Projektbericht BELLE Vorstandssitzung 19. Mai 2005 -3]mc 32by[k

Projektbericht BELLE Vorstandssitzung 19. Mai 2005 -3]mc 32by[k


KEK 　高エネルギ , ce^Tokyo 東京

Projektbericht BELLE

• Status BELLE Experiment

• Die Zukunft von BELLE

• Neue Resultate (Hot Topics)

Collaboration

• HEPHY Physik-Analysen


Lpeak=1.56 × 1034cm-2sec-1

design=1034cm-2sec

KEKB Collider

e-

8GeV

e+

3.5GeV

= 0.425

B-Factory(on the 4s resonance)

B-Factory(on the 4s resonance)

BBthreshold


~400 millionBB pairs

KEKB

PEP-II

~256 millionBB pairs


Belle Detector (2005)

• 7 sub-detectors for precise – Vertexing, – Tracking, – Particle ID, – Calorimetry


Upgrade plan (near future)Upgrade plan (near future)

CDC

・ Faster front end electronics・ Faster trigger signal・ Optimization of the tracking code

KLM

・ Scintillator tile with SiPM readout

ECL

・ Waveform sampling・ Pure CsI crystal for endcap・ Optimization of the clustering code

SVD・ Shorter strip/pixel for the inner layers・ Faster readout electronics・ Optimization of the vertex code

DAQ upgradeTDC based readout pipelined system　 Dead time free up to 5kHz trigger rateComputing system upgradeCPU, mass storage and network system


Layer 1 replacement is scheduled in 2007 summerSVD3 schedule depends on approval of the project.

2005 2006 2007 2008 2009 2010 2011

Luminosity (1034) 2.0 3.0 5.0 5.0 0 0 25

SVD2.0 Reinforcement

SVD2.0→SVD2.5 Replace L1 ladders

SVD2.5→SVD3 Full upgrade

R&D

Prod.

TestProd.

Test

R&D Installation

Direction SUPERBELLE

SVD Upgrade schedule


Simulation Study for Higher Beam Background

Detail was reported in the last WS by K.Senyo.

MC +BGx1 MC+BGx20


One possibility would be to measure the time between trigger and the hits. Thus off-time hits can be discarded. Hits in the selected trigger window are event candidates.

The APV25 has the possibility to store 3 consecutive samples (spaced by the system clock) of a signal (multi-peak mode) with one trigger.With a second trigger just 3 clocks later, you can get the next 3 time samples of the shaped input signal. We can use this possibility to determine the time between shaped detector signal and clock.

Background reduction using the multi-peak modeMost hits from background events are not correlated(in time) with the trigger (continuous beam). At the moment we have a time window to accept data of >2400 ns for the VA1TA and ~150ns (50ns peaking time) for the APV25. This window of 150ns should be reduced again.

Additional reduction of the time window (and thus of the background) by a factor around 8-10!

Interesting proposal by the Vienna group (M.Pernicka) to reduce background induced occupancy in Vertex detector reduction with the possibilities of APV25 andBackground reduction using the multi-peak mode

Hawai 05 Workshop

Summary by M. Giorgi


KEKB Collider Upgrade Scenario

~1010 B mesons/year !!

& also +-

Lpeak = 1.561034cm-2s-1

Ltot = 431fb-1 (May.14, 2005)

crabcavities

Major upgrade ofKEKB & Belle(>1yr shutdown)

world records !

1.5x1034

431 fb-1

~5x1034

~1 ab-1

~5x1035

~10 ab-1

Lpeak (cm-2s-1)Lint


Severe (financial) problems when it is compared with


Scenarios in the next decade

LHC finds SUSY

LHCturns on

LHC doesn’tfind SUSY

We are here

HEP

What canthe ILC say about

SUSY-breaking models?

What can a Super B Factory say aboutSUSY-breaking models?

Much interesting workhas already been doneon this topic.Can we find a more effective way to getthe message across?


Pessimistic (?) Conclusions of Hitlin (BaBar Spokesman)What is needed to make the case

• A credible integrated luminosity capability approaching 10 ab-1/year

– An accelerator with an upgrade path, as with the current B Factories

– A detector that is conservatively designed and able to cope with backgroundsurprises and future luminosity upgrades

• A credible plan for gathering a data sample of 10’s of ab-1 that allows the marquee important measurements to be made on a time scale that is competitive with LHCb and relevant to clarifying SUSY discoveries

– An algorithm that there demonstrates the power of a real-time dialog between the LHC, a Super B Factory and, eventually, the ILC, would be a killer app

• We have made real progress on this – more is needed

• Discussions on forming a truly international collaboration on an appropriately scaled accelerator and detector

– This would, for example, facilitate an ICFA endorsement

– This could provide a critical mass of people and funding potential to convince the community that a Super B Factory should go forward


Neue Resultate – X(3940)

ee J/ψ X, all currently available data (Exp7-41)

ηc

η‘c

χc0

X(3940)


Neue Resultate – X(3872)

B KX(3872), X ππJ/ψ, data from Exp7-39

X(3872)

ψ(2s)


JPC possibilities for X(3872)• J ≤ 2• DD allowed & P-violating unlikely• signal for X γJ/ψ

C=-1 ruled out• check of angular distributions

rules out 1±-,0±+,2-- • fits of Mππ

2-+ unlikely • X(3872) = χc1‘?

unlikely, since mass and BR ratio way off theo. expect.


