Radiative decays and quark content of f 0(980) and φ(1020)

The quark structure of φ(1020) and f ₀(980) is studied on the basis of data on the radiative decays φ(1020) → γπ ⁰, γη, γη′, γ a ₀(980), γ f ₀(980) and f ₀(980) → γγ. The partial widths are calculated under the assumption that all the mesons under consideration are $\bar qq$ states: φ(1020) is a dominantly $s\bar s$ state ( $\eta ' = n\bar nsin\theta + s\bar scos\theta $ component contributes not more than 1%); η, η′, and π ⁰ are standard $q\bar q$ states, $\eta = n\bar ncos\theta - s\bar ssin\theta $ and $\eta ' = n\bar nsin\theta + s\bar scos\theta $ with θ?37°; and f ₀(980) is a e5 meson with the flavor wave function $n\bar ncos\varphi + s\bar ssin\varphi $ . The transition φ → γπ ⁰ specifies the admixture of the $n\bar n$ component in the φ meson: it is on the order of 0.5%. We argue that this order of $n\bar n$ value does not contradict data on the decay φ(1020) → γ a ₀(980). The partial widths calculated for the decays φ → γη, γη? are in reasonable agreement with experimental data. The measured branching-ratio value Br(φ→γf ₀(980))=(3.4±0.4 _?0.5 ^+1.5 ×10^?4) requires 25°≤|?|≤90°. For the decay f ₀(980) → γγ, the agreement with data, Γ(f ₀(980) → γγ)=0.28 _?0.13 ^+0.09 keV, is attained at either ?=85°±8° or ?=?46°±8°. A simultaneous analysis of the decays φ(1020) → γ f ₀(980) and f ₀(980) → γγ favors the solution with the negative mixing angle of ?=?48°±6°, setting f ₀(980) very close to the flavor octet (? _octet=±54.7°).     

Similarities in the decomposition and dehydrogenation of cyclohexene on (4 × 4)-CMo(110) and Pt(111)

The decomposition and dehydrogenation of cyclohexene have been used as probing reactions to directly compare the surface reactivities of carbon-modified Mo(110) and Pt(111). By using temperature programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS), we find that the dominant decomposition pathway of cyclohexene can be converted from complete decomposition to atomic carbon and hydrogen on clean Mo(110) to partial dehydrogenation to benzene and hydrogen on (4 × 4)-CMo(110). The latter reaction mechanism is very similar to that observed on Pt(111). Furthermore, in contrast to the near identical catalytic properties that are commonly observed for bulk molybdenum carbide and nitride powder materials, we find that the reactivities of carbon-modified and nitrogen-modified Mo(110) surfaces are qualitatively different.     

Dispersive Contribution of ρ(1450,1700) Decays and X(1576)

We study whether the broad enhancement X（1576） arises from the final state interaction （FSI） of p（1450, 1700）→p^＋ p^- →K^＋ K^-decay,Both the absorptive and dispersive contributions of the above amplitudes are considered since the intermediate states are very close to p（1450, 1700）. AThe same mechanism leads to a similar enhancement around 1580 MeV in the π^＋ π^- specturm in the J/ψ →π^0 π^＋ π^- channel, which can be used to test whether X（1576） can be ascribed to the FSI effect ofp（1450, 1700） → p^＋ p^-.     

Ξ_(bb) and Ω_(bbb) molecular states

Using the vector exchange interaction in the local hidden gauge approach,which in the light quark sector generates the chiral Lagrangians and has produced realistic results for ?_c,Ξ_c,Ξ_b and the hidden charm pentaquark states,we study the meson-baryon interactions in the coupled channels that lead to the Ξ_(bb) and ?_(bbb) excited states of the molecular type.We obtain seven states of the Ξ_(bb) type with energies between 10408 and 10869 MeV,and one ?_(bbb) state at 15212 MeV.     

On the relation between Φ(1,2) and Φ(1,5) perturbed minimal models and unitarity

We consider the RSOS S-matrices of the Φ_(1,5) perturbed minimal models which have recently been found in a companion paper. These S-matrices have some interesting properties, in particular, unitarity may be broken in a stronger sense than seen before, while one of the three classes of Φ_(1,5) perturbations (to be described) shares the same thermodynamic Bethe ansatz as a related Φ_(1,2) perturbation. We test these new S-matrices by the standard Truncated Conformal Space method, and further observe that in some cases the BA equations for two particle energy levels may be continued to complex rapidity to describe (a) single particle excitations and (b) complex eigenvalues of the Hamiltonian corresponding to non-unitary S-matrix elements. We make some comments on identities between characters in the two related models following from the fact that the two perturbed theories share the same breather sector.     

High-Resolution Spectroscopy of Jet-Cooled (32)SO(2) and (34)SO(2): The ã(3)B(1)-;X(1)A(1), 2(1)(0) and 1(1)(0) Bands

Laser-induced excitation spectra of the two bands ?(3)B(1)-;X(1)A(1), 2(1)(0) and 1(1)(0) of (32)SO(2) and (34)SO(2) have been recorded in a supersonic jet at a resolution of 0.015 cm(-1). The rotational and electron-spin fine structure has been analyzed for both isotopic species. Analysis of the rotational and electron-spin fine structure yields precise values of the rotational constants A, B, and C and the spin constants alpha and beta for both (32)SO(2) and (34)SO(2) in the states ?(3)B(1) (010) and (100). No interaction between these two vibrational states with any nearby triplet state is observed for rotational levels with J 相似文献   

Interpretation of Z_b(10610)and Z_b(10650)in the ISPE mechanism and the Charmonium Counterpart~

The initial single pion emission(ISPE) mechanism is applied to the processes γ(55)→πB~((*))B~((*)),whose details have been recently reported at ICHEP2012,and we obtain reasonable agreement with Bell's measurements;that is,we succeed in reproducing the enhancement structures of Zb(10610) and Zb(10650).Inspired by this success,we also predict the corresponding enhancement structures in open charm one-pion decays of higher charmonia near the thresholds of D*D and D*D*.     

