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expected K - K - pp cross-section The free production CS in p+p collision is known to be ~ x total ~ 50 b The free * production CS at 2.83GeV is known to be * ~4.5 b ~ 0.1 x The double- production CS is expected to be ~ x ~ 50nb (= x x total ) Thus, the double- * production CS is expected to be ~ 0.01 x ~ 0.5nb The DISTO result indicates the K - pp production CS is as much as * production CS, so we simply assume K - K - pp production CS to be K-K-pp ~ ~ 0.5nb Of course, these are very rough estimations and depend on incident energy 3
Citation preview
search for double-kaonic nuclear cluster (K-K-pp)using p+p reaction
F.Sakuma, RIKEN
discussion is based on •Proc. Jpn. Acad., Ser. B, 87 (2011) 362-370., and•Phys. Rev. C 84 (2011) 015207[M. Hassanvand, Y. Akaishi and T. Yamazaki]
10GeV 陽子陽子衝突における二重K中間子核の生成 --- 実験フィージビリティ ---
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experimental principle
8GeV
decay
the produced K-K-pp can be identified by bothmissing-mass spectrum M(K+K+)invariant-mass spectrum M()
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production
expected K-K-pp cross-section• The free production CS in p+p collision is known to be
~ 10-3 x total ~ 50b• The free * production CS at 2.83GeV is known to be
* ~4.5b ~ 0.1 x
• The double- production CS is expected to be ~ 0.001 x ~ 50nb (= 10-3 x 10-3 x total)
• Thus, the double-* production CS is expected to be ~ 0.01 x ~ 0.5nb
• The DISTO result indicates the K-pp production CS is as much as * production CS, so we simply assume K-K-pp production CS to beK-K-pp ~ ~ 0.5nb
Of course, these are very rough estimations Of course, these are very rough estimations and depend on incident energyand depend on incident energy 3
8-10GeV proton yield @ high-p
Prof. Noumi
If yield of proton is assume to be as same as that of pion,
~108 proton/spill(6s) is expected with pp~8-10GeV 4
production-yield estimation
• CS : K-K-pp ~ 0.5nb• Beam : 8 GeV proton 108 / 6s x 1 month (30d) = 4x1013
• Target : LH2 target 0.85 g/cm2
(= SKS target, 0.0708 g/cm3 12 cm)
~104 / month K-K-pp5
kinematics
[momentum vs. cos(lab)]
p(K+2) vs. p(K+
1)
cos(lab)(K+2) vs.
cos(lab)(K+1)
cos(lab)(2) vs.cos(lab)(1)
p(2) vs. p(1)
production & decays are assumed to be isotropic
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B.E = 200MeV
K+
[momentum vs. cos(lab)]
kinematics (Cont’d)- from
[momentum vs. cos(lab)]
p from [momentum vs. cos(lab)]
cos(lab)(p) vs.cos(lab)() p(p) vs. p(-)
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B.E = 200MeV
requirements for detector• wide-coverage forward-
detector in order to detect double-K+ and double- (0-60 degrees)
• good kaon separation in trigger level (pK<~4GeV/c)
• high-resolution and high-rate detector
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n=1.008
n=1.026
KEK-PS E248 (AIDA)Past Experiment …Past Experiment …
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12GeV p+p K++K++X
experiment @ J-PARCfor example …
+15
-15
+15
-15+45 -45
e+e- acceptance
K+K- acceptance
E16 spectrometer + hadron-spectrometerwith 108 ppp
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acceptance calculation• As a first step, acceptance without magnetic
field is evaluated.• Angular distribution at the generated point is
used.
+15
-15
+15
-15+45 -45
e+e- acceptance
K+K- acceptance11
acceptance calculation (Cont’d)
detectoracceptance
(degree)
(deg
ree)
K+
- p
generated events
Acceptance will enlarge in horizontal direction if magnetic field is applied?
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B.E = 200MeV
acceptance calculation (Cont’d)
detectoracceptance
(degree)
(deg
ree)
K+
- p
double-K+ accepted (~16%)
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B.E = 200MeV
acceptance calculation (Cont’d)
detectoracceptance
(degree)
(deg
ree)
K+
- p
double- accepted (~0.7%)
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B.E = 200MeV
summary of acceptance calculation
acceptance for the exclusive measurement is 0.0%with this experimental setup w/o magnetic field
double-K+ accepted event double- accepted event
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acceptance = 16% 1600 / month acceptance = 0.7% 30 / month
K+
[mom vs. cos(lab)]
- from [mom vs. cos(lab)]
p from [mom vs. cos(lab)]
K+
[mom vs. cos(lab)]
- from [mom vs. cos(lab)]
p from [mom vs. cos(lab)]
decay :100% pp-- decay: 40%
Kaon identification
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n=1.02
K+
[mom vs. cos(lab)]
however, proton contamination is … ???
experiment @ J-PARCother choice?
New proposed spectrometer with 108 ppp
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kaon identification in trigger levelHigh resolutionHigh detection rate
anyway …
are elemental requirements.
from the Construction Proposal
summary• Feasibility of search for double kaonic-nuclear-cluster, K-K-pp,
using 8-10 GeV proton beam is discussed.• Experimental principle is:– 8GeV p+p K++K++X K++K+++– missing mass of K+K+ and/or invariant mass of
• Requirements for detectors are:– wide-coverage forward-detector (0-60 degrees)– good kaon separation in trigger level (pK<~4GeV/c)– high-resolution and high-rate detector
• With the upgraded E16 spectrometer, if double-K+ trigger is realized in momentum region < 4 GeV/c then inclusive K+K+ measurement could be possible.
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we will open new door to the high density matter physics, like the inside of neutron stars
Kaonic Nuclear Cluster (KNC)
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T.Yamazaki, A.Dote, Y.Akiaishi, PLB587, 167 (2004).
Density [1/fm3]
the density of the KNC is predicted to be high high densitydensity more than normal nuclear-density (0)
KKbarbarN interaction N interaction is clarified to be strongly attractive strongly attractive by Kaonic-atom experiments in 20th.
This leads the prediction of deeply-bound kaonic deeply-bound kaonic nuclear cluster (KNC)nuclear cluster (KNC), as many theorists pointed out.
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Experimental Situation of KNC
FINUDA@DANE
We need more evidences in various channels!
DISTO@SATURENPRL, 94, 212303 (2005) PRL,104,132502 (2010)
stopped-K- + A ( + p) + X 2.85GeV-p + p ( + p) + K+
B.E. = 115MeV = 67MeV
B.E. = 103MeV = 118MeV
Because there is a discrepancy between THEORETICAL PREDICTIONS and EXPERIMENTAL OBSERVATIONS…
KK--ppppp?p?KK--ppppp?p?
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Double-Kaonic Nuclear Cluster (DKNC)The double-kaonic nuclear clusters have been predicted theoretically.
How to produce the double-kaonic nuclear cluster?heavy ion collision(K-,K+) reactionpbarA annihilation
another choice, p+p collision
PL,B587,167 (2004).
The double-kaonic clusters have much stronger binding energy and a much higher density than single ones.(AMD calc.)
ppn
ppnK-
ppnK-K-
J-PARC LoI
8GeVdecay
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