HEPHY Physik-Analysen

Heinz Dibon: Parallelanalyse semileptonische D° Zerfälle Franz Mandl: Studie der inklusive Zerfälle D° K*X / X Gerald Richter: Dekohärenz Modelle verschränkter B-Paare Christoph Schwanda: Matrixelemente der HQET Laurenz Widhalm: Formfaktoren semileptonischer D° Zerfälle


Heinz Dibon

• Parallelanalyse semileptonischer D°-Zerfälle Zweck: Cross-Check der Analysemethode von LW, Quantifizierung von deren Effizienzvorteil Rekonstruktion des Neutrinos gelingt bereits (siehe plot), derzeit wird an der Optimierung der cuts gearbeitet

Neutrino Auflösung |ptrue| - |prec| in GeV


Franz Mandl

Inclusive Decays D0 K*0X and D0 0X Some time ago ( Fig)

reported:

B (D0 K*X) B (K* K-+) 6.67%

B (D0 K*X) 10%

Method: Full reconstruction of events:

D * D 0

K X+ 0, 1, 2 primary mesons

D * D 0

K

K 0

tag side signal side“right sign”

e+e-

preliminary studies on efficiences etc have been reported (also for D0 0X)

all particles “left over” in reconstruction should come from D0 (signal side)

ideal method for the determination of inclusive branching ratios for

D0 hX, h = K*0, 0, , , ……. (not yet known)


“some time ago”

B(D0 K*X) * B(K* K-+) = * 3.8% = 6.67%

125.971.7

K-+ effective masses of combinations of charged particles from kinematically selected D0 via recoil, tagging D*+D*-, D*+D*-0 and D*+D*-+- , …. events

not in PDG list

OLD

Franz Mandl


line: e+e D*+D* MC (2 pr)

red crosses: e+e D*+D* (0, data (2, 3, 4 pr)

D0 K*0 X (signal)

D0 KXD0 h1X

h2X

at least one particle misidentifiedM (K)

arbitrary normalization

ok for 3, 4 pr

Franz Mandl

QM coherence model investigations

● cτB0

= 462 μm (LAB)

● Δm = 0.489 1012 ћs-1 = 0.754 τ

B0

beam axis3.5 GeV e+8 GeV e-

B0

B 0interaction point

(IP) = primary vertex

decay point 1 =

secondary vertex

B0entanglement

region

entanglementregion

l-

decay point 2 =

secondary vertex

l+

K0s π-

π +

μ+

full reconstruction

side (FR)

partial reconstruction

side (PR)

example reaction

example reaction

z0 , t

0z

1 , t

1

z2 , t

2

full 50 0,2partial 120 0,5

zlab

tCMS [

B]

expected resolutions

expected resolutions

QM predicted asymmetry + CoMoQM predicted asymmetry + CoMo

(PV)

Gerald Richter


preliminary studies:ML-fit sensitivity for assumed Model and

errors

preliminary studies:ML-fit sensitivity for assumed Model and

errors

Status:preliminary studies finished, fit method delivers sufficient sensitivity

Gerald Richter


defining cuts on MC-data to achieve sufficient time

resolutions

defining cuts on MC-data to achieve sufficient time

resolutions

Status:improving primary vertex resolution full 70 0,28

partial 90 0,36PrimVtx 450 1,8

zlab

tCMS [

B]

resolutionsso far

resolutionsso far

Gerald Richter


Christoph Schwanda


Christoph Schwanda


Christoph Schwanda


K

D

D*

mass- / vertex fit

e+ e-3.5 GeV 8 GeV

K

KD*

D

e/µ

Method of „full inclusive reconstruction“

„inverse“ fit

additional primarymesons

Laurenz Widhalm


Overview Background Composition

neutrino invariant mass squared, all cuts applied except neutrino mass cutneutrino invariant mass squared, all cuts applied except neutrino mass cut

right sign*

wrong sign*

right sign*

wrong sign*

m² / GeV² m² / GeV²

signal

non-D° bkg

hadronic bkg, misidentified kaons

hadronic bkg, misidentified pions

bkg from D° Kl

bkg from D° K*lD° *l

++ D° eD° e D° D° DATA DATA

Laurenz Widhalm


q² distribution – comparison of models

ISGW2 model

lattice calc.

pole model

• Analyse derzeit in der Refereeing Stage / Präsentation auf Sommer Konferenzen in Vorbereitung

pole mass – comp. with CLEO & FOCUS

D0 lD0 l

Projektbericht BELLE Vorstandssitzung 19. Mai 2005 -3]mc 32by[kEreignisrekonstruktion in C++ bei BELLE PDA Seminar 11/02 Laurenz Widhalm


Baseline design for SUPERBELLE

CDC

SVDShoji Uno

Documents

Projektbericht BELLE Vorstandssitzung 19. Mai 2005 -3]mc 32by[k