• Survey of R04

• Data quality check of R04

• Conclusion

Checks of the R04 Data Quality

outlineJin Yi

May 25, 2004BES Annual Meeting JieXiu, Shanxi

Survey of R04

1. The main goals of 2004 data taking are precise R measurement and QCD studying.

2. Data taking time is about 64 days.

3. Data were taken at 3.07, 2.60, 2.20GeV.

4. Online data stat. VS. offline data stat.

OnlineNh = 103563Nb = 360350N = 12178L on = 2788 nb-1

OfflineNh = 34934Nb =1505506N =15645L off = 2364 nb-1

OnlineNh = 91255Nb = 276828N = 7621L on = 1305 nb-1

OfflineNh = 24900Nb = 1181177N = 13318L off = 1232 nb-1

OnlineNh = 21634Nb = 21000N = 1125L on = 65 nb-1

OfflineNh =1532Nb =71641N =1392L off = 64 nb-1

VS.

VS.

VS.

3.07 2.60 2.20(Hadron Run: 238) (Hadron Run: 361) (Hadron Run: 94)

Note: the data sample for 2.20 is small, so the data quality checks are mostly of 3.07 and 2.60.

5. Data quality checks for reliable physical analysis have been done.

Data Quality Check Contents

• BES Global Stability

• Subdetector Information

MDC

TOF

BSC

• PID

• Inclusive decay channels

BES Stability

Bhabha events:

• momentum-p VS. IIRUN

• deposited energy-ESUM VS. IIRUN

• dE/dx pulse height-PHMP8 VS. IIRUN

• modified dE/dx pulse height-PHMP11 VS. IIRUN

3.07 2.60 2.20

Brief Summary for Stability• The distributions of momentum and energy of

Bhabha events are fairly flat.

• Besides small fluctuations, the distribution of PHMP8 is flat too, and after offline modified, PHMP11 distribution is much flatter.

• These figures indicate that MDC and BSC are in good status during data taking.

MDC Information

• Track fit quality—MFIT

• Vertex resolution

• Momentum resolution

• dE/dx resolution

• θ, Φ distribution

MFIT-3.07

Distribution of vertex of hadronic events on r-Φ, r-z. The data with MFIT -19 won’t be used in physical analysis.

MFIT=2

MFIT=-19

MFIT-2.60

Distribution of track vertex of hadron events on r-Φ, r-z

MFIT=2

MFIT=-19

MFIT-2.20

Distribution of track vertex of hadron events on r-Φ, r-z

MFIT=2

MFIT=-19

MFIT=2 for 3.07, 2.60

(a) PHMP11 VS. p for hadronic events (b) beta VS. p for hadronic events

Vertex resolution-3.07, 2.60

Distribution of Bhabha events vertex on r-Φ, r-z

Momentum resolution-3.07, 2.60

α = 1.5%

α = 1.6%

(a) Distribution of momenta for Bhabha events (b) momenta VS.Φ (c) momenta resolution VS.Φ

dE/dx resolution-3.07, 2.60

Distribution of PHMP11 for Bhabha events

dE/dx resolution-3.07, 2.60, 2.20

Between 50~70o, there is the offset of χse value. It is because that for the leak currents in layer-7 and 9 of MDC, HV is reduced to 80%.

Distribution of χse on Φ

θ, Φ Distribution-3.07

Angular-θ, Φ distribution for Bhabha events

normal normal

TOF Information-3.07, 2.60

The fight time resolution for Bhabha events is about 200ps, and the offset is very limited.

Fight time VS. Φ

ΔT(=Tmea-Tex

p) VS. Φ

BSC Information-3.07, 2.60

(a) Deposited Energy Measurement VS. Φ for 3.07 (b) Deposited Energy Resolution VS. Φ

α = 24%

Distribution of deposited energy of Bhabha events

α = 24%

Electron-TOF

Distribution of Tmea-Texp in different momentum range. The offset is very limited.

0.6<p<0.8

0<p<0.25 0.25<p<0.4

0.4<p<0.5 0.5<p<0.6

0.8<p<1.2

Electron-dE/dx

Distribution of χse in different momentum range. The offset is only 0.1.

0<p<0.25 0.25<p<0.4

0.4<p<0.5 0.5<p<0.6

0.6<p<0.8 0.8<p<1.2

K Sample

K sample is selected from 2(Kπ). The offsets of TOF and dE/dx are about 0.

Data sample is pure.

(b) Momentum distribution of K(a) Invariant mass of Kπ

π sample

π sample is selected from inclusive K0s. The offsets are very limited.

Inclusive decay channels-K0

The sample of inclusive K0 at different CM energies (3.07, 2.60, 2.20).

fit mass value = 497MeV

total

Inclusive decay channels-K*0

The sample of inclusive K*0 at different CM energies (3.07, 2.60, 2.20).

total

fit mass value = 892MeV

Inclusive decay channels-Λ(Λ)

The sample of inclusive Λ(Λ) of total.

fit mass value= 1115.2MeV

Conclusion for data quality check

• As a whole, the detector is in good status during data taking.

• We have large data sample at 3.07, 2.60 and 2.20GeV.

• The data is of high reliability and quality.