V. A. Ivanova

From solar proton burning to pionic deuterium through the Nambu-Jona-Lasinio model of light nuclei

Within the Nambu-Jona-Lasinio model of light nuclei (the NNJL model), describing strong low-energy nuclear interactions, we compute the width of the energy level of the ground state of pionic deuterium. The theoretical value fits well the experimental data. Using the cross sections for the reactions nu_e + d ->p + p + e^- and nu_e + d ->p + n + nu_e, computed in the NNJL model, and the experimental values of the events of these reactions, detected by the SNO Collaboration, we compute the boron neutrino fluxes. The theoretical values agree well with the experimental data and the theoretical predictions within the Standard Solar Model by Bahcall. We argue the applicability of the constraints on the astrophysical factor for the solar proton burning, imposed by helioseismology, to the width of the energy level of the ground state of pionic deuterium. We show that the experimental data on the width satisfy these constraints. This testifies an indirect measurement of the recommended value of the astrophysical factor for the solar proton burning in terrestrial laboratories in terms of the width of the energy level of the ground state of pionic deuterium.

On kaonic deuterium. Quantum field-theoretic and relativistic covariant approach

We study kaonic deuterium, the bound K^-d state A_(K d). Within a quantum field theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic deuterium in terms of the amplitude of K^-d scattering for arbitrary relative momenta. Near threshold our formula reduces to the well-known DGBT formula. The S-wave amplitude of K^-d scattering near threshold is defined by the resonances Lambda(1405), Sigma(1750) and a smooth elastic background, and the inelastic channels K^- d ->NY and K^- d ->NY pion, with Y = Sigma^(+/-), Sigma^0 and Lambda^0, where the final-state interactions play an important role. The Ericson-Weise formula for the S-wave scattering length of K^-d scattering is derived. The total width of the energy level of the ground state of kaonic deuterium is estimated using the theoretical predictions of the partial widths of the two-body decays A_(Kd) ->NY and experimental data on the rates of the NY-pair production in the reactions K^-d ->NY. We obtain Gamma_{1s} = (630 +/-100) eV. For the shift of the energy level of the ground state of kaonic deuterium we predict epsilon_(1s) = (353 +/-60)eV.

On kaonic hydrogen. Phenomenological quantum field theoretic model revisited

Abstract.We argue that due to isospin and U-spin invariance of strong low-energy interactions the S-wave scattering lengths a00 and a10 of ¯N scattering with isospin I = 0 and I = 1 satisfy the low-energy theorem a00 +3a10 = 0 valid to leading order in chiral expansion. In the model of strong low-energy ¯N interactions at threshold (Eur. Phys. J. A 21, 11 (2004)) we revisit the contribution of the Σ(1750) resonance, which does not saturate the low-energy theorem a00 +3a10 = 0, and replace it by the baryon background with properties of an SU(3) octet. We calculate the S-wave scattering amplitudes of K-N and K-d scattering at threshold. We calculate the energy level displacements of the ground states of kaonic hydrogen and deuterium. The result obtained for kaonic hydrogen agrees well with recent experimental data by the DEAR Collaboration. We analyse the cross-sections for elastic and inelastic K-p scattering for laboratory momenta 70MeV/c < pK < 150MeV/c of the incident K--meson. The theoretical results agree with the available experimental data within two standard deviations.

Polarization of Λ0 hyperons as a signature for the quark-gluon plasma

The momentum distribution of Λ0 hyperons produced from the quark-gluon plasma (QGP) in ultra-relativistic heavy-ion collisions is calculated in dependence on their polarization. The momentum distribution of Λ0 hyperons is defined by matrix elements of relativistic quark Wigner operators, which are calculated within the effective quark model with chiral U(3)×U(3) symmetry and the quark-gluon transport theory. We show that the polarization of the Λ0 hyperon depends on the spin of the strange quark that agrees well with the DeGrand-Miettinen model. We show that Λ0 hyperons, produced from the QGP, are fully unpolarized. This means that a detection of unpolarized Λ0 hyperons, produced in ultra-relativistic heavy-ion collisions, should serve as one of the signatures for the existence of the QGP in intermediate states of ultra-relativistic heavy-ion collisions.

Energy-level displacement of excited np states of kaonic hydrogen

We compute the energy-level displacement of the excited np states of kaonic hydrogen within the quantum field theoretic and relativistic covariant model of strong low-energy KN interactions suggested by [Ivanov et al.Eur. Phys. J. A 21, 11 (2004)]. For the width of the energy-level of the excited 2p state of kaonic hydrogen, caused by strong low-energy interactions, we find {gamma}{sub 2p}=2 meV=3x10{sup 12} s{sup -1}. This result is important for the theoretical analysis of the x-ray yields in kaonic hydrogen.

On isospin-breaking corrections to the energy level displacement of the ground state of kaonic hydrogen

In the model of low-energy K N interactions near threshold (Ivanov A N et al 2004 Eur. Phys. J. A 21 11 (Preprint nucl-th/0310081), Ivanov A N et al 2005 Eur. Phys. J. A 23 79 (Preprint nucl-th/0406053)), we calculate isospin-breaking corrections to the energy level displacement of the ground state of kaonic hydrogen, investigated by MeiBner, Raha and Rusetsky (2004 Eur. Phys. ./. C 35 349 (Preprint hep-ph/0402261)) within the non-relativistic effective Lagrangian approach based on ChPT by Gasser and Leutwyler. Our results agree well with those by MeiBner et al. In addition we calculate the dispersive corrections, caused by the transition K - p → K 0 n → K - p with the K 0 n pair on-mass shell. We show also how hypothesis on the dominant role of the k 0 n-cusp for the S-wave amplitude of low-energy K - p scattering near threshold, used by MeiBner et al, can be realized in our approach. The result agrees fully with that of MeiBner et al.

On radiative np ---> 1s + gamma transitions, induced by strong low-energy interactions,in kaonic atoms

We calculate the radiative transition rates np{yields}1s+{gamma} in kaonic hydrogen and kaonic deuterium, induced by strong low-energy interactions and enhanced by Coulomb interactions. The obtained results should be taken into account for the theoretical analysis of the experimental data on the x-ray spectra and yields in kaonic atoms.

On the D-wave state component of the deuteron in the Nambu-Jona-Lasinio model of light nuclei

Abstract.The D-wave state component of the neutron-proton bound state in the deuteron is calculated in the Nambu-Jona-Lasinio model of light nuclei—the relativistically covariant quantum field-theoretic approach to the description of low-energy nuclear forces. The theoretical value of the fraction of the D-wave state relative to the S-wave state is equal to ηd = 0.0238. This agrees well with the phenomenological value ηd = 0.0256±0.0004 quoted by Kamionkowski and Bahcall (Astrophys. J. 420, 884 (1994)).

ON THE Σ0→Λ0 TRANSITION MAGNETIC MOMENT IN THE EFFECTIVE QUARK MODEL WITH CHIRAL SYMMETRY

We calculate the Σ0→Λ0 transition magnetic moment μΣ0Λ0 in the effective quark model with chiral U(3) × U(3) symmetry.5 We find that the dominant contribution is proportional to the quark condensate that indicates the important role of spontaneous breaking of chiral symmetry for its formation. Our result μΣ0Λ0 = -1.62 μN, where μN is a nuclear magneton, agrees well with the experimental data

ON NONLEPTONIC DECAYS OF THE Λ0-HYPERON IN THE EFFECTIVE QUARK MODEL WITH CHIRAL U(3)×U(3) SYMMETRY

\vert\mu^{\rm expt}_{\Sigma^0\Lambda^0}\vert = (1.61\pm 0.08)\mu_N