新一代直线对撞机设计进展

下一代直线对撞机后准直系统中束流光学和散射的研究

Studies of Beam Optics and Scattering in the Next Linear Collider Post-Linac Collimation System

我们提出了一个新的概念和光学设计的下一个直线对撞机后直线加速器准直系统。在具有大水平色散和垂直电子感应加速器功能的系统中实现了能量准直和对非能量束的被动保护。Betatron准直是在一个相对较低的β（FODO类）晶格中进行的，其中只有薄的扰流器在束芯附近拦截粒子，而厚的吸收体保持与束的大距离。两种可能的方案的扰流器被认为是：一个在其中的扰流器是能够容忍一定数量的破坏性的拦截每对撞机运行（“消耗”扰流器），和一个在其中的扰流器是潜在的损坏的每一个机器脉冲和自我修复（“可再生”扰流器）。系统的准直效率进行了评估，考虑到晕粒子被重新散射到光束和μ子secondaries通过相互作用区域。我们的结论是，新的设计是一个有前途的候选人的NLC后直线加速器系统。

Muon Cooling Progress and Prospects for an S-channel Muon Collider Higgs Factory

Muon-based accelerators have the potential to enable facilities at both the Intensity and the Energy Frontiers. Muon storage rings can serve as high precision neutrino sources, and a muon collider is an ideal technology for a TeV or multi-TeV collider. Progress in muon accelerator designs has advanced steadily in recent years. In regard to 6D muon cooling, detailed and realistic designs now exist that provide more than 5 order-of-magnitude emittance reduction. Furthermore, detector performance studies indicate that with suitable pixelation and timing resolution, backgrounds in the collider det…

μ子对撞机：计划、进展与挑战

Muon Collider: Plans, Progress and Challenges

我们物理学界期待LHC在未来几年内发现新的物理学。新物理学的特征和能量尺度仍然不清楚，但很可能LHC的数据需要得到轻子对撞机的信息的补充，轻子对撞机可以提供对新现象的精确检查。我们描述的概念，加速器的设计，和检测器的研发高能量μ子对撞机以及与机器和它的检测器环境的挑战。

"Colliders or Bust"

Charged-particle colliders have proven key instruments of discovery in high-energy physics. Pushing the frontiers of our knowledge ever further has relied on, and still keeps calling for, ever better performance and novel techniques. During more than four decades, Swapan Chattopadhyay has made numerous essential contributions to this endeavour. Often far ahead of his time, he helped advance many areas of collider development, notably in the domains of stochastic cooling, the development of asymmetric B factories, the design of next- and next-next-generation of high-energy colliders, and the ha…

A very high energy hadron collider on the Moon

The long-term prospect of building a hadron collider around the circumference of a great circle of the Moon is sketched. A Circular Collider on the Moon (CCM) of $\sim$11000 km in circumference could reach a proton-proton center-of-mass collision energy of 14 PeV -- a thousand times higher than the Large Hadron Collider at CERN -- optimistically assuming a dipole magnetic field of 20 T. Several aspects of such a project are presented, including siting, construction, availability of necessary materials on the Moon, and powering, as well as a discussion of future studies and further information …

REBCO -- a silver bullet for our next high-field magnet and collider budget?

High-field superconducting magnets with a dipole field of 16 T and above enable future energy-frontier circular particle colliders. Although we believe these magnets can be built, none exists today. They can also be a showstopper for future high-energy machines due to a prohibitively high price tag based on the current conductor and magnet fabrication cost. The high-temperature superconducting REBCO coated conductor can address both the technical and cost issues, a silver bullet to lay both monsters to rest. The challenges and unknowns, however, can be too arduous to make the silver bullet. We…

光子对撞机的进展

Progress in Photon Colliders

过去的两年在光子对撞机的历史上非常重要。该方案现已列入NLC、JLC和TESLA/SBLC项目的概念设计报告。所有的设计都预见了两个相互作用区域：一个是e+e-，第二个是gamma-gamma、gamma-e和e^-e^-碰撞。本文主要讨论三个方面：（1）光子对撞机的论证;（2）现有项目的参数;（3）最终的亮度和能量，新的想法。最近的研究表明，主要的碰撞效应--相干对的产生--在能量为2 E < 2 TeV的光子对撞机中由于束排斥而被抑制，原则上可以获得超过10^{35} cm^-2s^-1的伽马-伽马亮度。所需的具有非常小的发射率的电子束可以例如使用电子束的激光冷却来获得。这种新方法要求激光器的功率比电子“转换”为光子所需的功率高一个数量级。这样的激光器目前还没有，但希望它们能在线性对撞机建成时出现。高能γ-γ、γ-e对撞机的亮度可与e^+e^-对撞机媲美，在粒子物理学的许多现象的研究中是无可匹敌的。

Muon Collider进展：加速器

Muon Collider Progress: Accelerators

μ子对撞机将是探索轻子能量前沿的有力工具，并将补充大型强子对撞机目前正在进行的研究。这种装置将提供几个重要的好处。μ子和电子一样，都是点粒子，所以所有的质心能量都可以用来产生粒子。此外，由于它们的质量较高，μ子产生的同步辐射非常少，产生的束辐射也非常少。第一个特点允许使用一个圆形对撞机，它可以有效地利用昂贵的射频系统，并且它的占地面积与现有的实验室场地兼容。第二个特征导致在碰撞点处的相对窄的能量扩散。为μ子对撞机设计加速器复合体是一项具有挑战性的任务。首先，μ子是作为第三束产生的，因此需要高功率质子束和能够承受它的靶，以提供所需的~1 \times 10 ^34 cm^-2 s ^-1的亮度。其次，束最初产生具有大的6D相空间，这需要用于减小μ子束流发射度（“冷却”）的方案。最后，μ子的寿命很短，所以所有的束操纵都必须非常迅速地完成。μ子加速器计划由费米实验室领导，包括一些美国国家实验室和大学，已经开展了旨在最终建造μ子对撞机的设计和研发活动。这种设施的设计特点和配套的R&D计划进行了说明。