If the lightest dark matter neutralino has a sufficiently large Higgsino component, its spin-independent and spin-dependent cross sections on nucleons can be sizable enough to be detected soon in direct and indirect surveys. We outline in this paper some characteristic features expected of mixed bino-Higgsino dark matter. If the observed relic density is saturated by the bino-Higgsino dark matter, it fixes the amount of allowable bino-Higgsino mixing and provides predictions for other observables which can be tested at the Large Hadron Collider (LHC). We study the correlation between the cross sections and the branching ratio of B_s -> mu^+ mu^-. For a mixed bino-Higgsino dark matter, the mass differences of the neutralinos can be less than M_Z. This will cause an excess of lepton pairs, above the Standard Model predictions, from the decays of the two heavier neutralinos. We discuss implications of the dilepton invariant mass distribution, and outline a way to extract the neutralino parameters for testing gaugino mass unification and deducing the relic density from an interplay of astrophysical detection and LHC measurements.
The higgsino world is one of the popular natural SUSY scenarios, in which $|μ| \ll M_{gauginos} \ll M_{scalars}$. As such, searching for light degenerate higgsinos becomes an essential task of testing naturalness in supersymmetry (SUSY). In this work, we study the indirect effects of light higgsinos in the process $e^+e^- \to W^+W^-$ at future Higgs factories, such as Circular Electron Positron Collider (CEPC) in China. we find that the higgsino mass parameter $μ\lesssim 210$ GeV favored by naturalness can be covered if the accuracy of the measurement of $W^+W^-$ production can reach 0.1\% at …
Given the recent progress in dark matter direction detection experiments, we examine a light bino-higgsino dark matter (DM) scenario ($M_1<100$ GeV and $μ<300$ GeV) in natural supersymmetry with the electroweak fine tuning measure $Δ_{EW}<30$. By imposing various constraints, we note that: (i) For $sign(μ/M_1)=+1$, the parameter space allowed by the DM relic density and collider bounds can almost be excluded by the very recent spin-independent (SI) scattering cross section limits from the XENON1T (2017) experiment. (ii) For $sign(μ/M_1)=-1$, the SI limits can be evaded due to the cancelation e…
A 100 TeV proton-proton collider will be an extremely effective way to probe the electroweak sector of the Minimal Supersymmetric Standard Model (MSSM). In this paper, we describe a search strategy for discovering pair-produced Higgsino-like next-to-lightest supersymmetric particles (NLSPs) at a 100 TeV hadron collider that decay to Bino-like lightest supersymmetric particle (LSP) via intermediate Z and SM Higgs boson that in turn decay to a pair of leptons and a pair of b-quarks respectively: $\widetilde{N}_2^0\widetilde{N}_3^0 \rightarrow (Z\widetilde{N}_1^0)(h\widetilde{N}_1^0)\rightarrow b…
In natural SUSY models higgsinos are always light because μ^2 cannot be much larger than M_Z^2, while squarks and gluinos may be very heavy. Unless gluinos are discovered at LHC13, the commonly assumed unification of gaugino mass parameters will imply correspondingly heavy winos and binos, resulting in a higgsino-like LSP and small inter-higgsino mass splittings. The small visible energy release in higgsino decays makes their pair production difficult to detect at the LHC. Relaxing gaugino mass universality allows for relatively light winos and binos without violating LHC gluino mass bounds an…
Interpreting the High-Recoil LUX-ZEPLIN Event with Bino-/Singlino-like and Higgsino Dark Matter
Argonne National Laboratory（阿贡国家实验室）；University of Cincinnati（辛辛那提大学）；Johannes Gutenberg University（约翰内斯·古腾堡大学）；University of Chicago（芝加哥大学）；Perimeter Institute for Theoretical Physics（理论物理珀米特研究所）
