Physicists capture an elusive 4D ghost in the CERN particle accelerator

There's a ghost haunting CERN's particle accelerator tunnels.

In the Super proton synchrotronFinally, physicists have measured and quantified the amount of invisible structure that can divert the path of particles contained within it, and create problems for particle research.

It has been described as occurring in Stage spaceWhich can represent one or more states of a moving system. Since four states are needed to represent the structure, researchers view it as four-dimensional.

This structure is the result of a phenomenon known as echoBeing able to measure and measure them takes us a step closer to solving a global problem related to magnetic particle accelerators.

“With these echoes, what happens is that the particles don't follow exactly the path we want and then they fly away and get lost.” says physicist Giuliano Franchitti to GSI In Germany. “This degrades the beam and makes it difficult to reach the desired beam parameters.”

Resonance occurs when two systems interact and synchronize. It could be an emerging echo between Planetary orbits As they interact with gravity on their journey around a star, or tuning fork, they begin to spin Sympathetic loop When sound waves from another tuning fork collide with its teeth.

Use of particle accelerators Strong magnet That generate electromagnetic fields to direct and accelerate beams of particles where physicists want them to go. Ringing They can occur in an accelerator due to defects in the magnet, creating a magnetic structure that interacts with particles in problematic ways.

The more degrees of freedom a dynamic system exhibits, the more complex its mathematical description becomes. Particles moving through a particle accelerator are typically described using only two degrees of freedom, reflecting the two coordinates needed to locate a point on a flat grid.

Describing the structures therein requires mapping them using additional features in phase space beyond just the top-to-bottom and left-to-right dimensions; That is, four parameters are needed to map each point in space.

this, Researchers sayis something that can easily elude our engineering intuitions.

“In accelerator physics, thinking is often at only one level.” Franchitti says. However, in order to map the resonance, the particle beam must be measured across both the horizontal and vertical planes.

It sounds straightforward, but if you're used to thinking about something a certain way, it may take effort to think outside the box. Understanding the effects of resonance on the particle beam took a few years, as well as some massive computer simulations.

However, this information opened the way for Franchitti, along with physicists Hannes Bartosek and Frank Schmidt of CERN, to finally measure the magnetic anomaly.

Using beam position monitors along the Super Proton Synchrotron, they measured the particle position for about 3,000 beams. By precisely measuring where the particles were centered, or deflected to one side, they were able to create a map of the resonance chasing the accelerator.

“What makes our latest discovery so special is that it shows how individual particles behave in double resonance.” Bartosek says. “We can demonstrate that the experimental results are consistent with what was predicted based on theory and simulation.”

The next step is to develop a theory describing how individual particles behave in the presence of accelerator resonance. The researchers say this will ultimately give them a new way to mitigate beam degradation and achieve the high-resolution beams required for current and future particle acceleration experiments.

The team's research has been published in Nature physics.