HKS collaboration meeting @JLab2008/5/16

Akihiko&Yoko @ Wedding Party 2008/5/10

Topics

• Bug in REPLAY

• Blind analysis by Lulin

Bug in REPLAY

Multiplicity problemRun# 56089, eventID 1954

3 events @ JLab ENGINE2events @ Tohoku ENGINE

Ntuples are inconsistent parameter files and source codes should be checked

Bug in analyzer• Cut condition for ENGE momentum

(depends on “default” matrix)

• Different “default” matrix between USA and Japan

• Bug depends on multiplicity of ENGE

Event#1

Event#2

Event#3 (out of acceptance)

Event#4

…

Accept

Reject

Old ntuple vs. New ntuple

+12.1%+14.7%+17.5%+16.6%

•Fixed bug and re-analyze

Old RAP(12Jan08) vs. New RAP(04Apr08)

Target Old RAP

[events]

New RAP

[events]

Improve

CH2 25800 26530 +2.8 %

12C 159484 167387 +5.0 %

28Si 118755 125766 +5.9 %

7Li 64866 69123 +6.6 %

Number of events ….Coin ntuple Multiplicity (ENGE)RAP Coincidence between HKS and ENGE

Blind analysis by Lulin

Simulation data for blind analysis• Focal plane resolution in sigma

86 m (exf), 0.7 mrad (expfp), 210m(eyf), 2.8 mrad (eypf)110 m (hxf), 0.5 mrad (hxpfp), 110m(hyf), 0.7 mrad (hypf)

• Fixed beam energy (1853.1 MeV)• NO energy loss @ target• # of event & S/N (Updated)

moderately ( : ~2150 counts, : ~400 counts, 12B g.s. :~600 counts)

• Sieve Slit data is ready• Raster (0.25 cm × 0.25 cm) for CH2

Lulin’s blind analysis

• Tune CH2 & 12C– Add peaks of 12C one by one (maximum 6 peaks)

• Raster correction– only momentum of kaon

• Weight in the final step of tuning– 1.0(), 1.0(), 5.0 (B.E.=11.43), 0.0(B.E.=13.63),

6.0(B.E.=16.70), 3.0(B.E.=20.35), 4.5(B.E.=23.04), 6.0(B.E.=23.70)

Detailed will be shown in Lulin’s talk

* In the following pictures …… GOD : answer of simulation Lulin-tune : result from Lulin’s tuning

Lulin-tune CH2(tuned event)

Top : GOD. Bottom Lulin-tuneRED : coin. , BLACK : B.G.

Top : GOD, Bottom : Lulin-tunefor All event

Lulin-tune CH2(NOT tuned background event)

TOP : Lulin MM vs. GOD MMBOTTOM : wide region

TOP : GOD MMBOTTOM : LulinMM

Each component (xpt,ypt,dp)Lulin vs. GOD

expt eypt

edp

hxpthypt

hdp

offset due to different central momentum

Lulin-tune C12(tuned event)

Top : GOD. Bottom Lulin-tuneRED : coin. , BLACK : B.G.

Top : GOD, Bottom : Lulin-tunefor All event

Oka-tune C12(NOT tuned background event)

RED : coin. , BLACK : B.G.

Binding energy & YieldLulin analysis GOD

Binding energy

[MeV]

Yield

[counts]

Contamination

[%]

Binding energy

[MeV]

Yield

[counts]

S/N

11.43 (g.s.) ~491 4.4 11.37 (g.s.) 600 1.45

13.63 ~54 N/A N/A N/A N/A

16.70 ~191 83.6 16.31 30 0.09

20.35 ~142 42.4 20.31 100 0.27

23.70 & 23.04 ~407 1.5 23.37 550 1.28

How to estimate contamination

• Fit each peak by gaussian + offset• Fitted counts :

Integration of gaussian• Real counts :

# of real events in the peak(3)

(simulation data can be identified)• Contamination [%] =

((Fitted counts) – (Real counts)) / (Fitted counts) ×100

Contamination vs S/N ratio

Step by step missing mass

• Step 1Initial matrix ( *.1110 )

• Step 2After involving and (*.02121)

• Step 3After involving B.E.=11.43, 23.04, 23.70 (*.03307)

• Step4After involving B.E.=20.35 (*.03308)

• Step5After involving B.E.=16.70 (*.04022)

Missing mass of step1(Initial)

Top : CH2 for All eventBottom : Coin.(RED), B.G.(BLACK)

Top : C12 for All eventBottom : Coin.(RED), B.G.(BLACK)

Missing mass of step2(tune ,)

Top : CH2 for All eventBottom : Coin.(RED), B.G.(BLACK)

Top : C12 for All eventBottom : Coin.(RED), B.G.(BLACK)

Missing mass of step3(tune ,,2 major peaks)

Top : CH2 for All eventBottom : Coin.(RED), B.G.(BLACK)

Top : C12 for All eventBottom : Coin.(RED), B.G.(BLACK)

Missing mass of step4(tune ,,2 major peaks,

core#1)

Top : CH2 for All eventBottom : Coin.(RED), B.G.(BLACK)

Top : C12 for All eventBottom : Coin.(RED), B.G.(BLACK)

Missing mass of step5(tune ,,2 major peaks,

core#1,core#2)

Top : CH2 for All eventBottom : Coin.(RED), B.G.(BLACK)

Top : C12 for All eventBottom : Coin.(RED), B.G.(BLACK)

Summary

• The trend is the same as Okayasu’s result

• The linearity between reference masses ( and ) seems OK but the outside is deformed

• Background contamination in 12C peaks

• The background events that not used for tuning do not make peak

• Accuracy of binding energy : < 0.4 MeV

Comments on 7He

Okayasu Spectrum

Lulin Spectrum

Lulin Mass : 6716.71 MeV/c2(atomic masses are used)

Lulin Binging energy : -5.53 MeV/c2

Okayasu Mass : 6716.15 MeV/c2(nuclear masses are used)

Okayasu Binging energy : -5.07 MeV/c2

Lulin 7He + : 6722.2413 MeV/c2

7He + : 6721.20 MeV/c2

= 0.46 MeV