- Physical Review Journals
All JournalsPhysics Magazine
Access Provided by Xinjiang University

Physical Review D

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access
  • Access by Xinjiang University

Isospin dependence of the nuclear EMC effect from a global QCD analysis

C. Cocuzza1, T. J. Hague2, W. Melnitchouk2, N. Sato2, and A. W. Thomas3 (JAM Collaboration—PDF Analysis Group)

PDF

Phys. Rev. D 114, 054004 – Published 2 September, 2026

DOI: https://doi.org/10.1103/trd9-gtnr

Abstract

We perform a new global QCD analysis of unpolarized parton distribution functions (PDFs) in the nucleon from proton, deuteron, and A=3 data, including recent measurements of He3/D and H3/D cross section ratios from the MARATHON experiment at Jefferson Lab. Simultaneously inferring the PDFs and nucleon off-shell corrections allows both to be determined consistently, without theoretical assumptions about the isospin dependence of nuclear effects. The analysis provides strong evidence for the need of nucleon off-shell corrections to describe the A=3 data, with large isoscalar and a suggestion of nonzero isovector contributions in A≤3 nuclei. We find that the extracted EMC ratios of nuclear to nucleon structure functions for A=2 and 3 differ from those naively extrapolated from heavy nuclei down to low A.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (68)

