Projektbericht BELLE Vorstandssitzung 28. November 2005 KEK, Tokyo Projektbericht BELLE Status BELLE Experiment SVD Upgrade bei BELLE Neue Resultate Y(5S)

Projektbericht BELLE Vorstandssitzung 28. November 2005

KEK 　高エネルギ , Tokyo 東京

Projektbericht BELLE

• Status BELLE Experiment

• SVD Upgrade bei BELLE

• Neue Resultate Y(5S)

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


BELLE-DetectorBELLE-Detector

CDC

KLM

ECL

SVD


TTMS0

DockF0

sensors

Power SupplyF0

TTMS1

DockF1

sensors

Power SupplyF1

TTMS2

DockF2

sensors

Power SupplyF2

TTMS3

DockF3

sensors

Power SupplyF3

TTMS4

DockF4

sensors

Power SupplyF4

TTMS5

DockB0

sensors

Power SupplyB0

TTMS6

DockB1

sensors

Power SupplyB1

TTMS7

DockB2

sensors

Power SupplyB2

TTMS8

DockB3

sensors

Power SupplyB3

TTMS9

DockB4

sensors

Power SupplyB4

SVD front-endE-Hut Rad-Ctrl area

InsideEnd-cap

InsideCDC

1. S4 problem2. S1 problem


PrologueOct.05 12 hybrids (S1) stopped working

Oct.16 After a big earthquake, another 12 hybrids (S4) stopped working and recovered by itself by the next morning


Burned connectors

S1 S4

All the others in FWD also brownedOne in BWD (B4) slightly


What should we do for BWD?

We must replace the connector before being burned.Nobody knows when it will be.We don’t like to have fearful days so long.

During the coming winter shutdown would be the best

e.g.Dec.26~28 open end-yoke/end-capDec.26~28 cosmic ray runsDec.29,30 take boards outJan.04~09 repair boards and install, testJan.09~12 cosmic ray runsJan.10~12 close end-cap/end-yoke


Number of Bs in dataset

Y(5S) hadronic events

bb events

Bs events

bb continuum included

N ev = 560,872 ± 3,018 ± 28,630

fs = (16.4 ± 1.4 ± 4.1 )%

N ev = 91,983 ± 7,868 ± 23,470

f(Bs*Bs*) = (93 ± 10)%

N ev = 85,544 ± 11,754 ± 21,827Bs* Bs* channel

Bf(Bs->Ds+- ) = (9 ± 3) / 85544 / 2/ (0.00808 ± 0.00103) = (0.65 ± 0.22 ± 0.21)%

CDF : Bf(Bs->Ds+- ) = (0.40 ± 0.06 ± 0.06 ± 0.11 ± 0.06 )%

Lumi = 1.8574 fb-1

Y(5S)


Number of bb events.

2 ~ 1/Ecm

R = (hadrons) / ()

Ncont(5S) = Ncont(E=10.519)* L(5S) / L(cont) * (Econt/E5S)2

Y(5S) : exp 43 runs 1013-1034 (5S scan excluded)

N(hadron)= 6, 223, 974 events

Cont : exp 43 runs 924-972

N(hadron)= 11, 876,173 eventsLumi = 3.66997 ± 0.00135 (stat) fb-1

(1.8574/3.66997)*(10.5189/10.869)2 = 0.4740± 0.0019

Corrections for HadronB cuts:

1. Nch >3 => ( 0.5 ± 0.3)%

2. E/Ecm > 0.18 => ( 0.2 ± 0.1)%

Nbb(5S) = ( 6223974 – 11876173 * 0.474 *1.007 ) / 0.99 =

CLEO : 0.42 fb-1 Nbb(5S) = 130000 ± 1000 ± 22000 (events / lumi : ~2.5% larger)

Status of Y(5S) analysis, BGM, Nov 15, A. Drutskoy

Lumi = 1.85740 ± 0.00100 (stat) fb-1

560,872 ± 3,018 ± 28,630

Y(5S)


Inclusive analysis : Y(5S) -> Ds X

Y(5S)

Ds +

3775 ± 100 ev

P/Pmax< 1Theory : hep- ex/0508047 CLEO

Bf (Bs DsX) = (92 ± 11) %

PDG : Bf (Ds +)=(3.6 ± 0.9)%

Sum: Bf(Ds +) = (4.4 ± 0.5)%

Bf(Ds +)=(4.8 ± 0.6)% Babar :

