Sks Zero JPARC experiment with SKS Experiment Physics

Sks. Zero

J-PARC experiment with SKS Experiment Physics Reaction E 05 X Hyp (K-, K+) E 13 g ray (K-, p-) DCX (p-, E 10 E 22 E 19 Weak (Single L) Q search Beam 1. 8 1. 5 (1. 1 -1. 8) Scat. SKS Comment 1. 1 -1. 4 Sks. Plus Good momentum resolution 1. 4 Sks. Minus Large Acceptance With S- reaction K +) 1. 2 0. 8 -0. 9 SKS (Sks. Zero) (p+, K+) 1. 05 0. 63 -0. 73 SKS (Sks. Zero) Present SKS spec 0. 7 -0. 95 SKS (Sks. Zero) Flat acceptance (p-, K-) 1. 92 (1. 87, 1. 97) これら3通りの実験に適するように設計する

Sks. Zero acceptance Requirements l (p-, K+) reaction @ 1. 2 Ge. V/c ⇒ 0. 8 -0. 9 Ge. V/c scattered particles l p(p-, K+)S- reaction @ 1. 2 Ge. V/c S DCX (p+, K+) ⇒ 0. 6 -0. 7 Ge. V/c scattered particles l (p+, K+) reaction @ 1. 05 Ge. V/c ⇒ 0. 63 -0. 73 Ge. V/c scattered particles Q ○ : 2. 2 T Map × : 2. 4 T Map (2. 7 T map scaled) □ : 2. 7 T Map l p(p-, K-)Q+ reaction @ 1. 87, 1. 92, 1. 97 Ge. V/c ⇒ 0. 7 -0. 95 Ge. V/c scattered particles Comments l DCX, (p+, K+) ⇒ 2. 2 T l Q search ⇒ 2. 4 T

Sks. Zero acceptance Requirements l (p-, K+) reaction @ 1. 2 Ge. V/c qsct. <15° ⇒ 0. 8 -0. 9 Ge. V/c scattered particles l p(p-, K+)S- reaction @ 1. 2 Ge. V/c S DCX (p+, K+) ⇒ 0. 6 -0. 7 Ge. V/c scattered particles l (p+, K+) reaction @ 1. 05 Ge. V/c ⇒ 0. 63 -0. 73 Ge. V/c scattered particles Q ○ : 2. 2 T Map × : 2. 4 T Map (2. 7 T map scaled) □ : 2. 7 T Map l p(p-, K-)Q+ reaction @ 1. 87, 1. 92, 1. 97 Ge. V/c ⇒ 0. 7 -0. 95 Ge. V/c scattered particles Comments l DCX, (p+, K+) ⇒ 2. 2 T l Q search ⇒ 2. 4 T

SKS Acceptance (p+, K+) S 2. 2 T Map DCX Ø The simulated result is almost consist with the previous result, . ~105 msr (100 msr). Ø Absolute values is little larger than previous result. ⇒Size of SDCIn Ø The acceptance of lower momentum is smaller. ⇒AC position

Sks. Zero momentum resolution 0. 9 Me. V/c(FWHM) @ 0. 69 Ge. V/c S DCX (p+, K+) ○ : Previous SKS × : Sks. Zero 2. 2 T Map Ø The momentum resolution is 0. 69 Me. V/c(FWHM) @ 0. 72 Ge. V/c ⇔ 0. 70 Me. V/c(FWHM) for previous SKS Ø If the momentum resolution is twice worse, the resolution is less than 3 Me. V/c. 運動量分解能は良くなる

Sks. Zero momentum resolution Ø The momentum resolution is 0. 69 Me. V/c(FWHM) @ 0. 72 Ge. V/c ⇔ 0. 70 Me. V/c(FWHM) for previous SKS Q S (p+, K+) DCX Ø If the momentum resolution is twice worse, the resolution is less than 3 Me. V/c. ○ : Sks. Zero 2. 2 T Map × : Sks. Zero 2. 4 T Map (2. 7 T Map scaled) □ : Sks. Zero 2. 7 T Map

Problems • Beam through – The beam directly hits the down stream detectors by using the (p+, K+) reaction. • Trigger rate and background events – Acceptance is increased ⇒ Accepted background events are increased. – For DCX and Q search experiment, the beam hits the SKS magnet and makes the large background.

Beam through Ø The beam hits the down stream detectors by the (p+, K+) reaction at pp=1. 05 Ge. V/c Ø The setup of Sks. Zero is not optimized to avoid the beam through. 1. 05 Ge. V/c Ø 最適化の際にはビームが物質量 の小さい部分を通るように設計 Ø Qの場合、SKS磁石にビームがヒ ットする Ø Chargeが変わる実験でも同様

(p±, K+) kinematical region @1. 2 Ge. V/c up to 20 degree こんな雰囲気です p(p-, K+)S- 12 C(p+, K+)12 LC g. s : -10. 8 Me. Vのとき

p(p-, K-)Q kinematical region up to 20 degree こんな雰囲気です 1. 87 Ge. V/c 1. 92 Ge. V/c 1. 97 Ge. V/c