Excited weak vector bosons facing the high energy and high precision frontier

If the recently discovered weak bosons W^± and Z were manifestations of a composite structure of the weak interactions rather than the commonly assumed gauge bosons of a fundamental gauge symmetry one is naturally led to expect a corresponding spectrum of excited weak vector bosons. Experiments at LEP I/SLC and LEP II may be uniquely suited to shed light on this question with their power to perform high precision tests of the standard model.     

高精度保偏光纤偏振测试系统的设计

介绍了保偏光纤的偏振串音和h参数以及它们的相互关系。给出了高精度起偏系统和检偏系统的光路结构。对影响测试精度的各种因素进行了详细分析,并使用自制的测试系统对国内几个单位生产的保偏光纤进行了测试,得到了理想的测试结果。其中,2m长的保偏光纤的偏振串音达到了-50dB以下,其测试精度达到了国际先进水平。     

Neutral vector bosons in Bhabha scattering

The colliding-beam experiments ofe ⁺ ande ^?-annihilation scattering mediated by a weakly coupled neutral vector bosonW ⁰ as suggested by various authors are recalculated in more detail. It is shown that the height of the resonance, which is to be expected at the mass-shell energies of W⁰, can be determined exactly by renormalizing the second-order self-energy diagram ofW ⁰. It is further shown, how the special form of the cross-section could serve as a test for the correctness of aV- A ansatz in neutral current interactions.     

Searching for new heavy vector bosons inp \bar p colliders

Production and detection of new heavy vector bosons is studied at present (or near future)p \(\bar p\) collider experiments. Application to CERN and Tevatron experiments is considered in detail, but some results for the UNKp \(\bar p\) collider, at \(\sqrt s \) = 6TeV, are also presented. Rather than considering a number of detailed models, we prefer to discuss some general, although necessarily schematic, classes of new vector bosons ranging from strongly interacting Higgs sector models to extended gauge models. We study in particular signals and backgrounds in the \(\ell \overline \ell jj\) channels, where ? are leptons andj are hadron jets.     

Anomalously interacting new extra vector bosons and their first LHC constraints

In this review phenomenological consequences of the Standard Model extension by means of new spin-1 chiral fields with the internal quantum numbers of the electroweak Higgs doublets are summarized. The prospects for resonance production and detection of the chiral vector Z* and W*^± bosons at the LHC energies are considered on the basis of quantitative simulations within the CompHEP/CalcHEP package. The Z* boson can be observed as a Breit-Wigner resonance peak in the invariant dilepton mass distributions in the same way as the well-known extra gauge Z?? bosons. However, the Z* bosons have unique signatures in transverse momentum, angular and pseudorapidity distributions of the final leptons, which allow one to distinguish them from other heavy neutral resonances. In 2010, with 40 pb^?1 of the LHC proton-proton data at the energy 7 TeV, the ATLAS detector was used to search for narrow resonances in the invariant mass spectrum of e ⁺ e ^? and ??⁺??^? final states and high-mass charged states decaying to a charged lepton and a neutrino. No statistically significant excess above the Standard Model expectation was observed. The exclusion mass limits of 1.15 and 1.35 TeV/c ² were obtained for the chiral neutral Z* and charged W* bosons, respectively. These are the first direct limits on the W* and Z* boson production. Based on the above, a novel strategy for the chiral boson search in the LHC dijet data is discussed. For almost all currently considered exotic models the relevant signal is expected in the central dijet rapidity region y _1,2 ? 0 and |y ₁ ? y ₂| ? 0. On the contrary, the chiral bosons do not contribute to this region but produce an excess of dijet events far away from it. In particular, for these bosons the appropriate kinematical restrictions lead to a dip in the centrality ratio distribution over the dijet invariant mass instead of a bump expected in the most exotic models.     

新型高精度绝对重力仪

精密测量地球表面的重力加速度(g, 常用值9.81 m/s²) 是探测地球重力场的重要途径, 已广泛应用于计量、测绘、地质、地震与资源勘探等领域. 随着我国"2000国家重力基本网"和"中国地壳运动观测网络"的建成, 对高精度绝对重力测量的需求日益增加. 为深入研究现有绝对重力测量技术可能存在的系统误差, 并满足国内多个领域对高精度绝对重力仪的迫切需求, 自主研制T-1型可搬运式高精度绝对重力仪样机, 采用经典的真空自由落体方案, 通过激光干涉测量和数据拟合方法获得重力加速度值. T-1型绝对重力仪主要包括以下几部分: 高真空度自由落体装置、小型化激光干涉测量装置、超低频垂直隔振系统、高速信号采集系统、仪器控制与数据处理系统. 绝对重力测量的长度基准为稳频He-Ne激光器, 时间基准为铷原子钟, 这两项现有基准的测量不确定度都优于1× 10^-9. 测试结果表明, T-1型绝对重力仪在12 h内重力测值的标准差可优于1 μupGal (1 μupGal = 10^-8 m/s²), 测量结果的复现性优于3 μupGal, 可实现微伽量级不确定度的精密重力测量, 有望在我国多个关键领域发挥重要应用.     

