4,135 research outputs found

    An Extension for Direct Gauge Mediation of Metastable Supersymmetry Breaking

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    We study the direct mediation of metastable supersymmetry breaking by a \Phi^2-deformation to the ISS model and extend it by splitting both Tr\Phi and Tr\Phi^2 terms in the superpotential and gauging the flavor symmetry. We find that with such an extension the enough long-lived metastable vacua can be obtained and the proper gaugino masses can be generated. Also, this allows for constructing a kind of models which can avoid the Landau pole problem. Especially, in our metastable vacua there exist a large region for the parameter m_3 which can satisfy the phenomenology requirements and allow for a low SUSY breaking scale (\sim 100 TeV).Comment: version in Europhys. Let

    Virtual Effects of Split SUSY in Higgs Productions at Linear Colliders

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    In split supersymmetry the gauginos and higgsinos are the only supersymmetric particles possibly accessible at foreseeable colliders like the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). In order to account for the cosmic dark matter measured by WMAP, these gauginos and higgsinos are stringently constrained and could be explored at the colliders through their direct productions and/or virtual effects in some processes. The clean environment and high luminosity of the ILC render the virtual effects of percent level meaningful in unraveling the new physics effects. In this work we assume split supersymmetry and calculate the virtual effects of the WMAP-allowed gauginos and higgsinos in Higgs productions e+e- -> Z h and e+e- -> \nu_e \bar_\nu_e h through WW fusion at the ILC. We find that the production cross section of e+e- -> Zh can be altered by a few percent in some part of the WMAP-allowed parameter space, while the correction to the WW-fusion process e+e- -> \nu_e \bar_\nu_e h is below 1%. Such virtual effects are correlated with the cross sections of chargino pair productions and can offer complementary information in probing split supersymmetry at the colliders.Comment: more discussions added (7 pages, 10 figs

    Mining Site Reclamation Planning Based on Land Suitability Analysis and Ecosystem Services Evaluation: A Case Study in Liaoning Province, China

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    Restoration of the degraded ecosystem is a global priority for achieving sustainable development. Although increasing ecosystem service is an important goal of ecological restoration, it is rarely used to inform mine reclamation. This study proposed a reclamation strategy that incorporated land suitability analysis and ecosystem service evaluation for a mining site in Liaoning Province, China. We assessed the land suitability for three reclamation alternatives and identified suitable land uses for each location by comparing their suitability levels. For areas that were suitable for multiple land uses with the same suitability level, the future land uses cannot be identified by land suitability analysis alone, and we employed ecosystem services evaluation to determine the optimal reclamation strategy. The results showed that forest could be restored throughout the entire mining site, agricultural land were most suitable in the western and southern parts, and developed land were in northern parts that were closer to roads and city centers. Our study showed that a large mining site can be reclaimed to different land uses and provided a practical framework for integrating ecosystem services into mine reclamation

    The State-Action-Reward-State-Action Algorithm in Spatial Prisoner's Dilemma Game

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    Cooperative behavior is prevalent in both human society and nature. Understanding the emergence and maintenance of cooperation among self-interested individuals remains a significant challenge in evolutionary biology and social sciences. Reinforcement learning (RL) provides a suitable framework for studying evolutionary game theory as it can adapt to environmental changes and maximize expected benefits. In this study, we employ the State-Action-Reward-State-Action (SARSA) algorithm as the decision-making mechanism for individuals in evolutionary game theory. Initially, we apply SARSA to imitation learning, where agents select neighbors to imitate based on rewards. This approach allows us to observe behavioral changes in agents without independent decision-making abilities. Subsequently, SARSA is utilized for primary agents to independently choose cooperation or betrayal with their neighbors. We evaluate the impact of SARSA on cooperation rates by analyzing variations in rewards and the distribution of cooperators and defectors within the network

    Higgs boson production in photon-photon collision at ILC: a comparative study in different little Higgs models

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    We study the process \gamma\gamma->h->bb_bar at ILC as a probe of different little Higgs models, including the simplest little Higgs model (SLH), the littlest Higgs model (LH), and two types of littlest Higgs models with T-parity (LHT-I, LHT-II). Compared with the Standard Model (SM) prediction, the production rate is found to be sizably altered in these little Higgs models and, more interestingly, different models give different predictions. We find that the production rate can be possibly enhanced only in the LHT-II for some part of the parameter space, while in all other cases the rate is suppressed. The suppression can be 10% in the LH and as much as 60% in both the SLH and the LHT-I/LHT-II. The severe suppression in the SLH happens for a large \tan\beta and a small m_h, in which the new decay mode h->\eta\eta (\eta is a light pseudo-scalar) is dominant; while for the LHT-I/LHT-II the large suppression occurs when f and m_h are both small so that the new decay mode h->A_H A_H is dominant. Therefore, the precision measurement of such a production process at the ILC will allow for a test of these models and even distinguish between different scenarios.Comment: Version in JHEP (h-g-g & h-gamma-gamma expressions added

    Design and trajectory tracking control of CuRobot: A Cubic Reversible Robot

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    In field environments, numerous robots necessitate manual intervention for restoration of functionality post a turnover, resulting in diminished operational efficiency. This study presents an innovative design solution for a reversible omnidirectional mobile robot denoted as CuRobot, featuring a cube structure, thereby facilitating uninterrupted omnidirectional movement even in the event of flipping. The incorporation of eight conical wheels at the cube vertices ensures consistent omnidirectional motion no matter which face of the cube contacts the ground. Additionally, a kinematic model is formulated for CuRobot, accompanied by the development of a trajectory tracking controller utilizing model predictive control. Through simulation experiments, the correlation between trajectory tracking accuracy and the robot's motion direction is examined. Furthermore, the robot's proficiency in omnidirectional mobility and sustained movement post-flipping is substantiated via both simulation and prototype experiments. This design reduces the inefficiencies associated with manual intervention, thereby increasing the operational robustness of robots in field environments

    Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials

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    The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3) has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed
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