We study the search for electroweakinos at the 13 TeV LHC in the case of heavy scalar superpartners. We consider both the direct production mode and the one associated with the decay of heavy Higgs bosons, and concentrate on the case of light Higgsinos and Binos. In this case, the direct production searches becomes more challenging than in the light Wino scenario. In the direct production mode, we use the current experimental searches to set the reach for these particles at larger luminosities, and we emphasize the relevance of considering both the neutral gauge boson and the neutral Higgs dec…
We explore the implications of third family ($t-b-τ$) quasi-Yukawa unification (QYU) for collider and dark matter (DM) searches within the framework of a supersymmetric $SU(4)_c \times SU(2)_L \times SU(2)_R$ model. The deviation from exact Yukawa unification is quantified through the relation $y_t : y_b : y_τ= |1+C|:|1-C|:|1+3C|$, with $C$ being a real parameter ($|C| \leq 0.2$). We allow for the breaking of left-right symmetry both by the soft scalar and gaugino mass parameters and obtain a variety of viable solutions that predict the sparticle mass spectrum including LSP DM (whose stability…
We study the scenario of higgsino dark matter in the context of a non-standard cosmology with a period of matter-domination prior to Big-Bang nucleosynthesis. Matter-domination changes the dark matter relic abundance if it ends via reheating to a temperature below the higgsino thermal freeze-out temperature. We perform a model independent analysis of the higgsino dark matter production in such scenario. We show that light higgsino-type dark matter is possible for reheating temperatures close to 1 GeV. We study the impact of dark matter indirect detection and collider physics in this context. W…
There are many extensions of the standard model that predict the existence of electroweakly interacting massive particles (EWIMPs), in particular in the context of the dark matter. In this paper, we provide a way for indirectly studying EWIMPs through the precise study of the pair production processes of charged leptons or that of a charged lepton and a neutrino at future 100 TeV collider experiments. It is revealed that this search method is suitable in particular for Higgsino, providing us the $5σ$ discovery reach of Higgsino in supersymmetric model with mass up to 850 GeV. We also discuss h…
A light singlino is a promising candidate for dark matter, and a light higgsino is natural in the parameter space of the NMSSM. We study the combined constraints on this scenario resulting from the dark matter relic density, the most recent results from direct detection experiments, LEP and the LHC. In particular limits from a recent search for electroweak production of charginos and neutralinos at $\sqrt{s}=13$ TeV after 35.9 fb$^{-1}$ by CMS and constraints on spin-independent dark matter-nucleon cross sections from XENON1T after one tonne$\times$year exposure are considered. We find that sc…
We examine updated prospects for detecting WIMPs in supersymmetric models via direct and indirect dark matter search experiments. We examine several historical and also still viable scenarios: projections for well-tempered neutralinos (WTN), projections from the MasterCode (MC), BayesFits (BF) and Fittino (FO) collaborations, non-thermal wino dark matter (NThW) and finally mixed axion-higgsino dark matter from SUSY with radiatively-driven naturalness (RNS). The WTN is ruled out by recent limits from XENON and LUX collaborations. The NThW scenario, previously on tenuous ground due to gamma-line…
The electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM) can account for variety of experimental data. The EW particles with masses of a few hundred GeV evade the LHC searches owing to their small production cross sections. Such a light EW sector can in particular explain the reinforced $4.2\,σ$ discrepancy between the experimental result for the anomalous magnetic moment of the muon, \gmin2, and its Standard Model (SM) prediction. The lightest supersymmetric particle (LSP), assumed to be the lightest neutralino, $\tildeχ_1^0$, as a Dark Matter (DM) candidate is furtherm…
