Hyperfine structure of CH3OH

Hyperfine structure of the (0, 0, 1) - (1, 0, 1) transition of methanol has been investigated by beam absorption and of the (J, 1, 3?) → (J, 1, 3+) transitions for J = 2, 3, and 6 by beam-maser spectroscopy. The best-fit results for the spin-rotation and spin-spin coupling constants $\text{C}{}_{\mathrm{JK\tau \pm }}{}^{\mathrm{(i)}}$ and $\text{D}{}_{\mathrm{JK\tau \pm }}{}^{\mathrm{(i)}}$, respectively, are in kHz¹: $\text{C}{}_{101}{}^{\mathrm{(1)}}\text{= 2.4(10)}$, $\text{C}{}_{101}{}^{\mathrm{(2)}}\text{= ?0.6(10)}$, $\text{D}{}_{101}{}^{\mathrm{(1)}}\text{= ?13.8(9)}$, $\text{D}{}_{101}{}^{\mathrm{(2)}}\text{= 7.0(9)}$, $\text{C}{}_{\mathrm{213?}}{}^{\mathrm{(1)}}\text{= ?5.0(10)}$, $\text{C}{}_{\mathrm{213?}}{}^{\mathrm{(2)}}\text{= ?5.5(10)}$ and ($\text{C}{}_{\mathrm{J13?}}{}^{\mathrm{(2)}}\text{- C}{}_{\mathrm{J13+}}{}^{\mathrm{(2)}}\text{) = 0.98(9)}$.     

The ground state of methane 12CH4 through the forbidden lines of the ν3 band

High resolution spectra of the ν₃ band of methane, ¹²CH₄, were recorded by using a “third generation vacuum Fourier interferometer”; a large pressure range (from 0.009 to 10 Torr) with a sample path fixed at eight meters was used, enabling observation of transitions with intensity ratios as low as $\text{1}\text{10 000}$. More than 350 forbidden transitions of the ν₃ band, including about 125 transitions of the Q⁺ branch, were unambiguously identified. Of the 277 transitions retained for computations, one-hundred have 11 ≤ J ≤ 16. From combination difference relations using pairs of transitions having the same upper state energy level (forbidden-allowed and forbidden-forbidden pairs were used), 276 independent differences between ground state energy levels could be determined with uncertainties of about 0.001 cm^?1.These data yielded the following values for the ground state structure constants of ¹²CH₄ along with their standard deviations (in cm^?1): $\text{β}{}^{\mathrm{o}}\text{hc}\text{=5.2410356±0.0000096}$, $\text{γ}{}^{\mathrm{o}}\text{hc}\text{=(?1±0.00074) 10}{}^{\mathrm{?4}}$, $\text{π}{}^{\mathrm{o}}\text{hc}\text{=(5.78±0.18) 10}{}^{\mathrm{?9}}$, $\text{?}{}^{\mathrm{o}}\text{hc}\text{=(?1.4485±0.0023) 10}{}^{\mathrm{?6}}$, $\text{?}{}^{\mathrm{o}}\text{hc}\text{=(1.768±0.126) 10}{}^{\mathrm{?10}}$, $\text{ξ}{}^{\mathrm{o}}\text{hc}\text{=(?1.602±0.067) 10}{}^{\mathrm{?11}}$, Thus, for the first time, the scalar constant π⁰ has been evaluated and ir values have been obtained for the two tetrahedral constants ?⁰ and ξ⁰; furthermore, these values are in very good agreement with the ones recently determined from radiofrequency data, i.e., in cm^?1: $\text{?}{}^{\mathrm{o}}\text{hc}\text{=(?1.45061±0.00014) 10}{}^{\mathrm{?6}}$, $\text{?}{}^{\mathrm{o}}\text{hc}\text{=(1.7634±0.0068) 10}{}^{\mathrm{?10}}$, $\text{ξ}{}^{\mathrm{o}}\text{hc}\text{=(?1.5432±0.0040) 10}{}^{\mathrm{?11}}$ From these values, the 276 differences can be reproduced with an overall rms deviation equal to 0.0009 cm^?1.Finally, the ground state energies of ¹²CH₄ have been calculated for J ≤ 16.     

