UCLA CUORE Neutrino Physics Research Program

中微子是宇宙中最丰富的粒子之一，但我们不知道它们的许多性质。例如，我们不知道它们的绝对质量尺度，也不知道它们的粒子-反粒子性质。由于它们的丰富，即使是一个很小的质量也可能对理解它们在我们宇宙演化中的作用产生深远的影响。了解中微子是否是它们自己的反粒子，可能会对理解我们宇宙的物质-反物质不对称性产生影响。无中微子双贝塔衰变(NLDBD)实验解决了这两个基本问题。双贝塔衰变是一种罕见的核衰变，在能量有利的情况下，已经在几个原子核中测量到了这种衰变。一些原子核对普通的贝塔衰变是稳定的，但对于双贝塔衰变是不稳定的，在双重贝塔衰变中，原子核中的两个中子同时转化为质子，并发射两个电子。双贝塔衰变可以通过几种模式进行。实验测量的过程，即两个中微子模式，其中两个电子反中微子也被发射，完全由已知的物理描述。NLDBD是一种尚未被检测到的衰变，它在最终状态中没有中微子，必然会表明中微子是它们自己的反粒子。这种衰变的速度决定了有效中微子质量的大小。意大利阿瑟吉Gran Sasso实验室的CUORE(稀有事件低温地下天文台)实验是寻找NLDBD的下一代实验之一。它使用130-Te同位素，根据核结构计算，它对有效中微子质量的设计灵敏度在40-70 meV之间。UCLA集团的主要硬件责任包括与米兰和南卡罗来纳州集团合作测试所有前端电子产品，以及安装和调试LNGS的电子系统。他们的分析重点将是通过蒙特卡罗模拟了解残留的背景源。CUORE所使用的技术是该领域最具创新性和最大规模的技术之一，该技术基于毫克开尔文测辐射。如果他们的电子产品被证明是设计好的，它可能会影响其他领域。NLDBD实验解决了基本物理问题，这些问题具有超越粒子和核物理的科学影响。例如，如果中微子是Majorana粒子，而中微子质量来自拉锯机制，那么轻子扇区可能会违反CP(电荷宇称)对称性，并对宇宙的物质和反物质不对称做出贡献。该小组还将帮助培训本科生和NSF-REU学生的研究计划，并为他们提供中微子物理和现代探测器技术的研究经验。

Neutrinos are amongst the most abundant particles in the Universe and yet we do not know many of their properties. For example, we do not know their absolute mass scale or their particle-antiparticle nature. Because of their abundance, even a small mass could have far-reaching consequences for understanding their role in the evolution of our Universe. Knowing if neutrinos are their own antiparticles could have implications in understanding the matter-antimatter asymmetry of our Universe. Neutrino-less double beta decay (NLDBD) experiments address these two fundamental questions. Double beta decay is a rare nuclear decay that has been measured in several nuclei when it is energetically favorable. Some nuclei are stable against ordinary beta decay but are unstable for double beta decay in which two neutrons in the nucleus are simultaneously converted to protons and two electrons are emitted. Double beta decay can proceed through several modes. The experimentally measured process, the two-neutrino mode in which two electron antineutrinos are also emitted, is completely described by known physics. NLDBD is an as-yet-undetected decay that involves no neutrinos in the final state and necessarily would indicate that neutrinos are their own antiparticle. The rate of such decays determines the scale for the effective neutrino mass.The CUORE (Cryogenic Underground Observatory for Rare Events) experiment at the Gran Sasso laboratory (LNGS), Assergi, Italy, is one of the next generation experiments to search for NLDBD. It uses the 130-Te isotope with a design sensitivity to the effective neutrino mass ranging between 40-70 meV, depending on nuclear structure calculations. The UCLA group's major hardware responsibilities include the testing of all the front-end electronics and the installation and commissioning of the electronics system at LNGS in collaboration with the Milan and South Carolina groups. Their analysis focus will be on understanding of the residual background sources through Monte Carlo simulations.The technology being used in CUORE which is based on milliKelvin bolometry is one of the most innovative and largest scale in the field. If their electronics proves out as designed, it will likely influence other fields. The NLDBD experiments address fundamental physics issues that have a scientific impact beyond particle and nuclear physics. For example, if neutrinos are Majorana particles and neutrino masses are from the See-Saw Mechanism, the lepton sector could violate CP (Charge-Parity) symmetry and contribute to the matter and anti-matter asymmetry of the Universe. The group will also help train undergraduate and NSF-REU students in their research programs and provide them with research experiences in neutrino physics and modern detector technology.