Beate Heinemann talks about her new role as director of particle physics at DESY and the importance of building a future collider that benefits both science and society.
What attracted you to the position of DESY director of particle physics?
DESY is one of the largest and most important particle-physics laboratories in the world. I was born and grew up in Hamburg and took my first career steps at DESY during my university studies. I received my PhD there in 1999 and returned as a scientist in 2016, so I know the lab very well. It is a great lab and department, with many opportunities and so many excellent people. I am sure it will be fun to work with all of them and to develop a strategy for the future.
What previous management roles do you think will serve you best at DESY?
Being ATLAS deputy spokesperson from 2013 to 2017 was one of the best roles I’ve had in my career, and I benefitted hugely from the experience. I was fortunate to have an excellent spokesperson in Dave Charlton and I learned a lot from him, as well as from many others I worked with. I try to understand enough details to make educated decisions but not to micromanage. I also think motivating people, listening to them and promoting their talents is key to achieving common goals.
What are the current and upcoming experiments at DESY?
The biggest on-going experimental activities in particle physics are the ATLAS and CMS experiments. We have large groups in both, and for each we are building a tracker end-cap based on silicon-strip detectors at our detector assembly facility, primarily together with German universities. This is a huge undertaking that is currently ongoing for the HL-LHC. Another important activity is to build a vertex detector to be installed in 2023 at the Belle II experiment running at KEK in Japan. We also have a significant programme of local experiments covering axion searches. One of the big projects next summer will be the start of the ALPS II experiment, which will look for axion-like particles by shining an intense laser on a “wall” and seeing if any laser photons appear on the other side, having been transformed into axions by a large magnetic field. We have two other axion experiments planned: BabyIAXO, which looks for axion-like particles coming from the Sun, for which construction is now starting; and MadMax, which looks for axions in the dark-matter halo. Axions were postulated by Peccei and Quinn to solve the strong-CP problem but are also a good candidate for dark matter if they exist. A further experiment, which DESY theorist Andreas Ringwald and I proposed, LUXE, would deliver the European XFEL 16.5 GeV electron beam into a high-intensity laser so that the beam electrons experience a very strong electromagnetic field within their rest frame. LUXE would reach the so-called Schwinger limit, and allow us to see what happens when QED becomes strong and transitions from the perturbative to the non-perturbative regime.
There are many accelerators at DESY, such as PETRA, where the gluon was discovered in the 1970s. Today, PETRA is one of the best synchrotron-radiation facilities in the world and is used for a wide range of science, for example imaging of small structures such as viruses. It is an application of accelerators where the impact on society is more direct and obvious than it is in particle physics.
How can we increase the visibility of particle physics to society?
This is a very important point. The knowledge we get from particle physics today is clear, but it is less clear how we can transfer this knowledge to help solve pressing problems in society, such as climate change or a pandemic. Humankind desires to increase its knowledge, and it is important that we continue with fundamental research purely to increase our knowledge. We have already come so far in the past 5000 years. And, many technical innovations were made for that purpose alone but then resulted in transformative changes. Take the idea of the accelerator. It was developed at Berkeley during the 1930s with no particular application in mind, but today is used routinely around the world to prolong life by irradiating tumours. Or the transistor, without which there would not be any computers, which was developed in the 1920s based on the then-emerging understanding of atoms. It is important to promote both targeted research that directly addresses problems as well as fundamental research, which every now and again will result in groundbreaking changes. When thinking about our projects and experiments we need to keep in mind if and how any of our technical developments can be made in a way that addresses big societal problems.
It is important that we inspire the general public, in particular the young, about science. Educational programmes are key, such as Beamline for Schools, which is one of CERN’s flagship schemes. This was hosted by DESY during Long Shutdown 2 and a team at DESY will continue the collaboration.
CERN recently launched its Quantum Technology Initiative. Does DESY have plans in this area?
DESY received funding from the state of Brandenburg to build a centre for quantum computing, the CTQA, which is located at DESY’s Zeuthen site. Karl Jansen, one of our scientists there, has spent most of his life working on lattice QCD calculations and is leading this effort. I myself am involved in research using quantum computing for particle tracking at the LUXE experiment. The layout of the tracker for this experiment is simpler compared to the LHC experiments, which is why we want to do it here first. We have to understand how to use quantum computers in conjunction with classical computers to solve actual problems efficiently. There is no doubt that quantum computing solves questions that are otherwise not possible, and we also think they will be able to solve problems more efficiently by using less resources compared to classical machines. That could also contribute to reducing the impact of computing on climate change.
