LHC上高能$K^0_S$再生过程中的Odderon交换
Odderon exchange in high-energy $K^0_S$ regeneration at the LHC
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中文总结 AI 辅助
本研究针对LHC上通过高能中性K介子再生探测Odderon交换的问题，分析了相干前向与非前向衍射两种再生模式的信号特征与本底限制，提出了主动双再生体扣除的测量策略思路。
中文摘要 AI 辅助
我们重新探讨了通过高能中性K介子再生探测Odderon交换的可能性，重点研究了质心系能量$\u2009=13.6\u2009$TeV的$pp$碰撞产生的、能量约为$0.2-2\u2009$TeV的$K^0_L$介子在物质中的$K^0_L\to K^0_S$转换过程，以及在LHC相互作用点的极前向区域实现此类测量的实际约束。本分析包含两个互补部分。第一部分，我们复现了最初针对液氢再生体的相干前向再生估算，并将其拓展至符合LHC几何尺寸的实际碳（C）、铜（Cu）和铅（Pb）再生体，同时纳入了中性K介子的衰减效应。我们发现，Odderon诱导的再生相位会在TeV量级的K介子能量下，对$K^0\toπ^0π^0$衰变顶点分布产生可测量的畸变，但来自相互作用点的原初$K^0_S$介子的存活对基线长度提出了严苛要求，而与之竞争的$C=-1$电磁（光子交换）振幅则限制了将相干模式作为纯净Odderon测量的解读。第二部分，我们研究了K介子能量更低（0.2-0.8 TeV）的非前向（衍射）再生过程，该过程中原初$K^0_S$的污染会被自然抑制，同时估算了Odderon、Pomeron-Odderon切割、ω-Reggeon以及光子交换对再生振幅的竞争贡献。我们确定中子诱导的仅中性奇异粒子产生和非弹性Regge本底是主要限制因素，量化了观测到Odderon信号所需的本底抑制水平，并提出了主动双再生体扣除策略的核心要素。
英文摘要
We revisit the possibility of detecting the Odderon exchange through high-energy neutral-kaon regeneration, focusing on the in-matter $K^0_L\to K^0_S$ conversion of $(\sim\!0.2-2)$~TeV $K^0_L$ mesons originating from $pp$ collisions at $\sqrt{s}=13.6$~TeV, and on the practical constraints of realizing such a measurement in the very-forward region of an LHC interaction point. The analysis has two complementary parts. First, we reproduce the original coherent-forward-regeneration estimates for a liquid-hydrogen regenerator and extend them to realistic C, Cu and Pb regenerators of an LHC-compatible geometry, including neutral-kaon attenuation. We show that an Odderon-induced regeneration phase produces a measurable distortion of the $K^0\toπ^0π^0$ decay-vertex distribution at TeV kaon energies, but that the survival of primary $K^0_S$ mesons from the interaction point imposes severe baseline requirements, while a competing electromagnetic $C=-1$ (photon-exchange) amplitude limits the interpretation of the coherent mode as a clean Odderon measurement. Second, we examine non-forward (diffractive) regeneration at lower kaon energies of $0.2-0.8$~TeV, where the primary-$K^0_S$ contamination is naturally suppressed, and estimate the competing Odderon, Pomeron--Odderon-cut, $ω$-Reggeon and photon-exchange contributions to the regeneration amplitude. We identify neutron-induced neutral-only strangeness production and inelastic Regge backgrounds as the dominant limitations, quantify the background suppression required for an observable Odderon signal, and formulate the ingredients of an active double-regenerator subtraction strategy.
