結合された核基底状態における鏡対称性の違反

D E M Hoff¹, A M Rogers², S M Wang³

¹Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, MA, USA. dan@demhoff.com.

Nature

|April 3, 2020

まとめ

核鏡対称性は,ストロンチウム-73とブロミン-73の基本状態で破られる. この発見は原子核内の電荷対称性の破壊力に関する洞察を示しています

科学分野:

核物理学
粒子物理学
量子力学

背景:

保存法則は物理システムの対称性と内在的に結びついています
核子 (中性子と陽子) は,単一のフェルミオンの投影として,イソバリク・スピン (イソスピン) と見ることができる.
交換された中性子と陽子の数の鏡核は,鏡対称性のために同一の核状態を示すことが期待されます.

研究の目的:

特定の鏡核の基本状態における鏡対称性の潜在的な違反を調査する.
期待される鏡対称性から観測された偏差が核構造と力に及ぼす影響を調べる.

主な方法:

ルビジア-73のT = 3/2同位体-アナログ状態からの陽子放出パターンの分析.
鏡核ストロンチウム-73とブロミン-73の核状態の比較
核状態のスピンとパリティの割り当てを決定する.

主要な成果:

ストロンチウム-73とブロミン-73の結合核の基底状態で鏡対称性の違反の証拠が見つかりました
J^π = 5/2^-のスピン割り当ては,ルビジア-73の同位体同位体状態のために必要である.
ストロンチウム-73の基底状態は,その鏡のパートナーであるブロミン-73と異なる (J^π = 1/2^-).

結論:

観測された鏡対称性の違反は,原子核における電荷対称性の破壊力に関する直接的な証拠を提供します.
この発見は,核の基本状態における完全な鏡対称性の仮定に異議を唱える.
この研究は核の構造を制御する基本的な力について新たな洞察をもたらします

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