3

Workforce

OVERVIEW

The big questions and the amazing achievements of particle physics have a nearly universal public appeal. Much of the credit for this success goes to the bright, well-trained teams of students and early-career researchers, many of whom go on to have successful careers in a variety of technical fields.

Progress in the future requires that the field increases its engagement to recruit the brightest creative minds from across the nation and the globe. Yet the system for recruiting, training, and advancing the careers of students and postdoctoral particle physicists is now under stress, just when the needs of the workforce are increasing. Some of these stresses affect all science, technology, engineering, and mathematics (STEM) fields in the United States, but particle physics has particular challenges and opportunities.

This chapter examines the challenges and articulates a path forward. Specifically, this chapter explores the need for rethinking recruitment, compensation, funding sources for student stipends and benefits, and international student and postdoc visa and immigration. Universities and the federal government each have roles to create new program incentives and rethink existing policies. The findings and conclusions discussed in this chapter lead to the following recommendation.

Recommendation 6: The federal government should provide the means and the particle physics community should take responsibility for recruiting, training, mentoring, and retaining the highly motivated student and postdoctoral workforce required for the success of the field’s ambitious science goals.

THE VALUE OF PARTICLE PHYSICS TRAINING

Students and early-career researchers in particle physics undergo training in a wide variety of competencies, with significant value for future careers in the broader science and technology enterprise. The scale and complexity of particle physics requires effective collaboration and problem-solving within large multidisciplinary teams. This includes proficiency in mathematics and quantitative reasoning, essential for analytical problem-solving and data interpretation. The recent focus on quantum science provides a solid framework for advanced research and innovation in many new areas. Technical training in computing and data science encompassing machine learning (ML) and artificial intelligence (AI) is increasingly valuable, as is expertise in microelectronics, semiconductor technology, magnets, particle detectors, and high-powered radio frequency systems. Finally, particle

physics deploys such cutting-edge technologies at scale in complex devices, providing skills in large-scale technological integration.

The problem-solving and team-building skills and creativity valued in particle physics yield broader benefits for society, which will be described in more detail in Chapter 5. The American Institute of Physics (AIP) Data Service reports that more than four out of five scientists trained in PhD-level physics find their career employment in other technical fields. About three-quarters go to industry, and the AIP reports they receive higher median salaries than those who remain in physics in all areas except for the education sector.¹ Graduates of research programs in particle physics are highly valued in the private sector for their ability to contribute to innovation. This is but one example of how government investment helps sustain innovation outside of academic and government laboratory settings.

CURRENT TRENDS

Research in particle physics will continue to utilize large cohorts of young scientists, and their recruitment and training must be a priority for this field. This section identifies the challenges and opportunities of building this workforce. STEM-wide trends in the supply of students are discussed, as well as particular issues affecting particle physics. While these trends are STEM-wide, in many instances they affect particle physics more acutely.² Finally, the attitudes of the early-career scientists themselves reflected in recent surveys are examined.

Four Important Trends

The STEM workforce is affected by four general trends that broadly affect recruitment. These shifts directly impact particle physics, which is competing with other areas of physics research to attract talented scholars.

1. Decrease in U.S. school-age population. The U.S.-based population of college-ready 18-year-olds is expected to decrease in the coming decades. This “enrollment cliff” will affect higher education, increasing the cost per student as it reduces the total resources for education.^3,4,5 Although the enrollment cliff has not yet arrived, departments of physics are already experiencing a downward trend in bachelor’s degrees awarded; for example, from 9,296 in 2019–2020 to 8,295 in 2022–2023 after a decade of increasing numbers.⁶
2. Decrease in international scholars. Changing U.S. policies have created a less welcoming environment for international scholars.^7,8 This has led to fewer international scholars seeking educational opportunities in the United States, shrinking the talent pool.
3. Decrease in funding. Flat and/or reduced funding (see Figure 3-1) will inevitably reduce the physics doctorates awarded. As departments face increased labor costs without accompanying increases in funding, graduate programs are likely to decrease. For example, the 2023 University of California Collective Bargaining Agreement provides a 26 percent salary increase for graduate student researchers and 55 percent

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¹ American Institute of Physics, 2024, “Who’s Hiring Physics PhDs,” posted January 25, https://ww2.aip.org/statistics/whos-hiring-physics-phds.

² National Academies of Sciences, Engineering, and Medicine, 2018, Graduate STEM Education for the 21st Century, The National Academies Press, https://doi.org/10.17226/25038.

