<i>H</i>, <i>W</i>, <i>Z</i>Bosons, Dark Matter: Composite Particles?

The present article develops a model initially published in ref. [1]. It is a quasi-classical quantum model of composite particles with ultra-relativistic (UR) constituents (leptons and quarks). The model is used to calculate the mass energy of three composite particles: a UR tauonium, a UR bottomonium and a UR leptoquarkonium. The result is that these three hypothetic particles have masses close to 125 GeV: the Higgs boson mass energy. These results are recalled in the present article. Then the model is extended to calculate the mass energy of pi-mesons, W and Z bosons. Finally, the model provides a hypothesis on dark matter.

最小Z′模型下e^+e^-→Zh过程的研究

在最小Z′模型下研究了ILC对撞机上的希格斯玻色子辐射过程e^+e^-→Zh.首先在允许的参数空间范围内计算了该过程的产生截面,然后以e^+e^-→Zh→l+l-bb-为信号,对e^+e^-→Zh过程进行了详细的信号背景分析.结果表明:在给出的事例选取方案下,可以有效地压低背景凸显信号从而为ILC对撞机上通过e^+e^-→Zh研究最小Z′模型提供了理论参考.

The Harmonic Neutron Hypothesis: Prime Number Factor Patterns and Their Relationship to the Hierarchy of the Fundamental Particles and Bosons

The Harmonic Neutron Hypothesis, HNH, has demonstrated that many of the fundamental physical constants including particles and bosons are associated with specific quantum integers, n. These integers define partial harmonic fractional exponents, 1 ± (1/n), of a fundamental frequency, Vf. The goal is to evaluate the prime and composite factors associated with the neutron n0, the quarks, the kinetic energy of neutron beta decay, the Rydberg constant, R, e, a0, H0, h, α, W, Z, the muon, and the neutron gluon. Their pure number characteristics correspond and explain the hierarchy of the particles and bosons. The elements and black body radiation represent consecutive integer series. The relative scale of the constants cluster in a partial harmonic fraction pattern around the neutron. The global numerical organization is related to the only possible prime factor partial fractions of 2/3, or 3/2, as pairs of 3 physical entities with a total of 6 in each group. Many other progressively resonant prime number factor patterns are identified with increasing numbers of smaller factors, higher primes, or larger partial fractions associated with higher order particles or bosons.

LHCb 7 TeV W和Z数据对CT14HERA2 PDFs的影响

为了研究LHCb 7 TeV W+、W-和Z实验数据对CT14HERA2部分子分布函数(Parton Distribution Functions,PDFs)的影响,首先将收集到的数据进行了理论预测并将其和实验测量结果进行了比较,在误差允许的范围内理论和实验符合的很好。其次,用误差PDFs更新软件包(Error PDFs Updated Method Package,EPUMP)更新了CT14HERA2 PDFs,并和全局拟合的PDFs进行了比较。最后,加入协方差矩阵后的实验数据可以在较大和较小的x区域减少d(x,Q)/u(x,Q)误差,同时也对CT14HERA2 PDFs进行了优化。验证结果表明,LHCb 7 TeV W+、W-和Z产生的实验数据在较大的x区域对g(x,Q)、d(x,Q)、d(x,Q)/u(x,Q)、d(x,Q)/u(x,Q)、u(x,Q)、d(x,Q)和u(x,Q)PDFs的中心值约束较大,可以用前4个误差PDFs代替原来全局拟合或优化后得到的56个误差集。

识别Z玻色子喷注的卷积神经网络方法

高能物理中喷注识别任务是从背景中识别出感兴趣的特定信号,这些信号对于在大型强子对撞机上发现新的粒子,或者新的过程都有着非常重要的意义.量能器中产生的能量沉积可以看做是对喷注的一种拍照,分析这样产生的数据在机器学习领域中属于一个典型的视觉识别任务.基于喷注图片,本文探索了利用卷积神经网络(convolutional neural networks,CNNs)识别量子色动力学背景下的Z玻色子喷注,并与传统的增强决策树(boosted decision trees,BDTs)方法进行了对比.在本文利用的输入前提下,三种相关的性能参数表明,CNN比BDT带来了约1.5倍的效果提升.除此之外,通过最优与最差的喷注图与混淆矩阵,说明了CNN通过训练学习到的内容与整体识别能力.

