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Sep 21, 2013
09/13

by
A. Gal

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The relationship between the lower limit on the nuclear stability lifetime as derived from the non disappearance of `stable` nuclei ($T_{d}~\gtrsim~5.4~\times~10^{31}$ yr), and the lower limit thus implied on the oscillation time $(\tau_{n \bar n})$ of a possibly underlying neutron-antineutron oscillation process, is clarified by studying the time evolution of the nuclear decay within a simple model which respects unitarity. The order-of-magnitude result $\tau_{n \bar n} \approx 2...

Source: http://arxiv.org/abs/hep-ph/9907334v2

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Sep 21, 2013
09/13

by
A. Gal

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The state of the art in dibaryons with strangeness is reviewed, including the K^{-}pp dibaryon which signals the onset of antikaon-nuclear binding. A new type of strange dibaryons is highlighted, where the primary binding mechanism is provided by strong p-wave pion interactions, as demonstrated by a quasibound (I=3/2,JP=2+) pion-hyperon-nucleon dibaryon calculation.

Source: http://arxiv.org/abs/1011.6322v3

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Sep 23, 2013
09/13

by
A. Gal; E. Friedman

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Long-standing anomalies in K^+ nucleus integral cross sections could be resolved by extending the impulse-approximation t*rho optical-potential framework to incorporate K^+ absorption on pairs of nucleons. Substantially improved fits to the data at p(lab)=500-700 MeV/c are obtained. An upper bound of 3.5 mb for the absorption cross section of K^+ per nucleon is derived. We conjecture that the underlying microscopic absorption process is K^+ n N --> Theta^+ N, where Theta^+(1540) is the newly...

Source: http://arxiv.org/abs/nucl-th/0411052v3

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Sep 18, 2013
09/13

by
E. Friedman; A. Gal

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Experimental and theoretical developments of the last decade in the study of exotic atoms and some related low-energy reactions are reviewed, in order to provide information on the in-medium hadron-nucleon t matrix over a wide range of densities up to central nuclear densities. In particular, we review pionic deeply bound atomic states and related evidence for partial restoration of chiral symmetry in dense nuclear matter. The case for relatively narrow deeply bound atomic states for antikaons...

Source: http://arxiv.org/abs/0705.3965v2

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Sep 18, 2013
09/13

by
E. Friedman; A. Gal

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Realistic calculations of nuclear disappearance lifetimes induced by neutron-antineutron oscillations are reported for oxygen and iron, using antineutron nuclear potentials derived from a recent comprehensive analysis of antiproton atomic X-ray and radiochemical data. A lower limit of 3.3 x 10E8 s on the neutron-antineutron oscillation time is derived from the Super-Kamiokande I new lower limit of 1.77 x 10E32 yr on the neutron lifetime in oxygen. Antineutron scattering lengths in carbon and...

Source: http://arxiv.org/abs/0803.3696v3

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Sep 23, 2013
09/13

by
E. Friedman; A. Gal

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Analyses of comprehensive sets of strong-interaction data consisting of level shifts, widths and yields in strange atoms of K mesons and Sigma hyperons are reviewed. The introduction of density dependent optical potentials, in both cases, improves significantly the fit to the data. A strongly attractive antikaon-nuclear potential of order 150-200 MeV in nuclear matter is suggested by fits to the kaonic-atom data, with interesting possible repercussions on kaon condensation and on the evolution...

Source: http://arxiv.org/abs/0710.5890v1

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Sep 21, 2013
09/13

by
E. Friedman; A. Gal

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The strongly absorptive optical potentials $V_{{\rm opt}}$ which have been deduced from the strong-interaction level shifts and widths in X-ray spectra of $K^-$ and $\bar p$ atoms produce effective repulsion leading to substantial suppression of the {\it atomic} wave functions within the nucleus. The width of atomic levels then saturates as function of the strength of Im $V_{{\rm opt}}$. We find that `deeply bound' atomic states, which are inaccessible in the atomic cascade process, are...

Source: http://arxiv.org/abs/nucl-th/9907052v1

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Jun 29, 2018
06/18

by
E. Friedman; A. Gal

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Six widely different subthreshold $K^- N$ scattering amplitudes obtained in SU(3) chiral-model EFT approaches by fitting to low-energy and threshold data are employed in optical-potential studies of kaonic atoms. Phenomenological terms representing $K^-$ multinucleon interactions are added to the EFT inspired single-nucleon part of the $K^-$-nucleus optical potential in order to obtain good fits to kaonic-atom strong-interaction level shifts and widths across the periodic table. Introducing as...

