标题： 洛伦兹不变性和超光速粒子 显示英文标题

标题： Lorentz Invariance and Superluminal Particles

摘要： 如果教科书中的洛伦兹不变性实际上是描述某个临界距离尺度以上物质区的方程的属性，那么具有不同真空中临界速度的多个物质区可以共存，并且可能存在一个绝对静止参考系（真空静止参考系，可能与膨胀宇宙的局部静止参考系有关），而不会与“普通”粒子（其在真空中的临界速度等于$c$，即光速）所感受到的明显洛伦兹不变性相矛盾。由给定动力学区的所有粒子在真空中具有相同的临界速度这一事实所反映的区的洛伦兹不变性，将是对运动方程中一个参数的基本区对称性（例如，前子大统一或扩展超对称性）的表达。我们研究这种情况下洛伦兹不变性的破坏，重点在于“普通”区与超光速区之间的混合，并通过例子讨论现有数据的后果。真空中的高能速度值的区普遍性，即使精确，也不必然意味着洛伦兹不变性被破坏，也不能单独排除在加速器中产生超光速粒子或在专门研究高能宇宙射线的实验中发现它们的可能性。同样，低能下对洛伦兹对称性破坏的严格实验限制不能推广到高能现象。讨论了与洛伦兹对称性破坏可能影响相关的几个基本问题，并检查了潜在的特征。 显示英文摘要

摘要： If textbook Lorentz invariance is actually a property of the equations describing a sector of matter above some critical distance scale, several sectors of matter with different critical speeds in vacuum can coexist and an absolute rest frame (the vacuum rest frame, possibly related to the local rest frame of the expanding Universe) may exist without contradicting the apparent Lorentz invariance felt by "ordinary" particles (particles with critical speed in vacuum equal to $c$ , the speed of light). Sectorial Lorentz invariance, reflected by the fact that all particles of a given dynamical sector have the same critical speed in vacuum, will then be an expression of a fundamental sectorial symmetry (e.g. preonic grand unification or extended supersymmetry) protecting a parameter of the equations of motion. We study the breaking of Lorentz invariance in such a scenario, with emphasis on mixing between the "ordinary" sector and a superluminal sector, and discuss with examples the consequences of existing data. The sectorial universality of the value of the high-energy speed in vacuum, even exact, does not necessarily imply that Lorentz invariance is not violated and does not by itself exclude the possibility to produce superluminal particles at accelerators or to find them in experiments devoted to high-energy cosmic rays. Similarly, the stringent experimental bounds on Lorentz symmetry violation at low energy cannot be extrapolated to high-energy phenomena. Several basic questions related to possible effects of Lorentz symmetry violation are discussed, and potential signatures are examined.