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A critical appraisal of developments in MOND since its introduction by Milgrom in 1983 to the present day., Comment: 15 pages, 6 figures

A novel interpretation of MOND is presented. For galactic data, in addition to Newtonian acceleration, there is an attractive acceleration peaking at Milgrom's parameter a_0. The peak lies within experimental error where a_0 = cH_0/2\pi; H_0 is the present-time value of the Hubble constant and c the velocity of light. The physical interpretation of this relation and its connection to Dark Energy are discussed., Comment: 16 pages, 3 figures, substantial overlap with arXiv:1211.1625; one arithmetic correction made, subsection 4.1 rewritten; accepted for publication by the Canadian Journal of Physics

BES data on the sigma pole are refitted taking into account new information on coupling of sigma to KK and eta-eta. The fit also includes Cern-Munich data on pi-pi elastic phases shifts and Ke4 data, and gives a pole position of 500 +- 30 - i(264 +- 30) MeV. However, there is a clear discrepancy with the sigma pole position recently predicted by Caprini et al. using the Roy equation. This discrepancy may be explained naturally by uncertainties arising from inelasticity in KK and eta-eta channels and mixing between sigma and f0(980). Adding freedom to accomodate these uncertainties gives an optimum compromise with a pole position of 472 +- 30 - i(271 +- 30) MeV.

Ratios of coupling constants for these decays are compared with q-qbar predictions and Jaffe's 4-quark model. In both models, the predicted ratio g^2(kappa -> K-pi)/ g^2(sigma -> pi-pi) is much too small. Also, for q-qbar, the predicted ratio g^2(kappa -> K-eta ')/g^2(kappa -> K-pi) is much larger than observed. Both models fail for g^2(fo -> KK)/g^2(a0 -> KK). This ratio requires that fo has a dominant KK component. It arises naturally because the fo pole lies very close to the KK threshold, giving its wave function a long KK tail.

Earlier comparisons of galatic rotation curves with MOND have arrived at the conclusion that the parameter a_0 lies within ~20% of cH_0/2\pi, where c is the velocity of light and H_0 is the Hubble constant. It is proposed here that, for this value of H_0, signals propagating around the periphery of the Universe are phase locked by the graviton-nucleon interaction., Comment: 4 pages, 1 figure, one typing error corrected, Canadian Journal of Physics 2014

The background due to the direct diffractive dissociation of the photon into the $\pi^+\pi^-$-pair to the "elastic" diffractive $\rho^0$-meson production in electron-proton collisions is calculated. The amplitude for the background process $\gamma p \to \pi^+ \pi^- p$ is proportional to the $\pi$-meson - proton cross section. Therefore, describing the HERA data, we can estimate $\sigma (\pi p)$ at energy $s_{\pi p}\sim (2 - 3) 10^{3} GeV^2$ that is considerably higher the existing data. At large $Q^2$ the interference between resonant and non-resonant $\pi^+ \pi^-$ production leads also to the more slow increase of the $\sigma^L/\sigma^T$ ratio with the mass of the $2\pi$ (i.e. $\rho^0$-meson) state.

Belle report data on Upsilon (5S) -> Upsilon(1S,2S,3S)-piplus-piminus and chi_b(1P,2P)-piplus-piminus; they observe peaks in Upsilon-pi and chi_b-pi consistent with J^P=1^+. They interpret the peaks as molecular states Z_b(10608) and Z_b(10653). Their masses are just above Bbar-B^* and B^*bar-B^* thresholds at 10604.6 and 10650.2 MeV. An explanation in terms of cusps at these thresholds is presented here. The product of the rising phase space for Bbar-B^* and B^*bar B^* with the cusps creates peaks a few MeV higher in Bbar-B^* and B^*bar-B^*, and these peaks can de-excite to piplus-piminus-Upsilon(1S,2S,3S) and piplus-piminus-chi_b(1P,2P)., 5 pages, 5 figures. Major revision correcting a mistake in the earlier version, and including full calculations of cusp effects; two references added and corrections to Figs. 2(a) and 3(a)

It is proposed that meson resonances are linear combinations of q-qbar and meson-meson (MM); baryon resonances are combinations of qqq and meson-baryon (MB). Mixing between these combinations arises via decays of confined states to meson-meson or meson-baryon. There is a precise analogy with the covalent bond in molecular physics; it helps to visualise what is happening physically. One eigenstate is lowered by the mixing; the other moves up and normally increases in width. Cusps arise at thresholds. At sharp thresholds due to S-wave 2-particle decays, these cusps play a conspicuous role in many sets of data. The overall pattern of light mesons is consistent with nearly linear Regge trajectories, hence q-qbar components. There is no obvious reason why this pattern should arise from dynamically generated states without q-qbar content., Comment: 15 pages, 4 figures. A major revision of an earlier paper.