New experimental data on the proton electromagnetic polarizabilities

The γp-elastic scattering cross section has been measured in the photon energy range 70–110 MeV. As a monitor process the electron Compton-scattering was simultaneously measured. The values of the electric ($\text{α}$) and magnetic ($\text{β}$) polarizabilities of the proton were obtained from the experimental data: $\text{α}\text{= (10.7 ± 1.1) × 10}{}^{\mathrm{?43}}\text{cm}{}^3$; $\text{β}\text{= (?0.7 ± 1.6) × 10}{}^{\mathrm{?43}}\text{cm}{}^3$.     

Centrifugal distortion effects in the microwave spectrum of methylene cyanide

The rotational spectrum of methylene cyanide has been measured up to J = 62 and a total of 82 b-type transitions have been obtained. These data have been analyzed with a semirigid rotor Hamiltonian to give accurate rotational and centrifugal distortion constants. The rotational constants are (in MHz) $\text{A}$ = 20882.7537 ≠ 0.017, $\text{B}$ = 2942.3003. ≠ 0.0031, $\text{C}$ = 2616.7225 ≠ 0.0031 The quartic centrifugal distortion constants are (in MHz)

$\text{Δ}{}_{\mathrm{J}}\text{(1.855455 ≠ 0.014) x 10}{}^{\mathrm{?3}}\text{Δ}{}_{\mathrm{JK}}\text{= (?6.79218 ≠ 0.027) x 10}{}^{\mathrm{?2}}$

$\text{Δ}{}_{\mathrm{K}}\text{(8.621628 ≠ 0.013) x 10}{}^{\mathrm{?1}}\text{δ}{}_{\mathrm{J}}\text{= (4.892607 ≠ 0.016) x 10}{}^{\mathrm{?4}}$

$\text{δ}{}_{\mathrm{K}}\text{= (6.7501 ≠ 0.29) x 10}{}^{\mathrm{?3}}$

The uncertainties are twice the standard deviations in the constants obtained from the least squares analysis, and represent approximately 95% confidence limits.     

Inclusive production of K̄1(890) and K̄1(1420) in K̄−p interactions at 10 and 16 GeV/c

The inclusive production of K?¹(890) and K?¹(1420) is studied in K?^?p interactions at 10 and 16 GeV/c. At 10 GeV/c an enhancement in the ($\text{K}\text{?}{}^0\text{π}{}^{\mathrm{?}}$) mass distribution is found at 1.74 GeV, but no clear signal is seen at 16 GeV/c. The fraction of $\text{K}{}^0\text{'}\text{s}$ coming from decay of the $\text{K}{}^1\text{(890)}\text{or}\text{K}{}^1\text{(1420)}$ is large, being (50 ± 6)% and (45 ± 5)% at 10 and 16 GeV/c, respectively. The inclusive cross sections for K^1?(890) and $\text{K}{}^{10}\text{(890)}$ production are almost constant with energy from 8 to 32 GeV/c with values of 3.5 and 3.3 mb, respectively. The $\text{K}{}^1\text{(890)}$ production cross section is studied as a function of transverse and longitudinal variables and found to derive mainly from fragmentation of the incident K^? meson. The spectra of $\text{K}{}^0\text{'}\text{s}$ resulting from the decay of $\text{K}{}^1\text{(890)}$ are studied.     

Oscillator strengths in the Cameron system of carbon monoxide

Relative oscillator strengths in the Cameron system of CO(a³Π ← X¹Σ) have been observed in absorption for six bands (υ′ = 0–5, υ″ = 0) with the result, normalized to the absolute (0, 0) band measurement of Hasson and Nicholls, $\text{?}{}_{00}\text{= (1.62±0.07) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{10}\text{= (1.96±0.09) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{20}\text{= (1.41±0.04) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{\mathrm{3\; 0}}\text{= (0.72±0.03) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{40}\text{= (0.31±0.02) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{50}\text{= (0.14±0.01) × 10}{}^{\mathrm{?7}}$. The density of CO was modulated with a motor-driven vacuum valve and synchronous fluctuations (?1 per cent) in the transmitted intensity detected with a lock-in amplifier. Peak pressure in the 21 cm absorption cell was approximately 10 torr. A curve of growth analysis was used to correct saturation effects by less than 3 per cent.     

