A method to polarise antiprotons in storage rings and create polarised antineutrons

An intense circularly polarised g \gamma -beam interacts with a cooled antiproton beam in a storage ring. Due to spin-dependent absorption cross-sections for the reaction g+[`(p)]?p<sup>-</sup>+[`(n)]\ensuremath \gamma+\overline{p}\rightarrow\pi^{-}+\overline{n} a built-up of polarisation of the stored antiprotons takes place. Figures of merit around 0.1 can be reached in principle over a wide range of antiproton energies. In this process polarised antineutrons with polarisation P_[`(n)] \succ 70%\ensuremath P_{\overline{n}} \succ 70\% emerge. The method is presented for the case of a 300MeV/c cooled antiproton beam.     

Nucleon polarizabilities from deuteron Compton scattering within a Green’s function hybrid approach

We examine elastic Compton scattering from the deuteron for photon energies ranging from zero to 100MeV, using state-of-the-art deuteron wave functions and NN potentials. Nucleon-nucleon rescattering between emission and absorption of the two photons is treated by Green’s functions in order to ensure gauge invariance and the correct Thomson limit. With this Green’s function hybrid approach, we fulfill the low-energy theorem of deuteron Compton scattering and there is no significant dependence on the deuteron wave function used. Concerning the nucleon structure, we use the chiral effective field theory with explicit D \Delta(1232) degrees of freedom within the small-scale expansion up to leading-one-loop order. Agreement with available data is good at all energies. Our 2-parameter fit to all elastic g \gamma d data leads to values for the static isoscalar dipole polarizabilities which are in excellent agreement with the isoscalar Baldin sum rule. Taking this value as additional input, we find a_E^s \alpha_{E}^{s} = (11.3±0.7(stat)±0.6(Baldin)±1(theory))^.10^-4 fm^3 and b_M^s \beta_{M}^{s} = (3.2±0.7(stat)±0.6(Baldin)±1(theory))^.10^-4 fm^3 and conclude by comparison to the proton numbers that neutron and proton polarizabilities are the same within rather small errors.     

P -wave excited baryons from pion- and photo-induced hyperon production

We report evidence for N(1710)P ₁₁ , N(1875)P ₁₁ , N(1900)P ₁₃ , D \Delta(1600)P ₃₃ , D \Delta(1910)P ₃₁ , and D \Delta(1920)P ₃₃ , and find indications that N(1900)P ₁₃ might have a companion state at 1970MeV. The controversial D \Delta(1750)P ₃₁ is not seen. The evidence is derived from a study of data on pion- and photo-induced hyperon production, but other data are included as well. Most of the resonances reported here were found in the Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were challenged recently by the Data Analysis Center at GWU. Our analysis is constrained by the energy-independent p \pi N scattering amplitudes from either KH84 or GWU. The two p \pi N amplitudes from KH84 or GWU, respectively, lead to slightly different p \pi N branching ratios of contributing resonances but the debated resonances are required in both series of fits.     

Deconstructing <Superscript>1</Superscript>S<Subscript>0</Subscript> nucleon-nucleon scattering

A distorted-wave method is used to analyse nucleon-nucleon scattering in the ¹ S ₀ channel. Effects of one-pion exchange are removed from the empirical phase shift to all orders by using a modified effective-range expansion. Two-pion exchange is then subtracted in the distorted-wave Born approximation, with matrix elements taken between scattering waves for the one-pion exchange potential. The residual short-range interaction shows a very rapid energy dependence for kinetic energies above about 100MeV, suggesting that the breakdown scale of the corresponding effective theory is only 270MeV. This may signal the need to include the D \Delta -resonance as an explicit degree of freedom in order to describe scattering at these energies. An alternative strategy of keeping the cutoff finite to reduce large, but finite, contributions from the long-range forces is also discussed.     