Topics: High Energy Physics - Phenomenology, Nuclear Experiment, Nuclear Theory

Source: http://arxiv.org/abs/1610.04004

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Sep 19, 2013
09/13

by
E. Friedman; A. Gal

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The extraction of the isovector s-wave pi N amplitude from pionic atoms is studied with special emphasis on uncertainties and their dependence on the assumptions made regarding the neutron density distributions in nuclei and on the size of the data base used . Only `global' analyses of pionic-atom data reveal a discrepancy between the extracted isovector s-wave pi N amplitude b_1=-0.108\pm0.007 m_\pi^{-1} and its free pi N counterpart b_1^{free}=-0.0885^{+0.0010}_{-0.0021} m_\pi ^{-1}, where...

Source: http://arxiv.org/abs/nucl-th/0302038v2

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Sep 21, 2013
09/13

by
E. Friedman; A. Gal

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The state of the art in the study of pionic, kaonic and Sigmionic atoms, along with the in-medium nuclear interactions deduced for these hadrons, is reviewed. A special emphasis is placed on recent developments in antikaon-nuclear physics, where a strongly attractive density dependent antikaon-nuclear potential of order 150-200 MeV in nuclear matter emerges by fitting K^- atom data. This has interesting repercussions on antikaon quasibound nuclear states, on the composition of strange hadronic...

Source: http://arxiv.org/abs/1108.2156v1

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Sep 18, 2013
09/13

by
E. Friedman; A. Gal

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Recent work on the connection between in-medium subthreshold $K^-N$ amplitudes and kaonic atom potentials is updated by using a next to leading order chirally motivated coupled channel separable interaction model that reproduces $\bar KN$ observables at low energies, including the very recent SIDDHARTA results for the atomic $K^-$-hydrogen $1s$ level shift and width. The corresponding $K^-$-nucleus potential is evaluated self-consistently within a single-nucleon approach and is critically...

Source: http://arxiv.org/abs/1201.3770v3

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Sep 18, 2013
09/13

by
E. Friedman; A. Gal

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The experimental results for strong interaction effects in antiprotonic atoms by the PS209 collaboration consist of high quality data for several sequences of isotopes along the periodic table. Global analysis of these data in terms of a $\bar p$-nucleus optical potential achieves good description of the data using a s-wave finite-range \bar p N interaction. Equally good fits are also obtained with a poorly-defined zero-range potential containing a p-wave term.

Source: http://arxiv.org/abs/nucl-th/0306084v1

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Sep 23, 2013
09/13

by
A. Gal; E. Friedman

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Evidence for excitation of exotic S=+1 pentaquark degrees of freedom is presented by studying optical-potential fits to K^+ - nucleus total, reaction and elastic-differential cross section data at p(lab) = 500 - 700 MeV/c. Estimates of the underlying two-nucleon absorption K^+ n N --> Theta^+ N reaction cross section are made and are used for discussing the anticipated cross section of the strangeness exchange reaction K^+ N --> pi Theta^+.

Source: http://arxiv.org/abs/nucl-th/0511033v2

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Sep 18, 2013
09/13

by
E. Friedman; A. Gal

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A microscopic kaonic-atom optical potential $V^{(1)}_{K^-}$ is constructed, using the Ikeda-Hyodo-Weise NLO chiral $K^-N$ subthreshold scattering amplitudes constrained by the kaonic hydrogen SIDDHARTA measurement, and incorporating Pauli correlations within the Waas-Rho-Weise generalization of the Ericson-Ericson multiple-scattering approach. Good fits to kaonic atom data over the entire periodic table require additionally sizable $K^-NN$--motivated absorptive and dispersive phenomenological...

Source: http://arxiv.org/abs/1211.6336v3

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Jun 30, 2018
06/18

by
E. Friedman; A. Gal

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A general algorithm for handling the energy dependence of meson-nucleon amplitudes in the nuclear medium has been recently applied to antikaons and to eta mesons. Here we test this approach on $\pi N$ amplitudes in pionic atoms where direct comparison can be made with ample experimental results. Applying this algorithm to a large-scale fit of 100 pionic-atom data points across the periodic table, which also include the `deeply-bound' states in Sn and Pb, reaffirms earlier conclusions on the...

