Knight Shift of 90Nb, 93mMo, 96Tc,and 101mRh in Nb Using Brute-Force NMRON

Brute-force nuclear magnetic resonance on oriented nuclei (BF-NMRON) of ⁹⁰Nb, ^93mMo, ⁹⁶Tc, and ^101mRh was carried out in a new host metal, Nb. The resonance center frequencies at an external field of 11.922(6) T were obtained as ν(⁹⁰NbNb) = 56.572(9) MHz, ν(^93mMoNb) = 85.76(3) MHz, ν(⁹⁶TcNb) = 66.997(11) MHz, and ν(^101mRh Nb) = 111.010(19) MHz. A systematic analysis of the Knight shift of 4d elements in extremely dilute alloy systems is briefly discussed. This revised version was published online in September 2006 with corrections to the Cover Date.     

Magnetic hyperfine fields of Nb andMo in nickel by NMR-ON of90Nb and93mMo

The magnetic hyperfine splitting frequencies of⁹⁰NbNi and^93mMoNi in an external magnetic field of 0.2 T have been determined by the NMR-ON method to be 18.52(7) and23.73(10) MHz, respectively. With the assumption of Knight shift factorK=0 and with the knowng-factors, the hyperfine fields of⁹⁰NbNi and^93mMoNi were deduced asB _HF(⁹⁰NbNi)=-4.118(16) T andB _HF(^93mMoNi)=-3.491(33) T. The rather long spin-lattice relaxation time of 32(5) min was observed for⁹⁰NbNi at an external magnetic field of 0.2T and8 mK.     

Variational Operators,Symplectic Operators,and the Cohomology of Scalar Evolution Equations

For a scalar evolution equation u_t = K(t, x, u, u_x, . . . , u_2m+1) with m ≥ 1, the cohomology space H^1,2() is shown to be isomorphic to the space of variational operators and an explicit isomorphism is given. The space of symplectic operators for u_t = K for which the equation is Hamiltonian is also shown to be isomorphic to the space H^1,2() and subsequently can be naturally identified with the space of variational operators. Third order scalar evolution equations admitting a first order symplectic (or variational) operator are characterized. The variational operator (or symplectic) nature of the potential form of a bi-Hamiltonian evolution equation is also presented in order to generate examples of interest.     

Equation of state and thermal expansivity of LiF and NaF

The high-pressure and high-temperature behaviors of LiF and NaF have been studied up to 37 GPa and 1000 K. No phase transformations have been observed for LiF up to the maximum pressure reached. The B1 to B2 transition of NaF at room temperature was observed at ～28 GPa, this transition pressure decreases with temperature. Unit-cell volumes of LiF and NaF B1 phase measured at various pressures and temperatures were fitted using a P–V–T Birch–Murnaghan equation of state. For LiF, the determined parameters are: α₀ = 1.05 (3)×10^?4 K^?1, dK/dT = ?0.025 (2) GPa/K, V ₀ = 65.7 (1) Å³, K ₀ = 73 (2) GPa, and K′ = 3.9 (2). For NaF, α₀ = 1.34 (4)×10^?4 K^?1, dK/dT = ?0.020 (1) GPa/K, V ₀ = 100.2 (2) Å³, K ₀ = 46 (1) GPa, and K′ = 4.5 (1).     

The kappa in J/Ψ↦K<Superscript>+</Superscript>π

BES II data for J/Ψ↦K ^*(890)Kπ reveal a strong κ peak in the Kπ S-wave near threshold. Both magnitude and phase are determined in slices of Kπ mass by interferences with strong K ₀(1430), K ₁(1270) and K ₁(1400) signals. The phase variation with mass agrees within errors with LASS data for Kπ elastic scattering. A combined fit is presented to both BES and LASS data. The fit uses a Breit-Wigner amplitude with an s-dependent width containing an Adler zero. The κ pole is at (760±20(stat)±40(syst)) - i(420±45(stat)±60(syst)) MeV. The S-wave I = 0 scattering length a ₀ = 0.23±0.04 m _π ^-1 is close to the prediction 0.19±0.02 m _π ^-1 of Chiral Perturbation Theory at O(p ⁴). An erratum to this article can be found at .     

Strange hadron production in Σ-<Emphasis Type="Italic">A</Emphasis> interactions in the SELEX experiment

We report our observations on the resonance signals of masses of 1520, 1670, 1810 (1 820), and 2100 MeV c ⁻², produced inclusively in the reaction Σ⁻ + C(Cu) → p + K⁻ + X, and the signals of masses of 1020 and 1525 MeV c ⁻², produced inclusively in the reaction Σ⁻ + C(Cu) → K⁺ + K⁻ + X, with a 600-GeV c ⁻¹- momentum hyperon beam in the SELEX experiment at the Fermilab. The masses, widths, and branching ratios were measured. The resonance signal of mass of 1520 MeV c ⁻² correspond to the known Λ(1520) hyperon. The signals of masses of 1020 and 1525 MeV c ⁻² in the K⁺K⁻ system correspond to the φ⁰(1020)- and f ₂′(1525) mesons, respectively. The branching ratio of the resonance of mass of 1670 MeV c ⁻² relative to Λ(1520) is (24.92 ± 0.45 ± 0.48)%, while that of the resonance of mass of 1810 (or 1 820) MeV c ⁻² relative to Λ(1520) is (16.13 ± 0.38 ± 0.45)%. The branching ratio of the f ₂′(1525) resonance relative to φ⁰(1020) is (10.75 ± 0.25 ± 0.45)%. Data analysis was performed over 6 × 10⁷ trigger events registered by the SELEX setup on the FNAL Tevatron.     

