Precise Measurement of Nuclear Fragmentation Cross Sections for the Understanding of Particle Production in the Galaxy

新一代天基宇宙射线探测器已经以前所未有的百分比精度测量了银河宇宙射线的通量。这些测量提供了银河系中宇宙射线传播的独特诊断，并有机会发现银河系中暗物质湮灭的特征和超越粒子物理标准模型的新物理现象。反质子和正电子的测量通量超出标准天体物理学背景的预期的原因最近引起了许多猜测。然而，银河系中粒子产生的非标准成分的牢固建立依赖于对宇宙射线与星际介质相互作用的碎片横截面的良好了解。在这个建议中，我们建议对银河系中对解释次级宇宙射线很重要的所有碎片通道进行精确测量。通过拟议的测量活动，银河系宇宙射线在地球上的通量预测的碎片相关不确定性可以从目前的20%降低到与宇宙射线数据精度相匹配的百分比水平。方法：我们建议使用欧洲核子研究中心SPS的NA61/SHINE设备在同位素水平上进行所需的截面测量。该项目将对Li、Be、B、C和N核的碎片进行测量，这些元素对限制银河系中宇宙射线的传播特别重要。为了在实际的SPS光束时间内达到所需的测量统计精度，我们将致力于NA61/SHINE探测器系统的持续升级，目标是将探测器系统的最大读出率提高十倍。此外，我们将开发一种新的光束探测器系统，以确保精确测量光束粒子。研究项目对科学发展的预期影响拟议的测量活动将为现在和将来的宇宙射线研究建立一个独特的反应数据库。这些数据不仅对了解银河系宇宙射线的起源至关重要，而且对于精确预测天体物理背景，以寻找银河系暗物质湮灭的特征和超越粒子物理标准模型的新物理现象。双方合作的附加值德国集团是世界领先的宇宙射线研究机构之一的一部分，而波兰集团在重离子物理和光束探测器的建设方面拥有经验。这项合作将在波兰研究所开辟一个新的科学课题，对碎片数据的联合分析将结合两个研究所的物理和硬件专业知识，以存档所需的测量精度。

Project objectives A new generation of space-based cosmic-ray detectors has measured the fluxes of Galactic cosmic rays to an unprecedented precision at the percent-level. These measurements provide a unique diagnostic of cosmic-ray propagation in the Galaxy and an opportunity to find signatures of dark matter annihilation in the Galaxy and new physics phenomena beyond the Standard Model of Particle Physics.The origin of the excess of the measured fluxes of anti-protons and positrons with respect to the expectations from standard astrophysical backgrounds has attracted a lot of speculation recently. However, a firm establishment of a non-standard component of particle production in the Galaxy relies on a good knowledge of fragmentation cross sections of cosmic-ray interactions with the interstellar medium.In this proposal we suggest to perform a precise measurement of all the fragmentation channels important for the interpretation ofsecondary cosmic rays in the Galaxy. With the proposed measurement campaign, the fragmentation-related uncertainties of predictions of the fluxes of Galactic cosmic rays at Earth can be decreased from the current 20% to the percentage level matching the precision of cosmic-ray data.MethodologyWe propose to use the NA61/SHINE facility at the SPS at CERN to perform the needed cross section measurements at isotope level. The program will perform measurements of the fragmentation of Li, Be, B, C and N nuclei, which are the elements that are of particular importance to constrain the propagation of cosmic rays in the Galaxy. To reach the desired statistical accuracy of the measurements within a realistic amount of SPS beam time, we will contribute to the ongoing upgrade of the NA61/SHINE detector system and aim at a tenfold increase of the maximal readout rate of the detector system. Moreover, we will develop a new beam detector system that will assure a precise measurement of the beam particles.Expected impact of the research project on the development of science The proposed measurement campaign will lead toa unique reaction database for present and future studies of cosmic rays. This data will not only be essential for the understanding of the origin of Galactic cosmic rays, but also for a precise prediction of the astrophysical background for searches for the signatures of dark matter annihilation in the Galaxy and new physics phenomena beyond the Standard Model of Particle Physics.Added value of bilateral cooperation The German group is part of one of the world-leading institutes for the study of cosmic rays, whereas the Polish group has a experience in the heavy ion physics and the constructions of beam detectors. The collaboration will open a new scientific topic at the Polish institute and the joint analysis of the fragmentation data will combine the physics and hardware expertise of both institutes needed to archive the desired precision of the measurement.