What was your participation in the 2020 update of the European strategy for particle physics (ESPPU) and how have things progressed since?
It was exciting to be part of the ESPPU drafting process. I was very impressed by the sincerity and devotion of the people in the hall in Bad Honnef when the process concluded. There was a lot of respect and understanding of the different views on how to balance the scientific ambitions with the realities of funding, R&D needs and other factors.
The ESPPU recommended first and foremost to complete the HL-LHC upgrade. This is a big undertaking and demands our focus. For the future, an electron-positron Higgs factory is the highest priority, in addition to ramping up accelerator R&D. Last year an accelerator R&D roadmap was prepared following the ESPPU recommendation. Very different directions are laid out, and now the task is to understand how to prioritise and streamline the different directions, and to ensure the relevant aspects are progressing significantly by the next update (probably in 2026). For instance CERN’s main focus is R&D on the next generation of magnets for a new hadron machine, while DESY has a strong progamme in plasma-wakefield accelerators for electron machines. But both DESY and CERN are also contributing to other aspects and there are other labs and universities in Europe which make important contributions. At DESY we also try to exploit synergies between developing new accelerators for photon science and high-energy physics.
What is the best machine to follow the LHC?
The next machine needs to be a collider that can measure the Higgs properties at the per-cent and even in some cases the per-mille level – a Higgs factory. In addition to the excellent scientific potential, factors to consider are timescale and cost, but also making it a “green” accelerator and considering its innovation potential. Finding a good balance there is not easy, and there are several proposals that were studied as part of the ESPPU.
What are your three most interesting open questions in particle physics?
Mine are related to the Higgs boson. One is the matter–antimatter asymmetry, because the exact form of the electroweak phase transition is closely related to the Higgs field. If it was a smooth transition, it cannot explain the matter–antimatter asymmetry; if it was violent, it could potentially be able to explain it. We should be able to learn something about this with the HL-LHC, but to know for sure we need a future collider. The second question is why is there a muon? Flavour physics fascinates me, and the Higgs-boson is the only particle that distinguishes between the electron, the muon and the tau, which is why I would like to study it extensively. The third question is what is dark matter? One intriguing possibility is that the Higgs boson decays to dark-matter particles, and with a Higgs factory we could measure this, even if it only happens for 0.3% of all Higgs bosons. The Higgs boson is so important for understanding our universe, that’s why we need a Higgs factory, although we will already learn a lot from the LHC and HL-LHC.
Today, women make up more than 30% of the scientists at DESY, whereas in 2005 it was less than 10%
Is the community doing a good job in communicating beyond the field?
It is crucial that scientists communicate scientific facts, especially now when there are “post-truth” tendencies in society. We have a duty as people who are publicly funded to communicate our work to the public. Many people are excited about the origin of the universe and the fundamental laws of physics we are studying. Activities such as the CERN and DESY open days attract many visitors. We also see really good turnouts at public lectures as well as during our “science on tap” activity in Hamburg. I gave a talk about the first minutes of the universe, and the bar was packed and people had many questions during one of these events. We should all spend some of our time communicating science. Of course, we have to mostly do the actual research, otherwise we do not have anything to communicate.
You are the first female director in DESY’s 60-year history. What do you think about the situation for women in physics, for instance the “25 by ‘25” initiative?
The 25 by ‘25 initiative is good. We have been fortunate at DESY that there was a strong drive from the German government. Research funding has increased a lot during the past 10–15 years and there was dedicated funding available to attract women to large research centres. Today, women make up more than 30% of the scientists at DESY, whereas in 2005 it was less than 10%. Having special programmes unfortunately appears to be necessary as change happens too slowly by itself otherwise. Having women in visible roles in science is important. I myself was inspired by several women in particle physics, such as Beate Naroska, the only female professor at the physics department when I was a student, Young-Kee Kim, who was spokesperson of the CDF experiment when I was a postdoc and later deputy-director of Fermilab, and last but not least Fabiola Gianotti, who was spokesperson of ATLAS when I joined and is now the Director-General of CERN.