We report on our Stochastic Variational Method (SVM) calculations of
η
-nuclear quasi-bound states in s-shell nuclei as well as the very recent calculation of the p-shell nucleus
6
Li. The
ηN
...potentials used were constructed from
ηN
scattering amplitudes obtained within coupled-channel models that incorporate
N
*(1535) resonance. We found that
η
6
Li is bound in the
ηN
interaction models that yield Re
a
ηN
≥ 0.67 fm. Additional repulsion caused by the imaginary part of
ηN
potentials shifts the onset of
η
-nuclear binding to
η
4
He, yielding very likely no quasi-bound state in
η
3
He.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The onset of binding η(548) mesons in nuclei is studied in the He isotopes by doing precise ηNNN and ηNNNN few-body stochastic variational method calculations for two semi-realistic NN potentials and ...two energy dependent ηN potentials derived from coupled-channel models of the N⁎(1535) nucleon resonance. The energy dependence of the ηN subthreshold input is treated self consistently. It is found that a minimal value of the real part of the ηN scattering length aηN close to 1 fm is required to bind η mesons in 3He, yielding then a few MeV η binding in 4He. The onset of η-meson binding in 4He requires that ReaηN exceeds 0.7 fm approximately. These results compare well with results of recent ηNNN and ηNNNN pionless effective field theory calculations. Related optical-model calculations are also discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The Non-Symmetrized Hyperspherical Harmonics method (NSHH) is introduced in the hypernuclear sector and benchmarked with three different ab-initio methods, namely the Auxiliary Field Diffusion Monte ...Carlo method, the Faddeev–Yakubovsky approach and the Gaussian Expansion Method. Binding energies and hyperon separation energies of three- to five-body hypernuclei are calculated by employing the two-body
Λ
N
component of the phenomenological Bodmer–Usmani potential (Bodmer and Usmani in Nucl Phys A 477:621,
1988
; Usmani and Khanna in J Phys G 35:025105,
2008
), and a hyperon-nucleon interaction (Hiyama et al. in Phus Rev C 65:011301,
2001
) simulating the scattering phase shifts given by NSC97f (Rijken et al. in Phys Rev C 59:21,
1999
). The range of applicability of the NSHH method is briefly discussed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We report on our recent study of in-medium ηN interactions and η-nuclear quasi-bound states. The ηN scattering amplitudes considered in the calculations are constructed within coupled-channel models ...that incorporate the S11 N*(1535) resonance. The implications of self-consistent treatment and the role played by subthreshold dynamics are discussed.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Williams syndrome (WS) is a genetic condition caused by a hemizygous microdeletion on chromosome 7q11.23. WS is characterized by a distinctive social phenotype composed of increased drive toward ...social engagement and attention toward faces. In addition, individuals with WS exhibit abnormal structure and function of brain regions important for the processing of faces such as the fusiform gyrus. This study was designed to investigate if white matter tracts related to the fusiform gyrus in WS exhibit abnormal structural integrity as compared to typically developing (TD; age matched) and developmentally delayed (DD; intelligence quotient matched) controls. Using diffusion tensor imaging data collected from 40 (20 WS, 10 TD and 10 DD) participants, white matter fibers were reconstructed that project through the fusiform gyrus and two control regions (caudate and the genu of the corpus callosum). Macro‐structural integrity was assessed by calculating the total volume of reconstructed fibers and micro‐structural integrity was assessed by calculating fractional anisotropy (FA) and fiber density index (FDi) of reconstructed fibers. WS participants, as compared to controls, exhibited an increase in the volume of reconstructed fibers and an increase in FA and FDi for fibers projecting through the fusiform gyrus. No between‐group differences were observed in the fibers that project through the control regions. Although preliminary, these results provide further evidence that the brain anatomy important for processing faces is abnormal in WS.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Binding energies and widths of three-body K¯NN, and of four-body K¯NNN and K¯K¯NN nuclear quasibound states are calculated in the hyperspherical basis, using realistic NN potentials and subthreshold ...energy dependent chiral K¯N 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 ground-state binding energies to relatively low values of about 30 MeV. The lightest strangeness −2 particle-stable K¯ nuclear cluster is most probably K¯K¯NN. The calculated K¯N→πY conversion widths range from approximately 30 MeV for the K¯NNN ground state to approximately 80 MeV for the K¯K¯NN ground state.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Well-functioning error monitoring of the inner and outer environments is essential for adaptively altering behavior, while malfunction characterizes conditions such as obsessive–compulsive disorder ...(OCD). The underlying brain processing is manifested as Error-Related Negativity (ERN) signal elicited following error comission, and Perceived Error Related Theta Activity (PERTA) signal elicited following detection of discrepancy in the environment. Yet, while enhanced ERN was repeatedly demonstrated in OCD patients and was found to be potentiated among their unaffected first degree relatives, no comparable observations were reported with regard to PERTA. We recorded EEG activity while OCD patients, OCD patients’ siblings (Family), and healthy controls (HC) performed computerized tasks. For the examination of ERN we used the Stroop task and for the examination of PERTA we presented correct and incorrect mathematical equations. Increased ERN (0–120 ms post response) was observed in both the OCD and Family groups, but only the OCD patients’ signal significantly differed from that of HC's. Similarly, modified PERTA activity was observed in both the OCD and Family groups in the N1 peak (65–125 ms post perceived error), but only for the OCD group this activity significantly differed from that of HC. Both ERN and PERTA's N1 are fast occurring peaks, which suggests that OCD is associate with a constantly over-activated detection system that monitors the inner and outer environment and reacts promptly following detection of a mistake. Furthermore, the modified but non-significantly different activity of the Family group suggests that the pathological condition evolves in vulnerable individuals with neuronal predisposition.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Experiments at DAΦNE-Frascati and at J-PARC are scheduled to produce K−D atoms and observe their X-ray cascade down to the 1S ground state (g.s.), thereby measuring its strong-interaction width and ...shift away from a purely Coulomb state. A width Γ1S≲1 keV will ensure good resolution of the X-ray transitions feeding the 1S g.s. Here we study the expected K−D 1S g.s. width from the perspective of global fits to level shifts and widths in heavier kaonic atoms across the periodic table, using K− nuclear optical potentials constructed from K¯N chiral interaction models. Special attention is paid to the subthreshold energy at which the K¯N subsystem interacts in the K−D atom g.s. Within this approach we predict strong-interaction upward level shift of close to 700 eV and width of about 1.2 to 1.3 keV for the K−D atom 1S g.s., in fair agreement with genuinely three-body K−D atom calculations. Comparison is made with π−D atom phenomenology.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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