Tensor Susceptibilities of QCD Vacuum and Parameterized Quark Propagator

Based on the parameterized fully dressed quark propagator proposed by us, the tensor susceptibilities of QCD vacuum and quark vacuum condensates are investigated. Our predicted values of the tensor susceptibilities are in agreement with those predicted by many other theoretical models with QCD feature. The results also show that the tensor susceptibility of QCD vacuum strongly depends on flavor of quark but not sensitive to variation of quark vacuum condensates. However, the quark vacuum condensate is very sensitive to the change of cut-off-parameter μ^2 of the integration, that is, it depends on the separation point of perturbative and non-perturbative QCD region. The successful predictions clearly indicate the extensive validity of our parameterized fully dressed quark propagator used here.     

Grand unification of quark and lepton flavor changing neutral currents

In the context of supersymmetric grand unified theories with soft breaking terms arising at the Planck scale, it is generally possible to link flavor changing neutral current and CP violating processes occurring in the leptonic and hadronic sectors. We study the correlation between flavor changing squark and slepton mass insertions in models à la SU(5). We show that the constraints coming from lepton flavor violation exhibit a strong impact on CP-violating B decays.     

On predictions from spontaneously broken flavor symmetries

We discuss the predictive power of supersymmetric models with flavor symmetries, focusing on the lepton sector of the standard model. In particular, we comment on schemes in which, after certain ‘flavons’ acquire their vacuum expectation values (VEVs), the charged lepton Yukawa couplings and the neutrino mass matrix appear to have certain residual symmetries. In most analyses, only corrections to the holomorphic superpotential from higher-dimensional operators are considered (for instance, in order to generate a realistic _θ13${\theta }_{13}$ mixing angle). In general, however, the flavon VEVs also modify the Kähler potential and, therefore, the model predictions. We show that these corrections to the naive results can be sizable. Furthermore, we present simple analytic formulae that allow us to understand the impact of these corrections on the predictions for the masses and mixing parameters.     

A new three-flavor oscillation solution of the solar neutrino deficit in <Emphasis Type="Italic">R</Emphasis>-parity violating supersymmetry

We present a solution of the solar neutrino deficit using three flavors of neutrinos and R-parity non-conserving supersymmetry. In this model, in vacuum, the is massless and unmixed, mass and mixing being restricted to the - sector only, which we choose in consistency with the requirements of the atmospheric neutrino anomaly. The flavor changing and flavor diagonal neutral currents present in the model and the three-flavor picture together produce an energy dependent resonance-induced - mixing in the sun. This mixing plays a key role in the new solution to the solar neutrino problem. The best fit to the solar neutrino rates and spectrum (1258-day SK and 241-day SNO data) requires a mass square difference of eV² in vacuum between the two lightest neutrinos. This solution cannot accommodate a significant day-night effect for solar neutrinos nor CP violation in terrestrial neutrino experiments. Received: 26 December 2001 / Revised version: 16 February 2002 / Published online: 26 July 2002     

Non-perturbative Aspects of QCD and Parameterized Quark Propagator

Based on the Global Color Symmetry Model, the non-perturbative Q, CD vacuum is investigated in the parameterized fully dressed quark propagator. Our theoretical predictions for various quantities characterized the QCD vacuum are in agreement with those predicted by many other phenomenologieal QCD inspired models. The successful predictions clearly indicate the extensive validity of our parameterized quark propagator used here. A detailed discussion on the arbitrariness in determining the integration cut-off parameter ofμ in calculating QCD vacuum condensates and a good method, which avoided the dependence of calculating results on the cut-off parameter is also strongly recommended to readers.     

Quark and lepton masses from Gaussian landscapes

The flavor structure of the standard model (SM) might arise from random selection on a landscape. We propose a class of simple models, "Gaussian landscapes," where Yukawa couplings derive from overlap integrals of Gaussian wave functions on extra-dimensions. Statistics of vacua are generated by scanning the peak positions of these zero-modes, giving probability distributions for all flavor observables. Gaussian landscapes can account for all observed flavor patterns with few free parameters. Although they give broad probability distributions, the predictions are correlated and accounting for measured parameters sharpens the distributions of future neutrino measurements.     