³ J. Bauman, 2024, “Colleges Were Already Bracing for an ‘Enrollment Cliff.’ Now There Might Be a Second One,” The Chronicle of Higher Education, posted February 7, https://www.chronicle.com/article/colleges-were-already-bracing-for-an-enrollment-cliff-now-there-might-be-a-second-one.

⁴ M. Mazzucato, 2015, The Entrepreneurial State: Debunking Public vs. Private Sector Myths, Revised edition, Public Affairs.

⁵ N.D. Grawe, 2018, Demographics and the Demand for Higher Education, Johns Hopkins University Press.

⁶ American Insitute of Physics, 2024, “Roster of Physics Departments with Enrollment and Degree Data, 2023,” October 11, https://www.aip.org/statistics/roster-of-physics-department-with-enrollment-and-degree-data-2023.

⁷ R. Jia, M.E. Roberts, Y. Wang, and E. Yang, 2022, “The Impact of U.S.-China Tensions on U.S. Science,” working paper for the National Bureau of Economic Research.

⁸ Y. Xie, X. Lin, J. Li, Q. He, and J. Huang, 2023, “Caught in the Crossfire: Fears of Chinese—American Scientists,” Proceedings of the National Academy of Sciences 120(27):e2216248120, https://doi.org/10.1073/pnas.2216248120.

3. salary increase for teaching assistants,⁹ which in the absence of additional funding would lead to alarming decreases in the graduate student population.
4. Decrease in STEM preparation. Secondary school preparation in science and mathematics has been declining in the United States, reducing the talent pool of U.S.-based graduate students in all STEM fields. More than half of U.S. high schools do not offer calculus; four of ten do not offer physics; more than one in four do not offer chemistry; and more than one in five do not offer Algebra II. Qualified STEM teachers are in short supply. About 28 percent of public secondary school science teachers do not hold a degree in science or science education. About 40 percent of mathematics classes in high-poverty schools across the United States were taught by teachers without a degree in the subject.¹⁰

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⁹ UAW Local 2865, n.d., “Collective Bargaining Agreement By and Between the Board of Regents of the University of California and the International Union, United Automobile, Aerospace and Agricultural Implement Workers of America, AFL-CIO and Its Local Union 2865,” https://uaw2865.org/sr-contract, accessed May 1, 2025.

¹⁰ G. Athanasia, 2022, “The U.S. Should Strengthen STEM Education to Remain Globally Competitive,” Center for Strategic and International Studies, posted April 1, https://www.csis.org/blogs/perspectives-innovation/us-should-strengthen-stem-education-remain-globally-competitive.

Looming Shortfalls

Accelerators, instrumentation, and computing are three technical areas where the shortfall of new scientists is becoming acute and threatens the future of particle physics.

Accelerator science is an exciting discipline that is well suited to academia, and in high demand at national laboratories and in industry. The need for PhD accelerator scientists exceeds supply by factors of 3 to 4, with shortfalls at the bachelor’s level as well.¹¹ However, only a handful of universities offer accelerator physics courses or research opportunities for undergraduate students and formal graduate training in accelerator science and technology. Most undergraduate students are not even aware of accelerator physics as a research area.

Finding: The design and construction of future colliders and neutrino sources will require a large number of accelerator scientists. This, and the demand for such scientists in other scientific fields, industry and in medicine, will create a shortfall, estimated to be a factor of 3 to 4. Moreover, fewer than 10 U.S. universities currently offer graduate education or programs in accelerator physics.

A factor in the disappearance of university-based accelerator physics was the suspension of the National Science Foundation (NSF) accelerator program in 2018.¹² NSF support for basic accelerator research is now confined to plasma wakefield acceleration, as well as research in a single Science and Technology Center that will sunset in 2026.^13,14 No further NSF support for university training in accelerators is planned, and the new NSF Directorate for Technology, Innovation and Partnerships (TIP),¹⁵ which could potentially provide support for accelerator science and technology, has not done so yet. Given the importance to both particle physics and to industry (see Chapter 5), TIP could in the future provide a home for accelerator research at NSF; for example, in partnership with the Directorate for Mathematical and Physical Sciences.

