Super fragment search in CHORUS I Progress note after the last Nagoya meeting (Apr-’02) II Hyper...

Super fragment search in CHORUS

I Progress note after the last Nagoya meeting (Apr-’02)

II Hyper fragment candidates

III An event with 3 vertices

Overview of the event

pβ measurement

IV Efficiency of image analysis

Vertex finding efficiency

Black finding efficiency

V Plan of paper

Progress note after the last Nagoya meeting (Apr.-’02)

after Apr-’02 Before Apr-’02

#images analyzed Run 96

50.0K(39.2K)

Run 97

48.9K(40.1K)

1ry found 16.4K(12.1K) 20.3K(14.8K)

viewer check 5.3K(4.4K) 6.8K(5.7K)

manual check 105 157

further analysis (track follow, range…)

22 17

Angle measurement of tracks of normal events

175 events 1564 tracks (818 thins, 78 grays, 668 blacks)

Analysis to search super fragmentAnalysis to search super fragment

Analysis to estimate efficiencyAnalysis to estimate efficiency

Multi-vertices events (>2prong)

1ry vertex 2ry vertex

MDT Event Pl# Pμ Ns Ng Nb #brg Fast P Visible E

22B 51631132 36u -9.8 5 1 4 3 14.9 27.1

21B 53673748 21u -13.8 2 7 4 16.9 30.9

+ 12B 53834444 29d -11.3 1 1 10 4 26.8 61.7

47T 54821792 29d -14.5 3 1 3 2 10.7 12.2

* 47T 56431728 13d -9.5 4 3 14 2 38.6 38.9

* 11T 60402507 17u -22.1 4 3 12 4 >15.2 >30.2 3 vertices

12B 60843716 19u (-1.8) 3 1 10 2 13.9 26.6

35T 61413914 20d -5.8 5 2 11 3 14.8 24.6

47T 61490764 28u -12.8 7 6 3 3.3 8.7

* 35T 62471849 17u -3.7 9 3 17 5 37.4 53.8

* 26T 62710567 14u -17.6 6 2 10 3 >56.4 >65.4

35T 64381436 09d -13.7 5 11 4 6.3 12.8

16B 65941591 05u -22.3 7 3 12 2 13.8 24.9

Multi-vertices events (1prong or background?)

1ry vertex 2ry V

MDT Event Pl# Pμ Ns Ng Nb #brg

11T 50152646 21d -19.2 2? parent(=thin) + knock-on e?

21T 51642405 27d -10.4 1

16T 52353125 12u -10.7 1 gray → 1black?

15T 57500013 27u -25.8 3? black + bg black?

31T 59092274 19u -21.6 3? black + bg black?

15B 64921264 12u -12.8 3 16 1? Fast P=3.0(GeV/c)

21B 65220334 04d -21.1 1 6 1 Fast P=6.6(GeV/c)

48T 60801788 28u -13.9 1

12T 69042454 20u -26.4 3? black + bg black?

62471849 2 vertices

WA95 MDT 35T EV 62471849

PL#17up

parent ( ) (dx,dy,dz) = ( 1.0, 6.7, -3.0)μ m in stage system

Track# Length(μ ｍ) E(MeV) ID

0 7.4

1 7.0 0.6 (P)

2 27 1.6 (P)

3 179 5.1 (P)

4 5500 37.4 (P)

5 465 9.1 (P)