From crystal to amorphous: A novel route to unjamming in soft disk packings

Numerical studies on the unjamming packing fraction of bi- and polydisperse disk packings, which are generated through compression of a monodisperse crystal, are presented. In bidisperse systems, a fraction f ₊ = 0.400 up to 0.800 of the total number of particles has their radii increased by D \Delta R , while the rest has their radii decreased by the same amount. Polydisperse packings are prepared by changing all particle radii according to a uniform distribution in the range [- D \Delta R,D \Delta R] . The results indicate that the critical packing fraction is never larger than the value for the initial monodisperse crystal, f₀ \phi_{0}^{} = p \pi/?{12} \sqrt{{12}} , and that the lowest value achieved is approximately the one for random close packing. These results are seen as a consequence of the interplay between the increase in small-small particle contacts and the local crystalline order provided by the large-large particle contacts.     

N-Vortex Equilibria for Ideal Fluids in Bounded Planar Domains and New Nodal Solutions of the sinh-Poisson and the Lane-Emden-Fowler Equations

We prove the existence of equilibria of the N-vortex Hamiltonian in a bounded domain ${\Omega\subset\mathbb{R}^2}We prove the existence of equilibria of the N-vortex Hamiltonian in a bounded domain W ì \mathbbR²{\Omega\subset\mathbb{R}^2} , which is not necessarily simply connected. On an arbitrary bounded domain we obtain new equilibria for N = 3 or N = 4. If Ω has an axial symmetry we obtain a symmetric equilibrium for each N ? \mathbbN{N\in\mathbb{N}} . We also obtain new stream functions solving the sinh-Poisson equation -Dy = rsinhy{-\Delta\psi=\rho\sinh\psi} in Ω with Dirichlet boundary conditions for ρ > 0 small. The stream function y_r{\psi_\rho} induces a stationary velocity field v_r{v_\rho} solving the Euler equation in Ω. On an arbitrary bounded domain we obtain velocitiy fields having three or four counter-rotating vortices. If Ω has an axial symmetry we obtain for each N a velocity field v_r{v_\rho} that has a chain of N counter-rotating vortices, analogous to the Mallier-Maslowe row of counter-rotating vortices in the plane. Our methods also yield new nodal solutions for other semilinear Dirichlet problems, in particular for the Lane-Emden-Fowler equation -Du=|u|^p-1u{-\Delta u=|u|^{p-1}u} in Ω with p large.     

Developing a generalized diffraction model for elastic pd scattering at intermediate energies

A generalization of the Glauber-Sitenko diffraction model that includes the spin dependence of NN amplitudes, the D-wave of the deuteron, and the charge exchange effects is constructed for elastic pd scattering at intermediate energies. The developed model was used to analyze differential cross sections and some spin observables (analyzing powers) at the incident proton energies T _p = 1 GeV, 440 and 250 MeV. It was shown that predictions of the generalized diffraction model agree both with the experimental data and with the exact Faddeev calculations at low transfer momenta.     

D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter

We study the properties of D and [`(D)] \bar{{D}} mesons in hot isospin asymmetric strange hadronic matter, arising due to their interactions with the hadrons in the hyperonic medium. The interactions of D and [`(D)] \bar{{D}} mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). The nucleons, hyperons, the scalar isoscalar meson, σ and the scalar-isovector meson, d \delta as modified in the strange hadronic matter, modify the masses of D and [`(D)] \bar{{D}} mesons. It is found that, as compared to the [`(D)] \bar{{D}} mesons ([`(D<sup>0</sup>)] \bar{{D^0}}, D <sup>−</sup>), the properties of the D mesons (D <sup>0</sup>, D <sup>+</sup>) are more sensitive to the isospin asymmetry at high densities. On the other hand, the effects of strangeness fraction are found to be more dominant for the [`(D)] \bar{{D}} mesons as compared to the D mesons and these modifications are observed to be particularly appreciable at high densities. We also study the mass modifications of the charmonium states J/ψ, ψ(3686) and ψ(3770) in the isospin asymmetric strange hadronic matter at finite temperatures and investigate the possibility of the decay of the charmonium states into D [`(D)] \bar{{D}} pairs in the hot hadronic medium. The mass modifications of these charmonium states arise due to their interaction with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. The effects of finite quark masses are taken into account in the trace of the energy momentum tensor in QCD, while investigating the medium modification of the charmonium masses through the modification of the gluon condensate in the medium. We also compute the partial decay widths of the charmonium states to the D [`(D)] \bar{{D}} pairs in the hadronic medium. The strong dependence on density of the in-medium properties of the D, [`(D)] \bar{{D}} and the charmonium states, as well as the partial decay widths of charmonium states to D [`(D)] \bar{{D}} pairs, found in the present investigation, will be of direct relevance in observables like open charm enhancement as well as J/ψ suppression in the compressed baryonic matter (CBM) experiments at the future Facility for Antiproton and Ion Research, GSI, where the baryonic matter at high densities is planned to be produced.     

