The average transverse distance between partons as measured by nucleon form factors

The values of $\text{d}\text{F}{}_1\text{(q}{}^2\text{)}\text{d}\text{q}{}^2$ at q²=0 for the neutron and the proton provide a measure of the average transverse separations squared, 〈$\text{y}{}^2$〉, between a u or d quark and the rest of the partons in a nucleon. Using the measured values of the form factors (together with parton x-distributions), we find that 〈$\text{y}{}^2\text{= 17.4}\text{GeV}{}^{\mathrm{?2}}$ for u quarks and 16.4 GeV^?2 for d quarks in a proton. We speculate that the small difference between u and d quarks is caused by “quark pairing” and discuss other possible experimental signatures of quark pairing.     

Asymmetry in semi-inclusive annihilation

Interference between one- and two-photon processes for e⁺e^? annihilation into hadrons in a two-jet parton model leads to a charge asymmetry of detected final state hadrons along the directions of the incident leptons. The asymmetry near the lepton axis grows as $\text{2}\text{ln}{}^2\text{1}\text{2}\text{θ - 4}\text{ln}\text{1}\text{2}\text{θ}\text{ln}\text{s/ΔE}{}^2$, so that in spite of the O(α) suppression relative to the Born cross section, the asymmetry can amount to a 2% effect at θ = 2° for π^± or K^± inclusive measurements in a typical experiment. The precise size of the asymmetry depends on the parton charges. Our results are only meant to apply in the region ω ? 0.5,where the parton model appears to be relevant at present experimental energies.     

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 ($\text{C}{}_{\mathrm{J13?}}{}^{\mathrm{(2)}}\text{- C}{}_{\mathrm{J13+}}{}^{\mathrm{(2)}}\text{) = 0.98(9)}$.     

Some aspects of the quark parton model

A modified Kuti-Weisskopf model which satisfies the Feynman threshold constraints is considered further. Detailed predictions for the sum of neutrino and anti-neutrino differential cross sections on nucleon (which can be readily compared with forthcoming NAL data), the shapes of the structure functions $\text{?}{}_2{}^{\mathrm{\nu p,\nu n}}$ and the ratio $\text{?}{}_2{}^{\mathrm{\nu p}}\text{/?}{}_2{}^{\mathrm{\nu n}}$, and spin-dependence of inelastic electron-nucleon scattering versus scaling variable x are delineated. We also compare in some detail the general features of our model with the “model independent” approach of Feynman for quark parton theory.     

Antiproton-proton total elastic cross sections in the T and U regions (0.69−2.43 GeV/c)

Antiproton-proton total elastic cross sections at 21 incident momenta in the range 0.69 to 2.43 GeV/c have been deduced by combining p?p elastic differential cross sections over a c.m. angular range $\text{?0.95 ?}\text{cos}\text{θ}{}^1\text{? 0.93}$ with forward elastic cross sections derived from recent real-part measurements and p?p total cross sections. Two bumps are observed, at $\text{M}{}_1\text{? 2.155}$ and $\text{M}{}_2\text{? 2.345}\text{GeV}\text{/c}{}^2$, having widths of Г₁ ～ 0.135 and $\text{Г}{}_2\text{～ 0.135}\text{GeV}\text{/c}{}^2$. Corresponding structures in other p?p reaction channels are discussed.     

Structure functions of nucleons with excited supersymmetric particles

We calculate the QCD evolution equations for structure functions with supersymmetric particles excited for the following models: light gluinos, g? and heavy squarks q? with $\text{m}{}_{\mathrm{<mtext>g</mtext><mtext>?</mtext>}}\text{? Q}{}^2\text{? m}{}_{\mathrm{<mtext>q</mtext><mtext>?</mtext>}}{}^2$; light squarks, and heavy gluinos with $\text{m}{}_{\mathrm{<mtext>g</mtext><mtext>?</mtext>}}\text{? Q}{}^2\text{? m}{}_{\mathrm{<mtext>g</mtext><mtext>?</mtext>}}{}^2\text{;}\text{and}\text{m}{}_{\mathrm{<mtext>g</mtext><mtext>?</mtext>}}{}^2\text{, m}{}_{\mathrm{<mtext>g</mtext><mtext>?</mtext>}}{}^2\text{? Q}{}^2$. The momentum sum rules and the behaviour of structure functions as x → 1 are particularly discussed.     