Topics: High Energy Physics - Phenomenology, Nuclear Experiment, Nuclear Theory

Source: http://arxiv.org/abs/1405.7133

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Jul 20, 2013
07/13

by
E. Friedman; A. Gal

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Using optical potentials fitted to a comprehensive set of strong interaction level shifts and widths in $K^-$ atoms, we predict that the $K^-$ atomic levels which are inaccessible in the atomic cascade process are generally narrow, spanning a range of widths about 50 - 1500 keV over the entire periodic table. The mechanism for this narrowing is different from the mechanism for narrowing of pionic atom levels. Examples of such `deeply bound' $K^-$ atomic states are given, showing that in many...

Source: http://arxiv.org/abs/nucl-th/9902036v2

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Sep 22, 2013
09/13

by
E. Friedman; A. Gal

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The energy dependence of chirally expanded pi N isoscalar and isovector amplitudes b_0(E) and b_1(E) respectively, for zero-momentum off shell pions near threshold, is used to impose the minimal substitution requirement E -> E - V_c on the properly constructed pion optical potential within a large-scale fit to 100 pionic-atom data across the periodic table which also include the recently established `deeply bound' pionic atoms of Pb and Sn. This fit cannot be reconciled with the well known...

Source: http://arxiv.org/abs/nucl-th/0308030v3

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Sep 22, 2013
09/13

by
E. Friedman; A. Gal

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The binding energies of the deeply bound 1s and 2p states in pionic atoms of $^{207}$Pb, recently established experimentally in the $^{208}$Pb(d,$^3$He) reaction, have been used by several groups to derive the pion effective mass in nuclear matter. We show that these binding energies are fully consistent with `normal' pionic atoms and that the real part of the pion-nucleus potential at the center of $^{207}$Pb is 28$\pm$3 MeV and not 20 MeV as suggested previously.

Source: http://arxiv.org/abs/nucl-th/9805004v1

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Sep 21, 2013
09/13

by
A. Gal; D. J. Millener

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Hiyama et al. [PRL 104 (2010) 212502] have recently reported on a pioneering five-body alpha-alpha-n-Lambda-Lambda cluster-model calculation of Lambda-Lambda-11Be in order to confront a possible interpretation of the KEK-E373 HIDA event. Unfortunately, a six-body alpha-alpha-n-n-Lambda-Lambda calculation of Lambda-Lambda-12Be to confront another possible interpretation is beyond reach at present. Using experimental B-Lambda values with small corrections based on recently determined Lambda-N...

Source: http://arxiv.org/abs/1011.0181v3

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Sep 23, 2013
09/13

by
A. Gal; D. J. Millener

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Highlights of Lambda-Lambda emulsion events are briefly reviewed. Given three accepted events, shell-model predictions based on p-shell Lambda hypernuclear spectroscopic studies are shown to reproduce the Lambda-Lambda (LL) binding energies of LL10Be and LL13B in terms of the LL binding energy of LL6He. Predictions for other species offer judgement on several alternative assignments of the LL13B KEK-E176 event, and on the assignments LL11Be and LL12Be suggested recently for the KEK-E373 HIDA...

Source: http://arxiv.org/abs/1111.3831v2

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Sep 18, 2013
09/13

by
J. Schaffner-Bielich; A. Gal

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The hyperon-hyperon potentials due to a recent SU(3) Nijmegen soft-core potential model are incorporated within a relativistic mean field calculation of strange hadronic matter. We find considerably higher binding energy in bulk matter compared to several recent calculations which constrain the composition of matter. For small strangeness fractions, matter is dominated by a composition of nucleons, Lambdas, and Xis, and the calculated binding energy closely follows that calculated by using the...

Source: http://arxiv.org/abs/nucl-th/0005060v2

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Sep 19, 2013
09/13

by
I. N. Filikhin; A. Gal

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Evidence for particle stability of Lambda-Lambda hydrogen-4 (4LLH) has been suggested by the BNL-AGS E906 experiment. We report on Faddeev-Yakubovsky calculations for the four-body Lambda-Lambda-p-n system using Lambda-N interactions which reproduce the observed binding energy of Lambda hydrogen-3 (3LH) within a Faddeev calculation for the Lambda-p-n subsystem. No 4LLH bound state is found over a wide range of Lambda-Lambda interaction strengths, although the Faddeev equations for a three-body...