It is proposed that meson resonances are linear combinations of q-qbar and meson-meson (MM); baryon resonances are combinations of qqq and meson-baryon (MB). Mixing between these combinations arises via decays of confined states to meson-meson or meson-baryon. There is a precise analogy with the covalent bond in molecular physics; it helps to visualise what is happening physically. One eigenstate is lowered by the mixing; the other moves up and normally increases in width. Cusps arise at thresholds. At sharp thresholds due to S-wave 2-particle decays, these cusps play a conspicuous role in many sets of data., Comment: 11 pages, 2 figures; extended version of a talk at the Hadron09 conference

The formulae needed to parametrise sigma, kappa, a0(980) and f0(980) are reviewed. For sigma and kappa, the Adler zero due to Chiral Symmetry Breaking plays a crucial role. The f0(980) and a0(980) are locked to the KK threshold by a cusp mechanism which leads to a sharp peak in attraction at the threshold. This mechanism may play a wider role. A novel suggestion is that the confinement potential involves a cooperative effect between QCD effects (coloured quarks and gluons) and conventional meson exchanges., 10 pages. Proc. Lisbon meeting on Scalar Mesons, Feb 10-16

The mechanism by which a threshold may capture a resonance is examined. It involves a threshold cusp interfering constructively with either or both (i) a resonance produced via confinement, (ii) attractive t- and u-channel exchanges. The fo(980), X(3872) and Z(4430) are studied in detail. The fo(980) provides a valuable model of the locking mechanism. The X(3872) is too narrow to be fitted by a cusp, and requires either a resonance or virtual state. The Z(4430) can be fitted as a resonance but also can be fitted successfully by a cusp with no nearby resonant pole., 19 pages, 6 figures. Replaces 0709.1254

We describe the spectra and decays of pi pi and pi K atoms within a non-relativistic effective field theory. The evaluations of the energy shifts and widths are performed at next-to-leading order in isospin symmetry breaking. We provide general formulae for all S-states, and discuss the states with angular momentum one in some detail. The prediction for the lifetime of the pi K atom in its ground-state yields tau = (3.7 \pm 0.4) * 10^{-15} sec., 37 pages, 6 figures

A correct understanding and description of the I=2 pi-pi S-wave interaction is important for the extraction of the I=0 pi-pi S-wave interaction from experimental data and for understanding the I=0 pi-pi S-wave interaction theoretically. With t-channel rho, f2(1270) exchange and the pi pi -> rho rho -> pi pi box diagram contribution, we reproduce the pi-pi isotensor S-wave and D-wave scattering phase shifts and inelasticities up to 2.2 GeV quite well in a K-matrix formalism., Talk given at Hadron 03: 10th International Conference on Hadron Spectroscopy, Aschaffenburg, Germany, 31 Aug - 6 Sep 2003

The spectrum of qq states observed in Crystal Barrel data in flight is very simple: a set of parallel straight‐line trajectories of mass squared v. radial excitation number. There are 6 extra states, making candidates for 4 glueballs and 2 hybrids. Mass ratios of glueball candidates agree closely with the latest Lattice Gauge calculations. The evidence for 2−+ hybrids η2(1860) and π2(1880) is reviewed. Further data from a polarised target are highly desirable in channels 3π0, ηπ0, ωπ0 and ωη in order to separate cleanly triplet states with L = J ± 1. These data would provide precise measurements of tensor, spin‐orbit and spin‐spin splitting of masses.

A scheme is proposed identifying many q-barq 2{sup +} states up to 2300 MeV, but requiring strong mixing with a broad 2{sup +} glueball at about 2000 MeV.

