We revisit the current LHC constraints on the electroweak-ino sector parameters in the minimal supersymmetric standard model (MSSM) that are relevant to explaining the $(g-2)_μ$ anomaly via the dominant chargino and muon sneutrino loop. Since the LHC bounds on electroweak-inos become weaker if they decay via an intermediate stau or a tau sneutrino instead of the first two generation sleptons, we perform a detailed analysis of the scenario with a bino as the lightest supersymmetric particle (LSP) and a light stau as the next-to-lightest one (NLSP). Even in this scenario, the chargino sector parameters in the MSSM that can account for the $(g-2)_μ$ anomaly within $1 σ$ are already found to be significantly constrained by the 8 TeV LHC and the available subset of the 13 TeV LHC limits. We also estimate the current LHC exclusions in the left-smuon (and/or left-selectron) NLSP scenario from multilepton searches, and further combine the constraints from the multi-tau and multi-lepton channels for a mass spectrum in which all three generations of sleptons are lighter than the chargino. In the latter two cases, small corners of the $1 σ$ favoured region for $(g-2)_μ$ are still allowed at present.
A multitude of searches have already been performed by the ATLAS and CMS collaborations at the LHC to probe the heavy Higgses of the Minimal Supersymmetric Standard Model (MSSM) through their decay to the Standard Model particles. In this paper, we study the decay of the MSSM heavy Higgses into neutralino and chargino pairs and estimate the maximum possible branching ratios for these `ino' modes being consistent with the present LHC data. After performing a random scan of the relevant electroweakino parameters, we impose the SM 125 GeV Higgs constraints, low energy flavour data as well as curr…
We present simplified MSSM models for light neutralinos and charginos with realistic mass spectra and realistic gaugino-higgsino mixing, that can be used in experimental searches at the LHC. The formerly used naive approach of defining mass spectra and mixing matrix elements manually and independently of each other does not yield genuine MSSM benchmarks. We suggest the use of less simplified, but realistic MSSM models, whose mass spectra and mixing matrix elements are the result of a proper matrix diagonalisation. We propose a novel strategy targeting the design of such benchmark scenarios, ac…
For the search for charginos and neutralinos in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses of these particles an accurate knowledge of their production and decay properties is mandatory. We evaluate the cross sections for the chargino and neutralino production at e+e- colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanisms e+e- -> cha_c cha_c' and e+e- -> neu_n neu_n', including soft and hard photon radiation. We mostly restricted ourselves to a version of our renor…
Direct Chargino-Neutralino Production at the LHC: Interpreting the Exclusion Limits in the Complex MSSM
我们重新评估的排斥限制的参数描述的超对称(SUSY)电弱部门的MSSM从寻找直接chargino中性伴子生产在大型强子对撞机。我们从简化模型中获得的已发表的极限开始,其中对于重slepton的情况,相关的分支比BR(neu 2-> neu 1 Z)被设置为1。我们展示了如何衰减模式neu 2-> neu 1 h,这不能被忽视,在任何现实的模型,一旦运动学允许,大大减少了排除的参数区域。我们分析了排斥区对高更诺软超对称性破缺质量参数M_1的相位、对轻标量τ的质量、对tb以及对夸克和斯莱普顿质量尺度的依赖性。在所有设想方案中,都可以观察到被排除的参数范围大幅缩小。使用复杂MSSM的完整NLO计算来评估电荷伴子和中性伴子的分支比。研究了非线性光学计算对不相容边界影响的大小。我们还评估了收集100/fb后,在运行在13 TeV的大型强子对撞机的实验分析的潜在影响。
The $B-L$ MSSM is the MSSM with three right-handed neutrino chiral multiplets and gauged $B-L$ symmetry. The $B-L$ symmetry is broken by the third family right-handed sneutrino acquiring a VEV, thus spontaneously breaking $R$-parity. Within a natural range of soft supersymmetry breaking parameters, it is shown that a large and uncorrelated number of initial values satisfy all present phenomenological constraints; including the correct masses for the $W^{\pm}$, $Z^0$ bosons, having all sparticles exceeding their present lower bounds and giving the experimentally measured value for the Higgs bos…
We apply the covariant derivative expansion method to integrate out the neutralinos and charginos in the minimal supersymmetric Standard Model. The results are presented as set of pure bosonic dimension-6 operators in the Standard Model effective field theory. Nontrivial chirality dependence in fermionic covariant derivative expansion are discussed carefully. The results are checked by computing the $hγγ$ effective coupling and the electroweak oblique parameters using the Standard Model effective field theory with our effective operators and direct loop calculation. In global fitting the propo…
For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector a precise knowledge of their decay properties is mandatory. We evaluate all two-body decay modes of the Higgs bosons into charginos and neutralinos in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of all decay channels, also including hard QED radiation. We restricted ourselves to a version of our renormalization scheme which is valid for |M_1| < |M_2|, |mu| and M_2 != mu to simplify the an…
The long-standing discrepancy between the experimental determination by the Muon $g-2$ Collaboration at Brookhaven and the Standard Model predictions for the anomalous magnetic moment of the muon cannot be explained within simple unified framework like the Constrained Minimal Supersymmetric Standard Model, but it can within its extension with vector-like fermions. In this paper we consider a model with an additional vector-like $5+\bar{5}$ pair of $SU(5)$. Within this model we first identify its parameter space that is consistent with the current discrepancy and show that this implies the ligh…
The current experimental values of anomalous magnetic moments of muon and electron deviate from the Standard Model predictions by few standard deviations, which might be a hint of new physics. The sizes and signs of these deviations are different and opposite between the electron and muon, which makes it difficult to explain both of these anomalies in a consistent model without introducing large flavour-violating effects. It is shown that they can be simultaneously explained in the Minimal Supersymmetric Standard Model (MSSM) by arranging the sizes of bino-slepton and chargino-sneutrino contri…
This paper concludes the presentation of the non-relativistic effective field theory formalism designed to calculate the radiative corrections that enhance the pair-annihilation cross sections of slowly moving neutralinos and charginos within the general minimal supersymmetric standard model (MSSM). While papers I and II focused on the computation of the tree-level annihilation rates that feed into the short-distance part, here we describe in detail the method to obtain the Sommerfeld factors that contain the enhanced long-distance corrections. This includes the computation of the potential in…
We test the impact of the ATLAS and CMS multi-lepton searches performed at the LHC with 8 as well as 13 TeV center-of-mass energy (using only the pre-2018 results) on the chargino and neutralino sector of the NMSSM. Our purpose consists in analyzing the actual reach of these searches for a full model and in emphasizing effects beyond the MSSM that affect the performance of current (MSSM-inspired) electroweakino searches. To this end, we consider several scenarios characterizing specific features of the NMSSM electroweakino sector. We then perform a detailed collider study, generating Monte-Car…