119491970
Analysis of the vertices rho NN, rho Sigma Sigma and rho Xi Xi with light-cone QCD sum rules
In this article, we calculate the strong coupling constants of the {rho}NN, {rho}{sigma}{sigma}, and {rho}{xi}{xi} in the framework of the light-cone QCD sum rules approach. The strong coupling constants of the meson-baryon-baryon are the fundamental parameters in the one-boson exchange model which describes the baryon-baryon interactions successfully. The numerical values are in agreement with the existing calculations in part. The electric and magnetic F/(F+D) ratios deviate from the prediction of the vector meson dominance theory; the SU(3) symmetry breaking effects are very large.
118430852
Analysis of mass difference of the $\pi$ and $\rho$ with Bethe-Salpeter equation
In this article, we take into account the one-pion exchange force besides the onegluon exchange force to study the mass difference of the π and ρ mesons with the Bethe-Salpeter equation. After projecting the Bethe-Salpeter equation into an simple form, we can see explicitly that the bound energy |Eπ| ≫ |Eρ|. PACS number: 12.39.Ki, 12.39.Pn
15122700
Analysis of the Y(2175) as a tetraquark state with QCD sum rules
Abstract In this article, we take the point of view that Y ( 2175 ) be a tetraquark state which consists of color octet constituents, and calculate its mass and decay constant within the framework of the QCD sum rule approach. We release standard criterion in the QCD sum rules approach and take more phenomenological analysis, the value of the mass of Y ( 2175 ) is consistent with experimental data; there may be some tetraquark components in the state Y ( 2175 ) . If we retain standard criterion, larger mass than experimental data can be obtained, the current J μ ( x ) can interpolate a tetraquark state with larger mass, or Y ( 2175 ) has some components with larger mass. The dominating contribution comes from the perturbative term, which is in contrast to the sum rules with interpolating currents constructed from diquark pairs. The tetraquark states may consist of color octet constituents rather than diquark pairs.
119252067
Next-to-leading Order Perturbative Contributions in the QCD Sum Rules for Mesonic Two-point Correlation Functions with Unequal Quark Masses
In this article, we assume that the two quarks have unequal masses and calculate the next-to-leading order contributions to the spectral densities of the mesonic two-point correlation functions of the vector, axialvector, scalar and pseudoscalar currents. We take dimensional regularization to regularize both the ultraviolet and infrared divergences, and use optical theorem to obtain the spectral densities directly, furthermore, we present some necessary technical details for readers convenience. The analytical expressions are applicable in many phenomenological analysis besides the QCD sum rules.
118179000
Magnetic moment of the pentaquark state $\Theta^+(1540)$
In this article, we study the magnetic moment of the pentaquark $ \Theta^+(1540)$ as (scalar)diquark-(pseudoscalar)diquark-antiquark state with the QCD sum rules approach in the external electromagnetic field. Due to the special structure of the interpolating current, only the electromagnetic interactions of the $s$ quark with the external field have contributions to the magnetic moment with tensor structure $\{\sigma_{\mu\nu} {\hat p} +{\hat p}\sigma_{\mu\nu}\}$. The numerical results indicate the magnetic moment of the pentaquark state $ \Theta^+(1540)$ is about $\mu_{\Theta^+}=(0.16\pm0.03)\mu_N$.
119121085
ANALYSIS OF THE $B \to K^*_2(1430), a_2(1320), f_2(1270)$ FORM-FACTORS WITH LIGHT-CONE QCD SUM RULES
In this paper, we study the form-factors with the light-cone QCD sum rules, where the B-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of the B-meson light-cone distribution amplitude ϕ+(ω) have significant impacts on the values of the form-factors, and expect to obtain severe constraints on the parameters of the B-meson light-cone distribution amplitudes from the experimental data in the future.
121348798
Scaling theory of the Hall coefficient near the metal-insulator transition, a renormalization-group approach
Abstract We investigate the critical properties of the Hall conduxtivity in weak magetic fields near the disorder driven metal-insulator transition. We derive an effective lagrangian governing the interactions of the diffusive modes in the presence of time-reversal and particle-hole symmetry breaking and identify a new operator relevant to the scaling behavior of the weak-field Hall conductivity. A Wilson-Polyakov renormalization-group analysis is carried out and the flow equations are obtained near two dimensions. We show that the perturbative behavior of the Hall conductivity in the weakly localized regime, in two dimensions, is not simply related to the critical behavior of the Hall conductivity, due to the role played by a new scaling variable. Solving the renormalization-group equations close to the zero-field fixed point, our theory predicts that the Hall number vanishes at the mobility edge with an exponent g = 1 in agreement with several experimental observations. We clarify the connection between the field-theoretic approach and the conventional perturbative approach and elucidate why perturbation in the disorder, which is valid in the weak localization regime fails to predict the correct critical behavior.
33904752
Calculation of some properties of the vacuum
In this paper, we calculate the dressed quark propagator with the flat bottom potential in the framework of the rainbow Schwinger-Dyson equation, which is determined by mean field approximation of the global colour model Lagrangian. The dressed quark propagator exhibits a dynamical symmetry-breaking phenomenon and gives a constituent quark mass about 392 MeV, which is close to the value of commonly used constituent quark mass in the chiral quark model. Then based on the dressed quark propagator, we calculate some properties of the vacuum, such as quark condensate, mixed quark condensate gs , four quark condensate , tensor, pi vacuum susceptibilities. The numerical results are compatible with the values of other theoretical approaches.
119791200
Zero-Point Time of Quantum Fields
Based on the first principles and without resorting to any additional assumption, a new physical quantity describing the space-time position of particle-number center of quantum fields is introduced, which can be regarded as a generalized Noether charge related to the symmetry under a local gauge transformation. As an interesting result, one can show that quantum fields have a zero-point time, which is related to the zero-point energy of quantum fields via the Heisenberg uncertainty principle.
118394364
Zitterbewegung and its significance for the Hawking radiation
The Hawking radiation can be viewed from very different perspectives, not all of which can be proved to be rigorously equivalent to one another. On the other hand, an old interest in the zitterbewegung (ZB) of the Dirac electron has recently been rekindled by the investigations on spintronics and graphene, etc. In this letter, we show that, if particles emitted by black holes are electrons or positrons, one can also regard the Hawking radiation as a ZB process.
118530343
Tracking fast neutrons
Abstract Both neutron absorption and elastic scattering can be used to measure neutron momentum. Based on elastic collisions, the linear momentum of a fast neutron can be measured from as few as two consecutive recoil ion tracks plus the vertex position of the third collision, or ‘two and half’ ion tracks. If the time delay between the first two consecutive ion tracks is also measured, the number of ion tracks can be reduced to one and a half. The angular and magnitude resolutions are limited by ion range straggling to about 10%. Multi-wire proportional chambers and light-field imaging can be used for fast neutron tracking. Light-field imaging is free of charge-diffusion-induced image blur, but the limited number of photons available can be a challenge. 1 H, 2 H and 3 He could be used for the initial development of fast neutron trackers based on light-field imaging.