Electromagnetic annihilation of e+e− into quarkonium states with even charge conjugation

We calculate the production of narrow resonances with even charge conjugation ${}^3\text{P}{}_{\mathrm{J}}\text{=1,2}$ in e⁺e^? annihilation in the quarkonium and vectordominance models. We give unitarity bounds for $\text{Γ(}{}^3\text{P}{}_{\mathrm{J}}\text{→ e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}\text{)}$ in terms of $\text{Γ(}{}^3\text{P}{}_{\mathrm{J}}\text{→ γγ)}$ and $\text{Γ(}{}^3\text{P}{}_{\mathrm{J}}\text{→ e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}\text{)}$. The electromagnetic production dominates through the neutral current at low energies independent of details of the model. For masses above 10 GeV the situation is reversed.     

Ω− produced in K−p reactions at 4.2 GeV/c

Forty $\text{Ω}{}^{\mathrm{?}}$ events have been observed in a large (133 events/βb) experiment at 4.2 GeV/c incident K^? momentum. Thirty nine of the events come from the three-body reaction $\text{K}{}^{\mathrm{?}}\text{p}\text{→Ω}{}^{\mathrm{?}}\text{K}{}^{\mathrm{+}}\text{K}{}^0$. The $\text{Ω}{}^{\mathrm{?}}$ is mainly produced in the forward hemisphere (direction of the incident K^?). The lifetime is measured to be τ = (0.75 _+0.14?0.11 × 10^?10 sec substantially less than the Particle Data Group value of (1.3 _?0.3^+0.2) × 10^?10 sec. The mass is determined to be 1671.7 ± 0.6 MeV, in good agreement with other determinations. The decay asymmetry parameter α (for the decay mode $\text{Ω}{}^{\mathrm{?}}\text{→ Λ}\text{K}{}^{\mathrm{?}}$) is found to be ?0.2 ± 0.4.     

The rotational analysis of the 1Π-X 1Σ+ system at 649.5 nanometers of zirconium oxide

A red-degraded band head, normally badly overlapped by the gamma system, $\text{A}{}^3\text{Φ}\text{- X′}{}^3\text{Δ}$, of zirconium oxide, appears in emission spectra of zirconium arcs and in absorption spectra of S-type stars and of frozen rare gas matrices containing zirconium. The emission band has been examined at high-resolution with the aid of separated zirconium isotopes. Identification of the band as 0-0 of a ${}^1\text{Π}\text{- X}{}^1\text{Σ}{}^{\mathrm{+}}$ system of zirconium oxide is confirmed by rotational analysis where the following constants (cm^?1) are obtained for ⁹⁰Zr¹⁶O:

$\text{B}{}_0\text{′(R,P) = 0.40142 D}{}_0\text{′(R,P) = 3.51 × 10}{}^{\mathrm{?7}}$

$\text{B}{}_0\text{′(Q) = 0.40166 D}{}_0\text{′(Q) =3.52 × 10}{}^{\mathrm{?7}}$

$\text{B}{}_0\text{″ = 0.42263 D}{}_0\text{″ =3.19 × 10}{}^{\mathrm{?7}}$

$\text{ν}{}_0\text{= 15383.81s}$

The Λ-type doubling in the ¹Π state and the question of whether $\text{X}{}^1\text{Σ}{}^{\mathrm{+}}$ or $\text{X′}{}^3\text{Δ}$ is the true ground state of ZrO are discussed.     

