abstract

The purpose of this note is threefold: (i) to recall (with some points made more explicit) the mathematical Weyl algebra model formulation, given before, of the Staruszkiewicz theory of quantum Coulomb field; (ii) to add some new elements to the discussion of the representation of the Lorentz group within this model; (iii) to comment on some statements on the structure of the theory which appeared recently.

abstract

We systematically examine the alpha decay half-lives of 80 superheavy nuclei (SHN) with \(104\leq Z \leq 118\) employing the new analytical formula, which is obtained using the semi-classical Wentzel–Kramers–Brillouin (WKB) approximation within the framework of the alpha cluster model for the modified harmonic oscillator and spherical Coulomb potentials. We develop an empirical formula for the depth of the nuclear potential that satisfactorily describes the experimental data and compare our results with the universal decay law (UDL), Royer formula, and the effective liquid drop model (ELDM) in the literature. Relying on our model, which successfully explains the alpha decay half-lives of the synthesized superheavy nuclei, we predict the alpha decay half-lives of 101 superheavy nuclei with \(104 \leq Z \leq 120\), whose experimental alpha decay half-lives are unknown and compare the results with UDL, Royer and ELDM models. The variation of the alpha decay half-lives of these models as a function of the neutron number exhibits the shell closure effect at \(N=178\) and \(N=184\).

abstract

The future Compressed Baryonic Matter (CBM) experiment at FAIR, Darmstadt, Germany aims at analyzing Au+Au collisions at 10–45 \(A\) GeV to study observables related to QCD phase transition, with particular interest to determine the critical point of the QCD phase diagram. The CBM detector setup comprises several subdetectors for the identification of leptons and hadrons. The Time-of-Flight (ToF) detector is one of the core detectors of the CBM experiment that will be used to identify charged hadrons by measuring the time of flight from the collision vertex to the detector. In this work, an attempt has been made to identify light flavored hadrons using the tracking algorithm of the ToF detector of the CBM experiment and estimate their yields for central (impact parameter \(b=0\)–3 fm) Au+Au collisions at 10 \(A\) GeV beam energy. The effective temperatures of the fireball have also been estimated from the transverse mass spectra of the identified charged hadrons.

abstract

We present the results of the computation of the third-order corrections to the ground-state energy of the diluted gas of nonrelativistic spin \(1/2\) fermions interacting through a spin-independent repulsive two-body potential. The corrections are computed within the effective field theory approach which does not require specifying the interaction potential explicitly but to characterize it by only a few parameters — the scattering lengths \(a_0\), \(a_1,\dots \) and effective radii \(r_0,\dots \) — measurable in low-energy fermion–fermion elastic scattering. The corrections are computed semi-analytically, that is, are expressed in terms of two functions of the system’s polarization. The functions are given by the integrals which can be easily evaluated using the Mathematica built-in routine for numerical integration.

abstract

Suitability of the \({^{16}{\mathrm {O}}}({^{10}{\mathrm {B}}},{^9{\mathrm {Be}}}){^{17}{\mathrm {F}}}\) reaction near the Coulomb barrier energy for extraction of the ANC values and indirect determination of the astrophysical \(S\)-factor for proton radiative capture by \({^{16}{\mathrm {O}}}\) nucleus is studied. New experimental data on this reaction to the ground (\(5/2^+\)) and excited (\(1/2^+\), \(E^* = 0.495\) MeV) states of \({^{17}{\mathrm {F}}}\) at the \({^{10}{\mathrm {B}}}\) beam energy of 41.3 MeV from the U-200P cyclotron (HIL, University of Warsaw) are presented. The ANC squared values \(1.03\pm 0.13\) fm\(^{-1}\) and \(5430\pm 950\) fm\(^{-1}\) for the ground and first excited states of the \({^{17}{\mathrm {F}}}\) nucleus, respectively, were obtained using the modified DWBA analysis. The value \(S(0)=9.0\pm 1.5\) keVb was found for the \({^{16}{\mathrm {O}}}(p,\gamma ){^{17}{\mathrm {F}}}\) reaction using the ANC values.