Muon Accelerator Program staging study makes progress

The staging plan for the proposed Muon Collider includes a short- and long-baseline neutrino factory, a Higgs factory and a multi-TeV collider. Image: Muon Accelerator Program

This summer, physicists were abuzz discussing the preliminary conclusions of the Muon Accelerator Staging Study. The MASS working group is studying the physics potential for a series of facilities based on novel technologies being developed by the U.S. Muon Accelerator Program led by Fermilab.

The working group envisions a four-stage program intended to save energy, space and money in its design of a proposed Muon Collider. The Muon Collider is one of the several accelerators proposed to address particle physics’ more pressing future demands. Discoveries over the next few years will guide which technology the field pursues.

“The unique thing about muon accelerators is they have the potential to support cutting-edge physics on both the Energy and Intensity frontiers,” said Mark Palmer, head of MAP. “The availability of high-quality and high-intensity muon beams may also open the window to providing specialty beams for a whole range of other physics experiments.”

As the name suggests, a Muon Collider at Fermilab would collide elementary particles called muons so scientists could conduct high-precision studies of the components that make up our universe.

The Muon Collider would be a world-class facility, which, according to the MASS plan, would be the final step in an ensemble of facilities built in affordable stages. As it stands, each stage would provide unique physics capabilities, would build on the previous stages and would validate the technology needed for subsequent stages — thus allowing for better-informed decision-making.

The MASS staging concept starts with a short-baseline neutrino factory, called nuSTORM, then a long-baseline neutrino factory, NuMAX, deployed in increments of increasing beam intensity. A Higgs factory collider and, ultimately, a Multi-TeV Collider, could follow. It is an especially attractive plan for Fermilab, where the staging plan could build on existing concepts for a proposed high-intensity proton accelerator and a new underground detector facility for LBNE.

Before such a plan can get under way, though, MAP collaborators must first demonstrate the feasibility of these novel muon-based technologies, which will be the program’s primary focus for the remainder of this decade.

In the near term, MAP collaborators are tasked with developing an optimized baseline configuration of the stages outlined in the report. Setting a high-quality baseline is important in order to focus limited resources on the most promising paths for research and development.

“There are a number of excellent ideas proposed to address the MAP technical issues and challenges,” said SLAC’s Jean-Pierre Delahaye, head of the staging study.

By the end of 2015, Delahaye said, with the help of international experts weighing in, “we should be able to identify the most promising technologies and what we should focus on.”

Palmer said there is still much to figure out.

“No one has ever built an accelerator like this before, but Fermilab is uniquely suited to develop capabilities of the type being considered by MAP,” Palmer said.

“The muon-based accelerator technology is an attractive and promising technology for the future,” Delahaye added. “It provides a unique opportunity for facilities at Fermilab at both the Energy and Intensity frontiers.”

Sarah Witman