Together to the Next Frontier

COMMENT CONSERVATION Four views of MICROBIOLOGY Harold McGee EDUCATION Why Victorian OBITUARY Adrienne Asch, the US Endangered Species on festive feasting’s debt primers taught science by bioethics pioneer, Act as it turns 40 p.369 to fermentation p.372 way of fairies p.374 remembered p.377 ILLUSTRATION BY SCOTT GARRETT SCOTT BY ILLUSTRATION

Together to the next frontier As emerging players jostle old ambitions, Nigel Lockyer calls for the next generation of particle-physics projects to be coordinated on a global scale.

his year was a watershed for particle We really don’t know. Each physicist has Illinois, I have spent the past six months in physics. The decades-long quest to his or her own opinion, and countries and discussions about the future of US particle discover the Higgs boson is essen- regions are preparing to explore different physics. But particle physics is an interna- Ttially complete. Still abuzz after a Nobel prize strategies to identify the territories ripest tional pursuit, with projects in and partici- for the Higgs prediction, the particle-physics for exploration. What we do know is that the pants from many different countries. The community is feeling satisfied. It is time to next generation of particle accelerators will United States is well positioned to take the pause, reflect and consider what comes next. be expensive. And requests for government lead in some areas, such as neutrino phys- The Higgs boson is the last puzzle piece in funding will run up against fiscal constraint ics, but the global landscape is uncertain. the standard model of particle physics, but around the globe. Resources need to be pooled, and new the model does not explain some fundamen- NATURE.COM As the incoming players are emerging. China’s and India’s tal aspects of our Universe. From the neu- See Nature’s special director of the Fermi talent, infrastructure and ambitions must trino’s very small mass to dark matter and issue on the Large National Accel- now be factored into the global equation. dark energy, we know there is more going Hadron Collider: erator Laboratory We are at a critical moment for the on. But where might the next clue lurk? nature.com/lhc (Fermilab) in Batavia, field. Each country and major project

