Experimental value of G A/GV from a measurement of both P-odd correlations in free-neutron decay

A new experimental value of the fundamental weak-interaction parameter λ=G _A/G_V (?1.2686±0.0046) is obtained for the first time by an original method that consists in measuring both P-odd correlations in free-neutron decay.     

Determination of the ratio of the axial-vector to the vector coupling constant for weak interaction in triton beta decay

Data on the chemical shifts of the half-lives of atomic and molecular tritium are used to determine the ratio of the axial-vector to the vector coupling constant for weak interaction in triton beta decay. The result is (G_A/G_V)_t=?1.2646±0.0035.     

The neutron zero-energy total cross section and scattering lengths for tritium

New results for the neutron total cross section for tritium extrapolate to 1.70 ± 0.03 b at zero energy. With a theoretical constraint A₁/A₀=0.92 ± 0.04, the scattering lengths A₁=3.60 ± 0.10, A₀ = 3.91 ± 0.12, and A_c=3.68 ± 0.05 fm can be inferred independently of, but consistently with, the previous experimental value for the coherent length A_c=3.82 ± 0.24 fm.     

Hyperfine structure investigations of some odd levels of Co I by level crossing and optical methods

Using the level crossing technique the ratios and absolute values of the hyperfine structure (hfs) constants of the levelsz ⁴F_9/2 andz ⁴F_7/2 of the configuration 3d ⁷4s4p of Co I were measured:z ⁴ F _9/2: ¦A¦=(811±12)MHz; ¦B¦=(48±93) MHz;B/A=?0.06±0.11 A>0; B<0z ⁴ F _7/2: ¦A¦ = (659 ±11)MHz; ¦B¦=(33±84)MHz;B/A=?0.05±0.13 A>0; B<0. In addition the hfs constants of three other excited levels of Co I could be determined by optical methods:z ⁴ F _9/2:A=525±26 MHz;B=200 MHzy ⁴ F _9/2:A=300±30 MHz;B=?500 MHzy ⁴ G _11/2:A=315±20 MHz;B=400 MHz. The experimental results are compared with known experimental and also with theoretical values which where calculated using the parametric potential method.     

DasL/K- und dasM/L-Einfangverhältnis von65Zink

We have investigated theL/K- and theL/M-capture ratio of⁶⁵Zn. For the transitions to the first excited state of⁶⁵Cu we obtained (N _L/N _K) _A =0.120±3% and (N _M/N _L) _A =0.153±13% and for both transitions to the groundstate and the first excited state simultaneously we found (N _L/N _K) _G =0.118±3%. The values for (N _L/N _K) agree well with the results of Santos Ocampo and Conway but are higher than the results of Totzek and Hoffmann. All values are discussed in view of the different theoretical values obtainable.     

Higher order field equations II; Limit properties of green's functions

In a previous paper wave propagation was studied according to a sixth-order partial differential equation involving a complex mass M. The corresponding Yang-Feldman integral equations (indicated as SM-YF-equations), were formulated using modified Green's functions G^M_R(x) and G^M_A(x), which then incorporate the partial differential equation together with certain boundary conditions. In this paper certain limit properties of these modified Green's functions are derived: (a) It is shown that for |M| → ∞ the Green's functions G^M_R(x) and G^M_A(x) approach the Green's functions Δ_R(x) and Δ_A(x) of the corresponding KG-equation (Klein-Gordon equation). (b) It is further shown that the asymptotic behaviour of G^M_A(x) and G^M_A(x) is the same as of Δ_R(x) and Δ_A(x) - and also the same as for D_R(x) and D_A(x) for t→ ± ∞, where D_R and D_A are the Green n's functions for the KG-equation with mass zero. It is essential to take limits in the sense of distribution theory in both cases (a) and (b). The property (b) indicates that the wave propagation properties of the SM-YF-equations, the KG-equation with finite mass and the KG-equation with mass zero are closely related in an asymptotic sense.     

