Measured proton electromagnetic structure deviates from theoretical predictions

R. Li, N. Sparveris (), H. Atac, M. K. Jones, M. Paolone, Z. Akbar, C. Ayerbe Gayoso, V. Berdnikov, D. Biswas, M. Boer, A. Camsonne, J.-P. Chen, M. Diefenthaler, B. Duran, D. Dutta, D. Gaskell, O. Hansen, F. Hauenstein, N. Heinrich, W. Henry, T. Horn, G. M. Huber, S. Jia, S. Joosten, A. Karki, S. J. D. Kay, V. Kumar, X. Li, W. B. Li, A. H. Liyanage, S. Malace, P. Markowitz, M. McCaughan, Z.-E. Meziani, H. Mkrtchyan, C. Morean, M. Muhoza, A. Narayan, B. Pasquini, M. Rehfuss, B. Sawatzky, G. R. Smith, A. Smith, R. Trotta, C. Yero, X. Zheng and J. Zhou
Additional contact information
R. Li: Temple University
N. Sparveris: Temple University
H. Atac: Temple University
M. K. Jones: Thomas Jefferson National Accelerator Facility
M. Paolone: New Mexico State University
Z. Akbar: University of Virginia
C. Ayerbe Gayoso: The College of William and Mary
V. Berdnikov: Catholic University of America
D. Biswas: Hampton University
M. Boer: Temple University
A. Camsonne: Thomas Jefferson National Accelerator Facility
J.-P. Chen: Thomas Jefferson National Accelerator Facility
M. Diefenthaler: Thomas Jefferson National Accelerator Facility
B. Duran: Temple University
D. Dutta: Mississippi State University
D. Gaskell: Thomas Jefferson National Accelerator Facility
O. Hansen: Thomas Jefferson National Accelerator Facility
F. Hauenstein: Old Dominion University
N. Heinrich: University of Regina
W. Henry: Thomas Jefferson National Accelerator Facility
T. Horn: Catholic University of America
G. M. Huber: University of Regina
S. Jia: Temple University
S. Joosten: Argonne National Laboratory
A. Karki: Mississippi State University
S. J. D. Kay: University of Regina
V. Kumar: University of Regina
X. Li: Duke University
W. B. Li: The College of William and Mary
A. H. Liyanage: Hampton University
S. Malace: Thomas Jefferson National Accelerator Facility
P. Markowitz: Florida International University
M. McCaughan: Thomas Jefferson National Accelerator Facility
Z.-E. Meziani: Argonne National Laboratory
H. Mkrtchyan: Artem Alikhanian National Laboratory
C. Morean: University of Tennessee
M. Muhoza: Catholic University of America
A. Narayan: Veer Kunwar Singh University
B. Pasquini: University of Pavia
M. Rehfuss: Temple University
B. Sawatzky: Thomas Jefferson National Accelerator Facility
G. R. Smith: Thomas Jefferson National Accelerator Facility
A. Smith: Duke University
R. Trotta: Catholic University of America
C. Yero: Florida International University
X. Zheng: University of Virginia
J. Zhou: Duke University

Nature, 2022, vol. 611, issue 7935, 265-270

Abstract: Abstract The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton’s bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities1 that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities2 map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades2. Here we report measurements of the proton’s electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton’s electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.

Date: 2022
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41586-022-05248-1 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:611:y:2022:i:7935:d:10.1038_s41586-022-05248-1

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-022-05248-1

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().