The Department of Energy has an accelerator research program within the Office of High Energy Physics, the Accelerator Research and Development (R&D) and Production program (ARDAP).¹⁶ ARDAP supports use-inspired basic R&D of broad benefit, developing both cross-cutting accelerator technology (such as ultrafast laser technology, radio frequency power sources) and supporting first-of-a-kind benchtop tests of new accelerator technology applications. ARDAP is an innovative and broad program of support for accelerator science. The long timescales of many particle physics experiments reduce opportunities to participate in the design, prototyping, and building of detectors, resulting in a decline of instrumentation experience among early-career scientists. A significant and sustained decrease in technical infrastructure in the universities in the United States further affects training in instrumentation. The U.S. academic community gives little recognition to excellence in instrumentation—the perceived scientific value of skills in data analysis is favored, even when there are major scientific advances in detectors and instrumentation. This discourages early-career scientists from pursuing these enabling technical aspects of experimental particle physics.

Large detectors, boasting billions of electronic channels and systems sensitive to rare processes that operate at the quantum noise threshold, create large, complex data sets. Harnessing this wealth of data requires advanced computing techniques and mathematics, sophisticated statistical tools, and the transformative power of AI/ML. These skills are in high demand by industry. Industry jobs tend to come with a higher compensation than posi-

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¹¹ Department of Energy and National Science Foundation, 2015, High Energy Physics Advisory Panel Subcommittee Review of the United States Particle Accelerator School, https://science.osti.gov/-/media/hep/hepap/pdf/Reports/HEPAP_USPAS_Subcommittee_Final_Report.pdf.

¹² The end of the program was announced at the June 2017 meeting of the High Energy Physics Advisory Panel; see S. Lukin and J. Shank, 2017, “NSF Accelerator Science Program,” https://science.osti.gov/-/media/hep/hepap/pdf/201706/VLukin_NSF_Accelerator_Science_Program.pdf.

¹³ Cornell University, n.d., “The Center for Bright Beams: A National Science Foundation Science & Technology Center,” https://cbb.cornell.edu, accessed July 15, 2024.

¹⁴ National Science Foundation, 2016, “Award #1549132: Center for Bright Beams,” https://www.nsf.gov/awardsearch/showAward?AWD_ID=1549132.

¹⁵ National Science Foundation, n.d., “Technology, Innovation and Partnerships,” https://www.nsf.gov/tip/latest, accessed May 5, 2025.

¹⁶ Department of Energy, n.d., “Accelerator R&D and Production,” https://www.energy.gov/science/ardap/accelerator-rd-and-production, accessed May 5, 2025.

tions at universities and national laboratories. As a research discipline, particle physics must compete with newer scientific fields and new high-tech industries for the top talent in university PhD programs.¹⁷ While it is a good sign that industry wants the people who have been trained in particle physics, it is also important to retain a core subset of early-career scientists that can propel the field into the future.

Finding: Elementary particle physics is competing with other scientific fields for resources and also with industry for talent.

VIEWS OF EARLY-CAREER SCIENTISTS

Investigation of the level of fulfillment for early career scientists in particle physics reveals high overall satisfaction with career choice, but unease with career advancement opportunities, especially for those who work on large experiments.¹⁸ Such experiments often span decades and involve large collaborations, leading to unique challenges to the careers of scientists, especially early-career scientists. Credit must often be shared among thousands, so it is hard to feel like one is making a difference. Long time horizons, and even longer timescales for advances, mean fewer significant papers even though the efforts of individual scientists are steady and very significant.

Despite the fact that most students will transition to the private sector, early-career scientists expressed much more interest in applying for academic positions due to their love for teaching and research.¹⁹ However, the number of available academic positions per year has always been only a small fraction of the number of postdocs. The job market is perceived as more competitive now compared to the recent past; and further, graduate student programs and postdoc mentors might not adequately coach their students and postdocs on the opportunities that exist outside academia.

Visa insecurity has increased in recent years for foreign students and postdocs.²⁰ Current U.S. policies on visas have negatively affected institutions’ abilities to attract international students and postdocs. In a fully global science field, this affects not only the workforce pipeline but also U.S. competitiveness.

The demands of research can result in an unhealthy imbalance between work and personal life. The Snowmass 2021 survey²¹ reported that students are working overtime in all job categories and that they feel they have a poor work-life balance. Nearly half of graduate students and postdocs report that their salary is not adequate, indicating that there might be a systemic issue with adequately compensating early-career scientists for their contributions.

