l Background

l Available data — bubble chamber— SCIFI&IIT @ KEK

l Experimental Objectives at J-PARC

l Experiments

l Requests & Works

Hyperon-Proton Scattering Experiments at the J-PARC

M. Ieiri (KEK)K. Imai (Kyoto U.)B. Bassalleck (U.ofNM)P. Tlusty (NPI)JSPS meeting, September 10, 2003

Idea

1930

40

50

60

70

80

90

2000

Experiment('32 neutron)

('47 π+ - meson)

••• pp, npscattering

(YN scattering)('74 J/y)

(Hypernuclei)

E251, E289E452

•••Yp@KEKJ-PARC

Theory

('35 meson theory)

'51hard-core OPE @long-range

('64 Quark hypothesis)OBE

'77H-particleQCM

Inspiredby SU(3)

(established)

established

Support

Milestone

— Yp scatt. at bubble chamber era '60-'70s —

No Data for X-p @ pX ≤ 1 GeV/c

@ 12 GeV KEK-PS since 1990E251 S+p elastic [11 events]

E289 S-p elastic [30 events]S+p elastic [in analysis]Lp elastic [in analysis]

E452 S+p & Lp elastic [in analysis]

Available YN scatt. Data [1]

Available YN scatt. Data [2]

-40 -20 0 20 40

100

50

0

-50

-100

(mm)

π-

K+

S-

S-

p

π-

Scintillating Fiber (or Liquid Scintillator)with IIT-CCD Cameratriggered by Spectrometer system

IITs

SciFi

SpectrometerMagnet

Incident beam rate limit < 105 Hz

— Yp scatt. at the present 12 GeV KEK-PS : Method —

lE251, E289 for ds/dW (S+p & S-p) lE452 for polarization (S+p & Lp)

Available YN scatt. Data [3]

cosqCM

Julich

FSS

10

9

8

7

6

5

4

3

2

1

0-1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0

S-p Æ S-p elastic400 < PS- < 700 MeV/c

..

ds/d

W (m

b/sr

)

E251, E289

E289

E289(E452)

E289E452

— Yp scatt. at the present 12 GeV KEK-PS : Results —

List of Hyperon-proton scatterings

M = a + c (sn1+ sn

2) + b (sn1- sn

2) + msn1sn

2 + g(sP1sP

2 + sK1sK

2)+h(sP

1 sP2 - sK

1 sK2)

I0Py = 1/4 Tr(MM†sn1) = 2 Re[(a+m)c* + (a -m)b*]

( I0AyT = 1/4 Tr(Msn

2M†) = 2 Re[(a+m)c* - (a -m)b*] )

lS= - 2

lAnti-symmetric spin-orbit

27s

10a

10s

8a

8s

1a

S= 0 NN (T=1)S=-1 SN (T=3/2) SN-LN (T=1/2)S=-2 SS (T=2) XN-SL-SS (T=1) XN-SS -LL (T=0) S=-3 XS (T=3/2) XS-XL (T=1/2) S=-4 XX (T=1)

S= 0 NN (T=0)S=-1 SN-LN (T=1/2)S=-2 XN-SL (T=1)S=-3 XS (T=3/2)

S=-1 SN (T=3/2) S=-2 XN-SL-SS (T=1) S=-3 XS-XL (T=1/2) S=-4 XX (T=0)

S=-1 SN-LN (T=1/2)S=-2 XN-SL (T=1) XN-SS -LL (T=0) S=-3 XS-XL (T=1/2)

S=-1 SN-LN (T=1/2)S=-2 XN-SL (T=1) XN (T=0) S=-3 XS-XL (T=1/2)

S=-2 XN-SS -LL (T=0)

… better to wait for E452 results

pp, pn, nn

pn

X-p

X-p

X-p

X-p

X-p

X-p

Experimental Objectives at J-PARC

S+pÆS+p pS = 450 MeV/c0.3

0.2

0.1

0

-0.10 30 60 90 120 150 180

0 30 60 90 120 150 180qCM (deg)

1.0

0.5

0.0

-0.5

-1.0

LpÆLppL = 600 MeV/c

0 30 60 90 120 150 180qCM (deg)

0.6

0.4

0.2

0

-0.2

-0.4

LpÆLppL = 600 MeV/c

Calculation by Models

S=-2 X-p ÆLL, X-pÆ X-p

PS(q)QCM(RGM-H)QCM(FSS)OBE(NSC)OBE(Julich B)

PL(q) DL(q)

Polarization observables ( ≈ Anti-symmetric spin-orbit)

Request for Secondary Beam Line Momentum

Berge et al.Dauber et al.Burugun et al.

