Nuclear energy density functional from chiral pion-nucleon dynamics: Isovector terms

We extend a recent calculation of the nuclear energy density functional in the framework of chiral perturbation theory by computing the isovector surface and spin-orbit terms: ([(?)\vec] r_p - [(?)\vec] r_n\vec \nabla \rho _p - \vec \nabla \rho _n )² G _d(r \rho) + ([(?)\vec] r_p - [(?)\vec] r_n\vec \nabla \rho _p - \vec \nabla \rho _n ·([(J)\vec]_p - [(J)\vec]_n\vec J_p - \vec J_n )G _so(r \rho) + ([(J)\vec]_p - [(J)\vec]_n\vec J_p - \vec J_n )² G _J(r \rho) pertaining to different proton and neutron densities. Our calculation treats systematically the effects from 1p \pi -exchange, iterated 1p \pi -exchange, and irreducible 2p \pi -exchange with intermediate D \Delta -isobar excitations, including Pauli-blocking corrections up to three-loop order. Using an improved density-matrix expansion, we obtain results for the strength functions G _d(r \rho) , G _so(r \rho) and G _J(r \rho) which are considerably larger than those of phenomenological Skyrme forces. These (parameter-free) predictions for the strength of the isovector surface and spin-orbit terms as provided by the long-range pion-exchange dynamics in the nuclear medium should be examined in nuclear structure calculations at large neutron excess.     

Kaon-induced $ \Lambda$(1405) production on a deuteron target at DAFNE

The K^--induced production of L \Lambda(1405) in the K ^- d ? \rightarrow p \pi S \Sigma n reaction is investigated having in mind the conditions of the DAFNE facility at Frascati where kaons are obtained from the decay of slow-moving f \phi mesons. We find that the K ^- d ? \rightarrow L \Lambda(1405)n process favors the production of L \Lambda(1405) initiated by the K^-p channel, which gives largest weight to the higher mass L \Lambda(1405) appearing at 1420MeV in chiral theories. We find that the fastest kaons from the decay of the f \phi are well suited to see this resonance, particularly if one selects forward going neutrons in the center of mass, which reduce the contribution of single scattering and make the double scattering dominate where the signal of the resonance appears clearer.     

Scalar \sigma meson via chiral and crossing dynamics

We show that the non-strange scalar s\sigma meson, as now reported in the 1996 PDG tables, is a natural consequence of crossing symmetry as well as chiral dynamics for both strong interaction low energy pp\pi\pi scattering and also K ? 2pK \to 2\pi weak decays.     

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.     

Isospin breaking in pion Compton scattering

Using chiral perturbation theory we calculate for pion Compton scattering the isospin-breaking effects induced by the difference between the charged and neutral pion mass. At one-loop order this correction is directly proportional to mp±2-mp02\ensuremath{m_{\pi^\pm}^2-m_{\pi^0}^2} and free of (electromagnetic) counterterm contributions. The differential cross-section for charged pion Compton scattering p-g? p-g\ensuremath{\pi^-\gamma \rightarrow \pi^-\gamma} gets affected (in backward directions) at the level of a few permille. At the same time the isospin-breaking correction leads to a small shift of the pion polarizabilities by d(ap- bp) @ 1.3 ·10-5\ensuremath{\delta(\alpha_\pi- \beta_\pi) \simeq 1.3 \cdot 10^{-5}} fm^3. In case of the low-energy gg? p0p0\ensuremath{\gamma\gamma \rightarrow \pi^0\pi^0} reaction isospin breaking manifests itself through a cusp effect at the p+p-\ensuremath{\pi^+\pi^-} threshold. We give an improved estimate for it based on the empirical p \pi p \pi -scattering length difference a0-a2\ensuremath{a_0-a_2} .     