Source: http://arxiv.org/abs/nucl-th/0209003v1

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Sep 21, 2013
09/13

by
A. Gal; D. J. Millener

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It is shown how the recent shell-model determination of Lambda-N spin dependent interaction terms in Lambda hypernuclei allows for a reliable deduction of Lambda-Lambda separation energies in Lambda-Lambda hypernuclei across the nuclear p shell. Comparison is made with the available data, highlighting 11(Lambda-Lambda)Be and 12(Lambda-Lambda)Be which have been suggested as possible candidates for the KEK-E373 Hida event.

Source: http://arxiv.org/abs/1104.3429v2

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Sep 18, 2013
09/13

by
I. N. Filikhin; A. Gal

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New Faddeev-Yakubovsky calculations for light Lambda-Lambda hypernuclei are presented in order to assess the self consistency of the Lambda-Lambda hypernuclear binding-energy world data and the implied strength of the Lambda-Lambda interaction, in the wake of recent experimental reports on Lambda-Lambda-4H and Lambda-Lambda-6He. Using Gaussian soft-core simulations of Nijmegen one-boson-exchange model interactions, the Nijmegen soft-core model NSC97 simulations are found close to reproducing...

Source: http://arxiv.org/abs/nucl-th/0110008v2

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Sep 21, 2013
09/13

by
I. N. Filikhin; A. Gal

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New Faddeev-Yakubovsky calculations are reported for Lambda-Lambda-6He and Lambda-Lambda-10Be in terms of clusters of alpha's and Lambda's, using Lambda-Lambda s-wave potentials motivated by several of the Nijmegen model interactions. The self consistency of the Lambda-Lambda hypernuclear world data for these species is discussed. The newly reported Lambda-Lambda-6He event is found to be compatible with Lambda-Lambda interaction strengths provided by the Nijmegen soft-core one-boson-exchange...

Source: http://arxiv.org/abs/nucl-th/0203036v2

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Sep 18, 2013
09/13

by
C. J. Batty; E. Friedman; A. Gal

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Experiments with $\Xi^-$ atoms are proposed in order to study the nuclear interaction of $\Xi$ hyperons. The production of $\Xi^-$ in the ($K^{-}$, $K^{+}$) reaction, the $\Xi^-$ stopping in matter, and its atomic cascade are incorporated within a realistic evaluation of the results expected for $\Xi^-$ X-ray spectra across the periodic table, using an assumed $\Xi$-nucleus optical potential $V_{opt}$. Several optimal targets for measuring the strong-interaction shift and width of the X-ray...

Source: http://arxiv.org/abs/nucl-th/9809042v1

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Sep 21, 2013
09/13

by
E. Friedman; A. Gal; J. Mares

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Total and reaction cross sections are derived self consistently from the attenuation cross sections measured in transmission experiments at the AGS for K^+ on Li^6, C, Si and Ca in the momentum range of 500-700 MeV/c by using a V_{opt}=t_{eff}(rho)rho optical potential. Self consistency requires, for the KN in-medium t matrix, that Im t_{eff}(rho) increases linearly with the average nuclear density in excess of a threshold value of 0.088+-0.004 fm^-3. The density dependence of Re t_{eff}(rho)...

Source: http://arxiv.org/abs/nucl-th/9705026v1

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Jul 20, 2013
07/13

by
N. Barnea; A. Gal; E. Z. Liverts

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Binding energies and widths of three-body KbarNN, and of four-body KbarNNN and KbarKbarNN nuclear quasibound states are calculated in the hyperspherical basis, using realistic NN potentials and subthreshold energy dependent chiral KbarN interactions. Results of previous K^-pp calculations are reproduced and an upper bound is placed on the binding energy of a K^-d quasibound state. A self consistent handling of energy dependence is found to restrain binding, keeping the calculated four-body...

Source: http://arxiv.org/abs/1203.5234v3

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Sep 19, 2013
09/13

by
N. V. Shevchenko; A. Gal; J. Mares

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We report on the first genuinely three-body ${\bar K}NN - \pi \Sigma N$ coupled-channel Faddeev calculation in search for quasi-bound states in the $K^- p p$ system. The main absorptivity in the $K^- p$ subsystem is accounted for by fitting to $K^- p$ data near threshold. Our calculation yields one such quasi-bound state, with $I=1/2$, $J^{\pi}=0^-$, bound in the range $B \sim 55-70$ MeV, with a width of $\Gamma \sim 95-110$ MeV. These results differ substantially from previous estimates, and...

