A wake-up call from the next generation

The recent update of the European strategy for particle physics (ESPP) offered a unique opportunity for early-career researchers (ECRs) to shape the future of our field. Mandated by the European Committee for Future Accelerators (ECFA) to provide input to the ESPP process, a diverse group of about 180 ECRs were nominated to debate topics including the physics prospects at future colliders and the associated implications for their careers. A steering board comprising around 25 ECRs organised working groups devoted to topics including detector and accelerator physics, and key areas of high-energy physics research. Furthermore, working groups were dedicated to the environment and sustainability, and to human and social factors – aspects that have been overlooked in previous ESPP exercises. A debate took place in November 2019 and a survey was launched to obtain a quantitative understanding of the views raised.

The feedback from these activities was combined into a report reflecting the opinions of almost 120 signed authors. The survey suggests that more than half of the respondents are postdocs, around two-fifths PhD students and approximately a tenth staff members. Moreover, roughly one-third were female and two-thirds male. Several areas, such as which collider should follow the LHC and environmental and sustainability considerations, were highlighted by the participating ECRs. Among the many topics discussed, we highlight here a handful of aspects that we feel are key to the future of our field.

Building a sustainable future

A widespread concern is that the attractiveness of our field is at risk, and that dedicated actions need to be taken to safeguard its future. Certain areas of work are vital to the field, but are undervalued, resulting in shortages of key skills. Due to significant job insecurity many ECRs struggle to maintain a healthy work–life balance. Moreover, the lack of attractive career paths in science, compared to the flexible working hours and family-friendly policies offered by many companies these days, potentially compromises the ability of our field to attract and retain the brightest minds in the short- and long-term future. With the funding for the proposed Future Circular Collider (a key pillar of the ESPP recommendations) not yet clear, and despite it receiving the largest support among future-collider scenarios in CERN’s latest medium-term financial plan, an additional risk arises for ECRs to back the wrong horse.

The future of the field will depend on the success of reaching a diverse community

It is imperative to holistically include social and human factors when planning for a sustainable future of our field. Therefore, we strongly recommend that long-term project evaluations and strategy updates assess and include the impact of their implementation on the situation of young academics. Specifically, equal recognition and career paths for domains such as computing and detector development have to be established to maintain expertise in the field.

Next-generation colliders beyond the LHC will need to overcome major technical challenges in detector physics, software and computing to meet their ambitious physics goals. Our survey and debate showed that young researchers are concerned about a shortage of experts in these domains, where very few staff positions and even less professorships are open for particle physicists specialised in detector development and software and computing. In particular in the light of ever increasing project time scales, a sizable fraction of funding for non-permanent positions must be converted to funding for permanent positions in order to establish a sustainable ratio between fixed-term postdocs and staff scientists.

The possibility for a healthy work–life balance and the reconciliation of family and a scientific career is a must: currently, most of the ECRs consulted think that having children could damage their future and that moving between countries is generally a requirement to pursue a career in particle physics. These might constitute two reasons why only 20% of the polled ECRs have children. Put in a broader perspective, the future of the field will depend on the success of reaching a diverse community, with viable career paths for a wide spectrum of schemes of life. In order to reach this diverse community, it is not enough to simply offer more day-care places to parents. Similarly, the #BlackInTheIvory movement in 2020 shone a spotlight on the significant barriers faced by the Black community in academia – an issue also shared by many other minority groups. Discrimination in academia has to be counteracted systematically, including the filling of positions or grant-approval processes, where societal and diversity aspects must be taken into account with high priority.

The environmental sustainability of future projects is a clear concern for young researchers, and particle-physics institutes should use their prominent position in the public eye to set an example to other fields and society at large. The energy efficiency of equipment and the power consumption of future collider scenarios are considered only partially in the ESPP update, and we support the idea of preparing a more comprehensive analysis that includes the environmental impact of the construction as well as the disposal of large infrastructures. There should be further discussion of nuclear versus renewable energy usage and a concrete plan on how to achieve a higher renewable energy fraction. The ECRs were also of the view that much travel within our field is unnecessary, and that ways to reduce this should be brought to the fore. Since the survey was conducted, due to the ongoing COVID-19 pandemic, various conferences have already moved online, proving that progress can be made on this front.

Collider preference

In the context of the still-open questions in particle physics and potential challenges of future research programmes, the ECRs find dark matter, electroweak symmetry breaking and neutrino physics to be the three most important topics of our field. They also underline the importance of a European collider project soon after the completion of the HL-LHC. Postponing the choice of the next collider project at CERN to the 2030s, for example, would potentially negatively impact the future of the field: there could be fewer permanent jobs in detector physics, computing and software if preparations for future experiments cannot begin after the current upgrades. Additionally, it could be difficult to attract new, young bright minds into the field if there is a gap in data-taking after the LHC. While physics topics were already discussed in great detail during the broader ESPP process, many ECRs stated their discomfort about the way the next-generation scenarios were compared, especially by how the different states of maturity of the projects were not sufficiently taken into account.

About 90% of ECRs believe that the next collider should be an electron–positron machine

About 90% of ECRs believe that the next collider should be an electron–positron machine, concurring with the ESPP recommendations, although there is not a strong preference if this machine is linear or circular. While there was equal preference for CLIC and FCC-ee as the next-generation collider, a clear preference was expressed for the full FCC programme over the full CLIC programme. Given the diverse interest in future collider scenarios, and keeping in mind the unclear situation of the ILC, we strongly believe that a robust and diverse R&D programme on both accelerators and detectors must be a high priority for the future of our field.

In conclusion, both the debate and the report were widely viewed as a success, with extremely positive feedback from ECFA and the ECRs. Young researchers were able to share their views and concerns for the future of the field, while familiarising themselves with and influencing the outcome of the ESPP. ECFA has now established a permanent panel of ECRs, which is a major milestone to make such discussions among early-career researchers more regular and effective in the future.