[en] We summarize the main ideas behind a recent model-independent calculation of the energy levels and decay width of pionium, which heavily relies on modern non-relativistic effective field theory techniques. We compare our results with others which have appeared in the literature

[en] In a rather general set of one-component four-dimensional nonlinear scalar theories we analyse the existence of an interacting effective potential by means of a (nonperturbative) variational approach. We work in the Schroedinger picture with BCS-type trial functionals. We show that an effective potential, including the expectation value of the momentum as well as of the field, is (in many cases) enough to provide a physical renormalization scheme. We find that none of these theories enjoys an effective potential, both bounded from below and interacting. This indicates that the triviality of λφ₄⁴ cannot possibly be avoided by modifying the potential and the kinetic terms. (orig.)

[en] A 2+1 dimensional model is presented which consists of two commuting non-relativistic fields with opposite abelian charges minimally coupled to an abelian Chern-Simons theory, which implements the fractional statistics. The model enjoys a discrete symmetry which prevents the ficticious magnetic field to develop a non-zero expectation value in the finite density ground state, thus suppressing parity violating effects. The Hugenholz-Pines relation which guarantees the stability of standard superfluids holds. For statistics close to the bosonic limit we find a solution which exibits a superfluid component. (Author) 13 refs

[en] We prove that the recently discovered phase with positive bare coupling constant and infinite mean-field renormalization in λφ⁴ is not a proper new phase. Its gaussian effective potential turns out to be equivalent to the gaussian effective potential for the composite operator : λ_Bφ²(χ): calculated in the precarious phase (i.g. negative bare coupling constant and no mean-field renormalization). The N=∞ exactly soluble Gross-Neveu model is used as a guide. (orig.)

[en] The quark condsensate is obtained in terms of vacuum expectation values of gluonic gauge-invariants from the one-loop QCD effective action for chromomagnetic and self-dual constant background fields in presence of massive quarks. Heavy quark expansion results - as used in QCD sum rules - are recuperated for heavy quarks and a zero chiral limit is attained for < anti PSIPSI> unless a parity-violation condensate < Fsup(a)sub(μν)F tildesup(a)sub(μν)>=O(m) exists. (orig.)

[en] The photon strength functions (PSFs) and nuclear level density (NLD) are vital ingredients for the calculation of the photon interaction with nuclei, in particular, the reaction cross sections via the Hauser-Feshbach approach [1]. These cross sections are important, especially in nuclear astrophysics [2,3] and in the development of advanced nuclear technologies [4,5]. The role of the scissors mode in the M1 PSF of well-deformed actinides was investigated by several experimental techniques, see e.g. Refs. [6,7]. The analyses of these experiments show significant differences, especially on the strength of the mode. The shape of the low-energy tail of the giant electric dipole resonance is uncertain as well. In particular, some works proposed a presence of the E1 pygmy resonance just above 7 MeV. Because of these inconsistencies, additional information on PSFs in this region is of great interest. The γ-ray spectra from neutron-capture reactions on the 233U, 234U, 236U, and 238U nuclei have been measured with the total absorption calorimeter of the n_TOF facility at CERN [8]. The background-corrected sum-energy and multi-step-cascade spectra were extracted for several isolated s-wave resonances. The experimental coincident γ-ray spectra were compared with their simulated counterparts using Monte-Carlo code DICEBOX [9]. This approach allowed us to test different models of NLD and PSFs. Our results for odd compound nuclei were published in Ref. [10]. I want to highlight the main results from this study and show the first results from the capture on 233U. The integrated strength of the scissors mode was found to be significantly higher compared to values in Refs. [6,7]. The comparison of PSFs shall be discussed in detail. [1] W. Hauser and H. Feshbach, Phys. Rev. 87, 366 (1952). [2] M. Arnould and S. Goriely, Prog. Part. Nucl. Phys. 112, 103766 (2020). [3] J. J. Cowan et al., Rev. Mod. Phys. 93, 015002 (2021). [4] D. A. Brown et al., Nucl. Data Sheets 148, 1 (2018), Special Issue on Nuclear Reaction Data. [5] A. J. M. Plompen et al., Eur. Phys. J. A 56, 181 (2020). [6] M. Guttormsen et al., Phys. Rev. C 89, 014302 (2014). [7] J. L. Ullmann et al., Phys. Rev. C 96, 024627 (2017). [8] n_TOF Collaboration, C. Guerrero et al., Eur. Phys. J. A 49, 1 (2013). [9] F. Bečvář, Nucl. Instr. Methods A 417, 434 (1998). [10] n_TOF Collaboration, J. Moreno-Soto et al., Phys. Rev. C 105, 024618 (2022).

[en] The λφ⁴ gaussian effective potential for λ_B < 0 is compared with the free vacuum energy (E₀). It is shown that two phases exist: phase 1., where the gaussian vacuum energy (E_G) is equal to E₀, and phase 2., where E_G is lower than E₀. This result strongly suggests that confinement occurs in phase 2. (orig.)

[en] Distributions of natural gamma-emitting radionuclides were determined in three soil profiles developed on Tertiary sedimentary materials in mountain landscapes of the Central Spanish Pyrenees. Radioisotope activities (Bq kg^-1) lie in the range of 0-53 for ²³⁸U; 19-33 for ²²⁶Ra; 7-75 for ²¹⁰Pb; 24-48 for ²³²Th and 335-562 for ⁴⁰K. ²³⁸U and ²¹⁰Pb activities show an important variability down the soil profiles. ²³⁸U was markedly depleted in all upper soil layers and highly enriched in lower layers of two soil profiles. ²¹⁰Pb exhibits very dissimilar distribution patterns in all three soils. ²²⁶Ra and ²³²Th had quite uniform depth distributions. ⁴⁰K showed depletion in both upper and lower layers in one soil profile but remained fairly constant in the other two profiles. ²³⁸U/²²⁶Ra activity ratios (ARs) have been used to assess equilibrium in the ²³⁸U decay chain and as indicators of edaphogenesis in the studied soil profiles. Maintenance of initial proportionality in the ratio of ²³²Th/²³⁸U activities has been assessed through ARs of their progenies. Additionally, a variety of soil properties were measured down the soil profiles. Among soils, variation in radionuclide activities may be due to differences in carbonate content, organic matter and/or grain size. In this environment, soil properties differently affect mobilization of natural radionuclides. The association of some radiologic properties with soil layers suggest a relationship between soil processes and radionuclide distribution

[en] By using the background-gauge formalism, we calculate the effective lagrangian for the pure Yang-Mills theory in a constant background. The dependence on the field can be completely factorized out of the functional integral and the remaining constant term is proven to be well defined. The procedure can be extended to the case of non-zero temperature and a deconfining transition for finite T is observed. (orig.)

[en] Studies carried by us during last three years have produced a map of natural radiation for Spain. The map contains, by administrative region, the respective contributions of terrestrial gamma rays, both outdoors and indoors, cosmic rays and indoor radon. Terrestrial gamma rays have been measured outdoors 'in situ' in more than 1,000 locations. Data for indoor gamma rays were derived from the radioactivity content of more typical spanish building materials as also by 'in situ'measurements in approximately 100 houses. The cosmic ray component is calculated from latitude and altitude. Values for indoor radon exposure have been derived from a national survey and covering more than 2,000 individual measurements employing active and passive detectors. When account is taken of exposures elsewhere, the mean annual effective dose equivalent from these sources is evaluated. Doses from thoron decay products and internal exposure due to natural activity retained in the body from diet are not dealt with in this evaluation. (author)