Surface Gap Soliton Ground States for the Nonlinear Schr?dinger Equation

We consider the nonlinear Schr?dinger equation

Analysis of recent $ \eta$ photoproduction data

Recent data on h \eta -meson photoproduction off a proton target in the energy range 2￡ \le ?{s} \sqrt{{s}} ￡ \le3 GeV are analyzed with regard to their overall consistency. Results from the ELSA and CLAS measurements are compared with predictions of a Regge model whose reaction amplitude was fixed via a global fit to pre-2000 measurements of differential cross sections and polarization observables for g \gamma p ? \rightarrow h \eta p at higher energies. We find that all recent experimental results on differential cross sections for h \eta -meson photoproduction are in good agreement with each other, except for the CLAS data from 2009. However, the latter can be made consistent with the other data at the expense of introducing an energy-dependent renormalization factor. We point out that there are indications in the data for a possible excitation of baryon resonances with masses around 2.1 and 2.4GeV.     

DN interaction from meson exchange

A model of the DN interaction is presented which is developed in close analogy to the meson-exchange [`(K)] \bar{{K}} N potential of the Jülich group utilizing SU(4) symmetry constraints. The main ingredients of the interaction are provided by vector meson (r \rho , w \omega exchange and higher-order box diagrams involving D <sup>*</sup> N , D D \Delta , and D <sup>*</sup> D \Delta intermediate states. The coupling of DN to the p \pi L<sub>c</sub> \Lambda_{c}^{} and p \pi S<sub>c</sub> \Sigma_{c}^{} channels is taken into account. The interaction model generates the L<sub>c</sub> \Lambda_{c}^{}(2595) -resonance dynamically as a DN quasi-bound state. Results for DN total and differential cross sections are presented and compared with predictions of two interaction models that are based on the leading-order Weinberg-Tomozawa term. Some features of the L<sub>c</sub> \Lambda_{c}^{}(2595) -resonance are discussed and the role of the near-by p \pi S<sub>c</sub> \Sigma_{c}^{} threshold is emphasized. Selected predictions of the orginal [`(K)] \bar{{K}} N model are reported too. Specifically, it is pointed out that the model generates two poles in the partial wave corresponding to the L \Lambda(1405) -resonance.     

Coexistence of “ $ \alpha$ + 208Pb ” cluster structures and single-particle excitations in 212 84Po128

Excited states in ²¹²Po have been populated by a \alpha transfer using the ²⁰⁸Pb(¹⁸O,¹⁴C) reaction at 85MeV beam energy and studied with the EUROBALL IV g \gamma multi-detector array. The level scheme has been extended up to ∼ 3.2 MeV excitation energy from the triple-g \gamma coincidence data. Spin and parity values of most of the observed states have been assigned from the g \gamma angular distributions and g \gamma -g \gamma angular correlations. Several g \gamma -lines with E _γ < 1 MeV have been found to be shifted by the Doppler effect, allowing for the measurements of the associated lifetimes by the DSAM method. The values, found in the range [0.1-0.6]ps, lead to very enhanced E1 transitions. All the emitting states, which have non-natural parity values, are discussed in terms of a \alpha - ²⁰⁸Pb structure. They are in the same excitation-energy range as the states issued from shell-model configurations.     

