Opinion collides over whether a larger particle accelerator is necessary

Last month, scientists at the European Organization for Nuclear Research, CERN, unveiled concrete plans for a successor to the Large Hadron Collider (LHC), aptly named the Future Circular Collider (FCC), just over a decade after the LHC powered up for the first time.  CERN has a reputation of looking forward to the next project immediately after the completion of the previous one, and with the FCC they have been no different.  If the plan is approved, CERN would be looking to get tangible results from the FCC by 2050.  So, what would this new collider look like?  Why do some scientists want this development, yet others are sceptical of its benefits?

The concept design report details plans for the new 100km collider to be built around the site at CERN, requiring a new tunnel to be dug underneath Switzerland and France.  Dwarfing the 27km LHC, the FCC would take its crown in becoming the largest machine in the world.  Scientists are looking to engineer collisions of particles at energies of up to 100 TeV, over seven times the current limit of the LHC.  By analysing collisions of particles at higher energies, they can access rare particle decays which give an insight into how particles react with each other, as well as potentially discovering new particles.

Scientists are looking to engineer collisions of particles at energies of up to 100 TeV, over seven times the current limit of the LHC

The clear conclusion from work at the LHC is that the Standard Model is correct; the mathematical descriptions of elementary particles and their interacting forces have been repeatedly proven right.  Yet, much remains unanswered. The abundance of matter over anti-matter is still unexplained, as well as why the gravitational force is so weak compared to the other fundamental forces, suggesting we need an extension to the Standard Model. We are also no closer to finding out what Dark Matter is.  After ruling out it being a massive stellar object with low luminosity, many believe that it can be explained as a Weakly Interacting Massive Particle (WIMP) which must solely interact via gravitational forces.  Many hope the FCC will help shine light on these problems, having had its predecessor complete the Standard Model with the discovery of the Higgs boson.

As well as benefiting the scientific community with its potential for ground-breaking discoveries, if the reaction from the LHC launch is replicated, it could help inspire a new generation of scientists to tackle the outstanding problems in particle physics.  The LHC helped make particle physics appealing to the masses with the sheer size of the experiment, the particles travelling close to the speed of light, and the extremely low temperatures required to bring out the superconducting properties of the magnets used. Having always struggled to compete with the appeal of Astrophysics and the Apollo missions, the public excitement over the LHC shone a welcome spotlight on the branch of particle physics.

The LHC helped make particle physics appealing to the masses…

However, some sections of the media published articles fearing the creation of a ‘black hole machine’ prior to the LHC opening, worried about the destruction of our world with such high-energy collisions.  Significantly, these fears led to a new group of science communicators speaking out and educating the public on particle physics, one of whom being Professor Brian Cox.  Numerous TV and radio appearances and popular science books helped spark an interest in physics, such that the University of Manchester reported a ‘Brian Cox effect’, attributing a 52% increase in UCAS applications to undergraduate physics courses from 2008 to 2012 to his work.  If an increasing number of students can be inspired to take up higher education from the work of the FCC, this can only be a good thing in helping to drive scientific development.

Unfortunately building such a machine comes at a sizeable price. With initial estimates forecasting a cost of over €20bn, opinion is polarised over whether such an investment in this project is worthwhile.  A recent attempt to build a linear collider in Japan was halted due to the rising costs deemed too large to continue funding.  Would the FCC fall to the same fate?   CERN has set a precedent in managing to deliver projects close to being on time and on budget with the LHC, and so funding will likely be trusted with the expectation of CERN delivering the FCC.  Although the cost of a replacement particle collider may cause a few to baulk, splitting the cost over a minimum of twenty years across many participating nations makes the figure much more palatable.

With initial estimates forecasting a cost of over €20bn, opinion is polarised over whether such an investment in this project is worthwhile

The more damaging funding question is whether this money would be better spent on other pressing scientific issues.  In an interview with the BBC, the UK’s former Chief Scientific Advisor Professor Sir David King stated his reservations with the FCC, flaunting the possibility of future colliders finding minimal results: “We have to draw a line somewhere otherwise we end up with a collider that is so large that it goes around the equator.”  Professor King also elaborated on where the money would be better spent, arguing that: “A new high priority for human beings is now dealing with climate change.”  His comments come after the Trump administration reduced funding in the 2019 budget for the United States Agency for International Development by roughly 70% for environmental initiatives, compared to Obama-era spending.  Professor Jon Butterworth of UCL refutes King’s claim by suggesting the lack of progress on climate change is not down to research, but an unwillingness by groups to collaborate.  Instead, he stresses the importance of climate science alongside the work done at CERN, adding: “I wouldn’t necessarily start that effort by shutting down one of the more successful trans-national scientific research institutions.”

The FCC will be discussed along with other potential projects, as part of the European Particle Physics Strategy Update, giving a chance for scientists to constructively argue for which projects should receive funding in the future.  Whether such a large project receives backing from the scientific community will surely be a turning point in the direction of particle physics, irrespective of what results are found at future experiments.