标题： 超新星中微子味振荡的探测前景 显示英文标题

标题： Prospects for Detecting Supernova Neutrino Flavor Oscillations

摘要： 从II型超新星中产生的中微子或许是我们探测宇宙学上有意义的缪子中微子和/或陶子中微子质量的最佳机会。 这是因为物质增强的中微子振荡可能导致异常热的nu_e谱，从而在地面探测器中导致增强的带电流截面。 最近提出的两个超新星中微子观测站，OMNIS和LAND，将通过中性流和带电流中微子相互作用来探测从靶核中打出的中子。 由于这种信号不具有味特异性，因此很难立即确定是否可以从这些实验中提取出令人信服的中微子振荡信号。 为了解决这个问题，我们研究了一系列可能的轻质量和重质量靶材，包括9Be、23Na、35Cl和208Pb。 我们发现，仅使用中子计数率来探测振荡的策略至多是存在问题的，即使截面由辅助实验确定。 超新星中微子谱的合理不确定性往往会掩盖由振荡引起的速率增强。 然而，在208Pb的情况下，出现了一个主要具有味特异性的信号，并且对nu_e温度和发射两个中子的反应极其敏感。 这个信号及其味特异性与中性流和带电流反应的第一禁戒响应的强度和位置有关，这是208Pb中微子截面中之前未被讨论的方面。 强子自旋转移实验可能有助于确认支持我们结论的一些核结构物理。 显示英文摘要

摘要： The neutrinos from a Type II supernova provide perhaps our best opportunity to probe cosmologically interesting muon and/or tauon neutrino masses. This is because matter enhanced neutrino oscillations can lead to an anomalously hot nu_e spectrum, and thus to enhanced charged current cross sections in terrestrial detectors. Two recently proposed supernova neutrino observatories, OMNIS and LAND, will detect neutrons spalled from target nuclei by neutral and charged current neutrino interactions. As this signal is not flavor specific, it is not immediately clear whether a convincing neutrino oscillation signal can be extracted from such experiments. To address this issue we examine the responses of a series of possible light and heavy mass targets, 9Be, 23Na, 35Cl, and 208Pb. We find that strategies for detecting oscillations which use only neutron count rates are problematic at best, even if cross sections are determined by ancillary experiments. Plausible uncertainties in supernova neutrino spectra tend to obscure rate enhancements due to oscillations. However, in the case of 208Pb, a signal emerges that is largely flavor specific and extraordinarily sensitive to the nu_e temperature, the emission of two neutrons. This signal and its flavor specificity are associated with the strength and location of the first-forbidden responses for neutral and charge current reactions, aspects of the 208Pb neutrino cross section that have not been discussed previously. Hadronic spin transfer experiments might be helpful in confirming some of the nuclear structure physics underlying our conclusions.