STRENGTHENING THE WORKFORCE

The second half of this chapter outlines steps that can be taken, with some currently under way, to strengthen the recruitment, retention, and career advancement of the particle physics workforce.

University Programs

Particle physics depends on a variety of skill sets and research programs working together, including theory, modeling, experimental design, particle beams, accelerators, detectors, data handling, analysis, and systems engineering. Proficiency requires a combination of undergraduate and graduate coursework and several years of

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¹⁷ P. McBride, B. Fleming, M. Bai, et al., 2023, The Path to Global Discovery: U.S. Leadership and Partnership in Particle Physics, https://science.osti.gov/-/media/hep/hepap/pdf/Reports/2024/International_Benchmarking_HEPAP_2023.pdf.

¹⁸ G. Agarwal, J.L. Barrow, M.F. Carneiro, et al., 2022, “Snowmass 2021 Community Survey Report,” https://doi.org/10.48550/arXiv.2203.07328.

¹⁹ The Snowmass survey reports that younger and recently departed non-academic respondents seem less interested in an academic future, compared to their senior counterparts. Compared to the past, particle physics early careers who are planning to apply or currently applying for jobs seem less satisfied with the field of particle physics and have more desires to switch sectors (Agarwal et al., 2022, “Snowmass 2021 Community Survey Report”).

²⁰ American Physical Society, 2021, Building America’s STEM Workforce, https://www.aps.org/publications/reports/building-americas-stem-workforce.

²¹ G. Agarwal, J.L. Barrow, M.F. Carneiro, et al., 2022, “Snowmass 2021 Community Survey Report,” https://arxiv.org/abs/2203.07328.

apprenticeship in research teams to develop the skills needed for a successful career in particle physics. The committee has identified the following four areas for improvement:

1. Increase the number of accelerator training programs. Although the portfolio of approaches to particle physics has broadened, accelerator-based activities will continue to play a major role, and new accelerators are planned. As mentioned earlier, this demand, coupled with the need for such experts across various scientific disciplines, industries, and medical fields, is projected to exceed available talent significantly, and few universities in the United States currently provide graduate education in accelerator physics. The United States risks losing the ability to sustain development in the area of accelerator physics without a dramatic injection of resources into the development of accelerator training at the master’s and PhD level.^22,23
2. Broaden undergraduate exposure to particle physics. To help attract students to particle physics, recruitment must begin at the undergraduate level, as proposed in the Snowmass 2021 report. They must be trained and mentored through summer schools and summer programs, as well as courses in the undergraduate and the graduate curriculum.
3. Improve graduate curricula to better prepare students. Today there is a mismatch between how students are trained and what skills are necessary for professional success in particle physics and careers outside of academia.²⁴ In the context of technical training, computation and mathematical skills, such as statistics, that are necessary for execution of graduate research projects are often self-taught. Furthermore, students often become highly specialized—for example, theorists not understanding instrumentation and vice versa. While degree programs in physics at least emphasize technical competency, they tend to ignore providing training in technical writing and oral communication. Graduate programs in particular should create formal learning opportunities to develop writing and speaking skills as well as requiring modern statistical analysis as part of the coursework.
4. Strengthen particle-physics research at predominantly undergraduate institutions. Research in particle physics is currently concentrated at national laboratories and graduate degree-granting universities. Yet these institutions are not the only entry points of students into particle physics. Predominantly undergraduate institutions, including community colleges, are potentially valuable entry points for the particle physics pipeline.

Graduate Student and Postdoc Recruitment and Retention

A limited number of people receive specialty training in physics and the technical tools necessary to conduct research in particle physics. Therefore, graduate students and postdoctoral researchers are a precious resource for the community, and the challenges they face can have a long-term damaging effect on the sustainability of the field. Among those challenges are the following:

1. Competition: Particle physics faces competition from other areas of physics that have also captured the imagination of the next generation of researchers, as well as growing international competition for the best students. Particle physics, and more broadly physics, must make their case for why a graduate education in the United States—and in particle physics—is worthy of a young researcher’s consideration. To do so, particle physics must also ensure that it remains an attractive and welcoming place to work for the workforce of the 21st century.
2. Mentoring: Particle physics postdocs and graduate students often assume that their advancement to a research/faculty position is the expected norm, whereas in actuality it is not. This contributes to anxiety and low morale and points to a need for better mentoring. NSF recently included mentoring and mentor

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²² M. Bai, Z. Huang, and S.M. Lund, 2022, “Summary Report of AF1 to Snowmass 2021: Beam Physics and Accelerator Education Within the Accelerator Frontier,” https://doi.org/10.48550/arXiv.2209.07668.

