Hard and soft supersymmetry breaking for 'graphinos' in uniform magnetic fields

Using irreducible and reducible representations of the Dirac matrices, we study the two- and four-component quantum mechanical supersymmetric (SUSY) theories for ultrarelativistic fermions in .2 C 1/ dimensions ('graphinos') in a background uniform magnetic field perpendicular to their plane of motion. We then consider ordinary and parity-violating mass terms and identify the former as a soft SUSY breaking term and the latter as the hard SUSY breaking one.     

A note on supersymmetry breaking in 1+1 dimensions

The spontaneous breakdown of supersymmetry for a single chiral superfield in 1+1 dimensions is investigated and a number of puzzling features are resolved by noting that the loop expansion is not always valid. It is found that both broken and unbroken supersymmetry are stable with respect to radiative corrections.     

A note on self-dual gravitational fields

In this note we give two new simple derivations of the good-cut equation, the equation which governs (complex) self-dual asymptotically flat gravitational fields. One of these derivations is remarkably simple, involving only a few lines. Our main point of interest, however, is in the second derivation. Though it is slightly more complicated, this method of derivation is almost certainly generalizable to cover real asymptotically flat space-times and thus lead to a generalization of the good-cut equation.     

Gauge fields,nonlinear realizations,supersymmetry

This is a brief survey of the all-years research activity in the Sector “Supersymmetry” (the former Markov Group) at the Bogoliubov Laboratory of Theoretical Physics. The focus is on the issues related to gauge fields, spontaneously broken symmetries in the nonlinear realizations approach, and diverse aspects of supersymmetry.     

SUSY magnetic moments sum rules and supersymmetry breaking

It was recently shown that unbrokenN=1 Susy relates, in a model independent way, the magnetic transitions between states of different spin within a given charged massive supermultiplet. We verify explicitly these sum rules for a vector multiplet in the case of massless and massive fermions. The purpose of this analysis is to provide the ground for the broken susy case. We study the modifications of these results when an explicit soft Susy breaking realized through a universal mass for all scalars is present. As a by-product we provide a computation of theg — 2 of theW boson in the standard model which corrects previous evaluations in the literature.     

关于两种二维场类比计算的一点注记

指出《大学物理》1997年第6期上“一类二维时变磁场激发涡旋电场的静电场类比计算”中结果的一点不足之处,并进行了有益的补充。     

Muon anomalous magnetic moment from effective supersymmetry

We present a detailed analysis on the possible maximal value of the muon within the context of effective SUSY models with R parity conservation. First of all, mixing among the second and the third family sleptons can contribute at one loop level to and simultaneously. One finds that can be as large as – for any , imposing an upper limit on the branching ratio. Furthermore, the two loop Barr–Zee type contributions to may be significant for large , if a stop is light and and are large enough ( TeV). In this case, it is possible to have up to without conflicting with . We conclude that the possible maximal value for is about for any . Therefore the BNL experiment on the muon can exclude the effective SUSY models only if the measured deviation is larger than . Received: 29 March 2002 / Published online: 14 June 2002     

A note on irreducibility and existence of integer spin zero-rest-mass fields

It is shown that only for spins 1 and 2 (electronmagnetism and gravitation) does the generic integer spin, source-free, zero-rest-mass field generate an irreducible representation of the proper orthochronous Lorentz group,L+. The conclusion is then drawn that as these higher-spin fields can in no sense be considered as elementary we have strong mathematical (and physical) grounds for their (apparent) nonexistence in nature.     

Gauge fields on the world sheet: Strings with gauge- and supersymmetry breaking

It is shown that the introduction of two-dimensional gauge fields as dynamical degrees of freedom on the world sheet provides a general mechanism for obtaining spontaneous breakdown of spacetime gauge symmetries and supersymmetries in string theories. Other known methods of introducing symmetry breaking are seen to be included in the general world sheet gauge field formulation     

Nonlinear supersymmetry on the plane in magnetic field and quasi-exactly solvable systems

The nonlinear n-supersymmetry with holomorphic supercharges is investigated for the 2D system describing the motion of a charged spin-1/2 particle in an external magnetic field. The universal algebraic structure underlying the holomorphic n-supersymmetry is found. It is shown that the essential difference of the 2D realization of the holomorphic n-supersymmetry from the 1D case recently analysed by us consists in appearance of the central charge entering non-trivially into the superalgebra. The relation of the 2D holomorphic n-supersymmetry to the 1D quasi-exactly solvable (QES) problems is demonstrated by means of the reduction of the systems with hyperbolic or trigonometric form of the magnetic field. The reduction of the n-supersymmetric system with the polynomial magnetic field results in the family of the one-dimensional QES systems with the sextic potential. Unlike the original 2D holomorphic supersymmetry, the reduced 1D supersymmetry associated with x⁶+⋯ family is characterized by the non-holomorphic supercharges of the special form found by Aoyama et al.     

A note on electron beam focusing in magnetic lenses

The conditions under which a meridional electron trajectory can be focused but fail to intersect the optic axis at the focus are analysed; it is shown that conventional electron lens action does not satisfy these conditions.     

A stealth supersymmetry sampler

Journal of High Energy Physics - In the context of (2+1)-dimensional Chern-Simons SL(N, $ mathbb{R} $ ) × SL(N, $ mathbb{R} $ ) gauge fields and spin N black holes we compute the on-shell...     

Local duality, chiral supersymmetry and fermion-like formulation of non-Abelian pure gauge fields

This work generalizes the fermion-like formulation of the Maxwell theory to the non-Abelian Yang–Mills theory without matter fields. This is a new representation of the Lie algebra valued electric and magnetic fields. The resulting equations of motion are invariant under the chiral transformation. In this formulation, duality is a kind of chirality. We may also define local duality transformations in terms of space-time dependent parameters. There is an N=1 supersymmetry for the Dirac-like operator in this representation. Received: 19 June 2000 / Revised version: 10 October 2000 / Published online: 15 March 2001     

宇宙磁场

磁场在宇宙中无处不在,贯穿各种天体。磁场对天体形成、辐射和演化起重要作用,也是宇宙线研究的基础。以前人们对宇宙磁场的理解主要是来自对地球和太阳磁场的测量和物理解释。近20年来,对宇宙更大尺度天体的磁场测量取得很大进展：发现了银河系具备沿着银河旋臂的几万光年尺度磁场,强度为2—4 μG;发现了银河系晕里具有环向磁场,在银道面上下方向相反;发现了银河系中心有极向磁场的观测证据;发现了邻近旋涡星系可能具有万光年尺度磁场的证据;发现了星系团几千万光年范围内磁场存在的证据。宇宙学模拟也显示在宇宙超大纤维结构中应该有磁场存在。这些磁场可能都是宇宙早期产生并在天体形成和演化过程中得以发扬光大。