Accidental goldstone bosons
Accidental goldstone bosons
复制标题
偶然的戈德斯通玻色子
DOI：
10.1103/physrevd.71.076007
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Adam Martin
中科院分区：
文献类型：
--
作者：
K. Lane;Adam Martin
我们研究了一组无质量费米子的手性对称性被自发和显式破缺的理论中的真空对准。我们发现随着费米子对称性破缺哈密顿量参数的变化，费米子CP对称性的不同相位之间会发生跃迁。我们确定了一个新的阶段，我们称之为伪p保护。我们观察到不同相之间的一阶和二阶转变。在二阶（也可能是一阶）跃迁中，伪戈德斯通玻色子由于基态的离散而非连续对称的自发变化而变得无质量。我们将这些“偶然戈德斯通玻色子”（agb）的无质量与相变序参数的奇点联系起来。cp相变的相对频率使得agb的重量比它们潜在的强相互作用尺度轻得多。我们通过研究AGB的真空期望值来研究它们作为轻型复合希格斯玻色子的潜力，发现了令人鼓舞的结果：AGB的真空期望值也往往远低于它们的强尺度。
We study vacuum alignment in theories in which the chiral symmetry of a set of massless fermions is both spontaneously and explicitly broken. We find that transitions occur between different phases of the fermions' CP symmetry as parameters in their symmetry breaking Hamiltonian are varied. We identify a new phase that we call pseudoCP-conserving. We observe first and second-order transitions between the various phases. At a second-order (and possibly first-order) transition a pseudo-Goldstone boson becomes massless as a consequence of a spontaneous change in the discrete, but not the continuous, symmetry of the ground state. We relate the masslessness of these 'accidental Goldstone bosons' (AGBs) to singularities of the order parameter for the phase transition. The relative frequency of CP-phase transitions makes it commonplace for the AGBs to be light, much lighter than their underlying strong interaction scale. We investigate the AGBs' potential for serving as light composite Higgs bosons by studying their vacuum expectation values, finding encouraging results: AGB vevs are also often much less than their strong scale.