On the determination of the polarized sea distributions of the nucleon

The possibilities to determine the flavor structure of the polarized sea (antiquark) distributions of the nucleon via vector boson production at high energy polarized hadron–hadron colliders, such as the Relativistic Heavy–Ion Collider (RHIC), are studied in detail. In particular the perturbative stability of the expected asymmetries in two representative models for the (un)broken flavor structure are investigated by confronting perturbative QCD leading order predictions of the expected asymmetries with their next–to–leading order counterparts. Received: 28 November 2000 / Published online: 5 February 2001     

主成分回归法建立卷烟风格与组分的定量关系

为研究卷烟风格与卷烟化学成分之间的关系,应用主成分回归建立卷烟GC-MS数据与卷烟风格评吸值之间的定量模型.对于每种卷烟风格,均建立了4种候选模型,然后选取最佳者.通过最佳模型对测试集样品的30种风格进行预测,有23种风格的预测值与评吸值之间的平均绝对误差小于专家评吸时的最小计分单位,所以定量模型的预测结果可靠.此研究表明化学计量学方法在处理卷烟这种复杂体系时的可用性和有效性.这些定量模型可以作为专家评吸卷烟风格的辅助工具.在定量关系不明确的情况下,应当建立多个候选模型,然后从中选择最佳者.     

Measurement of Einstein-Podolsky-Rosen-type flavor entanglement in Upsilon(4S) --> B0 B0 decays

The neutral B meson pair produced at the Upsilon(4S) should exhibit a nonlocal correlation of the type discussed by Einstein, Podolsky, and Rosen. We measure this correlation using the time-dependent flavor asymmetry of semileptonic B(0) decays, which we compare with predictions from quantum mechanics and two local realistic models. The data are consistent with quantum mechanics, and inconsistent with the other models. Assuming that some B pairs disentangle to produce B(0) and B(0) with definite flavor, we find a decoherent fraction of 0.029 +/ -0.057, consistent with no decoherence.     

Study on Bd → ø KS Decay in EDQS Model

We study B_d → ø K_S decay in extra down-type quarks (EDQS) model with a non-universal Z boson associated with flavor changing neutral currents (FCNCs) at the tree level. With the up-to-date experimental data of Br(B_d → ø K_S, S_øKS, and A_øKS, we derive the bounds on the Z-b-s coupling parameter |U_bs| and the new weak phase ø, using the constrained parameter spaces, we finally give predictions for B_s → øø decay, which could be tested atthe Fermilab Tevatron and the LHC-b experiments.     

夸克的真空凝聚值和张量感应率及参数化的夸克传播子

利用以前提出的参数化的夸克传播子， 计算了夸克的真空凝聚值和QCD真空的张量感应率。 结果表明， 张量感应率对不同味道的夸克的依赖是很明显的， 而几乎不依赖于夸克的真空凝聚值的变化。 但夸克凝聚值却明显地与积分的截断值有关， 即依赖于微扰区与非微扰区的分界线， 在常用的积分截断值1—2 GeV2之间计算得到的夸克凝聚值与文献中常用的值及其他理论的预言值是一致的。 理论预言的张量感应率也与其他理论结果相一致。     

CP Violation and Flavor Changing Effects in K and B Mesons from Nonuniversal Soft Breaking Terms

We analyze CP violation and flavor changing effects in a minimal supersymmetric standard model with arbitrary nonuniversal soft breaking. Large flavor changing neutral current effects are naturally expected in the K system, even in the absence of quark-squark flavor misalignment. However, the B system is sensitive to new supersymmetric contributions only if nonuniversality implies, not only different soft terms for the three generations but also a large quark-squark misalignment. The only exceptions are processes with a leading chirality changing contribution proportional to tanbeta (as b-->sgamma).     

The horizontal axion alternative: The interplay of vacuum structure and flavor interactions

We classify all minimal N-generational SU(3) × SU(2) × U(1) axion models according to the structure of their vacuum manifold M, showing that n ≡ π₀(M) is such that 1 ? n ? N. For n < N, the purely axial U(1)_A must be explicitly broken in the Yukawa sector, implying that U(1)_PQ necessarily distinguishes some quark families. In fact, a complete distinction, i.e. a fully horizontal realization of U(1)_PQ does exist for arbitrary N, leading to definite flavor interaction patterns with non-trivial relative structure of the mass matrices M_u versus M_d. For each n, in particular for the domain-wall-free n = 1 case, we find a unique Yukawa pattern embeddable in unified SU(5), whereas SO(10) can only host n = N. It is emphasized that axion invisibility guarantees the invisibility of flavor changing neutral currents.     