Babar :CLEO : Bf (B DsX) = ( 9.0 ± 0.3 ±1.4 )%

Bf (B DsX) = ( 8.94 ± 0.16 ± 1.12 )%

After continuum subtraction and efficiency correction:

Bf (Y(5S) Ds X) 2 = (22.6 ± 1.2 ± 2.8) %CLEO measured: Bf (Y(5S) Ds X) / 2 = (22.35 ± 2.1 ± 4.95)%

fs = (16.4 ± 1.4 ± 4.1 )%=>

Using Ds mesons CLEO measured fs = (16.0 ± 2.6 ± 5.8 )%

Syst. err. dominated by Bf(Ds+)

Y(5S)


Exclusive Bs Ds(*)+ - decays

BsBs , Bs*Bs , Bs*Bs*

Ds+ + , Ds

+ K*0 K+, Ds+ Ks K

+

Cut on angle between Bs and beam direction was recently removed ( 1- 1- 1- )

(few more events).

Clear signal at Bs* Bs* channel ; signals in Bs* Bs and BsBs channels are not seen.

MC

Bs Ds+ -

9 events in Bs* Bs*

Bs Ds*+ -

4 events in Bs* Bs*

Y(5S)


E distribution, sum of all Bs decay modes

Decay (5S) -> Bs* Bs* , with Bs* -> Bs

E peak = Ecm(accel.)/2 – Ecm(real)/2 – E()

E peak = – 47.6 ± 2.6 MeV

Small signal , Nev = 1.5 ± 2.0 (7±10%)

Potential models predict Bs* Bs*dominance over Bs*Bs and BsBs

channels, but not so strong.

5.408< MBC<5.429 GeV/c2

Bs* Bs*Nev=20.0 ± 4.8

6.7

5.384< MBC<5.405GeV/c2

Bs* Bs

Y(5S)


MBC distribution, sum of all Bs decay modes

Mbc = E*B2 – P*B

2 Mbc = (E*B+ Epeak)2 – P*B2

Ecm = 10869 MeV ; E*B = Ecm/2

M (Bs*) = 5418 ± 1 ± (acc. err) MeV/c2

Photon momentum is neglected => does not change Bs* mass position, only smearing.

M (Bs) = 5370 ± 1 ± 3 MeV/c2

Photon energy smearing does not change Bs mass position

CDF: M (Bs) = 5366.0 ± 0.8 MeV/c2

Bs* Bs*

- 0.08<E<- 0.02 MeV

Bs* Bs*

- 0.08<E<- 0.02 MeV

Y(5S)


HEPHY Physik-Analysen

Christoph Schwanda: Momente der El und MX2 in BXc l

Laurenz Widhalm: Formfaktoren semileptonischer D° Zerfälle

Heinz Dibon: Parallelanalyse als Cross-Check Franz Mandl: BRs der inklusive Zerfälle D° X/ K*X /X Gerhard Leder: BRs der inklusive Zerfälle Ds Gerald Richter: Dekohärenz Modelle verschränkter B-Paare


Christoph Schwanda


Christoph Schwanda


Christoph Schwanda


tag side:

• reconstruction & fit of D0,± K, K2, K3• reconstruction & fit of D*0,± D, D• use either D or D* as primary meson

signal side:

• reconstruction & fit of inclusive D*0,± via recoil from e+e- D(*)

D*n/K• reconstruction & fit of inclusive D0 via recoil from D* D• reconstruction & fit of neutrino via recoil from D m

D

D*

e+ e-

D

e/µ

D*

tag signal

K

( )

K

K

additional primary mesons

Method of Reconstruction

Laurenz Widhalm


Summary of Signal / Background Decomposition

Ke K e

signal events 1318 .. 1248 .. 126 .. 107...

statistical error 37 .. 35... 12 .. 11 ..

systematics 5...