50

40

30

20

10

0

p(K-, K+)X-

1 1.5 2 2.5Plab (GeV/c)

Î p(K-, K+)X-

PK- : 1.6 ~1.8 GeV/c

( K- / p- > 1 )

Î p(p+, K+)S+ Pp+ : 1.5 ~1.7 GeV/c

Experimental Method

...basically, "double scattering" techniquehyperon production reactionhyperon scattering, and hyperon decay

• Vertex image detectorScintillating Fiber at KEK since 1990 KEK-PS E251 for S+P

E289 for S+p, S-p, LpLiquid Scintillator KEK-PS E452 for S+p, Lp asymmetry

• Liq. H2 + Cylindrical Drift Chamber(developed by BNL E906 group)

X-p

X-p scattering

K-

K+

π-π-

p p

5 kG

CDS• Size radius 30 cm

hight 60 cm

• Solenoidal field 5 kG• Time resolution 150 ps• Pos. resolution 200 µm

20 cm

Magnet TOFWCs

25°

5m

K-pÆ K+X-

X-pÆ X-p Lp-

pp-

X-p ÆLL pp-

pp-

Target region

K-

K+

π-

π-

p

pL

LX-

q_spectrometer

10 cm

CBA

X-pÆ LL

lTarget 5 cm wide ¥ 20 cm long A: production 1 cm Liq. Hydrogen B: degrader 0.5 cm Tungsten C: scattering 2 cm Liq. Hydrogen

l K+ spectrometer q_spectrometer ~ 25° at center

l K- beam (assumption @ LOI) Intensity 107 K-/sec Momentum 1.7 GeV/c Size s_horizontal 15 mm

s_vertical 1 mm

100

0

0 400 800 1200PX just before decay [MeV/c]

Liquid Hydrogen

Tungsten

Verti

cal p

ositi

on [m

m]

K1.8 beam line

Primary beam line

Production target

K1.8

K1.8Experimental

Area

lLength 42.35 mlIntensity 0.7¥107 K-/s@50GeV (1.0¥107 K-/s@37.5m&50GeV) (0.9¥107 K-/s@37.5m&40GeV)

lSize@Liq.H2 trial tuning just downstream of MS2

sx = 8.8 mmsq = 16.8 mrsy = 2.4 mmsf = 3.6 mr

94 % of K- beam pass through Liq. H2 of 20cm long with 1cm thickness & 5cm width

Yields estimation

1.0

0.5

0

-0.5

-1.0200 400 600 800 1000

PX [MeV/c]

X-p Æ LL

cosq

CM

• K- intensity [s-1] 107

• Number of Hydrogen [/cm2] 8.5¥1023 • Spectrometer [deg] 25• Spectrometer TOF [m] 5• Trigger rate (K+) [s-1] 11• Momentum of X - [MeV/c] 300 - 1100

X-p Æ X-p X-p Æ LL

• reaction rate [s-1] 0.009 0.0043• 100 days 78000 37000• Detectable number 2300 550

S+p & Lp : Method

R&D needed for …lImaging device Improve rate limit

105 Hz

107 Hz

lOnline trigger rate — (p, K) cut — Image brightness cut

Assuming success of these R&D, … an estimation from KEK-E45210000 S+p & Lp elastic @107 p+/sec , in 10 days

A high-speed gateable image pipelineBy Berkovski et. al. NIM A380(1996)537

Requests & Works

lSeparated beam line around 1.5 - 1.8 GeV/clK— intensity 107/sec with K/p > 1

lLiquid hydrogen facility

lReview of E251, E289 & E452 @ KEKlRealistic Optimization of SetuplBackground estimation (physical & instrumental)lFast imaging device, Trigger consideration

for X-p (S= -2), S+p & Lp (Polarization obs.)——— reasonably doable at J-PARC

If… (in the beginning)

lK— intensity is low at around 106/sec lNo Liquid hydrogen facility

Scintillating Fiber Block for Xp/ tracking

Tracking device like silicon-strip

X Production target

X-p / 12C(K-,K+LL) experiments with imaging device

K—

K+

X—

When…lPolarized H2 target available

Measure AyT, DT

E289 S-p simulation & Proposal

l Incidentπ-/spill 1.5x105 2x105

l Shifts 80 100l Total π- 8.6x1010 14.4x1010

l (π-, K+) S- 5.8x105 9.6x105

with vertex cut 2.8x105

l S-p [from H] 70 240l Eye-scan ,kinematical

45

obtained @E289 30 from H 68 from C&H