Radiative corrections to neutral pion-pair production

We calculate the one-photon loop radiative corrections to the neutral pion-pair photoproduction process p^-g ?p^-p⁰p⁰\pi^-\gamma \ensuremath \rightarrow\pi^-\pi^0\pi^0 . At leading order this reaction is governed by the chiral pion-pion interaction. Since the chiral p⁺ \pi^{+}_{} p^- \pi^{-}_{} ? \rightarrow p⁰ \pi^{0}_{} p⁰ \pi^{0}_{} contact vertex depends only on the final-state invariant mass it factors out of all photon loop diagrams. We give analytical expressions for the multiplicative correction factor R ~ a/2p\ensuremath R\sim \alpha/2\pi arising from eight classes of contributing one-photon loop diagrams. An electromagnetic counterterm has to be included in order to cancel the ultraviolet divergences generated by the photon loops. Infrared finiteness of the virtual radiative corrections is achieved (in the standard way) by including soft photon radiation below an energy cut-off l \lambda . The radiative corrections to the total cross-section vary between +2% and -2% for center-of-mass energies from threshold up to 7m_p\ensuremath 7m_{\pi} . We study also the radiative corrections to the p⁰p⁰\ensuremath \pi^0\pi^0 mass spectrum.     

A hidden local symmetry approach to rho-meson photoproduction

We study the photoproduction of r \rho -mesons in a model of hidden local symmetry. For this purpose, the r \rho -meson is introduced as a hidden-gauge boson in a non-linear sigma model. For charged r \rho -meson photoproduction, the model takes into account the r \rho -meson magnetic moments from the three-point vertex in the kinetic terms. We show that the magnetic interaction of the charged r \rho -meson has a significant effect on the total cross-sections through the r \rho -meson exchange process, which is proportional to the energy of the photon. The t -channel dominance may be used for the study of structures of various unstable particles.     

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.     

Improved Method for Partial-Wave Decomposition of Two-Pion Exchange Three-Nucleon Force

In this article an efficient method to calculate the matrix elements of three-nucleon force is presented. The new method is improved version of partial-wave decomposition of Hüber et al. (Few-Body Syst 22:107, 1997), which simplifies expression to be evaluated as well as permits to reduce computational effort. Proposed method naturally applies to Faddeev-type calculations.     

Universality Limits of a Reproducing Kernel for a Half-Line Schrödinger Operator and Clock Behavior of Eigenvalues

We extend some recent results of Lubinsky, Levin, Simon, and Totik from measures with compact support to spectral measures of Schrödinger operators on the half-line. In particular, we define a reproducing kernel S _L for Schrödinger operators and we use it to study the fine spacing of eigenvalues in a box of the half-line Schrödinger operator with perturbed periodic potential. We show that if solutions u(ξ, x) are bounded in x by ${e^{\epsilon x}}We extend some recent results of Lubinsky, Levin, Simon, and Totik from measures with compact support to spectral measures of Schr?dinger operators on the half-line. In particular, we define a reproducing kernel S _L for Schr?dinger operators and we use it to study the fine spacing of eigenvalues in a box of the half-line Schr?dinger operator with perturbed periodic potential. We show that if solutions u(ξ, x) are bounded in x by e^ex{e^{\epsilon x}} uniformly for ξ near the spectrum in an average sense and the spectral measure is positive and absolutely continuous in a bounded interval I in the interior of the spectrum with x₀ ? I{\xi_0\in I}, then uniformly in I,

