J-PARCにおけるその他の
ヘビークォーク物理実験の可能性
Acc. Specifications
• proton beam, Ekin = 30 GeV : s = 7.7 GeV
• proton beam, Ekin = 50 GeV : s = 9.8 GeV
– proton target at rest
– Beam intensity: up to 1012 per spil
– p = 10 GeV, p: s = 4.4,
K: s = 4.46
– p = 15 GeV, p: s = 5.3,
K: s = 5.4
– p = 20 GeV, p: s = 6.1,
K: s = 6.2
1.0E+09
Counts/sec
• Secondary beam
1.0E+08
1.0E+07
p+
pK+
1.0E+06
1.0E+05
1.0E+04
1.0E+03
0
5
10
Kpbar
15
GeV/c20
Sanford-Wang式より
生成角度=2.5 度, 15 kW ロス Pt標的
アクセプタンス：2 msr%, ビームライン長：132 m
Ξc
• p- + p -> Ξc + K0 + D-
– 生成: 2.4678 + 0.4976 + 1.86962 = 4.835 [GeV/c2]
– Secondary Beam の Threshold： 12GeV近辺
– Large beam intensity
• K- + p -> Ξc + D–
–
–
–
–
生成: 2.4678 + 1.86962 = 4.33 [GeV/c2]
Secondary Beam の Threshold： 10GeV近辺
Ｍｉｓｓｉｎｇ ｍａｓｓ 分光の可能性
Small beam intensity (p beam の二桁落ち)
p/K ビームセパレーション は難しい。（実験側の問題）
Double Charmed (Ξcc)
• 1次Proton Beam の使用を考える
• p + p -> Ξcc + D0 + D- + p
– この反応で合っていますか？
• 生成：3.5189 + 1.86486 + 1.86962 + 0.93827 =
8.19165 [GeV/c2]
• 30 GeVでは足りない。50GeV upgrade後なら大丈
夫。（但し、50 GeV upgradeもhope less）
• 原子核標的は？
– Fermi motion を利用できないか。
– Almost hope less: required momentum > 3.8 [GeV/c ]
• Storage Ringでも作るしかない
Bottom quark (Λb)
• p + p -> Λb + B+ + p
– Mass の和 ： 5.6194 + 5.27925 + 0.92827 =
11.83 [GeV/c2]
• No hope at J-PARC
ΛcN bound state
• Production: p + p -> Λc + D
– Minimum momentum: 4 GeV /c @ 15 GeV/c beam
– Target: 3He or heavy nucleus?
• Two step process and forward nucleon emission
• Tiny probability. How much?
• Production: pp-bar -> Λc + Λc-bar
– Almost stopped Λc
– How to make a bound state? Deuteron beam?
• Heavy ion collisions?
– Production + bound state with a spectator
Summary
• At this moment, Ξc is promising.
– I can’t see hope for other measurements.
• Anything else?
– Please give me interesting physics topic
– I will consider about it experimentally.

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