²³ S. Gourlay, T. Raubenheimer, V. Shiltsev, et al., 2022, “Snowmass ’21 Accelerator Frontier Report,” https://doi.org/10.48550/arXiv.2209.14136.

²⁴ O. Bitter, E.V. Hansen, S. Kravitz, V. Velan, and Y. You, 2022, “Transforming U.S. Particle Physics Education: A Snowmass 2021 Study,” https://doi.org/10.48550/arXiv.2204.08983.

2. training in its standards for responsible and ethical conduct of research.²⁵ More uniform adoption of best practices in mentoring, such as encouraging students to create an individual development plan, emphasizing the development of transferable communications, leadership, and technical skills, and de-stigmatizing broader career paths, could improve the morale of graduate students and postdocs, improve their career outcomes, and have a significant impact on attracting the next generation to join the field.^26,27,28,29
3. Funding stability: As shown in Figure 3-1, the rise in funding for particle physics in the United States since 2014 has been accompanied by a decline in funding for the scientists who carry out the research. The numbers of graduate students this research budget supports over a similar time period may be inferred by the graduation rates, which appears to be roughly constant, with approximately 250±50 new PhDs in particle physics per year.^30,31,32,33 When inflation and other program costs are considered, it becomes clear that the funding available to support graduate students has eroded, while the number of students has stayed constant and compensation for students (and postdocs) is rising well above inflation. This is unsustainable and something has to change.
4. STEM education: Physics education research has established itself as an essential subfield of physics research, which has already led to changes in how undergraduate physics education is delivered. The impact on graduate pedagogy has been more limited, in part because of the challenge of applying it to highly specialized educational environments. The potential positive impact of changes in how physics is taught on the particle physics pipeline, and more broadly the physics pipeline, is great.

Compensation and International Researchers

This section discusses recent policy changes in two areas, graduate student and postdoc compensation and visa rules, which are impacting the particle physics workforce in significant ways. Each could have negative consequences on the workforce.

Salaries and benefits must be adequate for early-career researchers, whose training period is significant—4 years of undergraduate education, 5 to 7 years of graduate education, and at least 3 years as a postdoctoral researcher. Moreover, this training coincides with adulthood, which means that some are starting families and adding new responsibilities. Adequate annual salaries and benefits that promote good lifestyle and wellbeing are essential. The years of slow or no progress on raising compensation have gradually led to an organized labor movement among graduate students and postdocs on many university campuses in the United States, leading to the establishment of graduate student labor unions at several major U.S. universities. While the funding agencies and the community support the move toward a living salary, it has significant budgetary consequences for particle physics.

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²⁵ National Science Foundation, 2024, “Proposal & Award Policies & Procedures Guide, NSF 24-1,” https://www.nsf.gov/policies/pappg/24-1/ch-9-recipient-standards#b-responsible-and-ethical-conduct-of-research-recr-9c7.

²⁶ J.A. Hobin, C.N. Fuhrmann, B. Lindstaedt, and P.S. Clifford, 2012, “You Need a Game Plan,” Science, September 7, https://www.science.org/content/article/you-need-game-plan.

²⁷ T.W.H. Ng, L.T. Eby, K.L. Sorensen, and D.C. Feldman, 2005, “Predictors of Objective and Subjective Career Success: A Meta-Analysis,” Personnel Psychology 58:367–408.

²⁸ A.E. Abele and B.S. Wiese, 2008, “The Nomological Network of Self-Management Strategies and Career Success,” Journal of Occupational and Organizational Psychology 81:733–749.

²⁹ G. Davis, 2005, “Doctors Without Orders,” American Scientist 93(3):S1–S13.

³⁰ American Institute of Physics (AIP), 2011, “Number of Physics PhDs Granted by Subfield from Physics Departments, Classes of 2007 & 2008 Combined,” updated June 1, https://ww2.aip.org/statistics/number-of-physics-phds-granted-by-subfield-from-physics-departments-classes-of-2007-2008-combined.

³¹ AIP, 2014, “Number of Physics PhDs Granted by Subfield from Physics Departments, Classes of 2010 & 2011 Combined,” updated February 1, https://ww2.aip.org/statistics/number-of-physics-phds-granted-by-subfield-from-physics-departments-classes-of-2010-2011-combined.

