First measurement of Xi(-) polarization in photoproduction

J. Bono*, L. Guo, B. A. Raue, S. Adhikari, M. C. Kunkel, K. P. Adhikari, Z. Akbar, M. J. Amaryan, L. Barion, M. Bashkanov, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, V. D. Burkert, F. Cao, D. S. Carman, A. Celentano, G. Charles, T. ChetryG. Ciullo, Brandon A. Clary, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, M. Defurne, A. Deur, S. Diehl, C. Djalali, M. Dugger, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, A. Filippi, A. Fradi, G. Gavalian, N. Gevorgyan, Y. Ghandilyan, F. X. Girod, D. I. Glazier, W. Gohn, E. Golovatch, R. W. Gothe, K. A. Griffioen, K. Hafidi, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, M. Holtrop, Y. Ilieva, D. G. Ireland, E. L. Isupov, H. S. Jo, S. Johnston, M. L. Kabir, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F. J. Klein, V. Kubarovsky, P. Lenisa, K. Livingston, I. J.D. MacGregor, N. Markov, B. McKinnon, T. Mineeva, R. A. Montgomery, C. Munoz Camacho, G. Niculescu, M. Osipenko, A. I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, O. Pogorelko, J. W. Price, Y. Prok, D. Protopopescu, M. Ripani, A. Rizzo, G. Rosner, F. Sabatié, C. Salgado, R. A. Schumacher, Y. Sharabian, Iu Skorodumina, D. Sokhan, N. Sparveris, S. Stepanyan, I. I. Strakovsky, S. Strauch, M. Taiuti, M. Ungaro, H. Voskanyan, E. Voutier, N. Zachariou, L. Zana, Z. W. Zhao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Despite decades of studies of the photoproduction of hyperons, both their production mechanisms and their spectra of excited states are still largely unknown. While the parity-violating weak decay of hyperons offers a means of measuring their polarization, which could help discern their production mechanisms and identify their excitation spectra, no such study has been possible for doubly strange baryons in photoproduction, due to low production cross sections. However, by making use of the reaction γp→K+K+Ξ, we have measured, for the first time, the induced polarization, P, and the transferred polarization from circularly polarized real photons, characterized by Cx and Cz, to recoiling Ξs. The data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab for photon energies from just over threshold (2.4 GeV) to 5.45 GeV. These first-time measurements are compared, and are shown to broadly agree, with model predictions in which cascade photoproduction proceeds through the decay of intermediate hyperon resonances that are produced via relativistic meson exchange, offering a new step forward in the understanding of the production and polarization of doubly-strange baryons.

Original languageEnglish
Pages (from-to)280-286
Number of pages7
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Early online date9 Jul 2018
Publication statusPublished - 10 Aug 2018

Bibliographical note

© 2018 The Author(s). Published by Elsevier B.V.


  • Cascade
  • Hyperon spectroscopy
  • Photoproduction
  • Polarization
  • Strange
  • Xi

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