Synthesis and Reactivity of Mg(II)–Fe(II)–Fe(III) Hydroxycarbonates

Green rust-like compounds (GRs) were discovered as natural minerals in various hydromorphic soils, where anoxic conditions allow their stability. They may control some redox processes in aquifers and participate to the transformation of various pollutants. Since Mg(II) cations are present in the fields where GRs were discovered, a partial substitution of Mg(II) to Fe(II) leading to intermediate compounds between GRs and usual Mg(II)–Fe(III) hydroxysalts is suspected. Mg(II)–Fe(II)–Fe(II) hydroxycarbonates can be obtained as intermediate oxidation products of (Mg, Fe)(OH)₂ in carbonate-containing aqueous media obeying to [Fe^II _4(1–x)Mg^II _4x Fe^III ₂(OH)₁₂]²⁺ [CO₃ ^2– nH₂O]^–2. TMS spectra at 12 K are similar to those of GRs, i.e., two quadrupole doublets, one due to Fe(II) with a large isomer shift =1.29 mms^–1 (with respect to -iron at room temperature) and quadrupole splitting E _Q=2.76 mms^–1, the other one due to Fe(III) with smaller hyperfine parameters =0.49 mms^–1 and E _Q=0.44 mms^–1. Fe(II) ions oxidise rapidly into Fe(III) with dissolved O₂. The reactivity is similar to that of Fe(II)–Fe(III) hydroxysalts GR, and thus the potential of Mg(II)–Fe(II)–Fe(III) compounds for reducing pollutants.     

Negative thermal expansion and photoluminescence in solid solution(HfSc)_(0.83)W_(2.25)P_(0.83)O_(12-δ)

A solid solution of(HfSc)_(0.83)W_(2.25)P_(0.83)O_(12-δ)is synthesized by the high-temperature, solid-state reaction and fastquenching method. It is shown that it possesses an orthorhombic structure with space group Pmmm(47) and exhibits negative thermal expansion(NTE) property with low anisotropy in thermal expansion. The coefficients of thermal expansion(CTEs) for a, b, and c axes are-1.41 × 10~(-6) K~(-1),-2.23 × 10~(-6) K-1, and-1.87 × 10~(-6) K-1, respectively. This gives rise to volume and linear CTEs of-3.10 × 10-6 K-1 and-1.03 × 10-6 K-1, respectively. Besides, it exhibits also intense photoluminescence from 360 nm to about 600 nm. The mechanism of NTE and the correlation of the PL with axial thermal expansion property are discussed.     

Spectroscopic and laser properties of Nd~(3 ) ions in LaMgAl_(11)O_(19) crystals

The spectroscopic properties, optic quality and thermal lensing effect of Nd~(3 ) ions in LaMgAl_(11)O_(19)(LNA) crystals are investigated and the dependence of the laser characteristics on above properties are discussed.     

Relanon between singularity expansion method(SEM) and resonance scattering theory(RST)

In recent years there are two theories for the acoustic scattering,one isthe Singularity Expansion Method(SEM),the other is the Resonance Scat-tering Theory(RST).In this paper,relation between these two theories wasestablished.For the examples of the acoustic scattering from the solid elasticcylinder and sphere immersed in water,we prove that the RST can be directlyderived from the SEM,so that these two theories are equivalent.By use of theMittag-Leffler theorem we expand the pure elastic scattering wave,which isextracted by isolating the rigid background from the total scattering wave,in anexact resonance expansion.We specially prove that the reradiation efficiencyand the resonance width are nearly proportional to the imaginary part of thecorresponding pole for most solid objects immersed in water.This shows thatthe resonance scattering behavious can be entirely determined by the complexfrequency poles.For the cases of an aluminum cylinder and a tungsten carbidesphere immersed in water,we calculate the     

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Depth and orientational dependencies of MRI T(2) and T(1ρ) sensitivities towards trypsin degradation and Gd-DTPA(2-) presence in articular cartilage at microscopic resolution

Depth and orientational dependencies of microscopic magnetic resonance imaging (MRI) T(2) and T(1ρ) sensitivities were studied in native and trypsin-degraded articular cartilage before and after being soaked in 1 mM Gd-DTPA(2-) solution. When the cartilage surface was perpendicular to B(0), a typical laminar appearance was visible in T(2)-weighted images but not in T(1ρ)-weighted images, especially when the spin-lock field was high (2 kHz). At the magic angle (55°) orientation, neither T(2)- nor T(1ρ)-weighted image had a laminar appearance. Trypsin degradation caused a depth- and orientational-dependent T(2) increase (4%-64%) and a more uniform T(1ρ) increase at a sufficiently high spin-lock field (55%-81%). The presence of the Gd ions caused both T(2) and T(1ρ) to decrease significantly in the degraded tissue (6%-38% and 44%-49%, respectively) but less notably in the native tissue (5%-10% and 16%-28%, respectively). A quantity Sensitivity was introduced that combined both the percentage change and the absolute change in the relaxation analysis. An MRI experimental protocol based on two T(1ρ) measurements (without and with the presence of the Gd ions) was proposed to be a new imaging marker for cartilage degradation.     

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