Source: http://arxiv.org/abs/nucl-th/0610022v2

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Jun 27, 2018
06/18

by
N. Barnea; E. Friedman; A. Gal

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We report on precise hyperspherical-basis calculations of $\eta NN$ and $\eta NNN$ quasibound states, using energy dependent $\eta N$ interaction potentials derived from coupled-channel models of the $S_{11}$ $N^{\ast}(1535)$ nucleon resonance. The $\eta N$ attraction generated in these models is too weak to generate a two-body bound state. No $\eta NN$ bound-state solution was found in our calculations in models where Re $a_{\eta N}\lesssim 1$ fm, with $a_{\eta N}$ the $\eta N$ scattering...

Topics: High Energy Physics - Phenomenology, Nuclear Experiment, Nuclear Theory

Source: http://arxiv.org/abs/1505.02588

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Jul 19, 2013
07/13

by
V. Krejcirik; A. Cieply; A. Gal

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DWIA calculations of Lambda-hypernuclear production rates in stopped K- reactions on several p-shell targets used recently in experiments by the FINUDA Collaboration are reported. Chirally motivated K- + N -> pion + Lambda in-medium transition amplitudes are employed and the sensitivity of the calculated rates to the initial K- atomic wavefunctions and final pion distorted waves is studied. The calculated rates are compared with measured rates, wherever available, confirming earlier...

Source: http://arxiv.org/abs/1005.2138v3

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Sep 20, 2013
09/13

by
J. Mareš; E. Friedman; A. Gal

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A comprehensive data base of K- atom level shifts and widths is re-analyzed in order to study the density dependence of the Kbar-nuclear optical potential. Significant departure from a t*rho form is found only for nuclear densities about and less than 20% of nuclear-matter density, and extrapolation to nuclear-matter density yields an attractive potential, about 170 MeV deep. Partial restoration of chiral symmetry compatible with pionic atoms and low-energy pion-nuclear data plays no role at...

Source: http://arxiv.org/abs/nucl-th/0601009v2

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Sep 22, 2013
09/13

by
E. Friedman; A. Gal; J. Mares

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Self consistency in the analysis of transmission measurements for K^+ on several nuclei in the momentum range of 500-700 MeV/c is achieved with a "t_{eff}(rho)rho" potential and new results are derived for total cross sections. The imaginary part of the t_{eff} amplitude is found to increase linearly with the average nuclear density in excess of a threshold value. This phenomenological density dependence of the K^+ nucleus optical potential also gives rise to good agreement with...

Source: http://arxiv.org/abs/nucl-th/9612008v1

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Jul 20, 2013
07/13

by
E. Friedman; A. Gal; J. Mareš

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The strong energy dependence of the s-wave eta-N scattering amplitude at and below threshold, as evident in coupled-channels K-matrix fits and chiral models that incorporate the S11 N*(1535) resonance, is included self consistently in eta-nuclear bound state calculations. This approach, applied recently in calculations of kaonic atoms and Kbar-nuclear bound states, is found to impose stronger constraints than ever on the onset of eta-nuclear binding, with a minimum value of Re a_{eta N}...

Source: http://arxiv.org/abs/1304.6558v2

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Jul 20, 2013
07/13

by
I. Filikhin; A. Gal; V. M. Suslov

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Configuration space Faddeev calculations are performed for the binding energy of Lambda-Lambda-6He and Lambda-9Be bound states, here considered as alpha-Lambda-Lambda and alpha-alpha-Lambda clusters respectively, in order to study the dependence of the calculated binding energy on the alpha-Lambda potential input. For Lambda-Lambda-6He, using realistic interactions, the uncertainty in extracting the Lambda-Lambda S=L=0 interaction strength does not exceed 0.1 MeV, which is a fraction of the...

Source: http://arxiv.org/abs/nucl-th/0406049v2

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Sep 21, 2013
09/13

by
J. Mares; E. Friedman; A. Gal

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The relativistic mean field (RMF) model is applied to a system of nucleons and a $\bar K$ meson, interacting via scalar and vector boson fields. The model incorporates the standard RMF phenomenology for bound nucleons and, for the $\bar K$ meson, it relates to low-energy ${\bar K}N$ and $K^-$ atom phenomenology. Deeply bound $\bar K$ nuclear states are generated dynamically across the periodic table and are exhibited for $^{12}$C and $^{16}$O over a wide range of binding energies. Substantial...

