Measurements of the electron-helicity asymmetry in the quasi-elastic A(e→,e′p) process

A1 Collaboration

doi:10.1016/j.physletb.2021.136798

Measurements of the electron-helicity asymmetry in the quasi-elastic A(e→,e^′p) process

A1 Collaboration

Racah Institute of Physics

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Abstract

We present measurements of the electron helicity asymmetry in quasi-elastic proton knockout from ²H and ¹²C nuclei by polarized electrons. This asymmetry depends on the fifth structure function, is antisymmetric with respect to the scattering plane, and vanishes in the absence of final-state interactions, and thus it provides a sensitive tool for their study. Our kinematics cover the full range in off-coplanarity angle ϕ_pq, with a polar angle θ_pq coverage up to about 8°. The missing energy resolution enabled us to determine the asymmetries for knock-out resulting in different states of the residual ¹¹B system. We find that the helicity asymmetry for p-shell knockout from ¹²C depends on the final state of the residual system and is relatively large (up to ≈0.16), especially at low missing momentum. It is considerably smaller (up to ≈0.01) for s-shell knockout from both ¹²C and ²H. The data for ²H are in very good agreement with theoretical calculations, while the predictions for ¹²C exhibit differences with respect to the data.

Original language	American English
Article number	136798
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	824
DOIs	https://doi.org/10.1016/j.physletb.2021.136798
State	Published - 10 Jan 2022

Bibliographical note

Funding Information:
We would like to thank the Mainz Microtron operators and technical crew for the excellent operation of the accelerator. This work is supported by the Israel Science Foundation (Grants 390/15 , 951/19 ) of the Israel Academy of Arts and Sciences, by the Israel Ministry of Science, Technology and Spaces, by the PAZY Foundation (Grant 294/18 ), by the Deutsche Forschungsgemeinschaft (Collaborative Research Center 1044 ), by the U.S. National Science Foundation ( PHY-1812382 ), by the United States-Israel Binational Science Foundation (BS) as part of the joint program with the NSF (grant 2017630 ), and by the Croatian Science Foundation Project No. 1680 . We acknowledge the financial support from the Slovenian Research Agency (research core funding No. P1–0102 ).

Publisher Copyright:
© 2021 The Author

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10.1016/j.physletb.2021.136798

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@article{43e1ec55a5674768a095ad5bb4691638,

title = "Measurements of the electron-helicity asymmetry in the quasi-elastic A(e→,e′p) process",

abstract = "We present measurements of the electron helicity asymmetry in quasi-elastic proton knockout from 2H and 12C nuclei by polarized electrons. This asymmetry depends on the fifth structure function, is antisymmetric with respect to the scattering plane, and vanishes in the absence of final-state interactions, and thus it provides a sensitive tool for their study. Our kinematics cover the full range in off-coplanarity angle ϕpq, with a polar angle θpq coverage up to about 8°. The missing energy resolution enabled us to determine the asymmetries for knock-out resulting in different states of the residual 11B system. We find that the helicity asymmetry for p-shell knockout from 12C depends on the final state of the residual system and is relatively large (up to ≈0.16), especially at low missing momentum. It is considerably smaller (up to ≈0.01) for s-shell knockout from both 12C and 2H. The data for 2H are in very good agreement with theoretical calculations, while the predictions for 12C exhibit differences with respect to the data.",

author = "{A1 Collaboration} and T. Kolar and Paul, {S. J.} and P. Achenbach and H. Arenh{\"o}vel and A. Ashkenazi and J. Beri{\v c}i{\v c} and R. B{\"o}hm and D. Bosnar and T. Brecelj and E. Cline and Cohen, {E. O.} and Distler, {M. O.} and A. Esser and I. Fri{\v s}{\v c}i{\'c} and R. Gilman and C. Giusti and M. Heilig and M. Hoek and D. Izraeli and S. Kegel and P. Klag and I. Korover and J. Lichtenstadt and I. Mardor and H. Merkel and Middleton, {D. G.} and M. Mihovilovi{\v c} and J. M{\"u}ller and U. M{\"u}ller and M. Olivenboim and E. Piasetzky and J. Pochodzalla and G. Ron and Schlimme, {B. S.} and M. Schoth and F. Schulz and C. Sfienti and S. {\v S}irca and R. Spreckels and S. {\v S}tajner and Y. St{\"o}ttinger and S. Strauch and M. Thiel and A. Tyukin and A. Weber and I. Yaron",

note = "Funding Information: We would like to thank the Mainz Microtron operators and technical crew for the excellent operation of the accelerator. This work is supported by the Israel Science Foundation (Grants 390/15 , 951/19 ) of the Israel Academy of Arts and Sciences, by the Israel Ministry of Science, Technology and Spaces, by the PAZY Foundation (Grant 294/18 ), by the Deutsche Forschungsgemeinschaft (Collaborative Research Center 1044 ), by the U.S. National Science Foundation ( PHY-1812382 ), by the United States-Israel Binational Science Foundation (BS) as part of the joint program with the NSF (grant 2017630 ), and by the Croatian Science Foundation Project No. 1680 . We acknowledge the financial support from the Slovenian Research Agency (research core funding No. P1–0102 ). Publisher Copyright: {\textcopyright} 2021 The Author",

year = "2022",

month = jan,

day = "10",

doi = "10.1016/j.physletb.2021.136798",

language = "American English",

volume = "824",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

}

TY - JOUR

T1 - Measurements of the electron-helicity asymmetry in the quasi-elastic A(e→,e′p) process

AU - A1 Collaboration

AU - Kolar, T.