Structure of Massive “Standard Model” Particles

The massive vector bosons Z o, W ± and the scalar Higgs-boson H o assumed in weak interaction theory, but also the six quarks required in strong interactions are well understood in an alternative quantum field theory of fermions and bosons: Z o and W ± as well as all quark-antiquark states (here only the tt¯state is discussed) are described by bound states with scalar coupling between their massless constituents and have a structure similar to leptons. However, the scalar Higgs-boson H o corresponds to a state with vector coupling between the elementary constituents. Similar scalar states are expected also in the mass region of the mesons ω (0.782 GeV) - Υ ( 9.46 GeV). The underlying calculations can be run on line using the Web-address https://h2909473.stratoserver.net.

Phenomenology of heavy neutral gauge boson at muon collider

Heavy neutral gauge boson Z' is proposed in many new physics models.It has rich phenomena at the future muon collider.We study the properties of Z' boson with the process of μ^(+)μ^(-)→qq,μ^(+)μ^(-)→l^(+)l^(-),μ^(+)μ^(-)→ ZH and μ^(+)μ^(-)→ W^(+)W^(-).The discrepancy of Z' coupling to different types of particles can be shown in the cross section distributions around the resonance peak of various decay modes.Angular distributions of the final quark or lepton in μ^(+)μ^(-)→qq/l^(+)l^(-)process are sensitive to the parameters such as mass of Z' and the Z-Z' mixing angle.The interaction of new gauge boson coupling to the standard model gauge particles and Higgs boson are also studied through μ^(+)μ^(-)→ ZH→l^(+)l^(-)bb and μ^(+)u^(-)→ W^(+)W^(-)→l^(+)l^(-)v_(l)v_(l).The cross section and the final particles' angular distributions with the contribution of Z' boson differ from those processes with only standard model particles.A forward-backward asymmetry defined by the angular distribution is provided to show the potential of searching for new physics at the muon collider.Especially,the beam polarization with certain value can effectively enlarge the forward-backward asymmetry.

The lepton flavor violating signal of the extra gauge boson Z′in photon-photon collision at the ILC

The hitherto unconstrained lepton flavor mixings,induced by the new gauge boson Z ,which are the prediction of many new physics models,such as topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models,may lead to the lepton flavor violating productions of τμˉ,τeˉ and μeˉ in photon-photon collision at the proposed International Linear Collider (ILC).Through a comparative analysis of these processes,we find that the better channel to probe the new physics models is the production of τμˉ or τeˉ which occurs at a much higher rate than μeˉ production due to the large mixing angle and the large flavor changing coupling,and may reach the detectable level of the ILC for a large part of the parameter space.Since the rates predicted by the Standard Model are far below the detectable level,these processes may serve as a sensitive probe for such new physics models.

Neutrino Production via e^-e^+ Collision at Z-Boson Peak

The production of the three normal neutrinos via e-e+ collision at Z-boson peak(neutrino production in a Z-factory) is investigated thoroughly. The differences of νe-pair production from νμ-pair and ντ-pair production are presented in various aspects. Namely the total cross sections, relevant differential cross sections and the forwardbackward asymmetry etc. for these neutrinos are presented in terms of figures as well as numerical tables. The restriction on the room for the mixing of the three species of light neutrinos with possible externals(heavy neutral leptons and/or sterile neutrinos) from refined measurements of the invisible width of Z-boson is discussed.

Angular distribution coefficients of Z(W) boson produced in e^+e^- collisions at s^(1/2) = 240 GeV

At the designed circular electron-positron collider(CEPC), similar to the hadron collider, the angular distribution coefficients of the decay lepton pair from the produced Z(W) boson in e^+e^- collisions are predicted. Their dependence on cosθZ(cosθW) are presented in four different polarization frames. Furthermore, the value of the angular distribution coefficients in different bins of cosθZ are presented in the C-S frame. In comparison with the case at the hadron collider, better accurate measurement for Z(W) is expected because there is less background, and W could be reconstructed from its leptonic decay channel. This works provides a method to precisely test the electroweak production mechanism or some effect induced from new physics in the future measurements at the CEPC.

