Gravity and electroweak sector from symmetry breaking of an $SO(3,3)$ BF theory
University of Madras（马德拉斯大学）；Tata Institute of Fundamental Research（塔塔基础研究所）；Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia（瓦伦西亚理工大学纯数学与应用数学大学研究所）
An $SO(3,3)$ BF-type gauge theory is formulated on a six-dimensional spacetime of split signature $(3,3)$, interpreted as the pre-electroweak-symmetry-breaking phase. A MacDowell--Mansouri-type symmetry breaking to $SU(2)\times SU(2)$ is implemented, and the corresponding stabilizer and coset structures are computed. The curvature decomposes into chiral sectors, and effective tetrads are introduced using components of the higher-dimensional connection. The resulting left and right sectors are formulated as constrained BF/Plebanski-like theories with appropriate simplicity and reality conditions. The six-dimensional theory yields two overlapping four-dimensional Lorentzian sectors of opposite signature, related via gluing constraints across their intersection. In the first sector, the selfdual two-forms ($Σ^{(+)}$) satisfy simplicity constraints that select the non-degenerate branch and reproduce Einstein gravity. Subsequently, the $SU(2)_R\times U(1)_{Y{\rm dem}}\to U(1)_{\rm dem}$ breaking pattern is outlined which admits an ultra-soft regime consistent with current phenomenological bounds under sufficiently suppressed couplings. In the second sector, the antiself dual two-forms ($Σ^{(-)}$) satisfy analogous simplicity constraints, realizing weak gauge dynamics as gravity on the opposite-signature sector. Subsequently, the $SU(2)_L\otimes U(1)_Y$ electroweak symmetry is realized within the Yang--Mills branch of the BF theory which incorporates the standard Higgs mechanism $SU(2)_L\otimes U(1)_Y \to U(1)_{\mathrm{EM}}$, recovering the conventional electroweak $W^\pm$, $Z$, and photon spectrum.
Dynamical Electroweak Symmetry Breaking in String Models with D-branes
研究了弦论中D膜模型中强耦合规范相互作用导致的动力学电弱对称破缺的可能性。引入了强耦合（人工色）的规范对称性，取代了基本标量希格斯偶场。作为这个方向的第一步，一个玩具模型，这是不完全现实的，具体分析了一些细节。该模型由在（T^2 x T^2 x T^2）/Z_3中保持超对称的轨道奇点处的D-膜和反D-膜组成。超对称性是通过膜超对称性破缺而破缺的。指出动力学电弱对称性破缺中的大S参数问题可以通过超荷U（1）规范玻色子与有质量反常U（1）规范玻色子之间动力学项混合的自然存在来解决。在分析中阐明了建立更符合实际的模型所要解决的问题。