AU - Paul, S. J.

AU - Achenbach, P.

AU - Arenhövel, H.

AU - Ashkenazi, A.

AU - Beričič, J.

AU - Böhm, R.

AU - Bosnar, D.

AU - Brecelj, T.

AU - Cline, E.

AU - Cohen, E. O.

AU - Distler, M. O.

AU - Esser, A.

AU - Friščić, I.

AU - Gilman, R.

AU - Giusti, C.

AU - Heilig, M.

AU - Hoek, M.

AU - Izraeli, D.

AU - Kegel, S.

AU - Klag, P.

AU - Korover, I.

AU - Lichtenstadt, J.

AU - Mardor, I.

AU - Merkel, H.

AU - Middleton, D. G.

AU - Mihovilovič, M.

AU - Müller, J.

AU - Müller, U.

AU - Olivenboim, M.

AU - Piasetzky, E.

AU - Pochodzalla, J.

AU - Ron, G.

AU - Schlimme, B. S.

AU - Schoth, M.

AU - Schulz, F.

AU - Sfienti, C.

AU - Širca, S.

AU - Spreckels, R.

AU - Štajner, S.

AU - Stöttinger, Y.

AU - Strauch, S.

AU - Thiel, M.

AU - Tyukin, A.

AU - Weber, A.

AU - Yaron, I.

N1 - Funding Information: We would like to thank the Mainz Microtron operators and technical crew for the excellent operation of the accelerator. This work is supported by the Israel Science Foundation (Grants 390/15 , 951/19 ) of the Israel Academy of Arts and Sciences, by the Israel Ministry of Science, Technology and Spaces, by the PAZY Foundation (Grant 294/18 ), by the Deutsche Forschungsgemeinschaft (Collaborative Research Center 1044 ), by the U.S. National Science Foundation ( PHY-1812382 ), by the United States-Israel Binational Science Foundation (BS) as part of the joint program with the NSF (grant 2017630 ), and by the Croatian Science Foundation Project No. 1680 . We acknowledge the financial support from the Slovenian Research Agency (research core funding No. P1–0102 ). Publisher Copyright: © 2021 The Author

PY - 2022/1/10

Y1 - 2022/1/10

N2 - We present measurements of the electron helicity asymmetry in quasi-elastic proton knockout from 2H and 12C nuclei by polarized electrons. This asymmetry depends on the fifth structure function, is antisymmetric with respect to the scattering plane, and vanishes in the absence of final-state interactions, and thus it provides a sensitive tool for their study. Our kinematics cover the full range in off-coplanarity angle ϕpq, with a polar angle θpq coverage up to about 8°. The missing energy resolution enabled us to determine the asymmetries for knock-out resulting in different states of the residual 11B system. We find that the helicity asymmetry for p-shell knockout from 12C depends on the final state of the residual system and is relatively large (up to ≈0.16), especially at low missing momentum. It is considerably smaller (up to ≈0.01) for s-shell knockout from both 12C and 2H. The data for 2H are in very good agreement with theoretical calculations, while the predictions for 12C exhibit differences with respect to the data.

AB - We present measurements of the electron helicity asymmetry in quasi-elastic proton knockout from 2H and 12C nuclei by polarized electrons. This asymmetry depends on the fifth structure function, is antisymmetric with respect to the scattering plane, and vanishes in the absence of final-state interactions, and thus it provides a sensitive tool for their study. Our kinematics cover the full range in off-coplanarity angle ϕpq, with a polar angle θpq coverage up to about 8°. The missing energy resolution enabled us to determine the asymmetries for knock-out resulting in different states of the residual 11B system. We find that the helicity asymmetry for p-shell knockout from 12C depends on the final state of the residual system and is relatively large (up to ≈0.16), especially at low missing momentum. It is considerably smaller (up to ≈0.01) for s-shell knockout from both 12C and 2H. The data for 2H are in very good agreement with theoretical calculations, while the predictions for 12C exhibit differences with respect to the data.

UR - http://www.scopus.com/inward/record.url?scp=85120302458&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2021.136798

DO - 10.1016/j.physletb.2021.136798

M3 - Article

AN - SCOPUS:85120302458

SN - 0370-2693

VL - 824

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 136798

ER -

Measurements of the electron-helicity asymmetry in the quasi-elastic A(e→,e^′p) process

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