论文标题
通过Exotic $ z \ toz'γ$衰减探测新的$ u（1）$量规对称性
Probing new $U(1)$ gauge symmetries via exotic $Z \to Z' γ$ decays
论文作者
论文摘要
涉及标准模型（SM）费米子的新$ U（1）$量规理论通常需要额外的电动效率来取消异常。我们在$ z-z'-γ$顶点函数中研究了这些新费米子的非耦合特性，称为anomalons，审查了完整模型与有效的Wess-Zumino操作员之间的连接。我们计算出$ u（1）_ {b-l} $和$ u（1）_b $型号中的exotic $ z \ toz'γ$衰减宽度，其中$ b $和$ l $表示SM Baryon和Lepton Number Mumber Sommetries。对于$ u（1）_ {b-l} $量规对称性，每一代SM费米子都是无异常的，并且异国情调的$ z \ to z_ {bl}'γ$衰减宽度完全由固元质量覆盖量完全诱导。相比之下，对于$ u（1）_b $量规对称性，存在两个不同的手性对称性源的来源使一组沉重的，无异常的费米子对$ z \ to z_b'γ$衰减宽度具有不可减至的贡献。我们表明，异国情调的$ z \至z'_bγ$衰减的当前LEP限制较弱，而低质量$ z'__b $ dijet共振搜索目前正在更加约束。我们在$ u（1）_b $上介绍了当前对撞机的界限，以及对$ z \ toz_b'γ$异国情调衰减的Teraz工厂的预测，并强调$ z \ toz'γ$衰减是如何象征新的Anmoalos $ u（1）$ symmemetries的象征。
New $U(1)$ gauge theories involving Standard Model (SM) fermions typically require additional electroweak fermions for anomaly cancellation. We study the non-decoupling properties of these new fermions, called anomalons, in the $Z-Z'-γ$ vertex function, reviewing the connection between the full model and the effective Wess-Zumino operator. We calculate the exotic $Z \to Z' γ$ decay width in $U(1)_{B-L}$ and $U(1)_B$ models, where $B$ and $L$ denote the SM baryon and lepton number symmetries. For $U(1)_{B-L}$ gauge symmetry, each generation of SM fermions is anomaly free and the exotic $Z \to Z_{BL}' γ$ decay width is entirely induced by intragenerational mass splittings. In contrast, for $U(1)_B$ gauge symmetry, the existence of two distinct sources of chiral symmetry breaking enables a heavy, anomaly-free set of fermions to have an irreducible contribution to the $Z \to Z_B' γ$ decay width. We show that the current LEP limits on the exotic $Z \to Z'_B γ$ decay are weaker than previously estimated, and low-mass $Z'_B$ dijet resonance searches are currently more constraining. We present a summary of the current collider bounds on $U(1)_B$ and a projection for a TeraZ factory on the $Z \to Z_B' γ$ exotic decay, and emphasize how the $Z \to Z' γ$ decay is emblematic of new anomalous $U(1)$ gauge symmetries.
