ± 0. 008 syst

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Form Factors – Comparison with Models fit results D 0 Kln modified pole model lattice calculation ISGW 2 model simple pole mass (Ge. V) Kln 1. 82 ± 0. 04 stat ± 0. 03 syst pln 1. 97 ± 0. 08 stat ± 0. 04 syst modified pole D 0 pln (poles fixed at theo. values) f+(0) Kln 0. 695 ± 0. 007 stat ± 0. 022 syst pln 0. 624 ± 0. 020 stat ± 0. 030 syst a Kln 0. 52 ± 0. 08 stat ± 0. 06 syst pln 0. 10 ± 0. 21 stat ± 0. 10 syst preprint hep-ex/0604049, submitted to PRL

Projektbericht BELLE Data • D 0 - Branching. Ratios D 0 (K+K-) X Generic MC D 0 K+ K- Vorstandssitzung 8. Juni 2006 X K 0

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 D 0 (K+K-) X Mass window D 0: 1. 84<M(D 0)<1. 89 Data Mass window : 1. 00<M( )<1. 04 Generic MC • PDG f f 1. 71% +/- 0. 76 1. 02%+/-0. 14 D 0 0. 37%+/-0. 04 Correct BGshape D from MC ? 0. 39%+/-0. 012 0 BG? = 4*35 Mass window D 0= 332 -80(sideband)=252 Mass window D 0=191 -25(sideband)=166 Mass window =458 -182(sideband-extr) =276 Mass window = 255 - 141(side-extr)=114

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 drydiff gen MC m(K+K-) comparison with data (*), green D 0 X pink not from D 0 blue D 0 K+K-X yellow no D 0 red no K+(K-) RS-WS scalefactor 0. 445

Projektbericht BELLE fitdat DATA FIT m(K+K-) Vorstandssitzung 8. Juni 2006 3 Gaussians + Polyn. 4 th order

Projektbericht BELLE Missing Mass for D 0 F X Vorstandssitzung 8. Juni 2006 Mass window : 1. 00<M( )<1. 04 Data K 0 Generic MC K 0

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Ds Method of Reconstruction (Event Topology) additional primary pions IP 3. 5 Ge. V e+ e- 8 Ge. V p K+ D Ktag p tag Signal • Ds inclusive Example Ds F X PDG: (18+/-10)% or exclusive: mass-constrained (semi)leptonic vertex fits Ds m n Ba. Bar (0. 65+/-0. 08)% µ D t n s p p (6. 4+/-1. 5)% Ds F l n side (2. 0+/-0. 5)% Ds *- . . . g Ds - „inverse“ fit n signal side p

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 • D s

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 New: Ds → mn and f. Ds c Helicity-suppressed leptonic decay: • directly related to decay constant f. Ds s • feeds interpretation of B, Bs mixing Analysis Method: “D reco” in e+e- → cc D reco side Signal peak in (normalize to Ds → fp) Ba. Bar (230 fb-1): Lattice QCD: Single best measurement of decay constant! Ba. Bar

Projektbericht BELLE Best Candidate Selection Ds invariant mass no best candidate selection Vorstandssitzung 8. Juni 2006 signal / no ambiguity signal / several associations signal / lost because wrong candidate selected background Ds invariant mass largest “slow” gamma energy taken • signal yield can be increased by a „best candidate selection“ in case of ambiguities, e. g. by choosing maximal „slow“ gamma momentum • improvement: ~40% • important: no bias on background! • a cut on the Ds fit (not done in the plots) further increases the yield

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 • first look into data (only 3. 2% of available data) • simple fit gaussian + linear curve for rough estimate • hope: reconstruction of muon and neutrino of Ds mn or Ds F m n will further reduce ambiguity enhancement of signal • cuts are still under development • Ds t n needs suppression of remaining energy in ECL, similar to B t n analysis Ds invariant mass Fit: 705 events ca. 22000 Ds expected in total DATA (ca. 3. 2% of available statistics) • Room for improvement • also best candidate selection might be further improved • Cross-check with hadronic channels, i. e Ds p

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Gerald Richter The decay typical Υ(4 S) resonance decay • βγcτB 0 = 196 μm(LAB) l+ z 1 , t 1 l. K 0 entanglement region π+ π 8 Ge. V e- s 3. 5 Ge. V e+ θ beam axis μ+ z 0 , t 0 z 2 , t 2 ● Δm = 0. 489 1012 ћs-1 = 0. 754 τB 0 -1

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Adapted response function model “gaussian pagoda” resolution function R(t) shown for t 1 parameter good accordance of fit function up to +/- 4 mm sum of 2 gaussians + back to back neg. exponential

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 applied cuts to get fit working ● ● varied the symmetric quantile cuts, to find point, where the ML fit is not disturbed by tails. with lower = upper percentage of histogram entries within the ± 40 τB 0 window removed t 1: 0, 1, 2, 4 % dt: 0, 1, 2 % lower tail cut upper tail cut

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 fit results on signal BELLE-MC with varied quantile cuts fit works • for 2 cases of fixed dt quantile cuts 1%, 2% • behaviour of the ML fit result for a given λTRUE = 0 BELLE-MC with different l in preparation • with increasing cut percentage, λFIT pulled towards 0 • cutting too much will impair error model correctness • 2% for both parameters looks like a good choice.

Projektbericht BELLE SVD 2. 5 Vorstandssitzung 8. Juni 2006

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Generated number of events (~May 22) k events 18 Mevents per 20 days 870 days for seed 0 -2 Need your help! • VIENNA • Service Jobs • Generic MC-Production for BELLE-Collaboration