Showing papers on "Pion published in 1974"
TL;DR: In this article, the authors measured correlations between like pions in the inclusive processes a + b → π ± + π + + X to study the space-time mechanism of multiple production.
176 citations
TL;DR: In this article, a simple description of the quenching in nuclear matter of the axial vector coupling constant in β-decay is given in terms of the model of Barshay, Brown and Rho constructed to provide a microscopic picture to the pion-nucleus optical potential for π-mesic atoms.
161 citations
CERN1
TL;DR: In this article, a modified Chew-Low extrapolation procedure is applied to the reaction π − p→ Δ ++ π−π−δ −π −δ to extract the I = 2 ππ elastic cross sections from threshold to 1260 MeV.
87 citations
TL;DR: In this paper, the amplitude of a single pion photoproduction in the resonance region has been fitted with a model used previously by one of the authors (RLW), and the procedure followed in making the fit has been changed so as to make greater use of the computer.
86 citations
TL;DR: The picture of Brodsky and Farrar for scattering processes at large transverse momentum is formulated in softened field theory as discussed by the authors, where a modest softening of the quark-quark-gluon vertex is introduced to suppress unwanted logarithm in the formalism.
Abstract: The picture of Brodsky and Farrar for scattering processes at large transverse momentum is formulated in softened field theory. A modest softening of the quark-quark-gluon vertex is introduced to suppress unwanted logarithms in the formalism. It is shown that the electromagnetic form factors of the proton and the pion yield asymptotically behaviours which agree with the result of simple dimensional counting. The threshold behaviours of the deep inelastic structure functions are calculated for the proton and the pion to give ∼ (1 −ω)3 and ∼ (1 −ω)2, respectively. Thus the Drell-Yan-West relation holds in the case of the proton target but is violated in the case of the pion target. It is also proved that the asymptotic behaviours of wide-angel elastic ππ and pp scattering naively predicted by dimensional counting and conjectured by Brodsky and Farrar on the basis of simple Born diagrams are actually the next-to-leading-order terms. The highest-order terms come from a certain set of diagrams that Landshoff studied.
76 citations
TL;DR: In this paper, the effects of repulsive nuclear forces on pion condensation are considered in a simple model, in which they retain only a simplified repulsive zero range nucleon-nucleon interaction proportional to σ · σ σ′ τ · τ ·τ′ the density for the pion threshold is very sensitive to the strength of this force.
65 citations
TL;DR: In this paper, it was shown that the weak production of a pion and its subsequent scattering off nucleons leads to effective nuclear renormalizations of the axial current form factors.
63 citations
TL;DR: In this paper, it was shown that if the P-wave interaction volumes relevant for construction of the pion-nucleus optical potential used in pionic atom studies turn out to be simply related empirically to the free-space pionnucleon scattering volumes, then this would be indicative of both sets of quantities being dominated by the DELTA (1236 MeV), which is to be treated as an independent baryonic excitation in nuclei.
Abstract: It is shown that if the P-wave interaction volumes relevant for construction of the pion-nucleus optical potential used in pionic atom studies turn out to be simply related empirically to the free-space pion-nucleon scattering volumes, then this would be indicative of both sets of quantities being dominated by the DELTA (1236 MeV), which is to be treated as an independent baryonic excitation in nuclei. Within this framework, a simple derivation of modifications to the optical potential coming from baryon-baryon shont-range correlations is given. (auth)
63 citations
58 citations
TL;DR: In this article, total cross sections for π + and π − mesons on 6 Li, 7 Li, 9 Be and C have been measured in the energy range from 90 to 860 MeV, and for oxygen from 88 to 228 MeV.
56 citations
TL;DR: In this paper, a simple statistical model was proposed to estimate the ratio of particles with various quantum numbers produced with center-of-mass momenta less than a few GeV.
Abstract: We construct a simple statistical model in order to estimate, for very energetic collisions, the ratios of particles with various quantum numbers produced with center-of-mass momenta less than a few GeV. Two conclusions are that (1) isobar decay can account for a large fraction of the SU(3) violation observed experimentally, and (2) at high transverse momentum the dominance of pions diminishes.
TL;DR: In this paper, a set of closed systems of partial-wave equations for pion-pion scattering valid for −28 mπ2 s ⩽ 125.31mπ2 was presented, which are rigorous consequences of axiomatic analyticity and three channel crossing symmetry.
TL;DR: In this paper, a number of constraints, several new, are exploited to obtain realistic quark parton distributions for baryons and mesons, and these distributions are used to make detailed predictions for NN or π N → l + l − + anything, potentially providing a quantitative test of the quark Parton model.
Journal Article•
TL;DR: In this paper, an image shift controller generates shifted image data by modulating the original image data to shift the display image sequentially along a preset shift path on the display panel.
