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1. chinaXiv:201605.01780 [pdf]

Virtual effects of split-SUSY in Higgs productions at linear colliders

Wang, Fei; Wang, Wenyu; Xu, Fuqiang; Yang, Jin Min; Zhang, Huanjun
Subjects: Physics >> The Physics of Elementary Particles and Fields

In split supersymmetry, 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 at 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 the Higgs productions e(+) e(-) -> Zh and e(+) e(-) ->nu(e)(nu) over bar (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) (nu) over bar (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.

submitted time 2016-05-15 Hits2418Downloads719 Comment 0

2. chinaXiv:201605.01779 [pdf]

Constraints on hybrid inflation from flat directions in supersymmetry

Xu, Fuqiang; Yang, Jin Min
Subjects: Physics >> The Physics of Elementary Particles and Fields

We examine the constraints on F-term hybrid inflation by considering the flat directions in the Minimal Supersymmetric Standard Model (MSSM). We find that some coupling terms between the flat direction fields and the field which dominates the energy density during inflation are quite dangerous and can cause the no-exit of hybrid inflation even if their coupling strength is suppressed by Planck scale. Such couplings must be forbidden by imposing some symmetry for a successful F-term hybrid inflation. At the same time, we find that in the D-term inflation these couplings can be avoided naturally. Further, given the tachyonic preheating, we discuss the feasibility of Affleck-Dine baryogenesis after the F-term and D-term inflations. (c) 2006 Elsevier B.V. All rights reserved.

submitted time 2016-05-15 Hits1084Downloads571 Comment 0

3. chinaXiv:201605.01756 [pdf]

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

Wang, Lei; Xu, Fuqiang; Yang, Jin Min
Subjects: Physics >> The Physics of Elementary Particles and Fields

We study the process gamma gamma -> h -> b (b) over 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 integral 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.

submitted time 2016-05-15 Hits1085Downloads591 Comment 0

4. chinaXiv:201605.01746 [pdf]

An extension for direct gauge mediation of metastable supersymmetry breaking

Xu, Fuqiang; Yang, Jin Min
Subjects: Physics >> The Physics of Elementary Particles and Fields

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 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 (h mu(2) similar to 100 TeV). Copyright (C) EPLA, 2009

submitted time 2016-05-15 Hits429Downloads237 Comment 0

5. chinaXiv:201605.01455 [pdf]

Processing of visually evoked innate fear by a non-canonical thalamic pathway

Wei, Pengfei; Liu, Nan; Liu, Xuemei; Tang, Yongqiang; Wu, Bifeng; Zhou, Zheng; Liu, Yaohan; Li, Juan; Zhang, Yi; Wang, Liping; Wei, Pengfei; Liu, Nan; Liu, Xuemei; Tang, Yongqiang; Wu, Bifeng; Zhou, Zheng; Liu, Yaohan; Li, Juan; Zhang, Yi; Wang, Liping
Subjects: Biology >> Biophysics

The ability of animals to respond to life-threatening stimuli is essential for survival. Although vision provides one of the major sensory inputs for detecting threats across animal species, the circuitry underlying defensive responses to visual stimuli remains poorly defined. Here, we investigate the circuitry underlying innate defensive behaviours elicited by predator-like visual stimuli in mice. Our results demonstrate that neurons in the superior colliculus (SC) are essential for a variety of acute and persistent defensive responses to overhead looming stimuli. Optogenetic mapping revealed that SC projections to the lateral posterior nucleus (LP) of the thalamus, a non-canonical polymodal sensory relay, are sufficient to mimic visually evoked fear responses. In vivo electrophysiology experiments identified a di-synaptic circuit from SC through LP to the lateral amygdale (Amg), and lesions of the Amg blocked the full range of visually evoked defensive responses. Our results reveal a novel collicular-thalamic-Amg circuit important for innate defensive responses to visual threats.

submitted time 2016-05-12 Hits1304Downloads584 Comment 0

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