14... 7 .. 9 ..

non-D bkg 12.6 12.4 12.3 11.5

semileptonic bkg 6.7 10.0 11.7 12.6

hadronic bkg 11.9 62.1 1.8 9.7

signal

non-D bkg

Kl bkg

D0 eD0 e

D0 D0

l bkgm² / GeV²

D0 eD0 e

D0 D0 hadronic bkg

Laurenz Widhalm


Absolute Branching Ratios

BRs (%)

this analysis PDG CLEO (hep-ex/0505035)

theory

K-e+ 3.45 ± 0.10stat ± 0.15syst 3.58 ± 0.18 3.44 ± 0.10stat ± 0.10syst 3.76 ± 0.30

K-+ 3.44 ± 0.10stat ± 0.15syst 3.19 ± 0.17 3.72 ± 0.30

-e+ 0.279 ± 0.025stat ± 0.013syst 0.36 ± 0.06 0.262 ± 0.025stat ± 0.008syst 0.31 ± 0.18

-+ 0.233 ± 0.022stat ± 0.016syst no entry yet 0.32 ± 0.03

K-+0 13.85 ± 0.63 13.0 ± 0.8 14.94 ± 0.56

K0+- 5.51 ± 0.39 5.97 ± 0.35

+-0 0.93 ± 0.07 1.1 ± 0.4

• measured event numbers normalized to number of inclusive D0

• efficiency corrected using the generic MC sample• corrected for bias from differences in the multiplicity distribution MC/data• reference hadronic channels as a cross-check

Laurenz Widhalm


Form Factors – Fit to Pole Model

D0 lD0 l

D0 lD0 l

q² / GeV²

arbitra

ry n

orm

alizatio

na

rbitrary

no

rma

lization

f+(q²) = 1-q²/m²

mKe=1.86 ± 0.06 GeVmK=1.78 ± 0.05 GeVme=2.01 ± 0.12 GeVm=1.91 ± 0.08 GeV

χ²/ndf=31/28

χ²/ndf=6/10

simple pole

f+(q²) = (1-q²/m²) (1-q²/m²)

modified pole

mKe=2.15 ± 0.08 GeVmK=2.04 ± 0.06 GeVme=2.21 ± 0.17 GeVm=2.07 ± 0.13 GeV

= 0.50 (Kl) = 0.44 (l)

theor.

f+(0)=0.704 ± 0.007 ± 0.010

f+(0)=0.628 ± 0.018 ± 0.026

Laurenz Widhalm


Current Status

• summer conference paper CONF-519 ready• archived as hep-ex/0510003• gives relative BF‘s and form factors• next step: journal publication• will give absolute BF‘s and form factors • second draft for PRL submitted to internal referees, waiting for response

first reaction from theory side (A. Kronfeld, preliminary)

Laurenz Widhalm


Heinz Dibon


Franz Mandl

•D0X (1.7 ±0.8%)

K+K- (49.1±0.6%)D0 K+K-

(0.389±0.015%)

•BR(D0X)=269 0.389------- ----------- =

160 0.491

1.33±0.14%


Gerhard Leder

T. Uglov at BGM•Ds inklusiv


The decay

• βγcτB0

= 196 μm(LAB) ● Δm = 0.489 1012 ћs-1 = 0.754 τ

B0-1

beam axis3.5 GeV e+8 GeV e-

interaction point(IP) =

primary vertex(PV) decay point 2

= secondary vertex

entanglement region

l-

decay point 1 =

secondary vertex

l+

K0s π-

π +

μ+

typical Υ(4S)

resonance decay

z0 , t

0

z1 , t

1

z2 , t

2

t

B0

B0

θ

B0 B0

Gerald Richter


Changing the parametrization

t1, t 2 t1, t ; t t 2 t1

new resolution function for t1, from double gaussian fit :

mean core - 42 um -0,21error core 250 um 1,25mean tail 4 um 0,02error tail 967 um 4,84

z abs B0t1

resolution function for Δt,single gaussian :

mean core 0 um 0error core 150 um 0,75

z absB0Δt

that should be on the safe side...

Gerald Richter


Parameter fit results

the scatter of fitted λ parameters shows a dependence on the true parameters, that can be modeled.

Gerald Richter


Electronic II

•From SVD 2.0 to SVD 2.5


Electronic II



Electronic II


Electronic II



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

Layer 1+2 replacement is scheduled in 2007 summerSVD3 schedule depends on approval of the project.

R&D

Prod.

TestProd.

Test

R&D Installation

SVD Upgrade SVD 2.5



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 misidentified M (K)

arbitrary normalization

ok for 3, 4 pr

Franz Mandl


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

Documents

Projektbericht BELLE Vorstandssitzung 28. November 2005 KEK, Tokyo Projektbericht BELLE Status BELLE Experiment SVD Upgrade bei BELLE Neue Resultate Y(5S)