Backward K10 production in the reaction π−p→Λ0K+π− at 9 and 12 GeV/c

We have analysed about 85 000 fast Λ⁰ events, obtained in a fast proton triggered experiment performed at the CERN-Ω spectrometer at 9 and 12 GeV/c incident π^? beam. Nearly 2500 Λ⁰K⁺π^? events have been isolated. We find strong production of quasi-two-body processes $\text{Λ}{}^0\text{K}{}^{10}$ and $\text{∑}{}^{\mathrm{1?}}\text{K}{}^{\mathrm{+}}$ consistent with u-channel hyperon exchange. Results on Λ⁰ polarization, K¹⁰ decay parameters and differential cross sections are given for $\text{Λ}{}^0\text{K}{}^{10}\text{(892)}$ and $\text{Λ}{}^0\text{K}{}^{10}\text{(1430)}$ final states. A comparison is made with the associated backward $\text{Λ}{}^0\text{(1520)}\text{K}{}^{10}$ production seen in the four-prong reaction π^?p→pK^?K⁺π^? obtained in the same experiment.     

Spin assignments in 63Ni through 62Ni(d,p)63Ni

Angular distributions of vector analyzing power have been measured for the reaction ${}^{62}\text{Ni}\text{(}\text{d, p}\text{)}{}^{63}\text{Ni}$ at a beam energy of 10 MeV. The observed j-dependence of vector analyzing power allows unambiguous spin assignments to be made for the following states in ⁶³Ni (excitation energies in MeV): $\text{0,}\text{1}\text{2}{}^{\mathrm{?}}$; $\text{0.087,}\text{5}\text{2}{}^{\mathrm{?}}$; $\text{0.155,}\text{3}\text{2}{}^{\mathrm{?}}$; $\text{0.515,}\text{3}\text{2}{}^{\mathrm{?}}$; $\text{1.003,}\text{1}\text{2}{}^{\mathrm{?}}$; $\text{2.297,}\text{5}\text{2}{}^{\mathrm{+}}$; $\text{2.700,}\text{1}\text{2}{}^{\mathrm{?}}$; $\text{2.953,}\text{1}\text{2}{}^{\mathrm{+}}$; $\text{3.292,}\text{5}\text{2}{}^{\mathrm{+}}$; $\text{3.932,}\text{5}\text{2}{}^{\mathrm{+}}$; $\text{3.951,}\text{5}\text{2}{}^{\mathrm{+}}$; $\text{4.387,}\text{5}\text{2}{}^{\mathrm{+}}$. An assignment of $\text{9}\text{2}{}^{\mathrm{+}}$ is suggested for the state at 2.519 MeV. The data for the unresolved l_n = 4, 1 doublet (1.294, 1.327) MeV indicate the $\text{3}\text{2}{}^{\mathrm{?}}$ spin assignment for the 1.327 MeV state. The main features for all the data are in agreement with DWBA calculations.     

Inclusive K10(890) production in π−p interactions at 16 GeV/c

Inclusive $\text{K}{}^{10}$ production is studied in π^?p interactions at 16 GeV/c with x_? > 0.2. The $\text{K}{}^{10}$ is found to be pre-dominantly centrally produced with cross section $\text{σ(}\text{K}{}^{10}\text{) = (72 ± 12) μb}$ for x_? > 0.2 and compares closely to data on $\text{K}{}^{10}$ production in π⁺p interactions at the same energy.     

QCD effects in νN scattering above the threshold of W-boson production

The QCD effects are shown to result at $\text{s}\text{m}{}_{\mathrm{<mtext>w</mtext>}}{}^2\text{? 1}$ in a considerable increase of the νN cross section and modification of $\text{d}\text{σ}\text{d}\text{y}$ in comparison with scaling. At $\text{s}\text{m}{}_{\mathrm{<mtext>w</mtext>}}{}^2\text{≈ 3 × 10}{}^3$ the QCD cross section is twice that of scaling. At $\text{s}\text{m}{}_{\mathrm{<mtext>w</mtext>}}{}^2\text{? 1}$ the QCD structure functions of the nucleon acquire effective scaling behaviour.     

Experimental and theoretical studies of positive pion production on 10B and 40Ca by 163–186 MeV protons

The reactions ${}^{10}\text{B(p}\text{,π}{}^{\mathrm{+}}\text{)}{}^{11}\text{B}$ and ${}^{40}\text{Ca(p}\text{,π}{}^{\mathrm{+}}\text{)}{}^{41}\text{Ca}$ have been studied for proton energies between 163 and 186 MeV. Angular distributions for the ground states and the excited state at 2.13 MeV in ¹¹B are presented. Cross sections calculated in the one-nucleon model, under different assumptions about the interaction Hamiltonian as well as the pion and proton optical potentials, are compared with the experimental distribution from the $\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ state in ⁴¹Ca.     