Emission of quasi-thermal ions from a solid bombarded by cluster ions

Comparative studies of the emission of quasi-thermal atomic and cluster ions from V, Nb, Ta, Au, and In targets bombarded by cluster ions Au _m ⁻(m = 1–9), as well as from Si and Bi targets bombarded by cluster ions Au _m ⁻(m = 1–9) and Bi _m ⁻(m = 1–5), with energy E ₀ ranging from 6 to 21 keV are carried out. In the case of bombardment by heavy cluster ions, the fraction of the quasi-thermal component in the energy spectra of sputtered atomic ions reaches 50 (for V, In, and Au), 70 (Nb), or more than 90% (Ta). In addition, quasi-thermal ions play a considerable part in the emission of small cluster ions Au₂⁺, In₂⁺, In₃⁺, and Bi _n ⁺(n = 2–7). The results of the generalizing investigation favor the presence of thermal spike conditions at cluster bombardment and their appreciable contribution to the emission of atomic and small cluster ions.     

The magnetic moments of (vg 9/2)-levels in odd Zn isotopes

^69m,71mZn have been implanted with an isotope separator on-line into a cold iron host matrix. Nuclear magnetic resonance of the low-temperature oriented isotopes has been observed. The resonance frequencies for zero external magnetic field are v_L(^69mZnFe@#@) =36.814(35) MHz andv _L (^71mZnFe)=33.47(19) MHz. From these the magnetic moments of the 9/2⁺ iosmeric states have been derived as μ(^69mZn)=(?)1.138(18) n.m. andμ(^71mZn)=(?)1.035(18) n.m. The experimentally known magnetic moments of (vg _9/2)-levels in odd zinc isotopes are compared to theoretical estimates.     

Ground-state constants A 0 and DK 0 of 12CH3I from perturbation-allowed transitions

The upper levels of the bands v ₅ and v ₃ + v ₆ of CH₃I are coupled through a Fermi and an l(2, -1) resonance. This gives rise to perturbation-allowed transitions. Altogether, more than 200 such lines corresponding to three different K-value pairs have been observed between 1320 cm^-1 and 1520 cm^-1. By fixing the sextic constant H^K ₀ equal to zero, the following values were obtained: A ₀ = 5·173931(2) cm^-1 and D^K ₀ = 87·36(6) × 10^-6 cm^-1. The possible values of H^K ₀ and their effects on the results are discussed.     

Radiative widths of neutral kaon excitations

We observe 147 events of the axial vector pairK ₁(1270)–K ₁(1400) produced in the Coulomb field of a Pb target and measure the radiative widths Γ(K ₁(1400)→K ⁰ + γ) = 280.8 ±23.2(stat.) ±40.4(syst.) keV and Γ(K ₁(1270) →K ⁰ + γ) = 73.2 ±6.1(stat.) ±28.3(syst.) keV. These first measurements are lower than the quark-model predictions. We also place upper limits on the radiative widths forK*(1410) andK ₂ ^* (1430) and find that the latter is very small in accord withSU(3)invariance in the naive quark model.     

Resonances in the KSKSKL system produced in collisions of negative pions with a carbon target at a momentum of 40 GeV

The experimental spectrum of the K _S K _S K _L system from the reaction π ⁻C → K _S K _S K _L + Y at amomentum of 40 GeV was obtained experimentally with the aim of studying resonance states featuring open strangeness and occurring in the high-mass region. The experiment was performed at the 6-m spectrometer installed at the Institute for High Energy Physics (IHEP, Protvino). The spectrum displays, along with well-known resonances [K ₁(1640), K ₂(1770), K ₂(1820), K ₂(1980)], which fit in the quark-antiquark classification, the exotic resonances K ₂(2280) and K ₄(2500). The K ₂(2280) resonance exhibits the properties of a hybrid and has an exotic decay mode producing a triplet of known resonance states related to each other by quark-gluon mixing. The mechanism of the formation of the observed hybrid K ₂(2280) is dominated by the exchange of a natural spin-parity in the t channel of the reaction. The mode of decay into f ₀(980)K _L and the mode of decay into f ₂(1270)K _L are observed for the K ₂(1770) and the K ₂(1980) resonance, respectively. __________ Translated from Yadernaya Fizika, Vol. 66, No. 5, 2003, pp. 860–867. Original Russian Text Copyright ? 2003 by Tikhomirov, Erofeev, Erofeeva, Luzin.     

