Volker Burkert

Volker D. Burkert
OccupationsPhysicist, academic and researcher
AwardsBonner Prize, American Physical Society,
Outstanding Scientist Award, Governor of Virginia, USA
Fellow, American Physical Society
Academic background
EducationB.A.
M.S. Physics
PhD Philosophy
Alma materBonn University
Academic work
InstitutionsThomas Jefferson National Accelerator Facility (Jefferson Lab/JLab)

Volker D. Burkert is a German physicist, academic and researcher. He is a Principal Staff Scientist at the Thomas Jefferson National Accelerator Facility, also known as Jefferson Lab in Newport News, Virginia, United States.[1]

His work has focused on studies of nucleon structure and on the development of CLAS and CLAS12, large-acceptance spectrometers used in electron-scattering experiments.[2][3] In 2018, Burkert co-authored "The pressure distribution inside the proton", a study published in Nature, which described the first measurement of a mechanical property of a subatomic particle.[4][5]

Burkert is a Fellow of the American Physical Society and the recipient of the 2019 Virginia Governor's Outstanding Scientist Award.[6][7] In 2025, he received the Tom W. Bonner Prize in Nuclear Physics from the American Physical Society.[2]

Education

Burkert was educated at the University of Bonn in Germany, earning a BA in 1967, a master's degree in physics in 1969 and a PhD in 1975.[8]

Career

Burkert began his career as a research associate at Bonn University in 1975.[2] In 1978, he was promoted to the German equivalent of an assistant professorship, a position that he held until 1984.[2] During this time he was also on leave as a Scientific Associate at the European Council for Nuclear Research (CERN) in Switzerland, where he joined the Axial Field Spectrometer (AFS) team at the proton-proton Intersecting Storage Rings (ISR).[9] Following a sabbatical in the US in 1984, he joined the Continuous Electron Beam Accelerator Facility (CEBAF) in 1985 as a staff scientist.[9]

At CEBAF, which later became known as Jefferson Lab, he was involved with the development, construction and operation of the CEBAF Large Acceptance Spectrometer (CLAS).[10][2] In 1992, Burkert was promoted to senior staff scientist and developed a research program on the internal structure of nucleons, including studies of their excited states.[9]

In 2003, he was appointed group leader of Jefferson Lab's Experimental Hall B, where he led a team of scientists working with the CLAS detector system to study the internal quark and gluon structure of protons, neutrons and atomic nuclei.[1][7] During his time at Hall B, he developed the conceptual design for CLAS12, a large-acceptance spectrometer system built for experiments following the 12 GeV CEBAF upgrade.[3][9] CLAS12 began operation in 2018.[10]

In 2019, Burkert stepped down as Hall B leader and became a principal staff scientist in Jefferson Lab’s Experimental Nuclear Physics division.[2] Since 2020, Burkert has been part of Jefferson Lab's team for the Electron-Ion Collider science program.[9][1]

Research

Burkert has authored or co-authored over 460 scientific articles and has over 51,000 citations.[11] His research has focused on the internal structure of protons, neutrons and nuclei, including nucleon excitations, electron-scattering measurements, and the development and use of large-acceptance detector systems.[9]

Early research

His early research focused on nucleon excitations using high-energy polarized electron beams and spin-polarized hydrogen and deuterium targets.[12][9] At the Bonn University electron accelerator, Burkert developed an electron-spin polarimeter to measure the energy and strength of depolarizing resonances induced in the electron beam during synchrotron acceleration. The results enabled compensating measures that maintained high polarization during acceleration, as required for polarized-beam experiments.[10]

Burkert's research at CERN focused on hard scattering processes using two colliding proton beams, each with beam energies up to 31 GeV. This led to the first direct determination of the gluon structure function of the proton.[13][2]