Abstract: A display device includes a controller and a display panel. The controller receives original image data and output a display image signal. The display panel receives the display image signal and displays a display image corresponding to the display image signal. The controller includes an image shift controller and a memory. The image shift controller generates shifted image data by modulating the original image data to shift the display image sequentially along a preset shift path on the display panel. The memory stores a shift path value indicating a distance by which the display image has been shifted on the preset shift path. The image shift controller generates the display image signal by processing the shifted image data. When the display device is powered on, the image shift controller generates shifted image data corresponding to a shift path value stored in the memory.
TL;DR: In this paper, direct production of electrons and muons was observed in 300-GeV $p$-Be collisions, and the yields were much higher than predicted from current models.
Abstract: Direct production of electrons and muons is observed in 300-GeV $p$-Be collisions. The yields are much higher than predicted from current models. Data are consistent with charge symmetry and universality.
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TL;DR: In this paper, the pion radius has been measured by direct scattering of 50 GeV negative pions from stationary electrons in a hydrogen target, and the square of the radius was found to be (0.61 ± 0.15) fm 2.
TL;DR: In this article, it was shown that for a wide variety of configurations of the pion field density operator, the density operator can be written in diagonal form in the coherent-state representation.
Abstract: Hadron production at high energies is discussed in terms of coherent states. We suggest that the scattering operator and the pion field density operator take on simple forms in the coherent-state representation. In particular, we show that for a wide variety of configurations of the pion field the density operator can be written in diagonal form in the coherent-state representation. When this is possible, one obtains the statistical theory of pion production which we have discussed recently. We also construct a solvable unitary model in which the total, elastic, and inclusive cross sections go to constants at high energy, while the exclusive cross sections go to zero like a power of energy. In order to take into account the isotopic spin of the pions, we generalize the concept of coherent states and construct states with definite charge and isotopic spin.
TL;DR: In this paper, the deuteron and tritron (3 H) wave functions which reproduce the charge form factors yield results consistent with experimental angular distributions at 470, 590, 754 and 1192 proton lab energies.
TL;DR: In this paper, the pion-nucleus s-wave scattering lengths were calculated from a multiple scattering series in terms of the π-α scattering length, and agreement on the level of 10-20% with the values obtained from mesic-atom data was achieved for all nuclei with A ≦ 20.
TL;DR: In this paper, the dynamics of the reaction 12 C (p, π + ) 13 C (∗) are investigated by discussing various reaction mechanisms, and it is shown that the process is dominated by a two nucleon mechanism with virtual N ∗ formation.
TL;DR: In this article, integral equations connecting the fragmentation functions Duπ+ (z) and Duπ−(z) are obtained, assuming that the quark kicked by a virtual photon emits pions one by one.
TL;DR: In this paper, the Weinberg-Salam model of weak interactions for parity nonconserving nucleon-nucleon scattering was discussed and the one-boson-exchange potentials were determined by the use of the factorization method and current algebra.
TL;DR: In this paper, a systematic dispersion theoretic calculation of Compton partial amplitudes has been performed based on the nowadays available phenomenological multipoles for pion photoproduction, and it is found that the hitherto existing discrepancies between the data and theory remain.
TL;DR: In this article, Winkelmann, F.C., Abrams, G.S., Bingham, H.H., Chew, D.M., Daugeras, B.Y., Fretter, W.R., Johnson, A.D., Kadyk, J.A.
Abstract: Author(s): Winkelmann, F.C.; Abrams, G.S.; Bingham, H.H.; Chew, D.M.; Daugeras, B.Y.; Fretter, W.B.; Friedberg, C.E.; Goldhaber, G.; Graves, W.R.; Johnson, A.D.; Kadyk, J.A.; Stutte, L.; Trilling, G.H.; Yost, G.P.; Bogert, D.; Hanft, R.; Huson, F.R.; Ljung, D.; Pascaud, C.; Pruss, S.; Smart, W.M.
TL;DR: In this paper, the moments of both the charged and neutral pion multiplicity distributions are presented and model predictions are critically examined for pp annihilations into final states containing 3 to 9 pions at 4.6 GeV/c.
TL;DR: In this paper, a non-relativistic reduction of the pseudoscalar operator results in a nonGalilean invariant pion production operator and the recent Uppsala data are then fit with a DWBA calculation which takes the pion's distortion from the Kisslinger potential.
TL;DR: In this paper, the angular distribution for s-and p-waves of the pion in the πN cm-system was fitted to the cross section for three W -bins around the maximum of the resonance.
TL;DR: Pion optical potentials that are obtained from pi-nucleon collision matrices with non-divergent off-shell behavior are used in DWBA calculations of meson absorption and production cross sections.
TL;DR: In this article, the threshold for pion condensation in neutron star matter is estimated on the basis of a sufficiently realistic treatment of effective forces, and it turns out that the short range repulsion of the nucleon-nucleon force raises considerably the density at which the pion condensed phase can occur.