  1. J. J. Aubert et al., Phys. Lett. 123B, 275 (1983).
  2. J. Gomez et al., Phys. Rev. D 49, 4348 (1994).
  3. A. W. Thomas, A. Michels, A. W. Schreiber, and P. A. M. Guichon, Phys. Lett. B 233, 43 (1989).
  4. K. Saito, A. Michels, and A. W. Thomas, Phys. Rev. C 46, R2149 (1992).
  5. H. Mineo, W. Bentz, N. Ishii, A. W. Thomas, and K. Yazaki, Nucl. Phys. A735, 482 (2004).
  6. I. C. Cloet, W. Bentz, and A. W. Thomas, Phys. Lett. B 642, 210 (2006).
  7. J. R. Smith and G. A. Miller, Phys. Rev. C 65, 055206 (2002).
  8. P. A. M. Guichon, J. R. Stone, and A. W. Thomas, Prog. Part. Nucl. Phys. 100, 262 (2018).
  9. B. Schmookler et al., Nature (London) 566, 354 (2019).
  10. X. G. Wang, A. W. Thomas, and W. Melnitchouk, Phys. Rev. Lett. 125, 262002 (2020).
  11. E. P. Segarra, J. R. Pybus, F. Hauenstein, D. W. Higinbotham, G. A. Miller, E. Piasetzky, A. Schmidt, M. Strikman, L. B. Weinstein, and O. Hen, Phys. Rev. Res. 3, 023240 (2021).
  12. W. Xing, X. G. Wang, and A. W. Thomas, Phys. Lett. B 846, 138195 (2023).
  13. D. N. Kim, O. Hen, G. A. Miller, E. Piasetzky, M. Strikman, and L. Weinstein, Phys. Rev. C 111, 065201 (2025).
  14. D. F. Geesaman, K. Saito, and A. W. Thomas, Annu. Rev. Nucl. Part. Sci. 45, 337 (1995).
  15. P. R. Norton, Rep. Prog. Phys. 66, 1253 (2003).
  16. A. W. Thomas, Int. J. Mod. Phys. E 27, 1840001 (2019).
  17. A. J. Tropiano, J. J. Ethier, W. Melnitchouk, and N. Sato, Phys. Rev. C 99, 035201 (2019).
  18. G. V. Dunne and A. W. Thomas, Nucl. Phys. A455, 701 (1986).
  19. S. V. Akulinichev, S. A. Kulagin, and G. M. Vagradov, Phys. Lett. 158B, 485 (1985).
  20. R. P. Bickerstaff and A. W. Thomas, J. Phys. G 15, 1523 (1989).
  21. W. Melnitchouk, A. W. Schreiber, and A. W. Thomas, Phys. Rev. D 49, 1183 (1994).
  22. W. Melnitchouk, A. W. Schreiber, and A. W. Thomas, Phys. Lett. B 335, 11 (1994).
  23. S. A. Kulagin, W. Melnitchouk, G. Piller, and W. Weise, Phys. Rev. C 52, 932 (1995).
  24. S. A. Kulagin, G. Piller, and W. Weise, Phys. Rev. C 50, 1154 (1994).
  25. S. A. Kulagin and R. Petti, Nucl. Phys. A765, 126 (2006).
  26. I. R. Afnan, F. R. P. Bissey, J. Gomez, A. T. Katramatou, W. Melnitchouk, G. G. Petratos, and A. W. Thomas, Phys. Lett. B 493, 36 (2000).
  27. I. R. Afnan, F. R. P. Bissey, J. Gomez, A. T. Katramatou, S. Liuti, W. Melnitchouk, G. G. Petratos, and A. W. Thomas, Phys. Rev. C 68, 035201 (2003).
  28. E. Pace, G. Salme, S. Scopetta, and A. Kievsky, Phys. Rev. C 64, 055203 (2001).
  29. M. M. Sargsian, S. Simula, and M. I. Strikman, Phys. Rev. C 66, 024001 (2002).
  30. D. Abrams et al., Phys. Rev. Lett. 128, 132003 (2022).
  31. D. Abrams et al., Phys. Rev. Lett. 135, 062502 (2025).
  32. C. Cocuzza, C. E. Keppel, H. Liu, W. Melnitchouk, A. Metz, N. Sato, and A. W. Thomas, Phys. Rev. Lett. 127, 242001 (2021).
  33. S. A. Kulagin and R. Petti, Phys. Rev. C 82, 054614 (2010).
  34. L. T. Brady, A. Accardi, T. J. Hobbs, and W. Melnitchouk, Phys. Rev. D 84, 074008 (2011); 85, 039902(E) (2012).
  35. I. Schienbein et al., J. Phys. G 35, 053101 (2008).
  36. M. A. G. Aivazis, J. C. Collins, F. I. Olness, and W.-K. Tung, Phys. Rev. D 50, 3102 (1994).
  37. E. Moffat, T. C. Rogers, W. Melnitchouk, N. Sato, and F. Steffens, Phys. Rev. D 99, 096008 (2019).
  38. R. L. Jaffe, Nucl. Phys. B229, 205 (1983).
  39. F. E. Close and A. W. Thomas, Phys. Lett. B 212, 227 (1988).
  40. N. Sato, W. Melnitchouk, S. E. Kuhn, J. J. Ethier, and A. Accardi, Phys. Rev. D 93, 074005 (2016).
  41. N. Sato, J. J. Ethier, W. Melnitchouk, M. Hirai, S. Kumano, and A. Accardi, Phys. Rev. D 94, 114004 (2016).
  42. J. J. Ethier, N. Sato, and W. Melnitchouk, Phys. Rev. Lett. 119, 132001 (2017).
  43. N. Sato, C. Andres, J. J. Ethier, and W. Melnitchouk, Phys. Rev. D 101, 074020 (2020).
  44. E. Moffat, W. Melnitchouk, T. C. Rogers, and N. Sato, Phys. Rev. D 104, 016015 (2021).
  45. C. Cocuzza, W. Melnitchouk, A. Metz, and N. Sato, Phys. Rev. D 104, 074031 (2021).
  46. T. Anderson, W. Melnitchouk, and N. Sato, Phys. Rev. D 112, 094011 (2025).
  47. D. Biswas et al., Phys. Rev. Lett. 135, 151902 (2025).
  48. J. Seely et al., Phys. Rev. Lett. 103, 202301 (2009).
  49. S. Li et al., Nature (London) 609, 41 (2022).
  50. M. Cerutti, A. Accardi, I. P. Fernando, S. Li, J. F. Owens, and S. Park, Phys. Rev. D 111, 094013 (2025).
  51. S. I. Alekhin, S. A. Kulagin, and R. Petti, Phys. Rev. D 96, 054005 (2017).
  52. M. Lacombe, B. Loiseau, R. Vinh Mau, J. Cote, P. Pires, and R. de Tourreil, Phys. Lett. 101B, 139 (1981).
  53. A. Kievsky, E. Pace, G. Salme, and M. Viviani, Phys. Rev. C 56, 64 (1997).
  54. S. I. Alekhin, S. A. Kulagin, and R. Petti, Proc. Sci. DIS2024 (2025) 067.
  55. B. M. Badelek and J. Kwiecinski, Nucl. Phys. B370, 278 (1992).
  56. W. Melnitchouk and A. W. Thomas, Phys. Rev. D 47, 3783 (1993).
  57. W. Melnitchouk and A. W. Thomas, Phys. Lett. B 317, 437 (1993).
  58. B. Badelek and J. Kwiecinski, Phys. Rev. D 50, R4 (1994).
  59. W. Melnitchouk and A. W. Thomas, Phys. Rev. C 52, 3373 (1995).
  60. G. Piller, W. Ratzka, and W. Weise, Z. Phys. A 352, 427 (1995).
  61. J. Edelmann, G. Piller, and W. Weise, Phys. Rev. C 57, 3392 (1998).
  62. F. R. P. Bissey, V. A. Guzey, M. Strikman, and A. W. Thomas, Phys. Rev. C 65, 064317 (2002).
  63. G. Piller and W. Weise, Phys. Rep. 330, 1 (2000).
  64. J. T. Londergan, J. C. Peng, and A. W. Thomas, Rev. Mod. Phys. 82, 2009 (2010).
  65. T. J. Hobbs, J. T. Londergan, D. P. Murdock, and A. W. Thomas, Phys. Lett. B 698, 123 (2011).
  66. I. Albayrak et al., Nucl. Instrum. Methods Phys. Res., Sect. A 1062, 169190 (2024).
  67. T. Hobbs and W. Melnitchouk, Phys. Rev. D 77, 114023 (2008).
  68. R. M. Whitehill, M. M. Dalton, T. Liu, W. Melnitchouk, and N. Sato, arXiv:2606.26056.

Outline

Information

Phys. Rev. D 114, 054004– Published 2 September, 2026
  • Received 20 February 2026
  • Accepted 30 July 2026
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation