A study of alpha-decay using effective liquid drop model

In this paper, we have made an attempt to analyze the alpha-decay half-lives of in the atomic number range [Formula: see text] by considering an effective liquid drop model. The role of pre-formation probability by including iso-spin effect is included during an evaluation of half-lives. We have also compared the studied alpha-decay half-lives with that of semi-empirical formulae such as Viola Seaborg semi-empirical formulae (VSS) [J. Inorg. Nucl. Chem. 28 (1966) 741; Nucl. Phys. A 848 (2010) 279], Royer formulae [J. Phys. G: Nucl. Part. Phys. 26 (2000) 1149; Phys. Rev. C 101 (2020) 034307] and also with that of the available experiments. From this comparison, it can be concluded that the effective liquid drop model produces an alpha-decay half-lives close to the experiments.

Interrelations among frustration-free models via Witten's conjugation

We apply Witten’s conjugation argument [Nucl. Phys. B 202, 253 (1982)] to spin chains, where it allows us to derive frustration-free systems and their exact ground states from known results. We particularly focus on \mathbb{Z}_pℤp-symmetric models, with the Kitaev and Peschel–Emery line of the axial next-nearest neighbour Ising (ANNNI) chain being the simplest examples. The approach allows us to treat two \mathbb{Z}_3ℤ3-invariant frustration-free parafermion chains, recently derived by Iemini et al. [Phys. Rev. Lett. 118, 170402 (2017)] and Mahyaeh and Ardonne [Phys. Rev. B 98, 245104 (2018)], respectively, in a unified framework. We derive several other frustration-free models and their exact ground states, including \mathbb{Z}_4ℤ4- and \mathbb{Z}_6ℤ6-symmetric generalisations of the frustration-free ANNNI chain.

Unifying approaches: derivation of Balitsky hierarchy from the Lipatov effective action

We consider a derivation of the hierarchy of correlators of ordered exponentials directly from the Lipatov’s effective action (Lipatov in Nucl Phys B 452:369, 1995; Phys Rep 286:131, 1997; Subnucl Ser 49:131, 2013; Int J Mod Phys Conf Ser 39: 1560082, 2015; Int J Mod Phys A 31(28/29):1645011, 2016; EPJ Web Conf 125: 01010, 2016) formulated in terms of interacting ordered exponentials (Bondarenko and Zubkov in Eur Phys J C 78(8), 617 2018; Bondarenko et al. in Eur Phys J C 81(7):61, 2021). The derivation of the Balitsky equation (Balitsky in Nucl Phys B 463:99, 1996; Phys Rev D 60:014020, 1999; At the frontier of particle physics, vol. 2, p. 1237–1342; Nucl Phys B 629:290, 2002; Phys Rev D 72:074027, 2005) from the hierarchy is discussed as well as the way the sub-leading eikonal corrections to the Balitsky equation arise from the transverse field contribution and sub-leading eikonal corrections to the quark propagator. We outline other possible applications of the proposed calculation scheme.

Massive neutron stars with holographic multiquark cores

Phases of nuclear matter are crucial in the determination of physical properties of neutron stars (NS). In the core of NS, the density and pressure become so large that the nuclear matter possibly undergoes phase transition into a deconfined phase, consisting of quarks and gluons and their colour bound states. Even though the quark-gluon plasma has been observed in ultra-relativistic heavy-ion collisions (Gyulassy and McLerran, Nucl Phys A 750:30–63, 2005; Andronic et al., Nature 561: 321–330, 2018), it is still unclear whether exotic quark matter exists inside neutron stars. Recent results from the combination of various perturbative theoretical calculations with astronomical observations (Demorest et al., Nature 467:1081–1083, 2010; Antoniadis et al., Science 340:1233232, 2013) shows that (exotic) quark matter could exist inside the cores of neutron stars above 2.0 solar masses ($$M_{\odot }$$ M ⊙ ) (Annala et al., Nat Phys, 10.1038/s41567-020-0914-9, arXiv:1903.09121 [astro-ph.HE], 2020). We revisit the holographic model in Refs. (Burikham et al., JHEP 05:006, arXiv:0811.0243 [hep-ph], 2009; Burikham et al., JHEP 06:040, arXiv:1003.5470 [hep-ph], 2010) and implement the equation of states (EoS) of multiquark nuclear matter to interpolate the pQCD EoS in the high-density region with the nuclear EoS known at low densities. For sufficiently large energy density scale ($$\epsilon _{s}$$ ϵ s ) of the model, it is found that multiquark phase is thermodynamically prefered than the stiff nuclear matter above the transition points. The NS with holographic multiquark core could have masses in the range $$1.96{-}2.23~(1.64{-}2.10) M_{\odot }$$ 1.96 - 2.23 ( 1.64 - 2.10 ) M ⊙ and radii $$14.3{-}11.8~(14.0{-}11.1)$$ 14.3 - 11.8 ( 14.0 - 11.1 ) km for $$\epsilon _{s}=26~(28)$$ ϵ s = 26 ( 28 ) GeV/fm$$^{3}$$ 3 respectively. Effects of proton–baryon fractions are studied for certain type of baryonic EoS; larger proton fractions could reduce radius of the NS with multiquark core by less than a kilometer.

High energy scattering in Einstein–Cartan gravity

We consider Riemann–Cartan gravity with minimal Palatini action, which is classically equivalent to Einstein gravity. Following the ideas of Lipatov (Nucl Phys B 365:614–632, 1991, Phys Part Nucl 44:391–413, 2013, Subnucl Ser 49:131, 2013, Subnucl Ser 50:213–225, 2014, Int J Mod Phys A 31(28/29):1645011, 2016, EPJ Web Conf 125:01010, 2016) and Bartels et al. (JHEP 07:056, 2014) we propose the effective action for this theory aimed at the description of the high-energy scattering of gravitating particles in the multi-Regge kinematics. We add to the Palatini action the new terms. These terms are responsible for the interaction of gravitational quanta with gravitational reggeons. The latter replace exchange by multiple gravitational excitations. We propose the heuristic explanation of its particular form based on an analogy to the reggeon field theory of QCD. We argue that Regge kinematics assumes the appearance of an effective two-dimensional model describing the high-energy scattering similar to that of QCD. Such a model may be formulated in a way leading to our final effective theory. It contains interaction between the ordinary quanta of spin connection and vielbein with the gravitational reggeons.

Erratum to: "Comments on the article: O. M. Povoroznyk, O. K. Gorpinich. Experimental observation of neutron-neutron correlations in nucleus 6He from 3H(α, pα)nn reaction"

Original article: Yaderna Fizyka ta Energetyka (Nucl. Phys. At. Energy) 22(1) (2021) 111.