Document Type


Publication Date




Publication Title

Physical Review Letters






022501 (1-7)


We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e'pπ+ X events, where Δϕ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unexplored leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization.


Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) 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.

Data Availability

Article States: The supplemental materials contains all extracted asymmetry amplitudes with statistical and systematic uncertainties, the mean values of many different kinematic variables in each published bin and a description of the Monte Carlo used in this analysis.

Original Publication Citation

Avakian, H., Hayward, T. B., Kotzinian, A., Armstrong, W. R., Atac, H., Ayerbe Gayoso, C., Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Boiarinov, S., . . . Zurek, M. (2023). Observation of correlations between spin and transverse momenta in back-to-back dihadron production at CLAS12. Physical Review Letters, 130(2), 1-7, Article 022501.


0000-0002-4136-2572 (Bulumulla), 0000-0003-2086-2807 (Hattawy), 0000-0001-7282-8120 (Hyde), 0000-0003-2243-6836 (Kuhn)

Bueltmann-2023-SupplementalMaterial.pdf (1327 kB)
Supplemental Material