CLAS and CLAS12

At Jefferson Lab, Burkert led a research program on the structure of protons, neutrons and nuclei using high-energy electron and photon beams and polarized hydrogen and deuterium targets. He contributed to the design, construction and performance of the CEBAF Large Acceptance Spectrometer (CLAS).[10] CLAS had been instrumented for high-rate operation with intense electron beams and was used to detect and identify particles produced in these interactions. This enabled exclusive electron-scattering measurements in which particles generated in the interaction were detected and identified. Detector modifications to CLAS enabled the observation of the theoretically predicted Deeply Virtual Compton scattering (DVCS) process.[14] DVCS measurements provided an experimental basis for studies of generalized parton distributions, which are used to investigate the three-dimensional quark structure and mechanical properties of the proton.[5] These detector modifications were also used in measurements of excited proton states as part of the NSTAR program.[2]

Burkert oversaw the design, construction and commissioning of the CLAS12 spectrometer system and ancillary equipment. Built for experiments following the 12 GeV CEBAF upgrade, CLAS12 was designed for an order-of-magnitude increase in operating luminosity and higher event-rate capability compared with the original CLAS detector.[3][10]

Mechanical properties of the proton

In 2018, Burkert, Latifa Elouadrhiri and François-Xavier Girod published a Nature paper on the pressure distribution inside the proton.[4] The study was the first measurement of a mechanical property of a subatomic particle.[5] It found strong repulsive pressure near the center of the proton and binding pressure at greater distances. The paper also contributed to research on the gravitational and mechanical properties of protons, neutrons and nuclei, including pressure distributions, shear forces and physical radii.[4] Using extracted Compton form factors, the research produced tomographic information about the nucleon.[15] These results were based on measurements of differential cross sections and beam-spin asymmetries in hard exclusive photon electroproduction on the proton over a wide kinematic range and with high statistical precision.[16]

In 2023, Burkert co-authored a Reviews of Modern Physics colloquium on gravitational form factors of the proton, reviewing theoretical and experimental progress in interpreting these form factors in terms of the proton's mechanical properties.[17]

Nucleon resonances and exotic baryons

Burkert reviewed experimental claims from 2003 and 2004 concerning possible pentaquark states, including the proposed exotic baryon Θ+(1540).[18] A pentaquark state would consist of four quarks and one antiquark, unlike ordinary baryons, which are composed of three quarks.[18] In his review, Burkert discussed evidence from photoproduction experiments, including measurements on deuterium targets, as well as searches for heavier pentaquark candidates.[18] He concluded that later precision data had significantly weakened the evidence for the Θ+ state, leaving only the possibility of a very narrow hypothetical baryon state in the K+n system.[18]

Burkert has also worked on the electroexcitation of nucleon resonances, including studies of transition amplitudes in excited nucleon states.[19] In a 2012 review with Inna Aznauryan, he discussed experimental and theoretical progress on the electroexcitation amplitudes of the four lowest excited states.[19] The review found that a simple three-valence-quark model could not fully explain the resonance transition amplitudes at low photon virtuality, requiring additional contributions such as meson-baryon components. This work contributed to later discussions of the Roper resonance, the lowest-mass radial excitation of the nucleon.[20][21] Burkert later co-authored a review of the Roper resonance in Reviews of Modern Physics.[22] Similar, though smaller, effects were also reported for other excited states, including Δ(1232)3/2+, N(1520)3/2−, and N(1535)1/2−.[19]

Awards and honors

  • 2004 - Fellow, American Physical Society – Division Nuclear Physics[23]
  • 2013 - Member, Particle Data Group (PDG), Section Unstable Baryons
  • 2019 - Outstanding Scientist Award, Governor of Virginia[24]
  • 2021 - Outstanding Achievements in Nuclear and Particle Physics, MARQUIS Who's Who,[25]
  • 2025 - Tom W. Bonner Prize in Nuclear Physics, American Physical Society Division of Nuclear Physics, for work on large-acceptance spectrometers.[26]

