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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 L peak = 1.62 × cm -2 sec -1 design = cm -2 sec KEKB Collider e-e- 8GeV e+e+ 3.5GeV = B-Factory (on the 4s resonance) B-Factory (on the 4s resonance) BB threshold

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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Ikado et al hep-ex/ Signal One B (tag) fully reconstructed Remaining energy of signal B in ECL Pure leptonic decay (stat) 4.0

Projektbericht BELLE Vorstandssitzung 8. Juni

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

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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Current status 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 LoopConstraints from tree

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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006

K tag D mass-constrained vertex fits e+e- 3.5 GeV8 GeV K K D0D0 slow e/µ D* - inverse fit tag side Method of Reconstruction (Event Topology) D* signal side additional primary mesons IP note: all possible combinations tried in parallel cuts after complete reconstruction equal weight for remaining combinations no event loss due to particle exchanges! Semileptonic Formfactors

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Summary of Signal / Background Decomposition Results (282 fb -1 of BELLE data) Ke Ke signal events1318 ± 37 stat ± 7 syst 1249 ± 37 stat ± 25 syst 126 ± 12 stat ± 3 syst 106 ± 12 stat ± 6 syst fake D 0 bkg12.6 ± ± ± ± 4.5 semileptonic bkg*6.7 ± ± ± ± 1.9 hadronic bkg**11.9 ± ± ± ± 3.7 fake-D 0 bkg Kl bkg D 0 e D 0 l bkg D 0 e D 0 hadronic bkg m ² / GeV² *error dominated by MC statistics ** error dominated by fit errors & bias special bkgsample MC data remaining signal

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Absolute Branching Ratios BRs (%)this analysisPDG (2005) CLEO-c (hep-ex/ ) K - e ± 0.10 stat ± 0.19 syst 3.62 ± ± 0.10 stat ± 0.10 syst K ± 0.10 stat ± 0.21 syst 3.20 ± e ± stat ± syst ± ± stat ± syst ± stat ± syst 0.24 ± 0.04 ratio to total number of recoil D 0 tags efficiency correction corrected for bias due to differences data/MC (1.9%±3.9%)

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Form Factors – Comparison with Models ISGW2 model lattice calculation modified pole model D 0 l pole mass (GeV) Kl 1.82 ± 0.04 stat ± 0.03 syst l 1.97 ± 0.08 stat ± 0.04 syst simple pole Kl 0.52 ± 0.08 stat ± 0.06 syst l 0.10 ± 0.21 stat ± 0.10 syst modified pole (poles fixed at theo. values) fit results f + (0) Kl ± stat ± syst l ± stat ± syst preprint hep-ex/ , submitted to PRL

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 D 0 (K + K - ) X DataGeneric MC K0K0 K0K0 D0D0 D0D0 K+K-K+K- X D 0 - BranchingRatios

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Mass window = (side-extr)=114 D 0 (K + K - ) X Mass window D 0 : 1.84<M(D 0 )<1.89 Mass window : 1.00<M( )<1.04 Mass window D 0 = (sideband)=252Mass window D 0 =191-25(sideband)=166 Mass window = (sideband-extr) =276 Generic MC Data BG?= 4*35 Correct BGshape from MC ? D0D0 D0D0 0.37%+/ %+/ % +/ %+/ PDG

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

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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Missing Mass for D 0 X Data Mass window : 1.00<M( )<1.04 Generic MC K0K0 K0K0

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 K tag D mass-constrained vertex fits e+e- 3.5 GeV8 GeV K+K+ Ds-Ds- µ Ds*-Ds*- inverse fit tag side Method of Reconstruction (Event Topology) signal side additional primary pions IP... D s inclusive Example D s X PDG:(18+/-10)% or exclusive: (semi)leptonic D s BaBar (0.65+/-0.08)% D s (6.4+/-1.5)% D s l (2.0+/-0.5)% DsDs Signal

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 D s

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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Best Candidate Selection 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 Ds invariant mass signal / no ambiguity signal / several associations signal / lost because wrong candidate selected background no best candidate selection largest slow gamma energy taken

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 DATA (ca. 3.2% of available statistics) Ds invariant mass Fit: 705 events ca Ds expected in total 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 D s or D s will further reduce ambiguity enhancement of signal cuts are still under development D s needs suppression of remaining energy in ECL, similar to B analysis Room for improvement also best candidate selection might be further improved Cross-check with hadronic channels, i.e D s

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Thedecay βγcτ B0 = 196 μm(LAB) Δm = ћs -1 = τ B0 -1 beam axis 3.5 GeV e + 8 GeV e - entanglement region l-l- l+l+ K0sK0s π-π- π+π+ μ+μ+ typical Υ (4S) resonance decay z 0, t 0 z 1, t 1 z 2, t 2 θ Gerald Richter

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Adapted response function model sum of 2 gaussians + back to back neg. exponential gaussian pagoda resolution function R(t) shown for t1 parameter good accordance of fit function up to +/- 4 mm

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 applied cuts to get fit working lower tail cut 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 τ B0 window removed t1: 0, 1, 2, 4% dt: 0, 1, 2% upper tail cut

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

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 SVD 2.5

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 SVD 2.5

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 SVD 2.5

Projektbericht BELLE Vorstandssitzung 8. Juni 2006 Generated number of events (~May 22) k events 18Mevents per 20 days 870 days for seed0-2 Need your help! Generic MC-Production for BELLE-Collaboration VIENNA Service Jobs