Z′和τ的轻子味破坏衰变

许多超出标准模型的新物理预言了非普适规范玻色子Z′的存在 .此新粒子可产生许多新的物理现象 .本文计算了顶色辅助的人工色 (TC2 )模型和味普适TC2模型预言的非普适规范玻色子Z′对τ的轻子味破坏衰变过程τ→liγ ,τ→liljlk 的贡献 .结果表明 ,在整个参数空间内 ,过程τ→liljlk 的分支比比τ→liγ的分支比大 .在适当的参数空间内 ,分支比Br(τ→liljlk)可达到 10 -8.因此 ,在将来的高能实验中有可能探测到此新物理效应 .

味普适TC2模型与轻子味破坏衰变Z→l_il_j

讨论计算了味普适TC2模型预言的额外U(1)规范玻色子Z′对轻子味破坏 (LFV)衰变Z→lilj 过程的贡献 .结果表明Z′对此过程有较大贡献 ,在合理的参数取值范围内 ,Z→τμ和Z→τe的分支比可以接近实验测量值的上限 ,而Z→μe过程的实验测量值上限给味普适TC2模型自由参数以严格的限制 .

L3C宇宙线实验中Z^0数据的分析

μ子动量谱的精确测量是L3C宇宙线实验最重要的目标之一 .事例重建的好坏是该测量的关键 ,而能量确定的衰变为双 μ子的事例是检验重建程序的最好手段 .该数据分析利用在 2 0 0 0年中获取的数据作为样本 ,筛选出了LEP在 2 0 0 0年 4月、5月、8月和 9月等Z0 能量运行期间L3C宇宙线实验数据中记录的Z0 →μ+ μ-事例数据 ,得到通过重建程序后动量为 4 5GeV的 μ子动量分辨率为 (5 .4 7± 0 .2 5 ) % .

Parameterization of general Z-γ-Z′mixing in an electroweak chiral theory

A new general parameterization with eight mixing parameters among Z, γ and an extra neutral gauge boson Z is proposed and subjected to phenomenological analysis. We show that in addition to the conventional Weinberg angle θW , there are seven other phenomenological parameters, G , ξ, η, θl, θr, r and l, for the most general Z-γ-Z mixings, in which parameter G arises due to the presence of an extra Stueckelberg- type mass coupling. Combined with the conventional Z-Z mass mixing angle θ , the remaining six parameters, ξ, η, θl θ , θr θ , r and l, are caused by general kinetic mixing. In all eight phenomenological parameters, θW , G , ξ, η, θl, θr , r and l, we can determine the Z-Z mass mixing angle θ and the mass ratio MZ/MZ . The Z-γ-Z mixing that we discuss are based on the model-independent description of the extended electroweak chiral Lagrangian （EWCL） previously proposed by us. In addition, we show that there are eight corresponding independent theoretical coefficients in our EWCL, which are fully fixed by our eight phenomenological mixing parameters. We further find that the experimental measurability of these eight parameters does not rely on the extended neutral current for Z , but depends on the Z-Z mass ratio.

Analysis of Λ_b →Λl^+l^- rare decays in a non-universal Z’ model

We investigate the rare baryonic Λ_b→Λl^＋l^- decays in a non-universal Z＇ model, which is one of the wellmotivated extensions of the standard model（SM）. Considering the effects of Z-mediated flavour-changing neutral currents（FCNCs） we analyse the differential decay rate, forward-backward asymmetries and lepton polarisation asymmetries for the Λb→Λl^＋l^- decays. We find significant deviations from their SM predictions, which could indicate new physics arising from the Z gauge boson.