Analysis of pp → K+K− π+π− around 1 GeV/c

Approximately 100 000 four-prong antiproton annihilations in hydrogen were measured. A clean, unbiased sample of 842 K⁺K^?π⁺π^? events was obtained. This reaction is dominated by $\text{K}{}^1\text{(～45\%)}$ and ?⁰(～20%) production, with smaller amounts of A₂⁰(～15%) and ?(～5%) production. 25% of the reactions involved double resonance production. No significant three-body resonance production is observed.     

Knight shifts and absolute magnetic moments of (h9/2) n proton states in trans-bismuth nuclei

The Knight shiftsK(FrT1) andK(RaPb) have been measured in connection with a systematic study on magnetic moments of (h_9/2) ⁿ proton states. The Knight shifts were obtained directly by a comparison of precession frequencies and, indirectly, from relaxation times involving the Korringa relation. Good agreement is found among the results from the different methods; the average values areK(FrT1)=(0.89±0.09)% andK(RaPb)=(1.05±0.15)%.     

An experimental study of the K+ → πoμ+ν decay dalitz plot

A sample of K⁺_μ3 events, detected in the CERN 1.1 m³ heavy-liquid bubble chamber, has been used to investigate the q² dependence of the form factors, giving ξ(0) = ?1.1 ± 1.0 and ξ(6.6m²_π) = ?0.34 ± 0.20, for λ₊ = 0.027. A three parameter fit gives a value for λ₊ = 0.025 ± 0.017 in good agreement with the preceding K_e3 analysis.     

I=1/2 low-lying mesons in lattice QCD

Using a conventional constituent-quark model,I=1/2 scalarκ,vector K*(892),and axial vector K1mesons are studied in the asqtad-improved staggered fermion with wall-source and point-sink interpolators.The mass ratio of mκ/mK*(892)is numerically confirmed to apparently vary with quark mass,and the experimental ordering mK*(892)mκholds elegantly when the light u/d quark masses are sufficiently small,while the valence strange quark mass is fixed to its physical value.We also get reasonable signals for the K1 meson suggested by the SCALAR Collaboration from lattice QCD.The computations are conducted with the MILC Nf=3 flavor gauge configurations at three lattice spacings:a≈0.15,0.12,and 0.09 fm.     

η(1475) and <Emphasis Type="Italic">f</Emphasis><Subscript>1</Subscript>(1420) resonances in the decay processes <Emphasis Type="Italic">J</Emphasis>/ψ → γ(ρρ, γρ<Superscript>0</Superscript>, γϕ) and in γγ* collisions

A scenario that removes the contradiction between the suppression of the η(1475) → γγ decay width and the strong coupling of η(1475) to the ρρ, ωω, and γρ⁰ channels and which leads to a nontrivial prediction for the manifestation of η(1475) in γγ*(Q ²) collisions is considered. Data on the dependence of the cross section for the reaction γγ*(Q ²) → K[`(K)]pK\bar K\pi on the photon virtuality in the energy range 1.35–1.55 GeV are explained here by the production of an η(1475) resonance in contrast to their standard interpretation in terms of the f <sub>1</sub>(1420) resonance. Experimental verification of the present explanation requires determining the spin-parity of resonance contributions, R, in the reactions γγ*(Q <sup>2</sup>) R → R → K[`(K)]pK\bar K\pi and J/ψ → γR → γ(γρ⁰, γϕ).     

Mössbauer Studies of Dilute 119Sn and 57Fe in SrRuO3 and Sr2FeRuO6

Nuclear magnetic resonance on oriented ¹⁷⁵Hf in iron host has been measured. Samples of ¹⁷⁵HfFe were made by recoil implantation of the precursor ¹⁷⁵Ta isotope. The resonance frequency and the resonance line width have been determined to be 139.0 (1) MHz and FWHM = 2.7 (2) MHz, respectively, in an external magnetic field of 0.1 T. The resonance width was very narrow compared with the previously reported value of 11.0 (1.1) MHz. With the known value of the magnetic moment of μ(¹⁷⁵Hf) = −0.62 (3) μ_N, the hyperfine field has been deduced as B _HF = −73.6 (3.5) T.     

Decay studies of101m Rh and101g Rh

The level structure of¹⁰¹Ru has been investigated from the decays of^101m Rh and^101g Rh. For the gamma-ray measurements Ge(Li) detectors with effective volumes of 24 and 43 cm³ were used for singles and coincidence work, and several new transitions were observed. Conversion electron spectra from the^101m Rh decay were investigated with a 50 cm double-focussing beta spectrometer.K-conversion coefficients were determined by combining internal conversion and gamma-ray intensities. For the stronger transitions probable multipolarity assignments have been obtained from these coefficients and also fromK/L andL-subshell ratios. All transitions observed were fitted into a decay scheme, in which tentative spin-parity assignments of all states are given.