118845254
Analysis of the decay constants of the heavy pseudoscalar mesons with QCD sum rules
A bstractIn this article, we recalculate the contributions of all vacuum condensates up to dimension-6, in particular the one-loop corrections to the quark condensates $ {\alpha_s}\left\langle {\overline{q}q} \right\rangle $ and partial one-loop corrections to the four-quark condensates $ \alpha_s^2{{\left\langle {\overline{q}q} \right\rangle}^2} $, in the operator product expansion. Then we study the masses and decay constants of the heavy pseudoscalar mesons D, Ds, B and Bs using the QCD sum rules with two choices: I we choose the $ \overline{MS} $ masses by setting m = m(μ) and take perturbative corrections up to the order $ \mathcal{O}\left( {{\alpha_s}} \right) $; II we choose the pole masses m, take perturbative corrections up to the order $ \mathcal{O}\left( {\alpha_s^2} \right) $ and set the energy-scale to be the heavy quark pole mass μ = mQ. In the case of I, the predictions fD = (208 ± 11) MeV and fB = (189 ± 15) MeV are consistent with the experimental data within uncertainties, while the prediction $ {f_{{{D_s}}}}=\left( {241\pm 12} \right) $ MeV is below the lower bound of the experimental data $ {f_{{{D_s}}}}=\left( {260.0\pm 5.4} \right) $ MeV. In the case of II, the predictions fD = (211 ± 14) MeV, fB = (190 ± 17) MeV, $ {f_{{{D_s}}}}=\left( {258\pm 13} \right) $ MeV and $ {{{{f_{{{D_s}}}}}} \left/ {{{f_D}}} \right.}=1.22\pm 0.08 $ are all in excellent agreements with the experimental data within uncertainties.
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.
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.
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
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 $\mu_{\Theta^+}=(0.16\pm0.03)\mu_N$.
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.
14349816
The Near-infrared Counterpart to the Anomalous X-ray Pulsar 1e 1048.1−5937
We report our discovery of the likely near-infrared counter part to the anomalous X-ray pulsar (AXP) 1E 1048.1−5937, using observations from the 6.5 m Baade (Magellan I) te lescope in Chile. We derived a precise position for the X-ray source using archival data from t heChandra X-Ray Observatory. Since this position is inconsistent with a position reported earlier from XMM-Newton, we conservatively considered eight optical and near-infrared sources within both error circles as cand id te counterparts, although we also show that the XMM-Newton observation likely suffered from attitude reconstruction problems. Two of the infrared objects have unusual colors, and one of these has colors consistent with t hose of the identified counterparts of two other AXPs. The latter object is the only source detected within the Chandra error circle, and we identify it as the counterpart to 1E 1048.1 −5937. This is the first AXP counterpart detected in multiple i nfrared bands, with magnitudes J=21.7(3),H=20.8(3), andK=19.4(3). There is marginal evidence for spectral flattenin g at longer wavelengths. Subject headings: pulsars: individual (1E 1048.1 −5937) — stars: neutron
67805671
Projective ribbon permutation statistics: A remnant of non-Abelian braiding in higher dimensions
In a recent paper, Teo and Kane [Phys. Rev. Lett. 104, 046401 (2010)] proposed a three-dimensional (3D) model in which the defects support Majorana fermion zero modes. They argued that exchanging and twisting these defects would implement a set R of unitary transformations on the zero-mode Hilbert space which is a “ghostly” recollection of the action of the braid group on Ising anyons in two dimensions. In this paper, we find the group T2n, which governs the statistics of these defects by analyzing the topology of the space K2n of configurations of 2n defects in a slowly spatially varying gapped free-fermion Hamiltonian: T2n ≡ π1(K2n). We find that the group T2n = Z × T r
16893295
ASCA observations of two SNRs and NEI analysis
Based on the data from the ASCA observation of SNRs Kes79 and W49B, we present here the analysis of their X-ray spectra and morphologies. The Kes79 spectrum can be well fitted by a single NEI component, and the narrow-band images of that source show an inhomogeneous distribution of heavy elements. The heavy elements are richest in the positions S, SE and SW of Kes79, where there may exist interaction between shocks and molecular clouds implied by radio observations. For W49B we present here the non-equilibrium ionization (NEI) analysis based on its emission line diagnostics, and the spectral fit using two NEI components. The reverse shock in W49B may be still hot and we don't find evidence for a hotter blast wave in ASCA spectra.
119724230
The design simulation of the superconducting section in the ADS injector II
The high-current superconducting proton linac is being studied for the accelerator-driven system (ADS) project undertaken by the Chinese Academy of Sciences. The injector II will be operated at 162.5 MHz, and the proton out from the RFQ with an energy of 2.5 MeV will be accelerated to 10 MeV by two cryo-modules, which are composed of eight superconducting half wave resonance cavities and nine solenoids. In this paper, the design and beam simulation of the superconducting section of the injector II, the acceptance calculation and a stability analysis are presented.
27616584
Radial compression of protons and H3+ ions in a multiring trap for the production of ultralow energy antiproton beams.
Radial compression of a proton cloud was performed in a multiring trap which was designed to trap and cool a large number of antiprotons for the production of low-energy ( 10-1000 eV ) antiproton beams. The resonance frequency for the radial compression was almost constant from 3 x 10(5) to 3 x 10(6) protons. The collision process of the trapped protons was also investigated to estimate the energy of the protons inside the trap. This technique will be applied to the ASACUSA experiment at the antiproton decelerator, CERN, to extract ultraslow antiprotons with good emittance.