Memo

1 horizontally

2 forward

3 forward

4 backward stop at pl.23u


1ry

2ry 351 62471849 33 vz:533.4

atan(thy,thz) back lcal #dt atan(thy,thz) back lcal #dt

v 3 .939 .929 4.3 2 g 1 -.344 -.076 96.6 2

b 2 -.816 .533 39.2 2 g 2 -.460 -.132 103.1 2

b 3 -1.137 .743 33.1 2 g 3 1.549 .827 1 594.8 2

b 4 -.300 -.681 50.2 2 b 17 .783 1.132 1 7.6 2

b 5 .667 -.547 54.9 2 b 18 .145 .697 11.8 2

b 6 .447 .798 90.4 2 b 19 -.403 .013 26.0 2

b 7 -.040 -1.289 71.8 2 b 20 .631 .000 1 17.3 2

b 8 -.406 .840 147.7 2 b 21 -1.340 1.340 1 36.5 2

b 9 1.168 1.400 1 208.5 2 t 1 .018 .118 85.4 3

b 10 1.508 1.537 1 292.4 2 t 2 -.116 .196 94.1 4

b 11 .821 .842 1 79.1 2 t 3 -.065 .004 534.6 4

b 12 .566 .753 1 221.5 2 t 4 .005 -.023 533.0 4

b 13 -1.054 .968 1 176.4 2 t 5 .227 .463 103.5 3

b 14 -1.410 -1.311 1 203.6 2 t 6 .303 .605 116.5 3

b 15 .965 -.291 7.1 2 t 7 .197 -.301 84.1 5

b 16 -.426 -.208 1 114.9 2 t 8 -.442 1.039 95.1 3

t 9 1.347 1.486 75.9 3

-100-50050100

-100

-50

0

50

100

b2b3

b4

b5

b6

b7

b8b9b10

b11

b12

b13

b17

b15

b16 b14

b18

b19

b20

b21

g2

g3

g1

t1

t2

t3

t4

t5

t6t7

t8

WA95 MDT 26T EV 62710567

PL#14up

parent ( ) (dx,dy,dz) = (2.2, 2.2, - 2.0)μ m in stage system Track# Length(μ ｍ) E(MeV) ID

0 3.7

1 210 5.6 (P)

2 92 3.4 (P)

3 >11361 >56.4 >25.1

(P) (π )

out of pl.01

Memo

1ry

2ry

3 forward out of pl.01

2 forward

1 forward

62710567 2 vertices

261 62710567 21 vz:636.1


b 1 -.092 -.197 88.3 2 g 1 1.199 -1.237 228.7 2

b 2 .574 .534 65.7 2 g 2 1.182 -.900 292.6 2

b 3 -.165 .887 88.0 2 b 11 -.167 -1.291 10.7 2

b 4 1.494 -1.543 1 221.7 2 b 12 -.335 -.215 32.6 2

b 5 -1.435 1.439 389.2 2 b 13 .832 -.212 21.9 2

b 6 1.336 -.785 539.9 2 t 1 .145 -.141 197.5 5

b 7 -1.336 .700 1 127.3 2 t 2 -.052 .053 195.3 5

b 8 -1.032 .516 1 23.6 2 t 3 -.364 .054 144.8 4

b 9 -.552 1.077 1 166.7 2 t 4 -.568 .095 233.7 3

b 10 .421 .000 1 2.2 2 t 5 -.278 .350 208.9 3

t 6 -.132 .573 235.2 3

-100-50050100

-100

-50

0

50

100

b1

b2

b3

b4

b5

b6b7

b8

b9

b11

g1

b12

b13

b14

g2

t1

t2

t3

t4

t5

t6

56431728 2 vertices

WA95 MDT 47T EV 56431728

PL#13down

parent ( ) (dx,dy,dz) = (0.3, 2.9, - 1.0)μ m in stage system


0 3.1

1 3.7 0.3 (P)

2 5817 38.6 (P)

