In the Dark

The following is a guest post by William Barter, who recently finished a term as the ‘physics coordinator’ of LHCb-UK.

–o–

The European particle physics community recently undertook a two-year process to update our strategy – setting out the things that we, as a field, choose to prioritise. The highest priority in that update was “the full exploitation of the physics potential of the Large Hadron Collider”. Despite our consensus, UK Research and Innovation (UKRI) has decided to pull UK funding for the next-generation upgrade of LHCb, one of four large experiments at the LHC. This decision was made for financial reasons; the science case for the upgrade is not in question, and current LHCb operations are fully funded. With this cut, we are experiencing the same pain as many of our astrophysics colleagues. Our plans and ambitions have been hit by self-defeating decisions from the same funding body.

For decades we have known that our current theory of fundamental quantum physics – the Standard Model of Particle Physics – is incomplete, but a fuller picture eludes us. The LHCb Upgrade offers a unique way to explore this science. Our experiment, operated by around 2000 scientists from 28 countries, is dedicated to the study of beauty and charm quarks, fundamental particles whose behaviour can be measurably influenced by Beyond Standard Model phenomena. Through these studies we hope to unlock a new understanding of how nature works at its most fundamental levels. The upgrade, planned for the 2030s, would enable us to take five times more data than is possible with our current experiment.

LHCb has a tremendous record of success. We are responsible for discovering more particles than any other particle physics experiment in history, including new forms of matter: pentaquarks and tetraquarks. The LHCb Upgrade would be the only experiment capable of finding many more. That’s not all. One of the only things we know about the physics that lies beyond the Standard Model is that we expect it to introduce differences in the behaviour of matter and antimatter, in order to explain why our universe is made out of particles rather than antiparticles. LHCb is uniquely able to make the dedicated and precise measurements needed to probe this physics in the quark sector. Measurements at LHCb are also directly sensitive to the quantum imprints of new fundamental particles. We are able to explore energy scales far beyond those directly accessible at the LHC. In the same way that the discovery of radioactivity gave us key insights into the weak force more than 80 years before the observation of the fundamental particle responsible, the W boson, new fundamental particles can also influence our measurements of beauty and charm quarks. It will take us at least another 50 years to reach the same energies that LHCb probes using future particle colliders. Put simply: the LHCb Upgrade offers a unique and compelling physics programme that complements and extends what is possible at the other LHC experiments.

These opportunities were already recognised by UKRI, who had previously committed to funding the upgrade. In addition to making physics sense, this investment met UKRI’s funding strategy. UKRI has the goal of securing “an average of £3 of additional investment for every £1 of public funding”. International partners were expected to contribute their share of the overall cost of the project on top of the UK contribution, leveraging almost five times the UK contribution. Given the widespread international support for the project, it was no surprise when the previous executive chair of STFC, the part of UKRI responsible for funding particle physics, nuclear physics, and astrophysics, included the fact that he had “secur[ed] the UK’s investment in the LHCb Upgrade” in his successful government-backed manifesto for the CERN Director General role. The recent backpedalling from UKRI therefore has broader consequences: it has raised difficult questions about which promises our international partners can trust the UK to keep. It’s hard to see how we can be relied on in future international collaborations if we are the reason that the LHCb Upgrade falls apart now.

And there are other, potentially larger, ramifications. Other future projects across the STFC remit have seen similar cuts. The decisions amount to a lack of ambition for fundamental research in the 2030s. One of the key purposes of STFC is to fund research over long timescales, understanding that Big Science areas like particle physics and astronomy require a stable approach that goes beyond any individual government spending review period. However, the decision to resile from new particle physics goals and commitments for the 2030s because of claimed cost overruns in the next few years completely rejects this mission. This will have a lasting impact: LHCb is simply one of the first examples, with the UK programme in particle physics, astrophysics, and nuclear physics due to contract significantly in the coming years as a result of UKRI’s choices.

So, where does this leave things? All is not lost. These decisions were communicated to us by UKRI at a strange moment, when the UK government was handing over between Sir Keir Starmer and Andy Burnham, while DSIT – the government department that oversees UKRI – was being disbanded, and while its replacement, BIST, was being set up. We know that Big Science is key to the UK’s scientific strategy: our work enthuses and inspires the next generation of scientists and researchers. The people we train enter the workforce skilled in modern data science techniques, ready to tackle the biggest problems with new approaches. There is still a window of opportunity for BIST to act and find a solution to the problem they’ve been handed. When news of the UKRI cuts broke, the incoming Secretary of State, Jonathan Reynolds, committed to investing in “the next generation of scientific facilities and infrastructure”. We now wait to see whether he means what he said, and if he will save UK particle physics, astrophysics, and nuclear physics from the self-defeating damage unleashed by UKRI.