A measurement of the Ω− lifetime

In an experiment at the CERN-SPS charged-hyperon beam, a sample of $\text{2500 Ω}{}^{\mathrm{?}}\text{→ ΛK}{}^{\mathrm{?}}$ decays has been collected at Ω^? momenta of 98.5 and 115 GeV/c. The Ω^? lifetime is found to be $\text{τ}{}_{\mathrm{\Omega }}\text{= (0.822 ± 0.028) × 10}{}^{\mathrm{?10}}\text{s}$.     

Dielectronic satellite spectra from dense laser-produced plasmas

The Lyman-α and adjacent dielectronic satellite lines have been observed in the spectra from laser-irradiated solid targets. In a carbon plasma from a planar target, the relative intensity of the $\text{2p}{}^2{}^3\text{P?1s2p}{}^3\text{P}$ satellite line of C(V) increases as a function of electron density in the range 8 × 10¹⁹ to 2 × 10²⁰ cm^?3. As analysis of a series of imploded microballoon experiments indicates that the $\text{2p}{}^2{}^3\text{P?1s2p}{}^3\text{P}$ and $\text{2s2p}{}^3\text{P?1s2s}{}^3\text{S}$ satellite radiation of Si(XIII) increases for electron densities 1 × 10²²?2 × 10²³ cm^?3. The satellite intensity distributions have been numerically simulated using a rate equation model. It is shown that the carbon and silicon satellite data may be interpreted in a consistent manner, and the extension to higher atomic numbers Z and higher electron densities is considered.     

Peripheral behaviour of pp → K1±K∓ between 1 and 2.5 GeV/c

The reaction $\text{p}\text{p}\text{→}\text{K}{}^1\text{K}$ does not exhibit any s-channel resonance effect between 1 and 2.5 GeV/c. On the contrary, the data on $\text{p}\text{p}\text{→}\text{K}{}^{\mathrm{1?}}\text{K}{}^{\mathrm{\pm }}$ are compatible with an exchange mechanism in the t- and u-channels above 1.5 GeV/c. Strong similarities are found with $\text{p}\text{p}\text{→}\text{K}{}^{\mathrm{?}}\text{K}{}^{\mathrm{+}}\text{and}\text{K}{}^{\mathrm{1?}}\text{K}{}^{\mathrm{1+}}$. The polarisation of K^1± is given. The reaction $\text{p}\text{p}\text{→}\text{K}{}^{10}\text{K}{}^0$ vanishes above 1.5 GeV/c     

Rare decay modes of K1(1420) and K1(892)

A 2.5 standard deviation signal is observed for the decay $\text{K}{}^{\mathrm{1?}}\text{(1420) →}\text{K}{}^{\mathrm{1?}}\text{(892)π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}$. From this signal a partial width of 13.0 ± 5.0 MeV for the decay mode $\text{K}{}^1\text{(1420)→}\text{K}{}^1\text{(892)ππ}$ is deduced under the assumption that the ππ system is in an I = 1 state. For the rare decay mode $\text{K}{}^1\text{(892)→}\text{K}\text{ππ}$ no signal is observed. The following upper limits can be given for the decay widths: , , .     

Ellipsometric investigation of the skeletonization process of langmuir-blodgett films

When Langmuir-Blodgett films, consisting of a mixture of a long chain carboxylic acid and its salt are immersed in benzene, the acid dissolves, while the salt remains as a skeleton. The density of the film is lowered in this way and so is the refractive index. The process can thus be followed by performing ellipsometric measurements as a function of time of skeletonization. It is established that skeletonization is, in first instance, a diffusion-controlled process with a diffusion coefficient of about $\text{5 × 10}{}^{\mathrm{?14}}\text{cm}{}^2\text{sec}$ at room temperature. The salt also slowly dissolves at a rate of about $\text{1.6 × 10}{}^{10}\text{molecules}\text{/}\text{sec}\text{cm}{}^2$.