\fracSL(x0 + a/L, x0 + b/L)SL(x0, x0)? \fracsin(pr(x0)(a - b))pr(x0)(a - b),\frac{S_L(\xi_0 + a/L, \xi_0 + b/L)}{S_L(\xi_0, \xi_0)}\rightarrow \frac{\sin(\pi\rho(\xi_0)(a - b))}{\pi\rho(\xi_0)(a - b)},      11. P -wave excited baryons from pion- and photo-induced hyperon production      A. V. Anisovich  E. Klempt  V. A. Nikonov  A. V. Sarantsev  U. Thoma 《The European Physical Journal A - Hadrons and Nuclei》2011,47(2):27 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.      12. Random matrix structure of nuclear shell model Hamiltonian matrices and comparison with an atomic example      Manan Vyas  V. K. B. Kota 《The European Physical Journal A - Hadrons and Nuclei》2010,45(1):111-120 We present a comprehensive analysis of the structure of Hamiltonian matrices based on visualization of the matrices in three dimensions as well as in terms of measures for GOE, banded and two-body random matrix ensembles (TBRE). We have considered two nuclear shell model examples, 22Na with Jp T = 2+0\ensuremath J^{\pi} T = 2^+0 and 24Mg with Jp T = 0+0\ensuremath J^{\pi} T = 0^+0 and, for comparison we have also considered the SmI atomic example. It is clearly established that the matrices are neither GOE nor banded. For the TBRE structure we have examined the correlations between diagonal elements and eigenvalues, fluctuations in the basis states variances and structure of the two-body part of the Hamiltonian in the eigenvalue basis. Unlike the atomic example, nuclear examples show that the nuclear shell model Hamiltonians can be well represented by TBRE.      13. Stability of One-Electron Molecules in the Brown–Ravenhall Model      A. A. Balinsky  W. D. Evans 《Communications in Mathematical Physics》1999,202(2):481-500 In appropriate units, the Brown-Ravenhall Hamiltonian for a system of 1 electron relativistic molecules with K fixed nuclei having charge and position Zk, Rk, k=1,2, ?,Kk=1,2, \ldots,K, is of the form \bB1,K = L+ ( D0 + aVc) L+ \bB_{1,K}= \Lambda_+ \bigl( D_0 + \alpha V_c\bigr) \Lambda_+ , where v+ is the projection onto the positive spectral subspace of the free Dirac operator D0 and Vc = - ?k=1K \fracaZk\lmod \bx-Rk \rmod + ?k < l,  k,l=1K \fracaZk Zl\lmod Rk-Rl \rmod V_c= - \sum_{k=1}^K \frac{\alpha Z_k}{\lmod \bx-R_k \rmod} + \sum_{kZk ￡ aZc = \frac2p/2 + 2/ p\alpha Z_k \leq \alpha Z_c = \frac{2}{\pi /2 + 2/ \pi}, k=1,2, ?,Kk=1,2, \ldots,K, and a ￡ \frac2 p(p2+4)(2+?{1+ p/2})\alpha \leq \frac{2 \pi}{(\pi^2+4)(2+\sqrt{1+ \pi /2})}, \ \bB1,K 3 \operatornameconst \cdotp K\bB_{1,K} \geq \operatorname{const} \cdotp K.      14. Level structures in the <Stack><Subscript>49</Subscript><Superscript>107</Superscript></Stack>In nucleus and their microscopic description      L. Batist  M. Górska  H. Grawe  Z. Janas  M. Kavatsyuk  M. Karny  R. Kirchner  M. La Commara  I. Mukha  A. Plochocki  E. Roeckl 《The European Physical Journal A - Hadrons and Nuclei》2010,43(1):45-53 Excited states of the 49107In nucleus were populated through the 78Se ( 32S , p2n) fusion-evaporation reaction at beam energy, E lab = 125 MeV. The de-excitations were studied using in-beam g \gamma -ray spectroscopic techniques involving the Compton-suppressed clover detector array. The level scheme of 107In consisting of about seven bands is established up to spin ∼ 45/2ℏ with the addition of 25 new transitions. Spins and parities of various levels have been assigned through the DCO and polarization measurements. The level structures observed in 107In have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock (HF) and angular-momentum projection techniques. Various bands are reproduced in band mixing calculations with the configurations involving high-W \Omega p \pi g 9/2 and n \nu d 5/2 orbits, and low-W \Omega p \pi g 7/2 , n \nu g 7/2 and n \nu h 11/2 orbits.      15. Isospin analysis of charmless <Emphasis Type="Italic">B</Emphasis>-meson decays      J. Charles  O. Deschamps  S. Descotes-Genon  V. Niess 《The European Physical Journal C - Particles and Fields》2017,77(8):574 We discuss the determination of the CKM angle \(\alpha \) using the non-leptonic two-body decays \(B\rightarrow \pi \pi \), \(B\rightarrow \rho \rho \) and \(B\rightarrow \rho \pi \) using the latest data available. We illustrate the methods used in each case and extract the corresponding value of \(\alpha \). Combining all these elements, we obtain the determination \(\alpha _\mathrm{dir}={({86.2}_{-4.0}^{+4.4} \cup {178.4}_{-5.1}^{+3.9})}^{\circ }\). We assess the uncertainties associated to the breakdown of the isospin hypothesis and the choice of the statistical framework in detail. We also determine the hadronic amplitudes (tree and penguin) describing the QCD dynamics involved in these decays, briefly comparing our results with theoretical expectations. For each observable of interest in the \(B\rightarrow \pi \pi \), \(B\rightarrow \rho \rho \) and \(B\rightarrow \rho \pi \) systems, we perform an indirect determination based on the constraints from all the other observables available and we discuss the compatibility between indirect and direct determinations. Finally, we review the impact of future improved measurements on the determination of \(\alpha \).      