Selected publications

  • N* Physics and Nonperturbative Quantum Chromodynamics, S. Simula, B. Saghai, V. D. Burkert and N. C. Mukhopadhyay, eds. Springer, 1999. ISBN 978-3-211-83299-8.
  • Excited Nucleons and Hadronic Structure, Proceedings of the NSTAR 2000 Conference, 16–19 February 2000, Newport News, Virginia, V. D. Burkert, L. Elouadrhiri, J. J. Kelly and R. C. Minehart, eds. World Scientific, 2000.
  • "Observation of Exclusive Deeply Virtual Compton Scattering in Polarized Electron Beam Asymmetry Measurements". Physical Review Letters, 87(18), 182002 (2001).
  • "The CEBAF large acceptance spectrometer (CLAS)". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 503(3), 513–553 (2003).
  • "Have Pentaquark States Been Seen?" International Journal of Modern Physics A, 21(8n09), 1764–1777 (2006).
  • Electromagnetic Interactions and Hadronic Structure, F. Close, S. Donnachie and G. Shaw, eds. Cambridge University Press, 2007. ISBN 978-0-521-84420-8. doi:10.1017/CBO9780511534928.
  • The 8th International Workshop on the Physics of Excited Nucleons, Newport News, Virginia, 17–20 May 2011, V. D. Burkert, M. Jones, M. Pennington and D. Richards, eds. AIP Conference Proceedings, 2012.
  • 12th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon, D. Armstrong, V. Burkert, W. Detmold, J. Dudek, J. P. Chen, W. Melnitchouk and D. Richards, eds. AIP Conference Proceedings, 2011. ISBN 9780735409347.
  • "Electroexcitation of nucleon resonances". Progress in Particle and Nuclear Physics, 67(1), 1–54 (2012).
  • "Review of Particle Physics". Physical Review D, 98(3), 030001 (2018).
  • "The pressure distribution inside the proton". Nature, 557(7705), 396–399 (2018).
  • "Roper resonance: Toward a solution to the fifty year puzzle". Reviews of Modern Physics, 91(1), 011003 (2019).
  • "Review of Particle Physics". Progress of Theoretical and Experimental Physics, 2020(8), 083C01 (2020).
  • "The CLAS12 spectrometer at Jefferson Laboratory". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 959, 163419 (2020).
  • "Colloquium: Gravitational form factors of the proton". Reviews of Modern Physics, 95(4), 041002 (2023).