A highly bino-like Dark Matter (DM), which is the Lightest Supersymmetric Particle (LSP), could be motivated by the stringent upper bounds on the DM direct detection rates. This is especially so when its mass is around or below 100 GeV for which such a bound tends to get most severe. Requiring not so large a higgsino mass parameter, that would render the scenario reasonably natural, prompts such a bino-like state to be relatively light. In the Minimal Supersymmetric Standard Model (MSSM), in the absence of comparably light scalars, such an excitation, if it has to be a thermal relic, is unable…
An electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM) with masses of a few hundred GeV can account for variety of experimental data, assuming the lightest neutralino to be the lightest supersymmetric (SUSY) particle: the non-observation at the LHC searches owing to their small production cross sections, the results for the (upper limit of the) Dark Matter (DM) relic abundance and the DM Direct Detection (DD) limits. Such a light EW sector can in particular explain the reinforced $4.2\,σ$ discrepancy between the experimental result for $(g-2)_μ$, and its Standard Model …
The strong constraints on the R-parity conserving supersymmetry (SUSY) from the LHC searches motivate us to consider the new models in which the low-scale SUSY is still allowed. We propose a kind of R-parity violating SUSY scenarios with a non-zero $U^c_2 D^c_2 D^c_3$ operator. Three relevant LHC searches are recasted to test the status of this scenario in terms of four simplified models, with either light stop-Bino, stop-Higgsino, sbottom-Bino or sbottom-Higgsino. Some difficult scenarios for the LHC SUSY searches in these simplified models are identified. By extrapolate the current LHC searc…
We delineate the allowed parameter and mass range for a wino-like dark matter particle containing some Higgsino admixture in the MSSM by analysing the constraints from diffuse gamma-rays from the dwarf spheroidal galaxies, galactic cosmic rays, direct detection and cosmic microwave background anisotropies. A complete calculation of the Sommerfeld effect for the mixed-neutralino case is performed. We find that the combination of direct and indirect searches poses significant restrictions on the thermally produced wino-Higgsino dark matter with correct relic density. For $μ>0$ nearly the entire …
目前对希格斯质量的测量，引力介导的超对称破缺中普遍存在的环抑制的高吉诺质量，来自$\sim$ TeV质量高吉诺的残余暗物质密度，以及超对称规范耦合统一的成功，表明标量超伴侣质量大约为$m_{sc} \sim$ 100-1000 TeV。希格斯诺质量，如果不是在普朗克尺度，一般应该出现在相同的尺度。来自异常调解的高吉诺质量贡献，具有重希格斯诺阈值，通常会导致比标准异常调解更压缩的光谱，而在$m_{sc}$附近存在额外的矢量状物质通常会导致更压缩的光谱。相对于MSSM，重Higgsinos改善了规范耦合统一。重标量提出了新的可能性的味道物理-大的味道违反软质量现在允许，产生有趣的新FCNC的水平，并重新开放的辐射产生的费米子质量层次的吸引力的可能性。Gluinos和binos/winos必须通过更高维度的算子衰变，这对新物理学的存在提供了独特的处理尺度$m_{sc}$。Gluino衰变应该是壮观的，例如产生四个顶部的事件-在适度位移的顶点-和两个希格斯加上丢失的能量。高尺度的$m_{sc}$也可以在违反味道的胶子衰变中探测，以及胶子分支比到第三代的特定模式。最后，对于重希格斯玻色子，中性维诺和双星的主要衰变是通过希格斯玻色子$\tilde b \to \tilde w h$进行的。希格斯玻色子的重量可以从稀有衰变$\tilde b \to \tilde w Z$的分支比推断出来。
Electroweak WIMPs are under intense scrutiny from direct detection, indirect detection, and collider experiments. Nonetheless the pure (pseudo-Dirac) higgsino, one of the simplest such WIMPs, remains elusive. We present an up-to-date assessment of current experimental constraints on neutralino dark matter. The strongest bound on pure higgsino dark matter currently may arise from AMS-02 measurements of antiprotons, though the interpretation of these results has sizable uncertainty. We discuss whether future astrophysical observations could offer novel ways to test higgsino dark matter, especial…
TeV Higgsino Interpretation of the LZ High-Recoil Event with Intermediate-Scale Electroweak Gauginos
Institute of Physics, Henan Academy of Sciences（中国科学院河南分院物理研究所）；Centre for Theoretical Physics, Henan Normal University（河南师范大学理论物理中心）；School of Physics, Zhengzhou University（郑州大学物理学院）