Memo

1 forward


1ry

2ry

471 56431728 24 vz:183.2


b 1 .536 -.287 52.5 2 g 1 .628 .273 136.7 2

b 2 .824 .210 83.2 2 g 2 1.317 1.306 508.0 2

b 3 .985 -.797 158.6 2 b 14 -1.270 -.306 3.4 2

b 4 -.140 .652 88.9 2 g 3 .208 -.172 36.9 2

b 5 -1.163 1.161 79.9 2 b 15 -.002 -.739 5.5 2

b 6 -1.261 -.979 51.3 2 b 16 .248 -1.313 1 28.0 2

b 7 -1.140 -1.028 180.7 2 t 1 .044 .051 179.5 8

b 8 -1.292 1.428 1 231.0 2 t 2 -.149 -.044 180.2 8

b 9 -.729 -.216 1 120.2 2 t 3 -.280 .619 148.4 8

b 10 .948 .249 1 148.1 2 t 4 .542 -.302 224.1 6

b 11 -.439 .435 1 101.2 2

b 12 .458 -1.071 1 6.6 2

b 13 -.088 -.082 19.5 2

b 14 1.571 1.571 3.0 2

-100-50050100

-100

-50

0

50

100

b1

b2

b3

b16

b4

g1

b5b6b7

b8

b9

b10

b11

b15

g2g3

t1

t2t3

t4

-100-50050100

-100

-50

0

50

100

53834444 2 vertices

120 53834444 18 vz: 79.6


b 1 .215 .102 82.3 2 b 1 .210 .099 21.7 2

b 2 -.212 .039 80.9 2 b 2 -.174 .046 13.3 2

b 3 1.529 .569 120.9 2 g 1 .147 -.022 45.8 2

b 4 .348 -1.062 1 110.5 2 b 11 .115 .093 30.5 2

b 5 .245 -.874 1 161.0 2 b 12 1.150 .578 22.9 2

b 6 .535 -.625 1 196.8 2 b 13 -1.002 1.149 20.4 2

b 7 .854 -.920 1 48.5 2 b 14 -.116 -.542 1 20.1 2

b 8 .725 .505 1 82.9 2 t 1 .074 -.010 74.6 4

b 9 .338 1.032 1 221.1 2

b 10 .548 -.461 9.0 2

WA95 MDT 12B EV 53834444

PL#29down

parent ( ) (dx,dy,dz) = (3.5, -4.5, -6.1)μ m in stage system


0 8.4

1 119 4.0 (P)

2 ～300 7.0 (P)

3 3042 26.8 (P)

4 2506 24.0 (P)

Evis 61.7

Memo

1 forward

2 backward

2 backward

3 forward stop at pl.25d

4 forward stop at pl.27up

1ry

2ry

b1

b2

b3

b4

b5

b6

b7

b8

b9

b11

b12

b13

b14g1t1

60402507 3 vertices

V2

V1

V3

60402507 with 3 vertices

11t pl.17

～ 1134μm

60402507 sketch and data

7 backward stop at pl.18d

1 forward

2 forward

3 backward

4 backward

5 forward

6 forward

V1

V2

V3

WA95 MDT 11T EV 60402507

PL#17up

parent ( ) (dx,dy,dz) = (3.5, -10.3, -10.6)μ m in stage system


0 15.2

1 38 2.0 (P)

2 82 3.2 (P)

3 529 9.8 (P)

4 1134 15.2 (P)

5(4-1) 37 1.9 (P)

6(4-2) 73 3.0 (P)

7(4-3) 81 3.2 (P)

Memo

111 60402507 23 vz:735.1


b 1 .603 -.030 28.2 2 b 11 .614 -.152 9.6 2

b 2 1.412 1.147 110.0 2 b 12 .902 -.712 3.7 2

b 3 .694 .255 211.0 2 b 13 1.571 1.571 15.1 2

b 4 1.350 1.398 553.8 2 b 14 1.571 1.571 40.1 2

b 5 -1.570 -1.474 159916.7 2 b 15 1.571 1.571 25.2 2

b 6 .952 -1.321 1 173.7 2 t 1 -.002 -.009 290.9 19

b 7 -.039 -.052 736.3 2 t 2 -.035 .043 295.8 22

b 8 -.130 -1.204 213.7 2 t 3 -.324 -.840 458.9 4

b 9 -.298 .853 1 85.7 2 t 4 1.400 1.383 1 447.9 3

b 10 .602 -.394 3.7 2 b 15 1.447 1.532 1 51.3 2

g 1 .243 .066 151.1 2

g 2 .210 .319 147.9 2

g 3 .325 .926 1 97.1 2

-100-50050100

-100

-50

0

50

100

b1

b2

b14

b3

b4

b5

b6

b15

b7

b8

b9b12

b13g1

g2

g3

t1t2

t3

t4

7 backward stop at pl.18d

1forward

2forward

3 backward

4 back

kc 5 forward

6 forward

V1

V2

V3

WA95 MDT 11T EV 60402507

PL#17up parent (dx,dy,dz) = (3.5, -10.3, -10.6)μ m in stage system

Track# L(μ ｍ) E(MeV) ID

15.2 1 38 2.0 (P) 2 82 3.2 (P) 3 529 9.8 (P) 4 1134 15.2 (P)

5(4-1) 37 1.9 (P) 6(4-2) 73 3.0 (P) 7(4-3) 81 3.2 (P)

60402507 sketch zoom

A likely interpretation

V3 is σ-star (π- capture), if pβof #4 is 13MeV/c (estimated from range) at V2.

Then, V2 is a mesic decay of hyper fragment.

… is excluded because #4 looks like more energetic.

If #4 is π － , change in direction by scattering is almost same as the end of π+decay in emulsion.

-10000-9500-9000Xstage (m)

4600

4800

5000

5200

Yst

age

(m

)

200 m

-10000-9500-9000Xstage (m)

0

200

400

600

Zst

age

(m

) up em.

base

down em.