Source: http://arxiv.org/abs/nucl-th/0407063v2

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Sep 19, 2013
09/13

by
C. J. Batty; E. Friedman; A. Gal

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A successful unified description of $\bar p$ nuclear interactions near E=0 is achieved using a $\bar p$ optical potential within a folding model, $V_{{\rm opt}} \sim \bar v * {\rho}$, where a $\bar p p$ potential $\bar v$ is folded with the nuclear density $\rho$. The potential $\bar v$ fits very well the measured $\bar p p$ annihilation cross sections at low energies ($p_L < 200$ MeV/c) and the $1s$ and $2p$ spin-averaged level shifts and widths for the $\bar p$H atom. The density-folded...

Source: http://arxiv.org/abs/nucl-th/0010006v2

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Sep 17, 2013
09/13

by
A. Gal; E. Friedman; C. J. Batty

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Recent measurements of very low-energy ($p_{L} 0$, parallels the recent prediction, for $E < 0$, that the level widths of $\bar p$ atoms saturate and, hence, that $\bar p$ deeply bound atomic states are relatively narrow. Antiproton annihilation cross sections are calculated at $p_{L}=57$ MeV/c across the periodic table, and their dependence on $Z$ and $A$ is classified and discussed with respect to the Coulomb focussing effect at very low energies.

Source: http://arxiv.org/abs/nucl-th/0007029v2

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Sep 18, 2013
09/13

by
E. Friedman; .; A. Gal; J. Mares

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We report on global fits of optical-model parameters to 90 data points for $\bar p$ X-rays and 17 data points of radiochemical data put together. With the help of separate fits to the two kinds of data it is possible to determine phenomenologically the radial region where the absorption of antiprotons takes place and to obtain neutron densities which represent the average behaviour over the periodic table. A finite-range attractive and absorptive $\bar p$-nuclear isoscalar potential fits the...

Source: http://arxiv.org/abs/nucl-th/0504030v2

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Sep 18, 2013
09/13

by
A. Cieplý; E. Friedman; A. Gal; D. Gazda; J. Mareš

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In-medium subthreshold KbarN scattering amplitudes calculated within a chirally motivated meson-baryon coupled-channel model are used self consistently to confront K^- atom data across the periodic table. Substantially deeper K^- nuclear potentials are obtained compared to the shallow potentials derived in some approaches from threshold amplitudes, with Re V_{chiral} = -(85+/-5) MeV at nuclear matter density. When KbarNN contributions are incorporated phenomenologically, a very deep K^- nuclear...

Source: http://arxiv.org/abs/1102.4515v4

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Sep 21, 2013
09/13

by
A. Cieplý; E. Friedman; A. Gal; D. Gazda; J. Mareš

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A self consistent scheme for constructing K^- nuclear optical potentials from subthreshold in-medium Kbar-N s-wave scattering amplitudes is presented and applied to analysis of kaonic atoms data and to calculations of K^- quasibound nuclear states. The amplitudes are taken from a chirally motivated meson-baryon coupled-channel model, both at the Tomozawa-Weinberg leading order and at the next to leading order. Typical kaonic atoms potentials are characterized by a real part -Re...

Source: http://arxiv.org/abs/1108.1745v2

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Sep 22, 2013
09/13

by
J. Mares; E. Friedman; A. Gal; B. K. Jennings

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Strong interaction level shifts and widths in $\Sigma^-$ atoms are analyzed by using a $\Sigma$ nucleus optical potential constructed within the relativistic mean field approach. The analysis leads to potentials with a repulsive real part in the nuclear interior. The data are sufficient to establish the size of the isovector meson--hyperon coupling. Implications to $\Sigma$ hypernuclei are discussed.

Source: http://arxiv.org/abs/nucl-th/9505003v1

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Sep 21, 2013
09/13

by
A. Cieplý; E. Friedman; A. Gal; V. Krejčiřík

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1s(Lambda) hypernuclear formation rates in stopped K- reactions on several p-shell targets are derived from hypernuclear formation spectra measured recently by the FINUDA Collaboration and are compared with calculated 1s(Lambda) formation rates based on a KbarN coupled channels chiral model. The calculated rates are about 15% of the derived rates, depending weakly on the depth of the threshold K- nuclear potential. The A dependence of the calculated rates is in fair agreement with that of the...