Spinless bosons embedded in a vector Duffin-Kemmer-Petiau oscillator

Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties with each term of the DKP equation and the proper boundary conditions on the spinors are imposed. It is shown that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The exact solutions for the vector DKP oscillator (nonminimal vector coupling with a linear potential which exhibits an equally spaced energy spectrum in the weak-coupling limit) for spin-0 bosons are presented in a closed form and it is shown that the spectrum exhibits an accidental degeneracy.     

An apparatus for high precision measurements of ultrasonic wave velocity

An automatic gated-carrier pulse superposition system for high precision ultrasonic velocity measurements is described, having better stability and lower cost than previous equipment. The necessary new integrated circuitry, and the method of operation, are described in detail. The principal application is to the measurement of small changes in the velocity of MHz ultrasonic waves, such as occur when materials are subjected to stress. Results are presented confirming a detection sensitivity of 1 part in 10.     

Positron trapping measurements of high precision using a labelling technique

The small effects associated with positron trapping in metal defects are masked in practice not only by inherent statistical fluctuations, but also by electronic instabilities. the unique directional correlation of annihilation quanta allows us to use a very efficient labelling technique which facilitates simultaneous measurements of the annihilation energy spectrum in the sample and in a standard. The result is that the system becomes essentially free of drift, so that precision of energy determination is limited by the statistics of counting alone. We have used the efficient technique of Ge(Li) spectroscopy together with labelling to measure the annihilation lineshape. Lineshape parameters, including the first two moments, have been extracted from this data. The techniques are applied to the measurement of recovery at room temperature and to a determination of the binding energy of positrons to traps in aluminum. Paper B 25 presented at 3rd Internat'l Conf. Positron Annihilation, Otami, Finland (August 1973).     

Time-resolved measurements of high order harmonics confined by polarization gating

We investigate the temporal confinement of high order harmonic pulses generated by a femtosecond (fs) infrared (IR) pulse with a time varying polarization. We use a set of two birefringent quartz plates to modulate the IR polarization. It produces a short temporal gate of linear polarization where harmonics are efficiently generated during a small fraction of the IR pulse. By rotating one of the plates, the gate width can be continuously varied between 70 fs down to 7 fs. The XUV pulse duration is measured by cross-correlation with a probe IR pulse of 12 fs. When the gate width is decreased, a clear temporal confinement of the XUV emission is observed through the cross correlation signal. This experiment is the first direct experimental evidence in the temporal domain that the polarization gating technique can be used to significantly shorten the harmonic pulse duration. PACS 32.80.Wr; 42.65.Ky; 42.65.Re     

脉冲强磁场下的电极化测量系统

多铁性材料是当前物质科学研究的热点,具有重要的科学研究意义和应用前景.低温和强磁场实验环境为研究多铁性材料提供了一种有效途径.脉冲强磁场下的电极化测量系统能实现最高磁场强度60 T、最低温度0.5 K的铁电特性测量.该系统采用热释电方法,具有磁场强度高、控温范围广、转角测量等特点,可用于强磁场下的磁电特性研究.本文介绍了该系统的测量装置和实验原理,并展示了其在多铁性材料研究中的一系列应用,揭示了脉冲强磁场电极化测量系统在磁电特性探索中的重要作用.     

高精度大口径平面镜瑞奇-康芒定量检测方法研究

瑞奇 康芒法是检测大口径平面时的行之有效的方法。由于被检平面处于发散光路中,这就使得平面面形与系统波像差之间的关系(即影响函数)变得十分复杂,推导起来十分困难,故长期以来该方法只能作为一种定性或半定量的检测手段。给出了数学算法,推导出了被检平面镜面形误差与检验系统波像差之间的相互关系,实现了瑞奇 康芒的定量检测。     

A new Channeltron-detector setup for precision mass measurements at ISOLTRAP

Recent technical developments at ISOLTRAP include the design, installation and characterization of a new Channeltron-detector setup in order to increase the detection efficiency by about a factor of 3. Since a detection efficiency close to 100% is reached, true single-ion experiments can be performed for the first time and exotic nuclides further away from the valley of stability with lower production yields and/or shorter half-lives as compared to previous investigations are accessible. This publication comprises part of the thesis of C. Yazidjian.     

A new type of precision ellipsometer without employing a compensator

The apparatus is designed for ellipsometry based on the measurement of the principal angle of incidence. It is of the return-path type, somewhat like the Littrow-type spectrometer, requiring only one polarizer and no compensator.     

Dispersion relations of vector and scalar bosons in material media

Bulletin of the Lebedev Physics Institute - The dispersion relations of vector, scalar, and pseudo-scalar bosons of a dielectric medium are determined taking into account their resonant interaction...     

Dynamical light vector mesons in low-energy scattering of Goldstone bosons

We present a study of Goldstone boson scattering based on the flavor SU(3) chiral Lagrangian formulated with vector mesons in the tensor field representation. A coupled-channel computation is confronted with the empirical s- and p-wave phase shifts, where good agreement with the data set is obtained up to about 1.2 GeV. There are two relevant free parameters only, the chiral limit value of the pion decay constant and the coupling constant characterizing the decay of the rho meson into a pair of pions. We apply a recently suggested approach that implements constraints from micro-causality and coupled-channel unitarity. Generalized potentials are obtained from the chiral Lagrangian and are expanded in terms of suitably constructed conformal variables. The partial-wave scattering amplitudes are defined as solutions of non-linear integral equations that are solved by means of an N/D ansatz.