KEK 　高エネルギ ,

Projektbericht BELLE KEK　高エネルギ, Collaboration Rekordluminosität Neue wichtige Resultate HEPHY Physik-Analysen SVD Upgrade bei BELLE

KEKB Collider e- e+ Lpeak=1.62 × 1034cm-2sec-1 design=1034cm-2sec 8GeV 3.5GeV 600 fb-1 = 0.425 bg B-Factory (on the 4s resonance) BB threshold

BELLE-Detector ECL CDC KLM SVD

Pure leptonic decay Signal Remaining energy of signal B in ECL One B (tag) fully reconstructed 2.05+0.65-0.55(stat) Ikado et al hep-ex/0604018 4.0 s

10.75 0.245

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

Additional Constraints for Unitary Triangle    

Current status Constraints from “Loop” Constraints from tree CPV angles only: η=0.321±0.027 =0.193±0.57 sides only: η=0.342±0.02 =0.216±0.06

HEPHY Physik-Analysen Christoph Schwanda: Bp l n / Br l n / Bw l n  Vub Laurenz Widhalm: Formfaktoren semileptonischer D° ZerfälleFranz Mandl+G.L+H.D: BRs der inklusive Zerfälle D°  KK (F) X Gerhard Leder + L.W.: BRs der inklusive Zerfälle DsGerald Richter: Dekohärenz Modelle verschränkter B-Paare Winfried Mitaroff: Y(5S)Bs(*)Bs(*)[D0K0s]

Semileptonic Formfactors K p recoil p D*- K recoil pslow D0 „inverse“ fit recoil K/p+ e/µ- n p p Method of Reconstruction (Event Topology)  additional primary mesons IP 3.5 GeV e+ e- 8 GeV D* g p mass-constrained vertex fits D note: • all possible combinations tried in parallel • cuts after complete reconstruction • equal weight for remaining combinations  no event loss due to particle exchanges! Ktag p  signal side  tag side

Summary of Signal / Background Decomposition D0 Ken D0 pen remaining signal data fake-D0 bkg data D0 Kmn D0 pmn hadronic bkg data Kln bkg data K*/rln bkg MC mn² / GeV² *error dominated by MC statistics ** error dominated by fit errors & bias special bkgsample

Absolute Branching Ratios • ratio to total number of recoil D0 tags • efficiency correction • corrected for bias due to differences data/MC (1.9%±3.9%)

Form Factors – Comparison with Models D0 Kln fit results modified pole model simple pole lattice calculation ISGW2 model D0 pln modified pole (poles fixed at theo. values) preprint hep-ex/0604049, submitted to PRL

D0 - BranchingRatios D0(K+K-) X Data Generic MC D0 D0 K0 K+K- K0 X F F

D0(K+K-) X Mass window D0: 1.84<M(D0)<1.89 Data Mass window F: 1.00<M(F)<1.04 Generic MC • PDG f f 1.71% +/- 0.76 1.02%+/-0.14 D0 D0 Correct BGshape from MC ? 0.37%+/-0.04 0.39%+/-0.012 BG?= 4*35 Mass window D0= 332-80(sideband)=252 Mass window D0=191-25(sideband)=166 Mass window F=458-182(sideband-extr) =276 Mass window F= 255- 141(side-extr)=114

drydiff gen MC m(K+K-) RS-WS comparison with data (*), scalefactor 0.445 greenD0 X pink  not from D0 blueD0 K+K-X yellow no D0 redno K+(K-)

fitdat DATA FIT m(K+K-) 3 Gaussians+ Polyn. 4th order

Missing Mass for D0F X Mass window F: 1.00<M(F)<1.04 Data Generic MC K0 K0

Ds recoil Ds*- recoil „inverse“ fit p p Method of Reconstruction (Event Topology)  additional primary pions IP 3.5 GeV e+ e- 8 GeV p K+ p ... Signal • Ds inclusive Example DsF X PDG:(18+/-10)% or exclusive: (semi)leptonic Dsm n BaBar (0.65+/-0.08)% Dst n (6.4+/-1.5)% DsF l n (2.0+/-0.5)% g mass-constrained vertex fits D Ds- recoil µ- n Ktag p  signal side  tag side

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

Best Candidate Selection signal / no ambiguity signal / several associations signal / lost because wrong candidate selected background Ds invariant mass Ds invariant mass no best candidate selection 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

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 remainingenergy in ECL, similar to Bt n analysis Ds invariant mass DATA (ca. 3.2% of available statistics) Fit: 705 events  ca. 22000 Ds expected in total Room for improvement also best candidate selection might be further improved Cross-check with hadronic channels, i.e DsF p

Gerald Richter z1 , t1 μ+ z0 , t0 z2 , t2 The decay typical Υ(4S) resonance decay • βγcτB0 = 196 μm(LAB) l+ l- K0s π- entanglement region π+ θ 8 GeV e- 3.5 GeV e+ beam axis • Δm= 0.489 1012 ћs-1 = 0.754 τB0-1

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

lower tail cut upper tail cut 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 τB0 window removed • t1: 0, 1, 2, 4 % • dt: 0, 1, 2 %

for 2 cases of fixed dt quantile cuts 1%, 2% behaviour of the ML fit result for a given λTRUE = 0 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. fit results on signal BELLE-MC with varied quantile cuts fit works BELLE-MC with different l in preparation

SVD 2.5

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

KEK 高エネルギ ,