Electroweak precision measurements in supersymmetric models with a U(1)R lepton number
Electroweak precision measurements in supersymmetric models with a U(1)R lepton number
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DOI：
10.1007/jhep05(2014)051
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发表时间：
2014-05-12
影响因子：
5.4
通讯作者：
Gregoire, Thomas
中科院分区：
文献类型：
--
作者：
Beauchesne, Hugues;Gregoire, Thomas
随着对MSSM的参数空间及其紧密变化的实验约束变得更强，探索挑战MSSM的一些标准假设的超度量模型的动机也变得更强。例如，高吉诺是狄拉克而不是马约拉纳的模型最近受到了更多的关注。除了允许超软超对称性破坏机制，其中高吉诺只提供有限的阈值校正标量质量，横截面的夸克对的生产减少。此外，狄拉克高吉诺可以用来建立具有U（1）（R）对称性的模型。这种对称性可以用轻子数来识别，从而产生与传统情况截然不同的模型。这些模型中的超中微子可以获得一个质量，并将质量给予轻子和下型夸克。这种现象是新颖的，结合签名，是典型的R-宇称违反的情况下产生的签名leptoquark。相应地，来自弱电精密数据的约束也不同。在这些模型中，轻子与高吉诺和超势汤川耦合的混合可以在树水平上对EWPM做出贡献。此外，轻子普适性被打破。在本文中，我们适应汉和Skiba的运营商分析，包括轻子普适性的相关违反，并做一个全球性的电弱精密数据，包括所有相关的树级和环级效应的模型拟合。我们得到了超中微子的vev和模型的超势耦合的界。
As experimental constraints on the parameter space of the MSSM and close variations thereof become stronger, the motivation to explore supersyrnmetric models that challenge some of the standard assumptions of the MSSM also become stronger. For example, models where the gauginos are Dirac instead of Majorana have recently received more attention. Beside allowing for a supersoft SUSY breaking mechanism where the gauginos only provide finite threshold corrections to scalar masses, the cross section for the production of a squark pairs is reduced. In addition, Dirac gauginos can be used to build models that possess a U(1)(R) symmetry. This symmetry can then be identified with a lepton number, leading to models that are quite different from conventional scenarios. The sneutrinos in these models can acquire a vet, and give mass to the leptons and the down-type squark. The phenomenology is novel, combining signatures that are typical of R-parity violating scenarios with signatures arising from leptoquarks. Correspondingly the constraints from electroweak precision data are also different. In these models, one of the leptons mixes with gauginos and superpotential Yukawa couplings can contribute to EWPM at tree level. In addition, lepton universality is broken. In this paper we adapt the operators analysis of Han and Skiba to include the relevant violation of lepton universality, and do a global fit of the model to electroweak precision data, including all relevant tree-level and loop-level effects. We obtain bounds on the vev of the sneutrino and on the superpotential couplings of the model.