Recent analyses of NN and πN scattering data have resulted in values for the πNN coupling constant which are significantly smaller than those obtained prior to 1987. These controversial results prompted us to investigate the usefulness of high‐quality spin measurements towards resolving this issue. We found that the normal component spin transfer observable DNN′ for p+p elastic scattering is very sensitive to g20, particularly at small angles. We have therefore determined precise values of DNN′ for this reaction for θlab=5.0°, 7.2°, 8.4°, 9.7°, 11.8°, 14.6°, 18.8°, 24°, 30°, and 38° at an incident beam energy of 200 MeV. The forward‐going proton was detected in the IUCF K600 spectrometer and the coincident recoil proton was detected in a Si/CsI detector telescope. Our preliminary DNN′ values are reproduced reasonably well by Arndt’s C200 solution, the Nijmegen PWA93, and the Nijmegen I potential, but differ severely from both Arndt’s SM94 global solution and the predictions of the Bonn potential.

Peaks observed by Belle in DD at 3.878 GeV and in D*D* at 4.156 GeV may be fitted by phase space multiplied by a form factor with an RMS radius of interaction 0.63 fm. The peak observed in Lambda_C Lambda_C at 4.63 GeV may be explained by Y(4660), multiplied by a corresponding form factor with RMS radius 0.94 fm.

A pole in the Dπ S-wave analogous to σ and κ is predicted at MeV. The main objective of this paper is to provide formulae for fitting it to data.

A simple set-up for studying almost all K - p reactions is discussed. It is also suitable for studying πN and K + N inelastic scattering.

A review is given of phase shift data for N--N interactions in the MeV range. Elastic and inelastic scattering are considered as is dibaryon resonance production. (AIP)

Measurements of the spin-correlation parameter ALL at backward angles with errors of +or-0.02 eliminate the strong correlation between epsilon 1 (the parameter which mixes 3S1 and 3D1 states) and the 1P1 phase-shift, and stabilise the phase-shift solutions at 25 and 50 MeV.

Amplitudes are presented which fit extensive spin-dependent data from 450 to 800 MeV. The energy dependence of 3P2, 1D2 and 3F3 amplitudes agrees in both magnitude and phase with pi d to Delta N, with the nucleon playing the role of a spectator; the phases are close to delta NN+ delta pi d, the sum of elastic phase-shifts for NN and pi d scattering. The 3P1 amplitude is the sum of a repulsive threshold contribution and an attractive contribution due to the formation of an intermediate Delta . Data from 578 to 800 MeV give reliable determinations of the 1S0 amplitude and a rough determination of the 3F2 amplitude.

There is a conflict between Argonne measurements of Delta sigma L(pp) from 400 to 600 MeV and the real part of the corresponding forward amplitude between 150 and 600 MeV, and also with conventional wisdom about the dynamics of the inelastic channels. Proposed structure in Delta sigma L(I=0) is difficult to reconcile with existing np data. These conflicts throw some doubt on claims for the existence of dibaryon resonances.

The helicity amplitudes observed by the Mark III and DM2 groups in Psi /J to gamma theta (1690) require a large admixture of Ly=3. This is surprising for a qq state at this mass, but arises naturally if the theta is a glueball. A perturbative calculation for a (TM1)2 glueball gives a result close to experiment, but not one for a (TE1)2 glueball.

Wolfenstein parameters D, R and A' are sensitive to the meson-exchange mechanism of inelastic scattering of protons by nuclei, A(p,p')A*. Measurement of these parameters at momentum transfer q=(1.5-3)mpi would be a sensitive test of critical opalescence (i.e. the proximity of a pion condensate) in nuclei. At centre-of-mass scattering angle theta , the signature of pi exchange is D=-1, R=cos 1/2 theta , A'=-cos 1/2 theta , while the signature of the principle background, rho exchange, is D=A'=0, R=-cos 1/2 theta .