Z′ mediated flavor changing neutral currents in B meson decays

We study the effects of an extra U(1)′ gauge boson with flavor changing couplings with fermion mass eigenstates on certain B meson decays that are sensitive to such new physics contributions. In particular, we examine to what extent the current data on B_d→φK and B_d→η′K decays may be explained in such models, concentrating on the example in which the flavor changing couplings are left-chiral. We find that within reasonable ranges of parameters, the Z′ contribution can readily account for the anomaly in S_φKS but is not sufficient to explain large branching ratio of B_d→η′K with the same parameter value. S_φKS and S_η′KS are seen to be the dominant observables that constrain the extra weak phase in the model.     

Spontaneous CP violation in extended technicolor models with horizontal U(2)L ⊗ U(2)R flavor symmetries (I)

The Eichten, Lane, Preskill mechanism for CP violation in extended technicolor (ETC) models is examined in models with “horizontal” U(2)_L ? U(2)_R flavor symmetries. We identify a class of chiral perturbations which generate spontaneous CP violation when the vacuum alignment is determined by Dashen's theorem, and show that, in general, a discrete symmetry must be invoked to avoid strong CP non-conservation. CP-violating phases appearing in the electroweak and broken ETC interactions may be naturally suppressed by ratios of ETC vector boson masses.     

TeV-scale seesaw from a multi-Higgs model

We suggest new simple model of generating tiny neutrino masses through a TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model is a simple extension of the standard model by introducing extra one Higgs singlet, and one Higgs doublet with a tiny vacuum expectation value. Experimental constraints, electroweak precision data and no large flavor changing neutral currents, are satisfied since the extra doublet only has a Yukawa interaction with lepton doublets and right-handed neutrinos, and their masses are heavy of order a TeV-scale. Since active light neutrinos are Majorana particles, this model predicts a neutrinoless double beta decay.     

Characteristic predictions of topological soliton models

Characteristic predictions of the chiral soliton models (the Skyrme model and its extensions) are discussed. The chiral soliton model predictions of low-lying dibaryon states qualitatively agree with recent evidence for the existence of narrow dibaryons in reactions of the inelastic proton scattering on deuterons and the double photon radiation pp→ppγγ. The connection between magnetic moment operators and inertia tensors valid for arbitrary SU(2) skyrmion configurations allows us to estimate the electromagnetic decay width of some states of interest. Predictions of a different type are multibaryons with a nontrivial flavor (strangeness, charm, or bottom), which can be found, in particular, in high-energy heavy ion collisions. It is shown that the large-B multiskyrmions given by the rational map ansatz can be described within the domain-wall approximation or as a spherical bag with the energy and the baryon number density concentrated at the boundary.     

Flavor changing neutral currents in the Lee–Wick Standard Model

Recently an extension of the Standard Model (the Lee–Wick Standard Model) based on ideas of Lee and Wick (LW) was introduced. It does not contain quadratic divergences in the Higgs mass and hence solves the hierarchy puzzle. The LW Standard Model contains new heavy LW-resonances at the TeV scale that decay to ordinary particles. In this Letter we examine in more detail the flavor structure of the theory. We integrate out the heavy LW-fermions at tree level and find that this induces flavor changing Z-boson couplings. However, these flavor changing neutral currents are acceptably small since they are automatically suppressed by small Yukawa couplings. This is the case even though the theory does not satisfy the principle of minimal flavor violation. New couplings of the charged W-bosons to quarks and leptons are also induced. We also integrate out the LW–Higgs and examine the four-fermion operators induced.     

Weak decay constants of light and heavy pseudoscalar mesons

We investigate the weak leptonic decays of light and heavy pseudoscalar mesons in a relativistic quark model of independent quarks. We perform a static calculation of the decay constantf _M purely on grounds of simplicity. In order to minimize the possible uncertainty in the static calculation, we estimate the ratios of the decay constants which are found to be in good agreement, in the heavy flavor sector, with the predictions of other models available in the literature and existing experimental data. However, there is a noticeable discrepancy in the current prediction for pion decay constant which demonstrates the inherent limitations of the static approximation in the study of non-strange light mesons.     

Top quark condensation from broken family symmetry

We investigate the vacuum alignment in a fully dynamical “moose” model which breaks electroweak symmetry with a top quark condensate and show how the prefered vacuum depends on the explicit masses of the fermions involved. Our results are also applicable to the cases in which electroweak symmetry is broken by a fourth family of quarks, or by a technicolour mechanism. Such moose models allow the scale of new physics, Λ, to be in the TeV range with the absence of flavour changing neutral currents ensured by a GIM mechanism.