New results from the HAPPEX Experiments at Q<Superscript>2</Superscript> = 0.1GeV/c<Superscript>2</Superscript>

The nucleon's strange electric and magnetic form factors G _E ^s and G _M ^s can be probed via parity-violating electron scattering. The HAPPEX Collaboration has made new measurements of the parity-violating asymmetry A _PV in elastic scattering of 3GeV electrons off hydrogen and ⁴He targets with 〈θ_lab〉 ≈ 6.0^° . For ⁴He the preliminary result is A _PV = (+ 6.43±0.23(stat)±0.22(syst))×10^-6 . For hydrogen the preliminary result is A _PV = (- 1.60±0.12(stat)±0.05(syst))×10^-6 . From these values we extract G ^s _E = 0.004±0.014±0.013 at 〈Q ²〉 = 0.077 GeV/c^2 , and G ^s _E +0.09G ^s _M = 0.004±0.011±0.005 at 〈Q ²〉 = 0.109 GeV/c^2 , both consistent with zero, providing stringent new limits on the role of strange quarks in the vector structure of the nucleon.     

The microwave spectrum,structure and nuclear quadrupole coupling constants for stibabenzene

The microwave spectrum of 121-SbC₅H₅, 123-SbC₅H₅, β-dideutero 121-SbC₅H₃D₂ and 123-SbC₅H₃D₂ has been assigned in the region 26.5–40.0 GHz. The respective rotational constants and uncertainties are: A = 4512.69 ± 0.42, B = 1738.00 ± 0.01, C = 1254.51 ± 0.01; A = 4512.84 ± 0.30, B = 1729.80 ± 0.01, C = 1250.22 ± 0.01; A = 4176.18 ± 0.33, B = 1660.94 ± 0.01, C = 1188.15 ± 0.01; A = 4176.60 ± 0.61, B = 1652.94 ± 0.03, C = 1184.03 ± 0.03 (in MHz units). The structure is found to be planar, C_2v in symmetry. The $\text{d(}\text{Sb-C}\text{) = 2.050 ± 0.005}\text{A}\text{?}$ and ∠CSbC = 92.9° ± 1.0°. The nuclear quadrupole coupling constants for the 121 and 123 antimony isotopes are χ_aa = 456.4 ± 4.1 MHz, η = 0.396 ± 0.008, and χ_aa = 583.00 ± 5.3 MHz, η = 0.399 ± 0.008, respectively. Several alternate techniques using the coupling constants as data support a σ-donating property for antimony.     

Magnetic Resonance Imaging of Diffusion in the Presence of Background Gradients and Imaging of Background Gradients

The measurement of the self-diffusion coefficient D by an NMR technique that uses an applied gradient G_A can be corrupted by systems that have a background magnetic field gradient G₀ and also by imaging gradients G₁, when used in an imaging mode. In a nonimaging mode, the corrupting cross term G_A · G₀can be eliminated in the diffusion measurement by use of an alternating-pulse-field-gradient (APFG) sequence that allows an accurate and uncorrupted measurement of D. A Carr-Purcell echo train enables the measurement of the expectation value, 〈DG²₀〉; assuming D and G₀ to be uncorrelated will allow 〈G²₀〉 to be determined. An image of D or of 〈DG²₀〉 may be obtained without the corrupting G_A · G₀ and G_A · G_I terms by appending a standard imaging sequence to an APFG sequence or a Carr-Purcell sequence, respectively; assuming D and G₀ to be uncorrelated will allow (〈G²₀〉 to be determined within each pixel. Measurements of D and 〈G²₀〉 and their images are made in apple flesh in which minute air bubbles are shown to produce the large 〈G²₀〉. Their values in an 81 g Golden Delicious apple at a measuring frequency of 100 MHz were D = 1.42 × 10⁻⁵ cm²/s and [formula] = 8.9 G/cm.     

Das gyromagnetische Verhältnis des 137 keV Rotationsniveaus von Os185

The rotation of the angular correlation of the 631 keV-137keVγ-γ-cascade in the decay of Re¹⁸⁶ in an external magnetic field of 53 500 gauß was determined to:ωτ=0·098 ± 0·008. The half life of the 137 keV level was measured as: T_1/2=(0·84 ± 0·03) · 10^?9 sec. The coincidences between the 137 keVγ-radiation and theβ-group of 927 keV maximum energy were used in connexion with a time to pulse height converter circuit. The coefficients of the angular correlation of the 631 keV-137 keV γ-γ-cascade were found as: A₂=? 0·073 ± 0·010; A₄=+ 0·310 ± 0·014. These values imply corrections for 3·9% admixture of internal bremsstrahlung and a 1 % contribution by K-X-radiation. The solid angle-corrections were done according to the formula given by E.Rose. The comparison with the theoretical coefficients for a (2⁺ 2⁺ 0⁺)-cascade shows that the multipolarity of the 631 keV radiation is pure E₂, the M₁ admixture being less than 0· 1%. This result is in agreement with the K-selection rule. There is no appreciable attenuation by internal fields. The comparison with the theoretical angular correlation gives for the integral attenuation factor: G₄=0·95±0·04; Assuming only attenuation by electric quadrupole interaction one gets for: G₂=0·92±0·07; The nuclear g-factor of the 137 keV rotational state was derived from these results without any further correction as: g_R= + 0·316±0·028.     