Amplitudes for NN to pi d are fitted to data up to 580 MeV and are compared with the predictions of Blankleider (1980) and of Niskanen (1978). In this analysis, high partial waves are fixed at values calculated by Blankleider, and the phases of low partial waves are constrained (except for 3P1) to his phases. Further data on iT11, sigma (x0 mod iT11) and T20 are needed in order to fix all partial waves with orbital angular momentum L

Total cross sections of ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ mesons on protons and deuterons have been measured in a transmission experiment to relative accuracies of \ifmmode\pm\else\textpm\fi{}0.2% over the laboratory momentum range 0.46-2.67 GeV/c. The systematic error is estimated to be about \ifmmode\pm\else\textpm\fi{}0.5% over most of the range, increasing to about \ifmmode\pm\else\textpm\fi{}2% near both ends. Data have been obtained at momentum intervals of 25-50 MeV/c with a momentum resolution of \ifmmode\pm\else\textpm\fi{}0.6%. No new structure is observed in the ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}p$ total cross sections, but results differ in several details from previous experiments. From 1-2 GeV/c, where systematic erros are the smallest, the total cross section of ${\ensuremath{\pi}}^{\ensuremath{-}}$ mesons on deuterons is found to be consistently higher than that of ${\ensuremath{\pi}}^{+}$ mesons by (1.3\ifmmode\pm\else\textpm\fi{}0.3)%; about half of this difference may be understood in terms of Coulomb-barrier effects. The $\ensuremath{\pi}d$ and $\ensuremath{\pi}N$ total cross sections are used to check the validity of the Glauber theory. Substantial disagreements (up to 2 mb) are observed, and the conclusion is drawn that the Glauber theory is inadequate in this momentum range.

Proton-proton scattering has been studied at 970 MeV using the Birmingham University 1-BeV synchrotron and a 9-in.-diam liquid-hydrogen bubble chamber; 3945 events have been analyzed and cross sections determined for the various reactions. The elastic scattering cross section of 24.8\ifmmode\pm\else\textpm\fi{}0.9 mb is significantly higher than the result of Dowell et al. using counters. The two experiments agree on the shape of the angular distribution, but not on its normalization; possible reasons for this are discussed. The elastic scattering angular distribution is peaked strongly forward, but does not agree quantitively with pure diffraction. Polarization effects observed in the elastic scattering agree with previous and more accurate counter experiments. Inelastic scattering is strongly influenced by the ($\frac{3}{2},\frac{3}{2}$) ${\ensuremath{\pi}}^{+}p$ resonance and the peripheral mechanism. Theoretical predictions based on the single-pion exchange model are compared in detail with the experimental results and good quantitative agreement is obtained for small momentum transfers, particularly for the reaction $p+p\ensuremath{\rightarrow}n+p+{\ensuremath{\pi}}^{+}$. Even for small momentum transfers, asymmetries in the Treiman-Yang test and departure from the expected $(1+3 {cos}^{2}\ensuremath{\theta}) {\ensuremath{\pi}}^{+}\ensuremath{-}P$ angular distribution indicate that other mechanisms may be important. The cross section for double-pion production at 970 MeV is less than 0.2 mb.

A study of inelastic n-p interactions has been made using the Birmingham 1 GeV synchrotron and a 9 in. diameter liquid hydrogen bubble chamber. 1840 three-pronged events initiated by neutrons in the energy range (290 ÷ 970) MeV have been analysed, the possible reactions being: n + p → p + p + π−; n + p → n + p + π0, π0 → e+ + e- + γ, and n + p → n + p + π+ + π−. The ratio found for the integrated cross-sections σ(n + p → n + p + π0) /σ (n + p → p + p + ρ-) = 2.67 ± 0.43 is shown to resolve a long-standing conflict with charge independence. The energy-dependence of the n + p → p + p + π− cross-section has been inferred from the expected shape of the incident neutron spectrum with the aid of earlier cross-section measurements in the energy range. The laboratory kinetic energy distributions and centre-of-mass angular distributions for protons from ppπ- events suggest that the peripheral mechanism of interaction is important at lower energies and to a greater extent than indicated by the one-pion-exchange model. However the Treiman-Yang test for this model is satisfied for events involving small momentum transfer and (3, 3) isobar production. The cross-section for the reaction n + p → n + p + π+ + π- increases more quickly above threshold than required by the statistical model of Cerulus and Hagedorn, and much more so than required by one-pion-exchange processes. Comparison with p-p scattering results, in which double-pion production is far smaller, emphasizes the importance of theT=0 channel.

Measurements have been made of the total cross sections σ(p−p) and σ(p−d) over the laboratory momentum range 1.1 to 8 GeV/c, with relative errors of 0.1%. The absolute accuracies of these cross sections are limited to 0.3% by lack of information which will allow the Coulomb-nuclear interference to be calculated accurately. Values of the total cross sections σ(p−n) and σ(I=0) are deduced by assuming the Glauber correction. Structure is observed in σ(p−p) near a mass value of 2.75 GeV/c2; its interpretation is discussed. σ(I=0) rises rapidly in the range 2.3 to 2.9 GeV/c2, and this is attributed to the onset of strong inelastic scattering.