Source: http://arxiv.org/abs/1011.2855v3

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Sep 22, 2013
09/13

by
D. J. Millener; C. B. Dover; A. Gal

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The $\Lambda$ and neutron decay widths of $\Xi$ hypernuclear states, based on calculated $\Xi N \to \lala$ mixing amplitudes, are estimated. The widths which result from using the Nijmegen Model D interaction are sufficiently small, of order 1.5 MeV, that experiments to observe $\Xi$ hypernuclear states using the $(K^-,K^+)$ reaction may be feasible.

Source: http://arxiv.org/abs/nucl-th/9410035v2

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29

Sep 19, 2013
09/13

by
D. Gazda; E. Friedman; A. Gal; J. Mares

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We report on self-consistent calculations of single-K^- nuclear states and multi-Kbar nuclear states in 12C, 16O, 40Ca and 208Pb within the relativistic mean-field (RMF) approach. Gradient terms motivated by the p-wave resonance Sigma(1385) are found to play a secondary role for single-K^- nuclear systems where the mean-field concept is acceptable. Significant contributions from the Kbar N -> pi Lambda conversion mode, and from the nonmesonic Kbar NN -> YN conversion modes which are...

Source: http://arxiv.org/abs/0708.2157v3

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33

Sep 22, 2013
09/13

by
D. Gazda; E. Friedman; A. Gal; J. Mares

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Relativistic mean field calculations of multi-$\bar{K}$ hypernuclei are performed by adding $K^-$ mesons to particle-stable configurations of nucleons, $\Lambda$ and $\Xi$ hyperons. For a given hypernuclear core, the calculated $\bar{K}$ separation energy $B_{\bar{K}}$ saturates with the number of $\bar{K}$ mesons for more than roughly 10 mesons, with $B_{\bar{K}}$ bounded from above by 200 MeV. The associated baryonic densities saturate at values 2-3 times nuclear-matter density within a small...

Source: http://arxiv.org/abs/0906.5344v2

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72

Sep 23, 2013
09/13

by
D. Gazda; E. Friedman; A. Gal; J. Mareš

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We extend previous relativistic mean-field (RMF) calculations of multi-$\bar K$ nuclei, using vector boson fields with SU(3) PPV coupling constants and scalar boson fields constrained phenomenologically. For a given core nucleus, the resulting $\bar K$ separation energy $B_{\bar K}$, as well as the associated nuclear and $\bar K$-meson densities, saturate with the number $\kappa$ of $\bar K$ mesons for $\kappa > \kappa_{\rm sat} \sim 10$. Saturation appears robust against a wide range of...

Source: http://arxiv.org/abs/0801.3335v2

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Jun 30, 2018
06/18

by
A. Gal; H. Garcilazo; A. Valcarce; T. Fernández-Caramés

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The Lambda_c(2286)-N system is studied in a chiral constituent quark model and the resulting s-wave interaction is used in separable form within three-body models of the pi-Lambda_c-N system with quantum numbers (C,I,JP)=(+1,3/2,2+). Separable interactions are also used for the dominant p-wave pion-baryon channels dominated by the Delta(1232) and Sigma_c(2520) resonances. Faddeev equations with relativistic kinematics are solved on the real axis to search for bound states and in the complex...

Topics: High Energy Physics - Phenomenology, Nuclear Experiment, Nuclear Theory, High Energy Physics -...

Source: http://arxiv.org/abs/1405.5094

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12

Jun 29, 2018
06/18

by
A. Gal; E. V. Hungerford; D. J. Millener

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Extensions of nuclear physics to the strange sector are reviewed, covering data and models of Lambda and other hypernuclei, multi-strange matter, and anti-kaon bound states and condensation. Past achievements are highlighted, present unresolved problems discussed, and future directions outlined.

Topics: Nuclear Experiment, Nuclear Theory

Source: http://arxiv.org/abs/1605.00557

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Sep 18, 2013
09/13

by
I. N. Filikhin; A. Gal; V. M. Suslov

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Faddev calculations are reported for Lambda-Lambda-5H, Lambda-Lambda-5He and Lambda-Lambda-6He in terms of two Lambda hyperons plus the respective nuclear clusters, using Lambda-Lambda central potentials considered in past non-Faddeev calculations of Lambda-Lambda-6He. The convergence with respect to the partial-wave expansion is studied, and comparison is made with some of these Lambda-Lambda hypernuclear calculations. The Lambda-Lambda Xi-N mixing effect is briefly discussed.

Source: http://arxiv.org/abs/nucl-th/0303028v1