4600480050005200Ystage (m)

0

200

400

600

Zst

age

(m

) up em.

base

down em.

Black 15 11T 60402507 pl.17u

L ～ 1134μm pβ (E) (MeV) I/I0

π 13.1 ( 6.7) ～ 5.4

K 22.8 (11.6) ～ 9.4

P 30.2 (15.2) ～ 12

D 40.5 (20.3) ～ 17

T 47.8 (24.0) ～ 20

b15

(was track#4 in the previous figure)

An example of π+ → μ+ → e+ decay

71B 78902354 pl.19

Pl.19up

Pl.19upπ+ π+

μ+

μ+

e+

A

B

AB～ 610μm

Compared scattering of the end of π+ with track #4

-95000-94800-94600-94400Xstage (m)

94400

94600

94800

Yst

age

(m

)

+

+

e+

+base

100 m

-95000-94800-94600-94400Xstage (m)

0

200

400

600

Zst

age

(m

)

+

+e+

base

up em.

down em.

944009460094800Ystage (m)

0

200

400

600

+

+e+

base

up em

down em

MDT71B 78902354 pl.19π+ → μ+ → e+ (No.1)

Measured data

00

ln038.010136.0

X

X

X

Xp

plane

Ｘ０＝ 2 8 . 9 ｍｍ

θ⊿ ( i ) ｊ θ＝ j + i θ－ j

θ⊿ ( 1 ) １ θ＝２ θ－１ θ⊿ ( 2 ) １ θ＝３ θ－１

θ⊿ ( 1 ) ２ θ＝３－ θ ２ θ⊿ ( 2 ) ２ θ＝４ θ－２

・・・・・・・・・・

m e a s u r e w i t h o u t m o v i n g s t a g e ~ 6 0 μ m

θ １

θ ２

θ ３

θ ４

θ ５

L １

L ２

L ３

L ４

L ５

Pβ measurement

position along a tra

ck

3500400045005000Xstage (m)

-1000

-500

0

Yst

age

(m

)

200 m

3500400045005000Xstage (m)

0

200

400

600

Zst

age

(m

) up em.

base

down em.

-1000-5000Ystage (m)

0

200

400

600

up em.

base

down em.

Pβ measurement 11T 60402507 pl.17u

Measured data

380040004200Xstage (m)

-600

-500

-400

-300

Yst

age

(m

)

100 m

Pβ measurement 11T 60402507 pl.17u

Preliminary

pβ of black15

K- P Σ － Deuteron 3ΛH(pnΛ0)

Pβ range I/I0 range I/I0 range I/I0 range I/I0 range I/I0

50 4.61 5.1 2.73 8.4 2.29 10.2 1.63 14.3 1.17 20.

60 6.42 4.4 3.83 7.3 3.16 8.8 2.25 12.5 1.60 17.7

70 8.51 3.9 5.05 6.5 4.16 7.8 2.94 11.1 2.08 15.8

80 10.6 3.5 6.42 5.8 5.28 7.0 3.72 10.0 2.63 14.3

Measured at < L>μm⊿ < θ> rad⊿ pβ(MeV/c) (#data)

first 500μm (i = 1, 4) 317 0.0165 72 (4)

last 500μm (i = 10,13) 323 0.0204 58 (4)

Measurement result ( L⊿ i ＝ L i+5 – Li , θ⊿ i=θ i+5 – θi)

Table pβ - range(mm), I/I0 correlation (expected value theoretically)

No calibrated data now. It will be made later. Accuracy is unknown.

Possible interpretations

V1

V2

V3

AB

A V2 B V3 consistency

K － capture 3ΛH

(pnΛ0)mesic decay

3ΛH → p+n+p+π －

An expected fast π- is not observed.

K － Interaction with two nucleons

K － +p+n → Σ － +p

K － +p+p → Σ － +n

Σ － capture Is feature consistent with Σ － capture?

SuperF decay K － , Σ － capture Consistency?