16. Quenching of the E1 strength in <Superscript>149</Superscript>Nd      E.?Ruchowska  W.?A.?P?óciennik  H.?Mach  K.?Gulda  B.?Fogelberg  H.?Gausemel  L.?M.?Fraile  W.?Kurcewicz  K.?Mezilev  M.?Sanchez-Vega 《The European Physical Journal A - Hadrons and Nuclei》2010,45(1):1-10 Lifetime measurements of excited states in 149Nd have been performed using the advanced time-delayed b \beta g \gamma g \gamma(t) method. Half-lives of 14 excited states in 149Nd have been determined for the first time or measured with higher precision. Twelve new g \gamma -lines and 5 new levels have been introduced into the decay scheme of 149Pr based on results of the g \gamma g \gamma coincidence measurements. Reduced transition probabilities have been determined for 40 g \gamma -transitions in 149Nd . Configuration assignments for 6 rotational bands in 149Nd are proposed. Enhanced E1 transitions indicate that the ground-state band and the band built on the 332.9keV level constitute a pair of the Kp = 5/2±\ensuremath K^{\pi} = 5/2^{\pm} parity doublet bands. Potential energy surfaces on the (b2,b3)\ensuremath (\beta_{2},\beta_{3}) -plane have been calculated for the lowest single quasi-particle configurations in 149Nd using the Strutinski method and the axially deformed Woods-Saxon potential. The predicted occurrence of the octupole-deformed K = 5/2 configuration is in agreement with experiment. Unexpectedly low |D0|\ensuremath \vert D_0\vert values obtained for the Kp = 5/2±\ensuremath K^{\pi} = 5/2^{\pm} parity doublet bands may result from cancellation between the proton and neutron shell correction contributions to |D0|\ensuremath \vert D_0\vert .      17. A New Look into the Partial-Wave Decomposition of Three-Nucleon Forces      D. Hüber  H. Witała  A. Nogga  W. Glöckle  H. Kamada 《Few-Body Systems》1997,22(3):107-135 We demonstrate that the partial-wave decomposition of three-nucleon forces used up to now in momentum space has to be necessarily unstable for high partial waves. This does not affect the applications performed up to now, which were restricted to low partial waves. We present a new way to perform the partial-wave decomposition free of that defect. This is exemplified for the most common two-pion-exchange Tucson-Melbourne three-nucleon force. For the lower partial waves the results of the old method are reproduced. Received November 13, 1996; accepted for publication January 17, 1997      18. Partial-Wave Decomposition for Meson-Exchange Currents in Few-Nucleon Systems      V. V. Kotlyar  H. Kamada  J. Golak  W. Glöckle 《Few-Body Systems》2000,28(1):35-63  We develop an approach for calculating matrix elements of meson-exchange current operators between three-nucleon basis states in -coupling and a three-nucleon bound state. The contributions generated by π- and ρ-exchanges are included into the consideration. The matrix elements are expressed in terms of multiple integrals in momentum space. We apply a technique of partial-wave decompositions and carry out some angular integrations in closed form. Different representations appropriate for numerical calculations are derived for the matrix elements of interest. The momentum dependences of the matrix elements are studied and benchmark results are presented. The approach developed is of interest for investigations of deuteron-proton radiative capture and 3He photo- and electrodisintegration when the interactions in the initial or final states are taken into account by solving the Faddeev equations. Received April 2, 1999; accepted for publication December 30, 1999      19. $ \delta$ meson effects in the Nolen-Schiffer anomaly      D. P. Menezes  S. S. Avancini  C. Z. Vasconcellos  M. Razeira 《The European Physical Journal A - Hadrons and Nuclei》2009,42(1):97-103 In this work we revisit the Okamoto-Nolen-Schiffer (ONS) anomaly in the context of four parametrizations of effective hadronic models, two of them with constant couplings between the nucleons and the mesons and two with density-dependent couplings. A Thomas-Fermi approximation is performed and the effects of the isovector-scalar virtual d \delta(a 0(980)) mesons are investigated since they influence directly the proton and neutron effective masses in opposite ways. The r \rho -w \omega mixing term is claimed to be important in the explanation of the ONS anomaly and is added in our calculations. We have concluded that as far as the r \rho -w \omega mixing term is included, D \Delta M(Z, N) is clearly larger in models with d \delta than in models where this meson is not considered, which is not always the case if the coupling is discarded. None of the models is good enough to describe all experimental data, but the models that better describe the experimental values include the d \delta mesons.      20. From crystal to amorphous: A novel route to unjamming in soft disk packings      F. Q. Potiguar 《The European physical journal. E, Soft matter》2010,33(1):1-9 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.

