124955332
A New Derivation of Standard Quantum Chromodynamics Evolution Equation
Standard evolution equation including virtual graphs is derived in time ordered perturbative theory. We propose a new cutting rule in deep inelastic scattering processes, which provides a useful tool for discussing the connections among the real and virtual cut diagrams and better understanding of evolution equation.
124556870
A New Effect in the QCD Fusion of Nuclear Partons
The parton fusion in nucleus at the leading order of recombination is investigated based on perturbative QCD. We compute various cut diagrams including the nuclear parton fusion, and find that the parton-fusion effects depend on the nuclear QCD structure.
18244927
Nuclear Shadowing and Antishadowing in a Unitarized BFKL Equation
The nuclear shadowing and antishadowing effects are explained by a unitarized BFKL equation. The Q2and x-variations of the nuclear parton distributions are detailed based on the level of the unintegrated gluon distribution. In particular, the asymptotical behavior of the unintegrated gluon distribution near the saturation limit in nuclear targets is studied. Our results in the nuclear targets are insensitive to the input distributions if the parameters are fixed by the data of a free proton. PACS numbers: 13.60.Hb; 12.38.Bx. keywords: nuclear shadowing and antishadowing; unintegrated gluon distribution in nuclei; QCD evolution equation Supported by National Natural Science Foundation of China 10135060, 10475028 and 10205004. Corresponding author, E-mail: weizhu @mail.ecnu.edu.cn
124473583
Partonic Structure of the Pomeron in the Modified GLR Equation
The gluon recombination effect in the pomeron is studied by using the modified Gribov–Levin–Ryskin evolution equation. We find that the measured parton distributions in the pomeron can be generated dynamically from a purely gluonic input on assuming a small size for the pomeron.
119716730
A twist-4 effect in the parton evolution processes
Recently, a research group reported that they can fit the F2 data well by using the Altarelli-Parisi evolution equation with a valence-like initial gluon distribution, which means that we need not consider the high twist effects in the proton. In this letter, we point out that their valence-like initial gluon distribution is unreasonable for the proton structure function. With the reasonable initial distributions, we find that the high twist corrections to the Altarelli-Parisi evolution equation is necessary.
122365434
Bag skin effect for Friedberg-Lee model
Importance of the bag skin effect to determine the parameters of the Friedberg-Lee model is pointed out. The European Muon Collaboration (EMC) effect regarded as a bag skin effect can be used to determine the parameters of this model.
53643146
Constraints on unparticle interactions from particle and antiparticle oscillations
AbstractUnparticles have dramatic effects on particle and antiparticle oscillations in meson–antimeson and muonium–antimuonium systems. Unlike the usual tree-level contributions to meson oscillations from heavy-particle exchange, which results in a small Γ12, the unparticle may have sizeable contributions to both M12 and Γ12 due to the fractional dimension 
$d_{\mathcal{U}}$ 
of the unparticle. If the unparticle effect dominates the contributions (which may happen in D0–
$\bar{D}^{0}$ 
mixing) to the meson mixing parameters x and y, we find that 
$x/y=\cot(\pi d_{\mathcal{U}})$
. The mass difference Δm in meson mixing can provide interesting constraints on the unparticle interactions. The unparticle interaction can significantly enhance the CP asymmetry in meson mixing, which can be tested in more accurate experiments in the future. Interesting constraints on unparticle and particle interactions can also be obtained using muonion and antimuonion oscillation data.
123800661
Probing the nuclear symmetry energy using single and double pi(-)/pi(+) ratios from mirror reaction systems
118982861
Sudakov form factor in effective field theory
We discuss the Sudakov form factor in the framework of the soft-collinear effective theory. The running of the short distance coefficient function from high to low scale gives the summation of Sudakov logarithms to all orders. Our discussions concentrate on the factorization and derivation of the renormalization group equation from the effective theory point of view. The intuitive interpretation of the renormalization group method is discussed. We compared our method with other resummation approaches in the literatures.
119155459
Neutrino decay as a possible interpretation of the MiniBooNE observation with unparticle scenario
In a new measurement on neutrino oscillations, νμ→νe, the MiniBooNE Collaboration observes an excess of electron-like events at low energy and the phenomenon may demand an explanation that obviously is beyond the oscillation picture. We propose that the heavier neutrino, ν2, decaying into a lighter one, ν1, via the transition process νμ→νe+X, where X denotes any light products, could be a natural mechanism. The theoretical model we employ here is the unparticle scenario established by Georgi. We have studied two particular modes $\nu_{\mu}\to\nu_{e}+\mathcal{U}$ and νμ→νe+ν̄e+νe. Unfortunately, the number coming out of the computation is too small to explain the observation. Moreover, our results are consistent with the cosmology constraint on the neutrino life time and the theoretical estimation made by other groups; therefore, we can conclude that even though neutrino decay seems plausible in this case, it indeed cannot be the source of the peak at lower energy observed by the MiniBooNE Collaboration and there should be other mechanisms responsible for the phenomenon.
116907310
A solution to Higgs naturalness
The Standard Model (SM) is usually considered to be unnatural because the scalar Higgs mass receives a quadratic divergent correction. We suggest a new way to solve the naturalness problem from point of view of renormalization group method. Our approach is illustrated through the familiar $\phi^4$ theory. A renormalization group equation for scalar field mass is proposed by introducing a subtraction scale. We give a non-trivial prediction: the Higss mass at short-distance is a damping exponential function of the energy scale. It follows from a characteristic of the SM that the couplings to Higgs are proportional to field masses, in particular the Higgs self-interactions. In the ultraviolent limit, the Higgs mass approaches to a mass called by Veltman mass which is at the order of the electroweak scale. The fine-tuning is not necessary. The Higgs naturalness problem is solved by radiative corrections themselves.