We investigate dark matter in a constrained $E_6$ inspired supersymmetric model with an exact custodial symmetry and compare with the CMSSM. The breakdown of $E_6$ leads to an additional $U(1)_N$ symmetry and a discrete matter parity. The custodial and matter symmetries imply there are two stable dark matter candidates, though one may be extremely light and contribute negligibly to the relic density. We demonstrate that a predominantly Higgsino, or mixed bino-Higgsino, neutralino can account for all of the relic abundance of dark matter, while fitting a 125 GeV SM-like Higgs and evading LHC li…
We study a simplified scenario in the next-to-minimal supersymmetric standard model with a split electroweak spectrum, in which only the singlino and higgsinos are light and other superpartners are decoupled. Serving as a dark matter candidate, a singlino-dominated neutralino $\tildeχ_1^0$ should have either resonant annihilation effects or sizable higgsino components to satisfy the observed relic abundance. The sensitivities of LHC searches and dark matter detection experiments are investigated. With an integrated luminosity of $30 (300) \mathrm{fb}^{-1}$, $3l + E_\mathrm{T} \!\!\!\!\!\!\!/ \…
The possibility in supersymmetric scenarios that the dark matter candidate is a Higgsino-like neutralino means that its production can be associated with Higgs bosons. Taking advantage of this fact, we propose a LHC search strategy for gluinos with $τ$ leptons in the final state, coming from the decay of a Higgs boson. We consider the strong production of a pair of gluinos, one of which decays into the Higgsino plus jets while the other decays into the bino plus jets. In turn, this bino decays into the Higgsino plus a Higgs boson which finally decays into a $τ$-lepton pair. Therefore, the expe…
Split higgsinos are a compelling class of models to explain dark matter and may be on the verge of detection by multiple current experimental avenues. The idea is based on a large split in scales between the electroweak scale and decoupled scalars, with relatively light higgsinos between the two. Such models enjoy the merit of depending on very few parameters while still explaining gauge coupling unification, dark matter, and most of the hierarchy between the Planck and electroweak scales, and they remain undetected by past experiments. We analyze split higgsinos in view of current and next ge…
We study dark matter physics in the Minimal Supersymmetric Standard Model with non-universal gaugino masses at the unification scale. In this scenario, the specific ratio of wino and gluino masses realizes the electro-weak scale naturally and achieves 125 GeV Higgs boson mass. Then, relatively light higgsino is predicted and the lightest neutral particle, that is dominantly given by the neutral component of higgsino, is a good dark matter candidate. The direct detection of the dark matter is sensitive to not only a higgsino mass but also gaugino masses significantly. The upcoming XENON1T exper…
Higgsino dark matter in the Starobinsky supergravity with the MSSM in light of the LUX-ZEPLIN event
Utrecht University（乌得勒支大学）；Dutch Institute for Emergent Phenomena（荷兰涌现现象研究所）；Tokyo Metropolitan University（东京都立大学）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study（理化学研究所 Kavli 宇宙粒子与宇宙线研究所（WPI），东京大学前沿研究综合中心）
Even if the concerns related to the naturalness of the electroweak scale are repressed, the Higgs mass and stability of the electroweak vacuum do not allow arbitrarily large supersymmetry breaking scale, $M_S$, in the minimal models with split or high-scale supersymmetry. We show that $M_S$ can be raised to the GUT scale if the theory below $M_S$ contains a Higgs doublet, a pair of TeV scale Higgsino and widely separated gauginos in addition to the Standard Model particles. The presence of wino and gluino below ${\cal O}(100)$ TeV leads to precision unification of the gauge couplings consisten…
