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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-/[email protected]&50GeV) (0.9¥107 K-/[email protected]&40GeV)
[email protected] 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