Dual parton model and the photoproduction of pseudoscalar and vector mesons in the high energy region

On the basis of the dynamical dual model of strong interactions followed from the parton model of hadrons as discussed in an earlier paper, we study here the photo-production of pseudoscalar and vector mesons in the high energy region. To incorporate the concept of duality, it is taken that any two spin $\text{1}\text{2}$ pointlike constituents (partons) can form a π-meson cluster in the structure of a nucleon and the basic interaction involved in MB scattering is the interaction of the incident meson with the π meson in the structure of the nucleon. In this scheme, the amplitudes for the photoproduction of mesons such as γN → Nπ, γN → N?, and γN → Nω in the high energy region can be related with the amplitudes for the process γπ → ππ, γπ → π?, and γπ → πω, respectively. To calculate the amplitudes for the relevant process we also consider a factor corresponding to the structural rearrangement of partons involved in duality diagrams. To obtain the cross sections, we take into account the photon-vector meson analogy, though the naive form of the vector dominance model (VDM) has not been considered here. From a knowledge of the coupling constants $\text{γ?}{}^2\text{4π}$, $\text{γω}{}^2\text{?π}$, , and we obtain the differential cross sections which are in excellent agreement with experimental results. Also we obtain a good fit for the scattering process γN → Nπ at backward angles. For the vector meson production processes, we have contributions from the diffraction mechanism also apart from the amplitudes considered here. In the region where the contribution from the diffraction part is negligible, we obtain the relation

which is in nice agreement with experiments. Finally, it is shown that, though the vector meson dominance is not considered here, the universality of the vector meson coupling with hadrons follows directly from the present model.     

A study of the relativistic coulomb problem in momentum space

The quantum-mechanical solutions of the operator equation corresponding to the classical equation $\text{[(p ? eA)}{}^2\text{+ m}{}^2\text{]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? (E ? eU) = 0}$ are studied in the particular case of the one-dimensional Coulomb potential and compared to the standard solutions of the Klein-Gordon equation.     

Tests of the SU(2) ⊗ U(1) gauge group from neutral current phenomena

Cross section relations which provide tests of underlying SU(2) ? U(1) gauge group are presented. The tests require the knowledge of the inclusive neutral current cross-sections $\text{σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>p</mtext>}}\text{, σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>p</mtext>}}\text{, σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>n</mtext>}}\text{and}\text{σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>n</mtext>}}$ on proton and neutron targets. A particularly simple test is that the “sea” independent combinations ($\text{σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>p</mtext>}}\text{+ σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>p</mtext>}}\text{? σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>n</mtext>}}\text{? σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>n</mtext>}}$) and ($\text{σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>p</mtext>}}\text{? σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>p</mtext>}}\text{? σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>n</mtext>}}\text{+ σ}{}^{\mathrm{<mtext>\nu </mtext><mtext>n</mtext>}}$) cannot both be positive. Ways of distinguishing between various SU(2) ? U(1) models are also given.     

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.     

High-spin states in 201Bi populated in the (α, 6n) reaction

High-spin States in ²⁰¹Bi are investigated by observing γ-rays in the reaction ²⁰³Tl(α, 6n)²⁰¹Bi. Three isomers are observed with suggested spins of $\text{17}\text{2}{}^{\mathrm{+}}\text{,}\text{21}\text{2}{}^{\mathrm{+}}$ or $\text{25}\text{2}{}^{\mathrm{+}}$ and $\text{29}\text{2}{}^{\mathrm{?}}$ and half-lives of 9.5 ns, 210 ns, and 160 ns. The level systematic of odd Bi isotopes with 201 ? A ? 207 is presented.     

Activation energy of field emission flicker noise power due to adsorbed potassium on tungsten

The temperature dependence of the field emission flicker noise spectral density functions has been investigated for potassium adsorbed on tungsten (112) planes by a probe hole technique. By integration of the spectral density functions $\text{W(?) = B}{}_{\mathrm{i}}\text{?}{}^{\mathrm{?ge}}\text{i}$ the noise power $\text{(δn}{}^2{}_{\mathrm{\Delta ?}}$ for different frequency intervals Δ? is obtained. From the exponential temperature dependence of $\text{(δn}{}^2{}_{\mathrm{\Delta ?}}$ noise power “activation energies” q_Δ? are determined. Plots of these energies versus coverage show a similar “oscillating” behaviour as recently found for $\text{W(?}{}_{\mathrm{j}}\text{)}$ or which indicates phase transitions of the adsorbed potassium submonolayers. The noise activation energies are discussed in terms of existing models and a comparison is made between the experimental q values and surface diffusion energies E_d as determined by conventional methods.     