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.     

Random matrix structure of nuclear shell model Hamiltonian matrices and comparison with an atomic example

We present a comprehensive analysis of the structure of Hamiltonian matrices based on visualization of the matrices in three dimensions as well as in terms of measures for GOE, banded and two-body random matrix ensembles (TBRE). We have considered two nuclear shell model examples, ²²Na with J^p T = 2⁺0\ensuremath J^{\pi} T = 2^+0 and ²⁴Mg with J^p T = 0⁺0\ensuremath J^{\pi} T = 0^+0 and, for comparison we have also considered the SmI atomic example. It is clearly established that the matrices are neither GOE nor banded. For the TBRE structure we have examined the correlations between diagonal elements and eigenvalues, fluctuations in the basis states variances and structure of the two-body part of the Hamiltonian in the eigenvalue basis. Unlike the atomic example, nuclear examples show that the nuclear shell model Hamiltonians can be well represented by TBRE.     

Stability of One-Electron Molecules in the Brown–Ravenhall Model

In appropriate units, the Brown-Ravenhall Hamiltonian for a system of 1 electron relativistic molecules with K fixed nuclei having charge and position Zk, R_k, k=1,2, ?,Kk=1,2, \ldots,K, is of the form \bB_1,K = L₊ ( D₀ + aV_c) L₊ \bB_{1,K}= \Lambda_+ \bigl( D_0 + \alpha V_c\bigr) \Lambda_+ , where v₊ is the projection onto the positive spectral subspace of the free Dirac operator D₀ and V_c = - ?_k=1^K \fracaZ_k\lmod \bx-R_k \rmod + ?_{k < l,  k,l=1}^K \fracaZ_k Z_l\lmod R_k-R_l \rmod V_c= - \sum_{k=1}^K \frac{\alpha Z_k}{\lmod \bx-R_k \rmod} + \sum_{kZ_k ￡ aZ_c = \frac2p/2 + 2/ p\alpha Z_k \leq \alpha Z_c = \frac{2}{\pi /2 + 2/ \pi}, k=1,2, ?,Kk=1,2, \ldots,K, and a ￡ \frac2 p(p²+4)(2+?{1+ p/2})\alpha \leq \frac{2 \pi}{(\pi^2+4)(2+\sqrt{1+ \pi /2})}, \ \bB_1,K 3 \operatornameconst \cdotp K\bB_{1,K} \geq \operatorname{const} \cdotp K.     

Level structures in the <Stack><Subscript>49</Subscript><Superscript>107</Superscript></Stack>In nucleus and their microscopic description

Excited states of the ₄₉¹⁰⁷In nucleus were populated through the ⁷⁸Se ( ³²S , p2n) fusion-evaporation reaction at beam energy, E _lab = 125 MeV. The de-excitations were studied using in-beam g \gamma -ray spectroscopic techniques involving the Compton-suppressed clover detector array. The level scheme of ¹⁰⁷In consisting of about seven bands is established up to spin ∼ 45/2ℏ with the addition of 25 new transitions. Spins and parities of various levels have been assigned through the DCO and polarization measurements. The level structures observed in ¹⁰⁷In have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock (HF) and angular-momentum projection techniques. Various bands are reproduced in band mixing calculations with the configurations involving high-W \Omega p \pi g _9/2 and n \nu d _5/2 orbits, and low-W \Omega p \pi g _7/2 , n \nu g _7/2 and n \nu h _11/2 orbits.     

Isospin analysis of charmless <Emphasis Type="Italic">B</Emphasis>-meson decays

We discuss the determination of the CKM angle \(\alpha \) using the non-leptonic two-body decays \(B\rightarrow \pi \pi \), \(B\rightarrow \rho \rho \) and \(B\rightarrow \rho \pi \) using the latest data available. We illustrate the methods used in each case and extract the corresponding value of \(\alpha \). Combining all these elements, we obtain the determination \(\alpha _\mathrm{dir}={({86.2}_{-4.0}^{+4.4} \cup {178.4}_{-5.1}^{+3.9})}^{\circ }\). We assess the uncertainties associated to the breakdown of the isospin hypothesis and the choice of the statistical framework in detail. We also determine the hadronic amplitudes (tree and penguin) describing the QCD dynamics involved in these decays, briefly comparing our results with theoretical expectations. For each observable of interest in the \(B\rightarrow \pi \pi \), \(B\rightarrow \rho \rho \) and \(B\rightarrow \rho \pi \) systems, we perform an indirect determination based on the constraints from all the other observables available and we discuss the compatibility between indirect and direct determinations. Finally, we review the impact of future improved measurements on the determination of \(\alpha \).     