New ∆бL (pp) data from TRIUMF show that earlier results of Auer et al were too small by ~30% below 600 MeV, and resolve discrepancies which existed with other data. Together with I=0 phase shifts, they greatly weaken the case for an I=0 resonance in the 500–1000 MeV range. Models of the I=1 inelastic channels suggest that inelasticity will peak with increasing energy successively in 3P1, 1D2, 3F3 and 1G4 states, in qualitative agreement with ∆бL and ∆бL data. There is no compelling evidence at present proving the existence of dibaryon resonances in these states. The best signature would be a large phase variation in NN→N∆.

The NN experimental programmes in progress at TRIUMF and SIN are reviewed, and related to measurements at the Argonne. From up measurements of P, Dt, Rt, and At at TRIUMF, a unique and accurate set of I=0 phase shifts is now available up to 500 MeV. These show large systematic deviations from theoretical predictions in central, spin‐orbit and tensor combinations, and a major revision of coupling constants appears to be required. Real parts of I=1 phase shifts are defined accurately up to 515 MeV by elastic pp data. It is desirable to take inelasticities from models of the inelastic channels based on NN‐NΔ via π andρ exchange. However, at 425 and 515 MeV this leads to a serious conflict with Argonne measurements of ΔσL. Either these data or the model of the inelastic channels must be wrong.

Phase shift solutions for pp elastic scattering are unique up to 800 MeV, and for np up to 500 MeV. There is excellent agreement between three analyses for all phase shifts δ and for elasticity parameters η of dominant inelastic partial waves (1D2, 3F3 and 3P2). For low partial waves, notably 3P0, 3P1 and 1S0, there are some disagreements about η parameters, reflecting insensitivity of elastic data and some discrepancies amongst experiments. The need for further data is reviewed. Amplitudes for np→pn between 140 and 500 MeV are known accurately from phase shift analyis, and are almost purely real; they are useful for extracting nuclear matrix elements from (p,n) reactions.The Paris potential is the best potential model fit to data up to 425 MeV, but there are some small systematic discrepancies with data. Whether or not dibaryon resonances exist at higher energies is still controversial. If they exist, they are associated with the onset of strong inelasticity, and are weakly coupled to both NN and πd chan...

Theory of Meson Interactions with Nuclei. By Judah M. Eisenberg and Daniel S. Koltun. Pp.403. (Wiley-Interscience: 1980.) £21.25, $49.95.

Introduction to the Theory of Thermal Neutron Scattering. By G. L. Squires. Pp. 260. (Cambridge University Press: Cambridge, London, New York and Melbourne, 1978.) £16.

R B Miller 1982 New York: Plenum x + 351 pp price $45 Pulsed electron and ion beams have been developing, mainly in the USA in connection with inertial confinement fusion, to intensities of millions of amperes at 1–10 x 106 V, with durations of the order of 100 ns. The electron beams also find application in z-pinches, as drivers of pulsed gas lasers and as high power sources of coherent radiation (in the form of the relativistic microwave magnetron, the electron cyclotron maser and the free electron laser).

The depolarization parameter Donon in p p elastic scattering has been measured at LEAR for thirteen momenta between 679 and 1550 MeV/c in the backward angular region. Striking disagreement with theoretical models is observed.

Two high statistics measurements of antiproton-proton small-angle elastic scattering, at p = 233 MeV/c and p = 272 MeV/c, are presented. The measurements were carried out at the LEAR facility at CERN. By the Coulomb-nuclear interference method, values are obtained for the real-to-imaginary ratio ρ of the pp forward nuclear scattering amplitude and for its exponential slope b: ρ = + 0.041 ± 0.026 and b = 71.5 ± 4.5 (GeV/c)−2 at 233 MeV/c and ρ = −0.014 ± 0.027 and b = 47.7 ± 2.7 (GeV/c)−2 at 272 MeV/c. The method to derive these values is discussed in detail and so are the uncertainties contributing to their systematic error. The results are compared with predictions from forward dispersion relation calculations and with predictions from pp potential models.