The mixing of scalar mesons and the baryon-baryon interaction

By introducing the mixing of scalar mesons in the chiral SU(3) quark model, we dynamically investigate the baryon-baryon interaction. The hyperon-nucleon and nucleon-nucleon interactions are studied by solving the resonating group method (RGM) equation in a coupled-channel calculation. In our present work, the experimental lightest pseudoscalar p \pi, K,h \eta,h^￠ \eta^{{\prime}}_{} mesons correspond exactly to the chiral nonet pseudoscalar fields p \pi, K,h \eta,h^￠ \eta^{{\prime}}_{} in the chiral SU(3) quark model. The h \eta,h^￠ \eta^{{\prime}}_{} mesons are considered as the mixing of singlet and octet mesons, and the mixing angle q_ps \theta_{{ps}}^{} is taken to be -23^° . For scalar nonet mesons, we suppose that there exists a correspondence between the experimental lightest scalar f ₀(600) , k \kappa , a ₀(980) , f ₀(980) mesons and the theoretical scalar nonet s \sigma , k \kappa , s^￠ \sigma^{{\prime}}_{} , e \epsilon fields in the chiral SU(3) quark model. For scalar mesons, we consider two different mixing cases: one is the ideal mixing and another is the q_s \theta_{s}^{} = 19^° mixing. The masses of the s^￠ \sigma^{{\prime}}_{} and e \epsilon mesons are taken to be 980MeV, which are just the masses of the experimental a ₀(980) , f ₀(980) mesons. The mass of the s \sigma meson is an adjustable parameter and is decided by fitting the binding energy of the deuteron, the masses of 560MeV and 644MeV are obtained for the ideal mixing and the q_s \theta_{s}^{} = 19^° mixing, respectively. We find that, in order to reasonably describe the YN interactions, the mass of the k \kappa meson is near 780MeV for the ideal mixing. However, we must enhance the mass of the k \kappa meson for the q_s \theta_{s}^{} = 19^° mixing, the 1050MeV is favorably used in the present work. The experimental s \sigma and k \kappa scalar mesons are very strange, both have larger widths. Hence, no matter what kind of mixing is considered, all the masses of scalar mesons we used in the present work seem to be consistent with the present PDG information.     

Polarization phenomena in the intermediate energy elastic deuteron scattering from <Superscript>16</Superscript>C and <Superscript>16</Superscript>O nuclei

A model based on the multiple diffraction scattering theory and the α-cluster model with dispersion of target nuclei is proposed for describing the behavior of observables for the elastic deuteron scattering from ¹²C and ¹⁶O nuclei at intermediate energies. Differential cross-sections and analyzing powers calculated within this approach for incident-deuteron energies of 400 and 700 MeV are in a reasonable agreement with experimental data.     

Backward pion-nucleon scattering

A global analysis of the world data on differential cross-sections and polarization asymmetries of backward pion-nucleon scattering for invariant collision energies above 3GeV is performed in a Regge model. Including the N_a\ensuremath N_{\alpha} , N_g\ensuremath N_{\gamma} , D_d\ensuremath \Delta_{\delta} and D_b\ensuremath \Delta_{\beta} trajectories, we reproduce both angular distributions and polarization data for small values of the Mandelstam variable u , in contrast to previous analyses. The model amplitude is used to obtain evidence for baryon resonances with mass below 3GeV. Our analysis suggests a G₃₉\ensuremath G_{39} -resonance with a mass of 2.83GeV as member of the D_b\ensuremath \Delta_{\beta} -trajectory from the corresponding Chew-Frautschi plot.     

Critical Hardy–Lieb–Thirring Inequalities for Fourth-Order Operators in Low Dimensions

This paper considers Hardy–Lieb–Thirring inequalities for higher order differential operators. A result for general fourth-order operators on the half-line is developed, and the trace inequality

D?→Dπ and D?→Dγ decays: axial coupling and magnetic moment of D? meson

The axial coupling and the magnetic moment of D ^∗-meson or, more specifically, the couplings g_D^*Dpg_{D^{\ast}D\pi} and g_D^*Dgg_{D^{\ast}D\gamma }, encode the non-perturbative QCD effects describing the decays D ^∗→Dπ and D ^∗→Dγ. We compute these quantities by means of lattice QCD with N _f=2 dynamical quarks, by employing the Wilson (“clover”) action. On our finer lattice (a≈0.065 fm) we obtain g_D^*Dp⁺=20±2g_{D^{\ast}D\pi^{+}}=20\pm2, and g_{D^*0 D⁰g}=2.0±0.6 GeV^-1g_{D^{\ast0} D^{0}\gamma}=2.0\pm 0.6~{\rm GeV}^{-1}. This is the first determination of g_{D^*0 D⁰g}g_{D^{\ast0} D^{0}\gamma} on the lattice. We also provide a short phenomenological discussion and the comparison of our result with experiment and with the results quoted in the literature.     

