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Yong Zhou

Publications and source records attributed to Yong Zhou.

At least 199 records · Page 11Linked to original sources
arXiv2007

Gauge dependence of on-shell and pole mass renormalization prescriptions

We discuss the gauge dependence of physical parameter's definitions under the on-shell and pole mass renormalization prescriptions. By two-loop-level calculations we prove for the first time that the on-shell mass renormalization prescription makes physical result gauge dependent. On the other hand, such gauge dependence doesn't appear in the result of the pole mass renormalization prescription. Our calculation also implies the difference of the physical results between the two mass renormalization prescriptions cannot be neglected at two-loop level.

hep-ph↗
arXiv2006

Improved online hypercube packing

In this paper, we study online multidimensional bin packing problem when all items are hypercubes. Based on the techniques in one dimensional bin packing algorithm Super Harmonic by Seiden, we give a framework for online hypercube packing problem and obtain new upper bounds of asymptotic competitive ratios. For square packing, we get an upper bound of 2.1439, which is better than 2.24437. For cube packing, we also give a new upper bound 2.6852 which is better than 2.9421 by Epstein and van Stee.

cs.DS↗
arXiv2006

Local partial-likelihood estimation for lifetime data

This paper considers a proportional hazards model, which allows one to examine the extent to which covariates interact nonlinearly with an exposure variable, for analysis of lifetime data. A local partial-likelihood technique is proposed to estimate nonlinear interactions. Asymptotic normality of the proposed estimator is established. The baseline hazard function, the bias and the variance of the local likelihood estimator are consistently estimated. In addition, a one-step local partial-likelihood estimator is presented to facilitate the computation of the proposed procedure and is demonstrated to be as efficient as the fully iterated local partial-likelihood estimator. Furthermore, a penalized local likelihood estimator is proposed to select important risk variables in the model. Numerical examples are used to illustrate the effectiveness of the proposed procedures.

math.ST↗
arXiv2006

Persistence Properties and Unique Continuation of solutions of the Camassa-Holm equation

It is shown that a strong solution of the Camassa-Holm equation, initially decaying exponentially together with its spacial derivative, must be identically equal to zero if it also decays exponentially at a later time. In particular, a strong solution of the Cauchy problem with compact initial profile can not be compactly supported at any later time unless it is the zero solution.

math.AP↗
arXiv2005

Unstable particle's wave-function renormalization prescription

We strictly define two set Wave-function Renormalization Constants (WRC) under the LSZ reduction formula for unstable particles at the first time. Then by introducing antiparticle's WRC and the CPT conservation law we obtain a new wave-function renormalization condition which can be used to totally determine the two set WRC. We calculate two physical processes to manifest the consistence of the present wave-function renormalization prescription with the gauge theory in standard model. We also prove that the conventional wave-function renormalization prescription which discards the imaginary part of unstable particle's WRC leads to physical amplitude gauge dependent.

hep-ph↗
arXiv2005

Gauge dependence of fermion mass renormalization schemes

We discuss the gauge dependence of fermion mass definition and physical result under the conventional on-shell mass renormalization scheme and the recently proposed pole mass renormalization scheme in standard model. By the two-loop calculations of top quark's mass counterterm and the cross section of physical process $W^{-}W^{+}\to b\bar{b}$ we strictly prove that the on-shell mass renormalization scheme makes fermion mass definition and the physical result gauge dependent at the first time, while we don't find such gauge dependence in the pole mass renormalization scheme. Besides, our calculation also shows the difference of the physical result between the two mass renormalization schemes cannot be neglected at two-loop level.

hep-ph↗
arXiv2005

Imaginary part of Feynman amplitude, cutting rules and optical theorem

We discuss the algorithm of the cutting rules of calculating the imaginary part of physical amplitude and the optical theorem. We ameliorate the conventional cutting rules to make it suitable for actual calculation and give the right imaginary part of physical amplitude. The calculations of the imaginary parts of several Feynman diagrams show that the ameliorated cutting rules agrees with the conventional integral algorithm very well. The investigation helps us to find that the optical theorem has severe contradictions and problem, thus isn't right. Besides, the calculation of a physical amplitude show that the ameliorated cutting rules keeps the physical result gauge-parameter independent.

hep-ph↗
arXiv2005

Boson's field renormalization prescription

We discuss the problem of the present boson's field renormalization prescription induced by the imaginary parts of the unstable boson's propagation amplitudes and how to resolve it.

hep-ph↗
arXiv2005

Fermion field renormalization prescriptions

We discuss all possible fermion field renormalization prescriptions in conventional field renormalization meaning and mainly pay attention to the imaginary part of unstable fermion Field Renormalization Constants (FRC). We find that introducing the off-diagonal fermion FRC leads to the decay widths of physical processes $t\to c Z$ and $b\to s γ$ gauge-parameter dependent. We also discuss the necessity of renormalizing the bare fields in conventional quantum field theory.

hep-ph↗
arXiv2004

The Gauge Dependence of Imaginary Part of physical amplitude $W^{+}\to u_i \bar{d}_j$ in Quark Mixing Matrix Renormalization

We investigate the current renormalization prescriptions of quark mixing matrix and found that there is gauge dependence in the imaginary part of physical amplitude $W^{+}\to u_i \bar{d}_j$ in two main renormalization prescriptions. Our conclusion may affect the renormalization of the quark mixing matrix and indicates that it needs more investigation about the gauge independence in quark mixing matrix renormalization.

hep-ph↗
arXiv2003

Calculations of the Imaginary Part of Gauge Boson's Wave-function Renormalization Constants and the Modification of hep-ph/0301090

We have calculated the imaginary part of W and Z gauge boson's wave-function renormalization constants (wrc.) in the complex-pole mass renormalization scheme and made atonement for the paper hep-ph/0301090 where the imaginary part of gauge boson's wrc. has been ignored in the second renormalization scheme in section 4. But the conclusion of this section in hep-ph/0301090 doesn't change.

hep-ph↗
arXiv2003

Renormalization of the Cabibbo-Kobayashi-Maskawa Matrix at One-Loop Level

We have investigated the present renormalization prescriptions of Cabibbo-Kobayashi-Maskawa (CKM) matrix at one-loop level. We emphasize at one prescription which is formulated with reference to the case of no mixing of quark's generations and point out that it doesn't make the physical amplitude involving quark mixing ultraviolet finite. We then propose a revised prescription to solve this problem and simultaneously keep the unitarity of the CKM matrix. Through explicit calculations we also prove that in order to keep the CKM matrix gauge independent the unitarity of the CKM matrix must be preserved.

hep-ph↗