PAM analysis of the microwave spectra of thioacetic acid,CH3COSH and CH3COSD

The microwave spectra of two isotopic species of thioacetic acid, CH₃COSH and CH₃COSD, have been studied. Using the principal axis method (PAM), including terms through n = 6 in the perturbation series and the denominator correction, the spectra were analyzed and 45 lines for CH₃COSH and 40 lines for CH₃COSD were assigned. The parameters obtained by the least-squares analysis are A = 9913.29 ± 0.56 MHz, B = 4923.11 ± 0.23 MHz, C = 3354.60 ± 0.24 MHz, θ = 57.080 ± 0.030°, s = 6.2980 ± 0.0012, and I_α = 3.198 ± 0.020 amu$\text{A}\text{?}{}^2$ for CH₃COSH, and A = 9662.80 ± 0.78 MHz, B = 4810.74 ± 0.26 MHz, C = 3273.92 ± 0.18 MHz, θ = 55.097 ± 0.024°, s = 5.9742 ± 0.0016, and I_α = 3.171 ± 0.020 amu$\text{A}\text{?}{}^2$ for CH₃COSD. The barrier to internal rotation of the methyl group is V₃ = 222.6 ± 1.4 cal/mole for CH₃COSH and V₃ = 212.9 ± 1.4 cal/mole for CH₃COSD. The Stark effect measurements of A species transitions for CH₃COSH led to the dipole moment μ = 1.821 ± 0.013 D with the components μ_a = 0.191 ± 0.010 D and μ_b = 1.811 ± 0.013 D.     

Atomic effects in tritium beta decay and their role in determining the ratio GA/GV and the lifetime of the free neutron

The helium-isotope mass-spectroscopy method for measuring the triton decay constant for various cases of the electron environment was used to determine the tritium half-life without allowance for decay to beta-electron bound states and to calculate the respective reduced half-life, which proved to be (fT _1/2) _t = 1129.6 ± 30.0 s. The equations relating fT _1/2 to G _A /G _V made it possible to obtain the value of (G _A /G _V ) _t = −1.2646 ± 0.0035 and to estimate the neutron lifetime at τ _n = 890.3 ± 3.9(stat.) ± 1.4(syst.) s. __________ Translated from Yadernaya Fizika, Vol. 67, No. 3, 2004, pp. 484–489. Original Russian Text Copyright ? 2004 by Akulov, Mamyrin.     

Neutrino-induced deuteron disintegration in an experiment at the Krasnoyarsk nuclear reactor

The results of studying antineutrino interactions with deuterons (CCD and NCD reactions) and hydrogen (CCP) at the Krasnoyarsk underground reactor with the Deuteron detector are presented. The cross sections for NCD and CCD were measured with a precision of 9%. For CCP, the precision is 3%: σ _expt ^NCD =(3.35±0.31)×10^?44 cm²/fission ²³⁵U, σ _expt ^NCD =(1.08±0.09)×10^?44 cm²/fission ²³⁵U, and σ _expt ^NCD =(6.39±0.19)×10^?43 cm²/fission ²³⁵U. The precision of the experimental results is close to the theoretical one and is in good agreement with other experiments. The limit on the parameters of antineutrino oscillations into the sterile state was obtained: Δm ²≤4.7×10^?2 eV² for sin²(2?)=1.0 (68% C.L.). A comparison of the measured and theoretical cross section gives us the neutron-neutron scattering length of a _nn(S)=?17±6 fm in the approach of zero momentum transfers. The weak neutral current constant is in good agreement with the prediction of the Standard Model: G _A ^NC =G _A ^CC /0.932±0.056.     