Analysis of the <Emphasis Type="Italic">Y</Emphasis>(4140) and related molecular states with QCD sum rules

In this article, we assume that there exist scalar D^*[`(D)]<sup>*</sup>{D}^{\ast}{\bar {D}}^{\ast}, D<sub>s</sub><sup>*</sup>[`(D)]_s^*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B^*[`(B)]<sup>*</sup>{B}^{\ast}{\bar {B}}^{\ast} and B<sub>s</sub><sup>*</sup>[`(B)]_s^*{B}_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states, and study their masses using the QCD sum rules. The numerical results indicate that the masses are about (250–500) MeV above the corresponding D ^*–[`(D)]<sup>*</sup>{\bar{D}}^{\ast}, D <sub>s</sub> <sup>*</sup>–[`(D)]_s^*{\bar {D}}_{s}^{\ast}, B ^*–[`(B)]<sup>*</sup>{\bar{B}}^{\ast} and B <sub>s</sub> <sup>*</sup>–[`(B)]_s^*{\bar {B}}_{s}^{\ast} thresholds, the Y(4140) is unlikely a scalar D_s^*[`(D)]<sub>s</sub><sup>*</sup>{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast} molecular state. The scalar D<sup>*</sup>[`(D)]^*D^{\ast}{\bar{D}}^{\ast}, D_s^*[`(D)]<sub>s</sub><sup>*</sup>D_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B<sup>*</sup>[`(B)]^*B^{\ast}{\bar{B}}^{\ast} and B_s^*[`(B)]<sub>s</sub><sup>*</sup>B_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states maybe not exist, while the scalar D￠<sup>*</sup>[`(D)]^￠*{D'}^{\ast}{\bar{D}}^{\prime\ast}, D_s^￠*[`(D)]<sub>s</sub><sup>￠*</sup>{D}_{s}^{\prime\ast}{\bar{D}}_{s}^{\prime\ast}, B<sup>￠*</sup>[`(B)]^￠*{B}^{\prime\ast}{\bar{B}}^{\prime\ast} and B_s^￠*[`(B)]_s^￠*{B}_{s}^{\prime\ast}{\bar{B}}_{s}^{\prime\ast} molecular states maybe exist.     

Light meson mass dependence of the positive-parity heavy-strange mesons

We calculate the masses of the resonances D_s0^*(2317)\ensuremath D_{s0}^{\ast}(2317) and D_s1(2460)\ensuremath D_{s1}(2460) as well as their bottom partners as bound states of a kaon and a D^(*)\ensuremath D^{(\ast)} - and B^(*)\ensuremath B^{(\ast)} -meson, respectively, in unitarized chiral perturbation theory at next-to-leading order. After fixing the parameters in the D_s0^*(2317)\ensuremath D_{s0}^{\ast}(2317) channel, the calculated mass for the D_s1(2460)\ensuremath D_{s1}(2460) is found in excellent agreement with experiment. The masses for the analogous states with a bottom quark are predicted to be M_B^*s0=(5696±40)\ensuremath M_{B^{\ast}_{s0}}=(5696\pm 40) MeV and M_Bs1=(5742±40)\ensuremath M_{B_{s1}}=(5742\pm 40) MeV in reasonable agreement with previous analyses. In particular, we predict M_Bs1-M_Bs0^*=46±1\ensuremath M_{B_{s1}}{-}M_{B_{s0}^{\ast}}=46\pm 1 MeV. We also explore the dependence of the states on the pion and kaon masses. We argue that the kaon mass dependence of a kaonic bound state should be almost linear with slope about unity. Such a dependence is specific to the assumed molecular nature of the states. We suggest to extract the kaon mass dependence of these states from lattice QCD calculations.