Further analysis is required. Pβ calibration, ionization …

415 images (362 events) 　 (22t pl.21,22,23 36t pl.15,16,17 71b pl.20,21,22)

search vertex in a fiducial volume with image viewer175 events Vertex found between frame#9 and #40

Measured angle of all tracks in emulsion manually

1564 tracks

compare manual check and image analysis 108 vertices found by image analysis 272 blacks found

Analysis for efficiency estimation

818 thin 78 gray 668 black

350μm

fr#

19

4048

～ 60μm

～ 60μm

0 5 10 15Ns

0

10

20

30

#eve

nts

Nb disribution

175ev <Ns> = 4.8

= 2.5

0 10 20Nb

0

20

40

60

#eve

nts

Nb distribution

175ev <Nb> = 3.8

= 4.2

Ns, Nb Distribution (nearly no biased)

-100 0 100 (deg)

0

20

40

60

80

#tra

cks

/ bi

n

black

gray

thin

175 events 818 thin 78 gray 668 black

-1 -0.5 0 0.5 1direction cos

0

50

100

150

trac

ks/b

in

thin

gray

black

687

forwardbackward

Track angle distribution (nearly no biased)

0 5 10 15Ns

0

10

20

30

#eve

nts

175ev <Ns> = 4.8

= 2.5

108ev <Ns> = 5.0

= 2.5

0 5 10 15Ns

0

0.5

1

effi

cien

cy

<> = 61.7 %

Vertex finding efficiency vs. Ns

Vertex finding efficiency vs. Nb

0 10 20Nb

0

20

40

60

#eve

nts

175ev <Nb> = 3.8 (Nb=0 29.1%)

= 4.2

108ev <Nb> = 4.5 (Nb=0 18.5%)

= 4.4

0 10 20Nb

0

0.5

1

effi

cien

cy

<> = 61.7 %

0 200 400 6001ry vtx z(m)

0

10

20

30

#eve

nts

/ bi

n

base up em.down em.

upsidedownside0 200 400 600

1ry vtx z (m)

0

0.5

1

eff

/ bi

n

base up em.down em.

Vertex finding efficiency vs. vertex position

-1 -0.5 0 0.5 1direction cos

0

50

100

#bla

cks

/ bi

n

A

B

C

forwardbackward

-1 -0.5 0 0.5 1ditrection cos

0

0.5

1

eff

/ bi

n

Efficiency C/A

<> = 40.7 %

-1 -0.5 0 0.5 1ditrection cos

0

0.5

1

eff

/ bi

n

Efficienct C/B

<> = 65.4 %

Black finding efficiency vs. direction cos θ （ angle to the beam)

A: all blacks

B: blacks which vertices are found by image analysis

C: blacks found by image analysis

-100 0 100(deg)

0

20

40

60

#bla

cks

/ bi

n

Azimuthal angle distribution of black tracks

A

B

C

-100 0 100(deg)

0

0.5

1

eff

/ bi

n

Efficiency C/A

<> = 40.7 %

-100 0 100(deg)

0

0.5

1

eff

/ bi

n

Eff. C/B <> = 65.4%

Black finding efficiency vs. azimuthal angle (Φ)

Summary of finding efficiency

finding efficeiency

Vertex 62 % (for all events)

71% (Nb≧ １）

Black track 41% (for all events)

65% (for events which 1ry vtx found by image analyisis)

Plan of paper

・ Upper limit of Super fragment production

・ Hyper fragment production in νint.

Production of strange particle in νccint. (relative ratio)

νd(v)→μ － u+ss (14%)

νd(s)→μ － u+ss ( 1.7%)

νu →μ － d+ss ( 0.6%)

Production of charmed particle in νccint.

νd(v)→μ － c ( 3.7%)

νd(s)→μ － c ( 0.4%)

νs (+s) →μ － c (+s) (2.8%)

Others

νd(v)→μ － u+(uu or dd) (57%)

νd(s)→μ － u+(uu or dd) (17%)

νμ

μ －

W+

ss

νμ

μ －

W+

c

Non-leading s-quark goes to strange particle or hyper fragment

Leading c-quark goes to charm particle or super fragment

d,uu,d

d,s

50.0k images (39.2k events) in ’96 run are analyzed

12.1k 1ry vertices found by image analysis

13 Multi-vertices events found (2ry with >2prongs)

12 events with 2-vertices

1 event with 3-vertices

Hyper fragment candidates

3 events with fast proton

2 events with visible energy 30MeV≧

Summary

Future planIncrease statistic of track slope data to estimate efficiency

Pβ calibration (compare pβ obtained form range and from scattering measurement)

Make sure identification of hyper fragment

Background estimation

present preliminary result for a paper by the end of October (if possible)

Concurrently reanalyze images with improved program

Super fragment search in CHORUS I Progress note after the last Nagoya meeting (Apr-’02) II Hyper...

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Transcript of Super fragment search in CHORUS I Progress note after the last Nagoya meeting (Apr-’02) II Hyper...