References

  1. 1 2 3 "Volker Burkert". www.jlab.org. Retrieved 2026-08-18.
  2. 1 2 3 4 5 6 7 8 "Honoring a Career of Outstanding Achievement | Jefferson Lab". www.jlab.org. 2024-10-16. Retrieved 2026-08-18.
  3. 1 2 3 "Hall B Physics Program and Upgrade Plan" (PDF). Retrieved May 3, 2022.
  4. 1 2 3 Burkert, V. D.; Elouadrhiri, L.; Girod, F. X. (2018). "The pressure distribution inside the proton". Nature. 557 (7705): 396–399. doi:10.1038/s41586-018-0060-z. ISSN 1476-4687.
  5. 1 2 3 "Quarks Under Pressure in the Proton | Jefferson Lab". www.jlab.org. Retrieved 2026-08-18.
  6. ↑ "APS Fellow Archive". www.aps.org. Retrieved May 3, 2022.
  7. 1 2 "Volker Burkert Named Virginia Outstanding Scientist | Jefferson Lab". www.jlab.org. 12 September 2019. Retrieved May 3, 2022.
  8. ↑ "ORCID". orcid.org. Retrieved May 3, 2022.
  9. 1 2 3 4 5 6 7 "Hall B Scientific Staff Bios". www.jlab.org. Retrieved May 3, 2022.
  10. 1 2 3 4 5 Mecking, B.A.; et al. (May 2003). "The CEBAF large acceptance spectrometer (CLAS)". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 503 (3): 513–553. Bibcode:2003NIMPA.503..513M. doi:10.1016/S0168-9002(03)01001-5.
  11. ↑ "Burkert, Volker D. - Author details". Scopus. Elsevier. Retrieved August 18, 2026.
  12. ↑ Joo, K.; et al. (6 March 2002). "Q 2 Dependence of Quadrupole Strength in the γ * p → Δ + ( 1232 ) → p π 0 Transition". Physical Review Letters. 88 (12) 122001. arXiv:hep-ex/0110007. doi:10.1103/PhysRevLett.88.122001. PMID 11909446.
  13. ↑ Åkesson, T.; et al. (1987). "Direct-photon plus away-side jet production inpp collisions at $$\SQRT s = 63$$ GeV and a determination of the gluon distribution". Zeitschrift für Physik C. 34 (3): 293–302. doi:10.1007/BF01548810.
  14. ↑ Stepanyan, S.; et al. (October 10, 2001). "Observation of Exclusive Deeply Virtual Compton Scattering in Polarized Electron Beam Asymmetry Measurements". Physical Review Letters. 87 (18) 182002. arXiv:hep-ex/0107043. Bibcode:2001PhRvL..87r2002S. doi:10.1103/PhysRevLett.87.182002.
  15. ↑ Jo, H. S.; Girod, F. X.; Avakian, H.; Burkert, V. D.; Garçon, M.; Guidal, M.; Kubarovsky, V.; Niccolai, S.; Stoler, P.; Collaboration, the CLAS (November 17, 2015). "Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions". Physical Review Letters. 115 (21) 212003. arXiv:1504.02009. Bibcode:2015PhRvL.115u2003J. doi:10.1103/PhysRevLett.115.212003. PMID 26636848.
  16. ↑ Girod, F. X.; et al. (23 April 2008). "Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries". Physical Review Letters. 100 (16) 162002. arXiv:0711.4805. Bibcode:2008PhRvL.100p2002G. doi:10.1103/PhysRevLett.100.162002. hdl:20.500.11820/2350bd5e-cfb8-4d96-8842-2e415bcc6749. PMID 18518188.
  17. ↑ Burkert, V. D.; Elouadrhiri, L.; Girod, F. X.; Lorce, C.; Schweitzer, P.; Shanahan, P. E. (2023-03-15). "Colloquium: Gravitational Form Factors of the Proton". arXiv.org. Retrieved August 18, 2026.
  18. 1 2 3 4 Burkert, Volker D. (April 10, 2006). "Have Pentaquark States Been seen?". International Journal of Modern Physics A. 21 (8n09): 1764–1777. arXiv:hep-ph/0510309. Bibcode:2006IJMPA..21.1764B. doi:10.1142/S0217751X06032745.
  19. 1 2 3 Aznauryan, I. G.; Burkert, V. D. (January 3, 2012). "Electroexcitation of nucleon resonances". Progress in Particle and Nuclear Physics. 67 (1): 1–54. arXiv:1109.1720. Bibcode:2012PrPNP..67....1A. doi:10.1016/j.ppnp.2011.08.001.
  20. ↑ Roper, L. David (23 March 1964). "Evidence for a P 11 Pion-Nucleon Resonance at 556 MeV". Physical Review Letters. 12 (12): 340–342. doi:10.1103/PhysRevLett.12.340.
  21. ↑ Li, Zhenping; Burkert, Volker; Li, Zhujun (July 1992). "Electroproduction of the Roper resonance as a hybrid state". Physical Review D. 46 (1): 70–74. Bibcode:1992PhRvD..46...70L. doi:10.1103/PhysRevD.46.70. PMID 10014741.
  22. ↑ Burkert, Volker D.; Roberts, Craig D. (March 14, 2019). "Colloquium: Roper resonance: Toward a solution to the fifty year puzzle". Reviews of Modern Physics. 91 (1) 011003. Bibcode:2019RvMP...91a1003B. doi:10.1103/RevModPhys.91.011003.
  23. ↑ "APS Fellow Archive". www.aps.org. Retrieved May 3, 2022.
  24. ↑ "Volker Burkert Named Virginia Outstanding Scientist | Jefferson Lab". www.jlab.org. 12 September 2019. Retrieved May 3, 2022.
  25. ↑ Moderator, Marquis Who's Who (October 12, 2021). "Volker D. Burkert, Ph.D." Marquis Who's Who Top Scientists. Archived from the original on July 4, 2022. Retrieved May 3, 2022.
  26. ↑ "Bonner Prize in Nuclear Physics". www.aps.org. Retrieved 2026-08-18.
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