A clear test of perturbative QCD in large-pT photoproduction

It is shown that measurement of the cross-section differences $\text{E}\text{d}\text{σ}\text{d}{}^3\text{p(γ}\text{p}\text{→}\text{h}{}^{\mathrm{+}}\text{X}\text{) ?}\text{E}\text{d}\text{σ}\text{d}{}^3\text{p (γ}\text{p}\text{→}\text{h}{}^{\mathrm{?}}\text{X}\text{)}$ at large transverse momentum provides a good test of perturbative QCD. Such differences are insensitive to the parton Fermi motion and to the poorly known sea-quark and gluon distribution functions. Moreover the hadronized photon component is shown to contribute little compared to the point-like one. Presently available photon beams at the CERN-SPS and FNAL are sufficient to test QCD in large-p_T photoproduction.     

Optical second-harmonic generation in atomic thallium vapor

We observe coherent optical second-harmonic generation in atomic thallium vapor when the fundamental is tuned to half the resonance frequency of the following transitions: $\text{6}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? 7}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{6}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? 8}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ in the presence of a static magnetic field; and $\text{6}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? 7}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, 6}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? 8}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$in the absence of any external field.     

Dielectric susceptibility and correlation length of one-dimensional CDW with impurties. II. weak disorder

Dependence of static dielectric susceptibility and correlation length of charge density waves (CDW) with weak defects on parameter of incommensurability with lattice is investigated. In almost commensurate phase (h?h_ch_c), $\text{χ ～ (h?h}{}_{\mathrm{c}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{In}{}^{\mathrm{<mtext>-4</mtext><mtext>3</mtext>}}\text{h}{}_{\mathrm{c}}\text{/h?h}{}_{\mathrm{c}}$ and R_c ～ (h ? h_c)^{$\text{2}\text{3}$}. In${}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{h}{}_{\mathrm{c}}\text{/h ? h}{}_{\mathrm{c}}$. Far from commensurability $\text{(h?h}{}_{\mathrm{c}}\text{) χ～ (a+h}{}^2{}_{\mathrm{c}}\text{/h}{}^2\text{)}{}^{\mathrm{<mtext>-2</mtext><mtext>3</mtext>}}$, $\text{R}{}_{\mathrm{c}}\text{～ (a + h}{}^2{}_{\mathrm{c}}\text{/h}{}^2\text{)}{}^{\mathrm{<mtext>-2</mtext><mtext>3</mtext>}}$, where a is the dimensionless ratio of random potential intensities, corresponding to backward and forward scattering impurities.     

Forces d'oscillateur du potassium

We describe the results of measurements on emission and absorption of potassium I lines obtained in two series of experiments. The first concerns a low-pressure flame fed by a methane and oxygen mixture, seeded with potassium carbonate, and the other an atmospheric- pressure helium plasma seeded with potassium.A collation of the experimental results of the latter series and Drawin's theory about the conditions of validity for local thermodynamic equilibrium show that the transition-probability values measured by Heiërman are incorrect. Warner's theoretical values are more satisfactory. This study allows us to propose new oscillator strengths for the KI lines corresponding to the following transitions: $\text{4}{}^2\text{P}{}^0{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? 7}{}^2\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{4}{}^2\text{P}{}^0{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? 10}{}^2\text{S}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{? 11}{}^2\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of the sharp series and $\text{4}{}^2\text{P}{}^0{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{? 6}{}^2\text{D}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext><mtext>5</mtext><mtext>2</mtext>}}$ of the diffuse series.     

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.     

Measurement of Cl and N quadrupole coupling in ClCN

J = 1 ← 0 and J = 2 ← 1 transitions in ³⁵ClCN and ³⁷ClCN were measured using a C-band waveguide spectrometer and phase-locked sources. Parameters obtained from the data are: $\text{B(}{}^{35}\text{ClCN) = 5 970.820 ± 0.010 MHz}$, $\text{B(}{}^{37}\text{ClCN) = 5 847.246 ± 0.008 MHz}$, $\text{eqQ(}{}^{35}\text{Cl) = ?83.26 ± 0.04 MHz}$, $\text{eqQ(}{}^{37}\text{Cl) = ?65.61 ± 0.04 MHz}$ and $\text{eqQ(}{}^{14}\text{N) = ?3.60 ± 0.08 MHz}$.     

Parity violating effects in dilepton production using polarized targets

Parity violating effects in PP → μ⁺μ^?X and $\text{P}\text{P}\text{→ μ}{}^{\mathrm{+}}\text{μ}{}^{\mathrm{?}}\text{X}$ with the polarized targets have been calculated in the parton picture. The weak neutral currents used are based on an SU(2)_L × SU(2)_R × U(1) model. The result for the Weinbergy-Salam model occurs as a special case.