New Superparticle Models Outside the HLS Supersymmetry Scheme

Abstract

We consider the superparticle models invariant under the supersymmetries with tensorial central charges, which were not included in D = 4 Haag- Lopuszanski-Sohnius (HLS) supersymmetry scheme.

We present firstly a generalization of D = 4 Ferber-Shirafuji (FS) model with fundamental bosonic spinors and tensorial central charge coordinates. The model contains four fermionic coordinates and possesses three k-symmetries thus providing the BPS configuration preserving 3/4 of the target space supersymmetries. We show that the physical degrees of freedom (8 real bosonic and 1 real Grassmann variable) of our model can be described by OSp(8|1) supertwistor. Then we propose a higher dimensional generalization of our model with one real fundamental bosonic spinor. D = 10 model describes massless superparticle with composite tensorial central charges and in D = 11 we obtain 0-superbrane model with nonvanishing mass which is generated dynamically. The introduction of D = 11 Lorentz harmonics provides the possibility to construct massless D = 11 superparticle model which can be formulated in a way preserving 1=2, 17=32, 18=32, : : :, 31=32 supersymmetries. In a special case we obtain the twistor-like formulation of the usual massless D = 11 superparticle proposed recently by Bergshoeff and Townsend.