First observation of $\mathrm{\Sigma}^-$-$\mathrm{e}^-$ elastic scattering in the hyperon beam experiment WA89 at CERN

The WA89 Collaboration: M.I. Adamovich - et al.

doi:doi:10.1007/s100529901103

2022 Impact factor 4.4

Particles and Fields

Eur. Phys. J. C 8, 59-66
DOI 10.1007/s100529901103

First observation of $\ensuremath{\mathrm{\Sigma^-}}$ - $\ensuremath{\mathrm{e^-}}$ elastic scattering in the hyperon beam experiment WA89 at CERN

The WA89 Collaboration

M.I. Adamovich ⁸ - Yu.A. Alexandrov ⁸ - D. Barberis ³ - M. Beck ⁵ - C. Bérat ⁴ - W. Beusch ² - M. Boss ⁶ - S. Brons ⁵ - W. Brückner ⁵ - M. Buénerd ⁴ - C. Busch ⁶ - C. Büscher ⁵ - F. Charignon ⁴ - J. Chauvin ⁴ - E.A. Chudakov ⁶ - U. Dersch ⁵ - F. Dropmann ⁵ - J. Engelfried ⁶ - F. Faller ⁶ - A. Fournier ⁴ - S.G. Gerassimov ^5,8 - M. Godbersen ⁵ - P. Grafström ² - Th. Haller ⁵ - M. Heidrich ⁵ - E. Hubbard ⁵ - R.B. Hurst ³ - K. Königsmann ⁵ - I. Konorov ^5,8 - N. Keller ⁶ - K. Martens ⁶ - Ph. Martin ⁴ - S. Masciocchi ⁵ - R. Michaels ⁵ - U. Müller ⁷ - H. Neeb ⁵ - D. Newbold ¹ - C. Newsom - S. Paul ⁵ - J. Pochodzalla ⁵ - I. Potashnikova ⁵ - B. Povh ⁵ - R.D. Ransome - Z. Ren ⁵ - M. Rey-Campagnolle ⁴ - G. Rosner ⁷ - L. Rossi ³ - H. Rudolph ⁷ - C. Scheel - L. Schmitt ⁷ - H.-W. Siebert ⁶ - A. Simon ⁶ - V.J. Smith ¹ - O. Thilmann ⁶ - A. Trombini ⁵ - E. Vesin ⁴ - B. Volkemer ⁷ - K. Vorwalter ⁵ - Th. Walcher ⁷ - G. Wälder ⁶ - R. Werding ⁵ - E. Wittmann ⁵ - M.V. Zavertyaev ⁸

¹ University of Bristol, Bristol, UK
² CERN, CH-1211 Genève 23, Switzerland
³ Genoa University/INFN, Dipartimento di Fisica, I-16146 Genova, Italy
⁴ Grenoble ISN, F-38026 Grenoble, France
⁵ Heidelberg Max-Planck-Institut für Kernphysik, Postfach 103980, D-69029 Heidelberg, Germany
⁶ Universität Heidelberg, Physikal. Institut, D-69120 Heidelberg Germany
⁷ Universität Mainz, Institut für Kernphysik, D-55099 Mainz, Germany
⁸ Moscow Lebedev Physics Institute, 117924 Moscow, Russia

Received: 23 October 1998 / Published online: 1 March 1999

Abstract
We have investigated the elastic scattering of high energy $\Sigma^-$ off electrons from carbon and copper targets using the CERN hyperon beam. Scattering events are identified using a maximum likelihood technique exploring the kinematical relations of the scattered particles. The observed Q²-distribution of these events suggests a mean square charge radius of the $\Sigma^-$ of $<r^{2}_{ch}\gt(\Sigma^-) = 0.91 \pm 0.32 (stat.) \pm 0.4$ (syst.) fm². This constitutes the first measurement of $<r^{2}_{ch}\gt(\Sigma^-)$ and demonstrates the possibility to also measure the charge radii of other hyperons.