分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We briefly review the supersymetric explanation for the cosmic dark matter. Although the neutralino in the minimal supersymmetric model (MSSM), the next-to-minimal supersymmetric model (NMSSM) and the nearly minimal supersymmetric model (nMSSM) can natura
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The supersymmetric QCD corrections to top quark pair production by qq ̄ anni- hilation in pp ̄ collisions are calculated in the minimal supersymmetric model. We consider effects of the mixing of the scalar top quarks on the corrections to the total tt ̄production cross section at the Fermilab Tevatron. We found that such correction is less sensitive to squark mass and gluino mass than in no-mixing case, and in both cases the corrections can exceed 10% even if we consider the recent CDF limit on squark and gluino masses.
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The O(αmt 2/mW 2)O(αmt 2/mW 2)O(\alpha m_t~2/m_W~2) Yukawa corrections to top pair production in photon-photon collision are calculated in the standard model (SM), the general two-Higgs-doublet model (2HDM) as well as the minimal supersymmetric model (MSS
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We list all possible dimension-six CP-conserving SUc(3)×SUL(2)×UY(1)SUc(3)×SUL(2)×UY(1)SU_c(3)\times SU_L(2) \times U_Y(1) invariant operators involving the third-family quarks which could be generated by new physics at a higher scale. Expressions for the
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We evaluate the supersymmetric QCD corrections to single top quark production via qq?′→tb?qq?′→tb?q \bar q'\to t \bar b at the Fermilab Tevatron in the minimal supersymmetric model. We find that within the allowed range of squark and gluino masses the sup
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The dimension-six CP-violating SU_L(2)\times U_Y(1) invariant operators involving the tau lepton are studied. The constraints from the available experimental data on tau dipole moments are derived. Under the current constraints, the induced CP-violating e
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We examine the possibility of observing exotic top quark decays via RRR-Parity violating SUSY interactions in e+e?e+e?e^+e^- collisions at \sqrt{s = 500 GeV\sqrt{s = 500 GeV\sqrt{s = 500 GeV. We present cross-sections for tt?tt?t\bar t production followed
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-15
摘要: We split the two-Higgs-doublet model by assuming very different vevs for the two doublets: the vev is at weak scale (174 GeV) for the doublet Phi(1) and at neutrino-mass scale (10(-2) - 10(-3) eV) for the doublet Phi(2). Phi(1) is responsible for giving masses to all fermions except neutrinos; while Phi(2) is responsible for giving neutrino masses through its tiny vev without introducing the see-saw mechanism. Among the predicted five physical scalars H, h, A(0) and H-+/-, the CP-even scalar h is as light as 10(-2) - 10(-3) eV while the others are at weak scale. We identify h as the cosmic-dark-energy field and the other CP-even scalar H as the Standard Model Higgs boson; while the CP-odd A(0) and the charged H-+/- are the exotic scalars to be discovered at future colliders. Also we demonstrate a possible dynamical origin for the doublet Phi(2) from neutrino condensation caused by some unknown dynamics.
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-15
摘要: In split supersymmetry, gauginos and Higgsinos are the only supersymmetric particles that are potentially accessible at soon-to-be-completed colliders. While direct experimental research, such as the LEP and Tevatron experiments, have given robust lower bounds on the masses of these particles, cosmic dark matter can give some upper bounds and thus have important implications for research at future colliders. In this work we scrutinize such dark matter constraints and show the allowed mass range for charginos and neutralinos (the mass eigenstates of gauginos and Higgsinos). We find that the lightest chargino must be lighter than about 1 TeV under the popular assumption M-1 = M-2/2 and about 2 or 3 TeV in other cases. The corresponding production rates of the lightest chargino at the CERN large hadron collider (LHC) and the International Linear Collider (ILC) are also given. While in some parts of the allowed region the chargino pair production rate can be larger than 1 pb at the LHC and 100 fb at the ILC, other parts of the region correspond to very small production rates, and thus there is no guarantee of finding the charginos of split supersymmetry at future colliders.
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We systematically calculate various flavor-changing neutral-current top-quark processes induced by supersymmetry at the Large Hadron Collider, which include five decay modes and six production channels. To reveal the characteristics of these processes, we
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-04-06
摘要: Bismuth selenide (Bi2Se3) has proven to be an important material in thermoelectric and topological insulator applications. We report here a simple electrochemical self-assembly route for the preparation of well-defined hierarchical dendritic Bi2Se3 nanost
分类: 物理学 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: This talk is a brief review of the recent studies on probing new physics through single top quark processes and probing exotic top quark decays at the upgraded Tevatron.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: MXenes, a novel family of two-dimensional metal carbides, are receiving intense attention for lithium-ion batteries (LIBs) and super- capacitors because they have high volumetric capacitance exceeding all carbon materials. However, serious interlayer stacking exists in MXene particles, which greatly decreases the electrical conductivity in the bulk and hinders the accessibility of interlayers to electrolyte ions. Thus, multi-stacked MXene particles exhibit low capacitance and poor rate capability. Herein, we report an effective strategy to directly improve the electrochemical performance of multi-stacked MXene (Ti3C2Tx) particles as LIB anode materials. It was successfully realized by growing conductive “carbon nanofiber (CNF) bridges” within the gaps of each Ti3C2Tx particle as well as the outside. With the help of these CNFs, the as-prepared Ti3C2/CNF particles exhibited signifi- cantly improved reversible capacity compared with pure Ti3C2Tx particles. More remarkably, even at an ultrahigh rate of 100 C, the capacity of Ti3C2/CNF hybrid particles was just slightly lower than that of pure Ti3C2Tx particles at 1 C, and there was no capacity decay after 2900 cycles at 100 C, demonstrating excellent rate capability and superior long-term stability at the ultrahigh rate.
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-05-09
摘要: Perylene tetracarboxylic anhydride (PTCDA) was reacted with 6-aminocaproic acid to form the corresponding perylene bisimide (PBI). PBI was used as the foundation for oligomerisation of glycidol in a ring-opening reaction of glycidol leading to a hyper branched, water-soluble glycidol derivative of perylene (PBI-HPG). PBI-HPG was bound to the reduced graphene oxide via p–p stacking resulting in a compound termed PBI-HPG/RGO. The structure and morphology of PBI-HPG/RGO were investigated by infrared spectroscopy (FT-IR), wide angle X-ray diffractometry (WAXD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). PBI- HPG/RGO was blended at different loadings in order to improve the thermal and mechanical properties of epoxy composites. The maximum Tg of the epoxy composites was about 20 C and the decomposition temperature (Td) was 26 C higher than that of neat epoxy. The incorporation of PBI- HPG/RGO yields a material with an impact strength of 39.6 kJ m 2 and a tensile strength at 0.7 wt%. It increased by 50.8% and 62.3%, respectively, compared to the neat epoxy.