Precision Neutron Skins of ²⁰⁸Pb and ⁴⁸Ca from Parity-Violating Electron Scattering

@misc{collaboration2026precision,
  title = {{Precision Neutron Skins of $^208$Pb and $^48$Ca from Parity-Violating Electron Scattering}},
  author = {PREX Collaboration and D. Adhikari and H. Albataineh and D. Androić and K. A. Aniol and D. S. Armstrong and T. D. Averett and C. Ayerbe Gayoso and S. K. Barcus and V. Bellini and R. S. Beminiwattha and J. F. Benesch and H. Bhatt and D. Bhatta Pathak and D. Bhetuwal and B. Blaikie and J. A. Boyd III and Q. Campagna and A. Camsonne and G. D. Cates and Y. Chen and C. Clarke and J. C. Cornejo and S. Covrig Dusa and M. M. Dalton and P. Datta and A. Deshpande and D. Dutta and E. Fuchey and C. Gal and D. Gaskell and M. Gericke and C. Ghosh and I. Halilovic and J. -O. Hansen and O. Hassan and F. Hauenstein and W. Henry and C. J. Horowitz and C. Jantzi and S. Jian and S. Johnston and D. C. Jones and S. Kakkar and B. Karki and S. Katugampola and C. Keppel and P. M. King and D. E. King and K. S. Kumar and T. Kutz and N. Lashley-Colthirst and G. Leverick and H. Liu and N. Liyanage and S. Malace and J. Mammei and R. Mammei and M. McCaughan and D. McNulty},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.07518},
  eprint = {2609.07518},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.07518},
}

TY  - UNPB
TI  - Precision Neutron Skins of ^208Pb and ^48Ca from Parity-Violating Electron Scattering
AU  - PREX Collaboration
AU  - D. Adhikari
AU  - H. Albataineh
AU  - D. Androić
AU  - K. A. Aniol
AU  - D. S. Armstrong
AU  - T. D. Averett
AU  - C. Ayerbe Gayoso
AU  - S. K. Barcus
AU  - V. Bellini
AU  - R. S. Beminiwattha
AU  - J. F. Benesch
AU  - H. Bhatt
AU  - D. Bhatta Pathak
AU  - D. Bhetuwal
AU  - B. Blaikie
AU  - J. A. Boyd III
AU  - Q. Campagna
AU  - A. Camsonne
AU  - G. D. Cates
AU  - Y. Chen
AU  - C. Clarke
AU  - J. C. Cornejo
AU  - S. Covrig Dusa
AU  - M. M. Dalton
AU  - P. Datta
AU  - A. Deshpande
AU  - D. Dutta
AU  - E. Fuchey
AU  - C. Gal
AU  - D. Gaskell
AU  - M. Gericke
AU  - C. Ghosh
AU  - I. Halilovic
AU  - J. -O. Hansen
AU  - O. Hassan
AU  - F. Hauenstein
AU  - W. Henry
AU  - C. J. Horowitz
AU  - C. Jantzi
AU  - S. Jian
AU  - S. Johnston
AU  - D. C. Jones
AU  - S. Kakkar
AU  - B. Karki
AU  - S. Katugampola
AU  - C. Keppel
AU  - P. M. King
AU  - D. E. King
AU  - K. S. Kumar
AU  - T. Kutz
AU  - N. Lashley-Colthirst
AU  - G. Leverick
AU  - H. Liu
AU  - N. Liyanage
AU  - S. Malace
AU  - J. Mammei
AU  - R. Mammei
AU  - M. McCaughan
AU  - D. McNulty
PY  - 2026
DA  - 2026/09/07
PB  - arXiv
DO  - 10.48550/arxiv.2609.07518
UR  - https://arxiv.org/abs/2609.07518
AB  - We have measured the parity-violating elastic electron scattering asymmetry in the PREX and CREX experiments on ^208Pb and ^48Ca respectively; these are both doubly-magic nuclei whose excited states can be discriminated from the ground state by the high resolution spectrometers in Hall A at Jefferson Lab. This asymmetry provides a precise determination of the weak charge form factor at one Q^2 and pins down the neutron radius in these two nuclei in a relatively clean and model-independent way. This is because the Z^0 boson of the weak interaction couples primarily to neutrons. The heavier lead nucleus, with a neutron excess, provides an interpretation of the neutron skin thickness in terms of properties of bulk neutron matter. For the lighter ^48Ca nucleus, which is also rich in neutrons, comparisons to microscopic nuclear theory calculations are sensitive to poorly constrained 3-neutron forces. The weak neutral form factors F_W(Q^2) were extracted to be 0.368 ± 0.013 at Q = 0.3977 fm^−1 for ^208Pb from PREX-2 and 0.1304 ± 0.0055 at Q = 0.8733 fm^−1 for ^48Ca. The form factor differences (F_ch−F_W)(Q^2) were calculated to be 0.041 ± 0.013 at Q = 0.3977 fm^−1 for ^208Pb from PREX-2 and 0.0277 ± 0.0055 at Q = 0.8733 fm^−1 for ^48Ca. Correcting for Coulomb distortions and using nuclear model information, we find the neutron skin thicknesses to be R^208_skin = 0.283 ± 0.071 fm combining PREX-1 and PREX-2 and R^48_skin = 0.121 ± 0.035 fm. This paper provides a full description of the special experimental and data analysis techniques employed for precisely measuring these small asymmetries.
ER  -