Polarization and spin effects in neutralino production and decay

G. Moortgat-Pick; H. Fraas; A. Bartl; W. Majerotto

doi:doi:10.1007/s100520050046

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2024 Impact factor 4.8

Particles and Fields

Eur. Phys. J. C 9, 521-534
DOI 10.1007/s100529900076

Polarization and spin effects in neutralino production and decay

G. Moortgat-Pick¹ - H. Fraas¹ - A. Bartl² - W. Majerotto³

¹ Institut für Theoretische Physik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany (e-mail: gudi, fraas@physik.uni-wuerzburg.de)
² Institut für Theoretische Physik, Universität Wien, Boltzmanngasse 5, A-1090 Wien, Austria (e-mail: bartl@merlin.ap.univie.ac.at)
³ Institut für Hochenergiephysik, Österreichische Akademie der Wissenschaften, Nikolsdorfergasse 18, A-1050 Wien, Austria (e-mail: majer@qhepu3.oeaw.ac.at)

Received: 28 March 1999 / Published online: 28 May 1999

Abstract
We study the production of neutralinos $e^+ e^- \to\tilde{\chi}^{0}_i\tilde{\chi}^{0}_j$ with polarized beams and the subsequent decays $\tilde{\chi}^{0}_{i} \to \tilde{\chi}^0_k\ell^{+}\ell^{-}$ and $\tilde{\chi}^{0}_{j} \to \tilde{\chi}^0_l \ell^{+}\ell^{-}$ , including the complete spin correlations between production and decay. We present analytical formulae for the differential cross section of the combined process of production and decay of neutralinos. We also allow for complex couplings. The spin correlations have a strong influence on the decay angular distributions and the corresponding forward-backward asymmetries. They are very sensitive to the SUSY parameters and depend strongly on the beam polarizations. We present numerical results for the cross section and the electron forward-backward asymmetry for $e^+ e^- \to\tilde{\chi}^{0}_1\tilde{\chi}^{0}_2$ , $\tilde{\chi}^{0}_{2} \to \tilde{\chi}^0_1 e^{+} e^{-}$ . We study the dependence on the parameter M' for various mass splittings between $\tilde{e}_L$ and $\tilde{e}_R$ and different beam polarizations.