LFV decays of Z boson in Minimal R-symmetric Supersymmetric Standard Model

A future Z-factory will offer the possibility of studying rare Z decays Z → l_1l_2, such as those leading to lepton flavor violation(LFV) final states. In this work, by considering the constraints from radiative two-body decays l_2→ l_1γ, we investigate the LFV decays Z → l_1l_2 in the framework of the Minimal R-symmetric Supersymmetric Standard Model with two benchmark points from the existing literature. The flavor-violating off-diagonal entries Б~(12), Б~(13) and Б~(23) are constrained by the current experimental bounds of l_2→ l_1γ. Considering recent experimental constraints, we also investigate Br(Z → l_1l_2) as a function of M_D~W. The numerical results show that the theoretical predictions of Br( Z → l_1l_2) in the MRSSM are several orders of magnitude below the current experimental bounds. The LFV decays Z → eτ and Z →μт may be promising observation targets in future experiments.     

Oblique parameters in gauged baryon and lepton numbers with a 125 GeV Higgs

In an extension of the standard model,where baryon number and lepton number are local gauge symmetries,we analyze the effect of corrections from exotic fermions and scalars on the oblique parameters S,T,U.Because a light neutral Higgs ho with mass around 124-126 GeV strongly constrains the corresponding parameter space of this model,we also investigate the gluon fusion process gg→h_0 and two photon decay of the lightest neutral Higgs ho→γγ at the Large Hadron Collider.     

熔融制样-波长色散X射线荧光光谱法测定铁矿石中12种主次成分

采用熔融制样法对铁矿石进行熔融制样;以三氧化二钴(Co2O3)作为铁的内标,并对熔剂、氧化剂、脱模剂、熔融温度和熔融比例进行了讨论。采用理论α系数法、经验系数法校正基体效应和各元素的谱线重叠干扰。建立了波长色散X射线荧光光谱(WDXRF)测定铁矿石中12种组分的分析方法。本法测定铁矿标准物质(GBW07822-GBW07830)各组分的相对标准偏差(RSD)在0.41%~4.2%之间,测定值与标准值相符,且与电感耦合等离子发射光谱的对比测定结果一致。利用本法对实际铁矿样品的全铁含量进行测定,结果与化学分析法的测定结果基本一致。     

含均三嗪结构甲氧基丙烯酸酯化合物的合成及抑菌活性研究

采用亲核取代和消除反应,合成了7个含均三嗪结构的新型甲氧基丙烯酸酯化合物,目标化合物的结构经IR、1H NMR、HRMS进行表征。对目标化合物进行了真菌抑制活性实验,结果表明在50ug·m L-1浓度下,4个目标化合物表现出一定的真菌抑制活性。     

单分散聚苯乙烯微球的表面皱纹化

首先制备了不同粒径的未交联的单分散聚苯乙烯(PS)微球;而后通过离子溅射技术在PS微球表面沉积了一层均匀光滑的铂(Pt)壳层,得到了PS-Pt核壳结构的复合微球;最后借用溶剂溶胀法诱导微球表面起皱的发生,从而制备了表面带有皱纹微结构形貌的PS微球.系统考察了微球表面Pt层厚度(t)、微球粒径(D)、溶剂组成(即溶胀度)等因素对球面起皱和皱纹形貌的影响,获得了球面皱纹周期与Pt层厚度的指数关系;结合理论分析了其起皱行为,实验结果与理论分析相吻合.此外,将表面起皱与表面等离子体刻蚀技术相结合,实现了表面带有纳米点状凸起与皱纹复合微结构形貌的PS微球的可控制备.     

Oblique parameters in gauged baryon and lepton numbers with a 125 GeV Higgs

In an extension of the standard model, where baryon number and lepton number are local gauge sym- metries, we analyze the effect of corrections from exotic fermions and scalars on the oblique parameters S, T, U. Because a light neutral Higgs h0 with mass around 12-126 GeV strongly constrains the corresponding parameter space of this model, we also investigate the gluon fusion process gg→h0 and two photon decay of the lightest neutral Higgs h0→yy at the Large Hadron Collider.     

Clifford代数中的双曲相位变换群及其在四维相对论时空中的应用

将Clifford代数所定义的双曲复空间R_H和作用在双曲复空间R_H上的双曲相位变换群U₄(H)赋予了明确的物理意义. 双曲复空间R_H同构于四维Minkowski时空，而其上的双曲相位变换群U₄(H)就是四维相对论时空中的洛仑兹(Lorentz)变换群. 进一步，利用U₄(H)群的复合变换性质，自然导出了四维Minkowski时空中Lorentz变换和速度变换的一般表达式. 由此，将狭义相对论中的特殊Lorentz变换作为特例包含其中. 关键词： 双曲复数 双曲相位变换 Minkowski时空 Clifford代数     

五维大反弹宇宙学模型的重建及其相关宇宙学量的演化

在五维大反弹宇宙学模型框架下,通过给定三种不同的暗能量有效态方程,确定了在该模型中起重要作用的函数f(z),从而描述了五维大反弹模型中相关的宇宙学量随红移量z的演化.研究表明,与情形Ⅰ中有效态方程相对应的宇宙学量的演化规律和当前天文观测数据符合最好. 关键词： 大反弹宇宙学模型 暗能量 态方程     

Two loop electroweak corrections from heavy fermions to b→s＋γ

Applying an effective Lagrangian method and an on-shell scheme, we analyze the electroweak corrections to the rare decay b→, s＋γ from some special two loop diagrams in which a closed heavy fermion loop is attached to the virtual charged gauge bosons or Higgs. At the decoupling limit where the virtual fermions in the inner loop are much heavier than the electroweak scale, we verify the final results satisfying the decoupling theorem explicitly when the interactions among Higgs and heavy fermions do not contain the nondecoupling couplings. Adopting the universal assumptions on the relevant couplings and mass spectrum of new physics, we find that the relative corrections from those two loop diagrams to the SM theoretical prediction on the branching ratio of B → Xsγ can reach 5% as the energy scale of new physics ANp=200 GeV.     

次氯酸钠氧化碘-电感耦合等离子体质谱法同时测定地表水样品中的碘及铜、铅、锌、锰、铁的含量

取地表水样90.0mL置于100mL容量瓶中,用硝酸及氢氧化钠溶液调节其酸度至pH7～9之间,加水至96mL,加入0.6%(质量分数)次氯酸钠溶液1mL,放置2h使碘完全氧化至非挥发性碘酸盐,再加入硝酸3mL酸化使溶液总体积至100.0mL。这一处理实现了采用电感耦合等离子体质谱法同时测定碘与水样中铜、铅、锌、锰、铁的含量。在质谱分析中,测定207Pb和127I使用标准(STD)模式,其余元素均采用动能歧视(KED)模式。经试验,选用钬作为测定碘的内标。所测定6种元素的质量浓度在一定范围内与其相应的信号强度之间呈线性关系。另按规定方法对空白样品进行测定,计算得到6种元素的检出限(3s)依次为0.096,0.071,0.062,0.065,0.044,0.19μg·L~(-1)。以地表水实际样品为基体,各加入上述6种元素的标准溶液,按方法分析并进行回收试验,测得回收率在83.2%～116%之间。测定值的相对标准偏差(n=5)在2.4%～7.3%之间。同一样品经本方法和国家标准方法对所涉及的6种元素进行测定,两方法的结果基本一致。