A comparison of direct and indirect determinations of the masses of the Higgs Boson and the top quark

The indirect estimation of the Higgs Boson mass from electroweak radiative corrections within the Standard Model is compared with the directly measured value obtained by the ATLAS and CMS Collaborations at the CERN LHC collider. Treating the direct measurement of m_H as input, the Standard Model indirect estimation of the top-quark mass is also obtained and compared with its directly measured value. A model-independent analysis finds an indirect value of m_H of ■70 GeV, below the directly measured value of 125.7±0.4 GeV and an indirect value：m_t = 177.3±1.0 GeV, above the directly measured value： 173.21±0.87 GeV. A goodness-of-fit test to the Standard Model using all Z-pole observables and mW has a χ~2 probability of ■2%. The reason why probability values about a factor of ten larger than this, and indirect estimates of m H about 30 GeV higher, have been obtained in recent global fits to the same data is recalled.

LHCb实验利用电弱探针与光诱导过程研究核物质效应的进展

本文介绍了LHCb实验中的两项重要研究,旨在以电弱相互作用玻色子为工具探索原子核中的部分子分布函数(nuclear parton distribution functions,n PDFs).第一项研究利用质子-铅核对撞数据测量了Z玻色子的产生,用Z玻色子作为探针研究量子色动力学(quantum chromodynamics,QCD)和nPDFs.通过测量Z玻色子的产生截面,研究人员可以更准确地确定和理解部分子在核物质环境中的分布,从而完善现有的QCD理论并提高nPDFs的精度.第二项研究在铅核-铅核超周边对撞中研究了J/ψ和ψ(2S)介子的光致产生.这种对撞中,两个铅核通过光子和核内胶子的相互作用产生粲夸克偶素.相干光致产生涉及光子与整个原子核的胶子相互作用,能量交换较小,原子核保持完整.该研究验证了现有的微扰QCD和胶子交换模型,并提供了关于核遮蔽效应和核内胶子分布的重要信息.LHCb实验首次测量了粲夸克偶素随横动量变化的相干光致产生截面,并观测到了衍射效应,为未来高能核物理研究提供了宝贵数据.

TC2模型与轻子味破坏过程l_i→l_jν_l_l

许多超出标准模型的新物理预言了非普适规范玻色子Z′的存在 .此粒子可产生许多新物理现象 .本文计算了顶色辅助的人工色 (TC2 )模型预言的非普适规范玻色子Z′对轻子味破坏 (LFV)衰变过程li→ljνl νl 的贡献 .结果表明 ,在整个参数空间内 ,过程τ± →ljντ ντ 的分支比比τ± →ljνl νl(l =μ ,e)的分支比大得多 .考虑实验测量值上限Brexp(μ→ 3e)≤ 1× 10 -12 对TC2模型的自由参数的限制 ,我们给出了一些轻子味破坏过程的上限 .在大部分参数空间中 ,分支比Br(τ± →ljντ ντ)～ 10 -6,Br(τ± →ljνl νl)～ 10 -9.这些结果可以用来部分地解释中微子振荡数据 ,将来的高能实验有可能探测到此新物理效应 .

Light A physics in the lepton-specific two-Higgs doublet model

We examine various direct and indirect constraints on the lepton-specific two-Higgs doublet model and discuss its phenomenology at colliders in the allowed parameter space.The constraints we consider come from the precision electroweak data,the direct search for Higgs boson,the muon anomalous magnetic moment,as well as some theoretical consistency requirements.We find that in the allowed parameter space the CP-odd Higgs boson A is rather light (m A 【 30 GeV with 95% possibility),which is composed dominantly by the leptonic Higgs and decays dominantly into τ + τ;while the SM-like Higgs boson h (responsible largely for electroweak symmetry breaking) decays dominantly in the mode h → AA → 4τ with a large decay width,which will make the Higgs discovery more difficult at the LHC.Whereas,this scenario predicts rare Z decays Z → AAA and Z →τ + τA with their branching ratios ranging from 10-8 to 10-and 10-5 to 10-4 respectively,which may be accessible at the GigaZ option of the ILC.

Bounds on the magnetic moment of the τ-neutrino via the process e^+e-→νγ

Using Breit-Wigner resonance relation, bounds on the magnetic moment of the tau-neutrino are calculated through the reaction e^＋e^- →vv^-y at the neutral boson pole in the framework of a superstringinspired E6 model which has one extra low-energy neutral gauge boson and a LRSM.