High-resolution measurements of the anisotropic directional correlation between γ rays and KX rays in 169Tm

A high resolution measurement of the directional correlation between KX rays and the 131 keV γ ray verifies the existence of the anisotropy previously reported. We find: A₂₂(K_α1, γ)=-0.032±0.007, A₄₄(K_α1, γ)=+0.014±0.008A₂₂(K_α2, γ)=-0.017±0.007 and A₄₄(K_α2, γ)=+0.012±0.007.     

ESR study of vanadyl ion in tripotassium citrate

ESR spectra of VO²⁺ doped tripotassium citrate are recorded at room temperature. The observed spectra are fitted to a spin Hamiltonian of orthorhombic symmetry with g_x = 2.001 ± 0.001, g_y = 1.997 ± 0.001, g_z = 1.945 ± 0.001, A_x = (49.0 ± 1) × 10⁻⁴ cm⁻¹, A_y = (66.8 ± 1) × 10⁻⁴ cm⁻¹ and A_z = (168.4 ± 1) × 10⁻⁴ cm⁻¹. The covalency and Fermi contact terms are evaluated and compared with those of other lattices.     

Electron-nuclear-double-resonance of the VAl center in MgO

An ENDOR study of a hole center in MgO with g_|=2.0032±0.0001 and g_⊥=2.0385±0.0001 reveals that the hole interacts with an axial aluminum ion with A_⊥=±0.178±0.008 MHz, A_⊥=±0.074±0.008 MHz, and P= ±0.366±0.002 MHz. The structure of the center is consistent with the label, V_Al. It is suggested that the V_Al center may have been mistaken in the past for the V^- center because of the similarity of their g-values, method of production, and thermal properties.     

Least squares adjustment of the coupling constants in nuclear beta-decay

Assuming theV-A theory, fully polarized neutrinos, and lepton conservation, best values of the vector and axial vector coupling constants are deduced from all available data on neutron decay and from theft- values of¹⁴O,^26mAl and³⁴C1. Special consideration is given to the treatment of errors and to radiative corrections. For the determination of the coupling constantratio, radiative corrections are, at present, unimportant. We find ¦G_A/G_V¦=1.250 + 0.009 with a phase angle φ=(181.1±1.3)⁰. From the weighted mean ?t-value, including charge dependent and “outer” radiative corrections, we find an effective coupling constant G′_V=(1.413±0.002)x 10⁴⁹erg cm³. The error is mainly due to the uncertainty of charge dependent corrections.     

ESR study of vanadyl ion in trisodium citrate pentahydrate

ESR study of VO²⁺ doped trisodium citrate pentahydrate is undertaken at room temperature. The observed spectra are correlated with the available crystal structure data and are fitted to a spin Hamiltonian of orthorhombic symmetry with g_x = 1.998 ± 0.001, g_y = 1.992 ± 0.001, g_z = 1.934 ± 0.001, A_x = (70.0 ± 1) × 10^-4cm^-1, A_y = (66.6 ± 1) × 10^-4cm^-1 and A_z = (175.4 ± 1) × 10^-4cm^-1. The covalency and Fermi contact parameters are evaluated and compared with those of VO²⁺ in other lattices.     

On locally continuous cocycles

Cohomology groups of locally continuous cocycles of a topological group G with values in a topological G-module A_Ψ are considered and the role of those of degree 2 in the theory of topological extensions of G by A_Ψ is analyzed. The exactness of long sequence is proven. It is shown that, if G and A_Ψ are Polish and if all topological extensions of G by A_Ψ are fibered, the cohomology groups of Borel cocycles and those of locally continuous Borel cocycles are isomorphic for degree 0,1,2.     

Determination of A0 for CH335Cl and CH337Cl from the ν4 infrared and Raman bands

The ν₄ infrared and Raman bands of CH₃Cl were analyzed simultaneously. A direct fit yielded a complete set of constants for CH₃³⁵Cl, including A₀ = 5.20530 ± 0.00010 cm^?1 and D_K = (8.85 ± 0.13) × 10^?5cm^?1. For CH₃³⁷Cl an incomplete set of constants was obtained from the infrared band, and A₀ = 5.2182 ± 0.0010 cm^?1 was estimated by curve fitting of the Raman spectrum. The resulting equilibrium structure is $\text{r(}\text{CH) = 1.0854 ± 0.0005}\text{A}\text{?}$, $\text{r(}\text{CCl) = 1.7760 ± 0.0003}\text{A}\text{?}$, and <(HCH) = 110°.35 ± 0°.05.