Quenching of the E1 strength in <Superscript>149</Superscript>Nd

Lifetime measurements of excited states in ¹⁴⁹Nd have been performed using the advanced time-delayed b \beta g \gamma g \gamma(t) method. Half-lives of 14 excited states in ¹⁴⁹Nd have been determined for the first time or measured with higher precision. Twelve new g \gamma -lines and 5 new levels have been introduced into the decay scheme of ¹⁴⁹Pr based on results of the g \gamma g \gamma coincidence measurements. Reduced transition probabilities have been determined for 40 g \gamma -transitions in ¹⁴⁹Nd . Configuration assignments for 6 rotational bands in ¹⁴⁹Nd are proposed. Enhanced E1 transitions indicate that the ground-state band and the band built on the 332.9keV level constitute a pair of the K^p = 5/2^±\ensuremath K^{\pi} = 5/2^{\pm} parity doublet bands. Potential energy surfaces on the (b₂,b₃)\ensuremath (\beta_{2},\beta_{3}) -plane have been calculated for the lowest single quasi-particle configurations in ¹⁴⁹Nd using the Strutinski method and the axially deformed Woods-Saxon potential. The predicted occurrence of the octupole-deformed K = 5/2 configuration is in agreement with experiment. Unexpectedly low |D₀|\ensuremath \vert D_0\vert values obtained for the K^p = 5/2^±\ensuremath K^{\pi} = 5/2^{\pm} parity doublet bands may result from cancellation between the proton and neutron shell correction contributions to |D₀|\ensuremath \vert D_0\vert .     

A New Look into the Partial-Wave Decomposition of Three-Nucleon Forces

We demonstrate that the partial-wave decomposition of three-nucleon forces used up to now in momentum space has to be necessarily unstable for high partial waves. This does not affect the applications performed up to now, which were restricted to low partial waves. We present a new way to perform the partial-wave decomposition free of that defect. This is exemplified for the most common two-pion-exchange Tucson-Melbourne three-nucleon force. For the lower partial waves the results of the old method are reproduced. Received November 13, 1996; accepted for publication January 17, 1997     

Partial-Wave Decomposition for Meson-Exchange Currents in Few-Nucleon Systems

 We develop an approach for calculating matrix elements of meson-exchange current operators between three-nucleon basis states in -coupling and a three-nucleon bound state. The contributions generated by π- and ρ-exchanges are included into the consideration. The matrix elements are expressed in terms of multiple integrals in momentum space. We apply a technique of partial-wave decompositions and carry out some angular integrations in closed form. Different representations appropriate for numerical calculations are derived for the matrix elements of interest. The momentum dependences of the matrix elements are studied and benchmark results are presented. The approach developed is of interest for investigations of deuteron-proton radiative capture and ³He photo- and electrodisintegration when the interactions in the initial or final states are taken into account by solving the Faddeev equations. Received April 2, 1999; accepted for publication December 30, 1999     

$ \delta$ meson effects in the Nolen-Schiffer anomaly

In this work we revisit the Okamoto-Nolen-Schiffer (ONS) anomaly in the context of four parametrizations of effective hadronic models, two of them with constant couplings between the nucleons and the mesons and two with density-dependent couplings. A Thomas-Fermi approximation is performed and the effects of the isovector-scalar virtual d \delta(a ₀(980)) mesons are investigated since they influence directly the proton and neutron effective masses in opposite ways. The r \rho -w \omega mixing term is claimed to be important in the explanation of the ONS anomaly and is added in our calculations. We have concluded that as far as the r \rho -w \omega mixing term is included, D \Delta M(Z, N) is clearly larger in models with d \delta than in models where this meson is not considered, which is not always the case if the coupling is discarded. None of the models is good enough to describe all experimental data, but the models that better describe the experimental values include the d \delta mesons.     

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.