must take into account its impact on hopes to host the International Linear the 100-TeV machine? Construction of the overall enterprise. The opportunity is Collider (ILC) — a 30-kilometre-long, the machine would be cheaper in China, enormous: a truly coherent approach to 500-gigaelectronvolt electron–positron col- although the nation would need help from accelerate progress and combine disparate lider to study the Higgs boson that would the rest of the world to design and build it. strengths. But the risks are just as large: fail- surpass the LHC in terms of precision in the If China does jump ahead, it will change ing to agree on major efforts, losing inter- late 2020s. It is hoped that construction will the landscape of science, levelling the play- national partners and sacrificing progress begin later this decade. ing field with the emerging economies. Dis- in a downward spiral of too many partially Japan is about to begin a campaign to sign cussions about global progress in particle approved projects. up support for this international project, physics would need to explicitly include which would require US and European par- heads of state from China and India as well BEYOND THE HIGGS ticipation. Most particle physicists support as North America, Europe and Japan. The high-energy frontier neighbouring the the ILC but many would like to see what Higgs will soon be within reach of the Large discoveries will come out of the upgraded GLOBAL CONVERSATION Hadron Collider (LHC) at CERN, Europe’s LHC first. If no new particles emerge, then Physicists do not care where they do their particle-physics lab near Geneva, Switzer- the higher precision available to the ILC research. But the vast scale of particle- land — currently the highest-energy accel- would make building it even more attrac- physics projects means that all new mega- erator in the world. When it turns on again tive. If another discovery is made at the accelerators require global planning, in early 2015 after a two-year upgrade, the LHC, then the community might need agreement and joint construction. Govern- machine will operate close to its design a different machine to explore the new ments around the world will have to make energy of 14 teraelectronvolts (TeV) — energy regime. unprecedented financial investments in roughly twice that at which the Higgs was other countries, challenging the traditional discovered. Now that the standard model PASSING THE BATON political calculus in which public tax dol- is complete, any new particles found will Given that we are not sure which is the lars are primarily spent at home for direct, revolutionize our view of physics. next fertile energy range, many particle short-term benefit. Beyond that, there are plans to upgrade physicists believe that we should aim as Governments are trying to understand the LHC in the 2020s to provide even high as possible. Some argue for an even which models best suit their national brighter beams and detectors capable of higher-energy lepton collider, such as a interests. There is less talk of ‘brain gain handling the enormous rates of data that muon collider or the Compact Linear Col- and drain’ and more of ‘brain circulation’. will be produced. Even modest upgrades lider (a European higher-energy competi- Countries and intellectual communities will cost around US$1 billion, requiring tor to the ILC) that would reach 3–5 TeV. thrive by participating in the global con- contributions from non-member as well as Europe is assembling a team to design a versation, not necessarily by owning most member states. 100-TeV proton–proton collider, with of the players. Other frontiers hold promise. We still do a 100-kilometre-circumference tunnel, to Care must be taken to ensure the health of not understand how neutrinos interact, the probe any particles that may be discov- major regional laboratories, such as CERN, origin of their tiny masses or their role in ered by the upgraded LHC and at ener- Fermilab and the High Energy Accelerator the early Universe. Fermilab is heading a gies beyond. This machine could start Research Organization (KEK) in Tsukuba, US proposal to build a long neutrino-beam up in the 2030s. Japan: these are the only places where large experiment, running 1,300 kilometres from And the United States still has ambitions particle-physics projects are currently fea- Fermilab to the Homestake mine in South to host a high-energy frontier machine, sible. Demands from emerging economies Dakota. An ambitious 35-kilotonne liquid after turning off the such as China to host other projects will argon detector located nearly 1,500 metres “If China does Fermilab’s Tevatron challenge the long-term plans of the exist- below the surface emerged as the preferred jump ahead, accelerator in 2011 ing leaders. Scientists in the United States project when the US community met in it will change and failing to realize and Europe will have to find out how best to Minnesota for a ten-day planning sympo- the landscape the Superconducting use international competition as a spur for sium in July. It would help us to understand of science.” Super Collider in the advancing projects on their own soil while neutrino masses and whether these parti- 1990s. Perhaps the still being good international partners. This cles contribute to the matter–antimatter high-energy baton could be passed back to may become tricky. asymmetry of the Universe. the United States. Fermilab is still a world Higgs bosons are not export-controlled, With the total construction budget near- leader in high-field magnets for proton nor are pictures of deep space from advanced ing $1 billion, the experiment will require accelerators, which would be necessary for telescopes. But the technologies developed, international partners — a new approach any 100-TeV proton–proton collider. often through international collaborations, for US domestic science. The US Depart- To add to the suspense, there is the may have dual use — for defence applica- ment of Energy’s Office of Science has indi- changing role of China. Historically a tions or for economic gains, for example, as cated that it would support such a major small player in particle physics, it last well as for basic science. Countries will have proposal if there was involvement from year stepped onto the world stage with to decide how to oversee and exploit these Europe and Asia. impressive results in reactor-driven neu- opportunities responsibly. A long-baseline neutrino experiment trino physics, including showing that Particle-physics leaders need to be more is necessary, somewhere. Alternatives are two of the three types of neutrinos mix vocal and aggressive in defining and defend- on the table: one in Europe would see neu- together much more than expected. This ing the global programme. After all, a suite trinos travelling from CERN to Finland; large mixing implies that fundamental of global particle-physics facilities helps us to another has neutrinos travelling across symmetry differences between neutrinos understand how the Universe works. ■ Japan. But the world can afford only one. and antineutrinos might be observable Japan is perhaps the stiffest competitor, in a long-baseline experiment, telling us Nigel Lockyer is director of the Fermi with leading programmes in neutrino phys- about matter and antimatter imbalances National Accelerator Laboratory in Batavia, ics, a bottom-quark (‘b-quark’) factory and in the early Universe. Emboldened, might Illinois. kaon and muon experiments. The country the Chinese leapfrog the world by hosting e-mail: [email protected]