³² AIP, 2021, “Average Number of PhDs Granted by Subfield from Physics Departments Annually, Classes of 2017 and 2018 Combined,” updated February 1, https://ww2.aip.org/statistics/average-number-of-phds-granted-by-subfield-from-physics-departments-annually-classes-of-2017-and-2018-combined.

³³ AIP, 2022, “Physics PhDs Granted by Subfield,” updated February 1, https://ww2.aip.org/statistics/physics-phds-granted-by-subfield.

Increased salary and benefit expenses for students and no corresponding increase in funding will lead to a shortfall in graduate student researchers. With flat budgets and no action, the early-career research population will have to decrease.

Finding: Graduate students and postdocs provide a critical part of the particle physics workforce. The recent very significant rise—well beyond inflation—in the compensation for both is appropriate and overdue. It has also significantly increased the labor costs in particle physics and more broadly in science, where the available funding is not even keeping up with inflation.

Elementary particle physics is a global science enterprise, and exchange of scientists at all levels is important. At the early-career level, the United States attracts graduate students and postdocs from around the world. This benefits the field and the nation, as many of these talented individuals remain here and pursue careers in the private sector. At the moment, particle physics feels caught in the middle between competing priorities to attract sufficient numbers of highly talented scientists to join the particle physics workforce and recent policy directives that seek to limit the number of foreign scientists working in the United States.

Foreign students and postdocs are keenly aware of this. Recent changes in immigration policy have led to a shift in perceptions that the United States is the premier international destination for doctoral and postdoctoral training. It continues to be the case that nearly half of PhDs in physics from U.S. institutions are granted to international scholars who are not permanent residents. Furthermore, the conditions outlined above that will reduce the size of the U.S. graduate student cohort will drive a still stronger need to recruit foreign-trained postdocs to perform work on the U.S. program. As the next chapter will describe, it is essential to the health of U.S. particle physics to make international exchanges as easy as possible, consistent with national and economic security concerns.

IMPROVING THE WORKING ENVIRONMENT

Elementary particle physics attracts some of the brightest young people to science, offering the opportunity to advance knowledge in a field with grand opportunities. Keeping these young scientists, however, depends critically on sustaining an environment in which they can work effectively.

The organization and structure of particle physics can often distinguish it from other disciplines, even within physics, and these present both unique advantages and challenges.³⁴ For example, the large collaborations offer wonderful opportunities for teamwork and call for a wide array of talents and skills. Scientists with expertise in detector hardware, advanced computing techniques, group leadership, and myriad other areas are all in high demand. However, the field must harness these strengths and overcome the accompanying sociological challenges, including the long timescales of many experiments and the need to recognize individual contributions in the face of journal author lists that can number in the thousands.

Decades-Long Timescales

Big-project timescales in particle physics are measured in decades. The Large Hadron Collider (LHC), for example, was conceived in 1984, approved for construction in 1994, and began operations in 2010. Large facilities, including both colliders and large cosmic surveys, span similarly long periods. Publication of scientific results is traditionally the means by which an individual’s accomplishments are judged, whether for hiring, promotion, or for recognition. The long timespans without scientific results are worrisome. Nearly half of the respondents to the Snowmass 2021 survey expressed concern about this trend.³⁵

Many experimental particle physicists work on several experiments with staggered timelines or participate in smaller projects as well. Both approaches serve to eliminate large gaps in data and thereby enable a continuous

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³⁴ There are other disciplines that also have very large collaborations; for example, nuclear physics and astrophysics. They face similar challenges.

³⁵ G. Agarwal, J.L. Barrow, M.F. Carneiro, et al., 2022, “Snowmass Early Career,” https://doi.org/10.48550/arXiv.2210.12004.

stream of publications. Funding agencies can and should continue to support multi-pronged efforts of this sort by facilitating proposals that combine multiple scientific approaches.

It is also important to value the work on these smaller experiments. Science and society readily recognize big discoveries in particle physics—detection of the Higgs boson, for example, or the discovery of neutrino oscillations, or the detection of gravitational waves. Understanding also advances, however, through smaller steps and observations. The field must continue to recognize the importance of these contributions when awarding support to young physicists or awarding prizes, and departments should appreciate their value when considering promotions.

Recognition and Rewards

The large collaborations of particle physics have powered some of its most important accomplishments. These collaborations allow the design, construction, and operation of detectors that are enormously complex, combining ultrasensitive sensors, high-speed electronics, petabytes of data, advanced computing, and sophisticated AI-based data mining and analysis techniques. One of the two main detectors at the LHC produces 15–20 petabytes of data annually, comparable to the size of the digital collections held by the U.S. Library of Congress. Such an undertaking demands the combined expertise of 3,000 or more PhD scientists and students.

Such collaborations offer a wealth of opportunities for young scientists; the challenge is to recognize the contribution of an individual within such a large enterprise. Publication author lists are little help—typically all collaboration members are named in alphabetical order independent of their role. While this practice acknowledges the joint effort, it offers no help to those trying to decipher the contribution of a particular individual. With few exceptions, collaborations have not devised a practical method for ordering author lists of more than 1,000 for hundreds of publications annually.³⁶

Nevertheless, appropriate recognition is possible. Increasingly, scientists identify papers in their publication lists that they see as their most important work and provide a brief description of their contribution to each one. Letters of recommendation from collaborators can confirm and elaborate upon this information. University departments should solicit letters from such collaborators, adapting their conflict-of-interest policies if necessary to the needs and realities of large-scale collaborations.

At the same time, the collaborations should better highlight the contributions of their early-career scientists. They should document and advertise the names of subgroup leaders and convenors and should use collaboration-wide meetings and emails to celebrate outstanding team efforts, pointing out individual contributions where appropriate. Prizes could be awarded for achievements by young group leaders, building on existing prizes for exemplary doctoral theses (see Figure 3-2). Innovative contributions to instrumentation, design, and fabrication should be recognized at the same level as those to science results are, particularly at the PhD research thesis level.

CONCLUSIONS AND RECOMMENDATION

This chapter has described the current state and future prospects for the particle physics workforce. The most important message is that the future success of the field will continue to be reliant on recruiting and retaining the very best PhD students and postdocs from across the nation and around the world to the U.S. particle physics effort. In their later careers, these researchers form an important part of the trained technical and entrepreneurial talent that helps the United States maintain its influence in advanced technology as well as in science.

Student and postdoc salaries and benefits constitute a large fraction of the budgeted direct expenditures on university grants in particle physics, so that when this budget is reduced, or even if it remains flat, the personnel numbers must necessarily decrease over time. The recent significant rise in the compensation for both graduate students and postdocs is appropriate and overdue, but this has significantly increased further the labor costs in particle physics and more broadly in science, which will lead to further decreases in the research workforce.

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³⁶ Some astrophysics collaborations, such as the Sloan Digital Sky Survey, have mechanisms for elevating a “lead group” of authors to the top of an author list for a specific paper. However, the total number of authors is far less than 1,000.

The number of individuals entering U.S. graduate schools in physics has been stable for a long time, in part by attracting the best students internationally. International students are now finding that the United States is less welcoming compared to other alternatives for their training.

The design and construction of future particle accelerators will require a large number of accelerator scientists. The demand for such scientists in other scientific fields, industry, and in medicine will exacerbate a future shortfall, estimated to be a factor of two to four.³⁷ Moreover, fewer than 10 U.S. universities currently offer graduate programs in accelerator physics, so this problem is likely to be difficult to solve in the near term.

Early-career scientists are concerned about how the long timescales and uncertainties about future large projects will impact their careers. Elementary particle physics, which has traditionally been a magnet for highly talented STEM researchers, now competes with other scientific and high-tech industrial fields, some of which have grown faster than particle physics, and have resources to compete for top talent.

These factors lead to the chapter’s main conclusion about the particle-physics workforce of the future and the committee’s primary recommendation on this topic, repeated for emphasis:

Conclusion: Three workforce issues are threatening the future of particle physics: the morale of early-career scientists; a shortfall in the number of accelerator scientists; and growing barriers to international exchanges. It is essential to the future of elementary particle physics in the United States that it address its workforce issues.

Recommendation 6: The federal government should provide the means and the particle physics community should take responsibility for recruiting, training, mentoring, and retaining the highly motivated student and postdoctoral workforce required for the success of the field’s ambitious science goals.

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³⁷ P. McBride, B. Fleming, M. Bai, et al., 2023, “The Path to Global Discovery: U.S. Leadership and Partnership in Particle Physics,” https://science.osti.gov/-/media/hep/hepap/pdf/Reports/2024/International_Benchmarking_HEPAP_2023.pdf.