Abstract We revisit the 95~GeV $\gamma\gamma$ and $\tau\tau$ excesses in the Georgi--Machacek model using a combined fit to a single light $CP$-even custodial singlet $H$. Using the one-loop renormalization group-improved effective potential and positive-definiteness conditions for vacuum stability, together with perturbative unitarity, electroweak precision tests, $B$-physics, and Higgs data, we identify a narrow but viable parameter region. In the allowed region $\mu_{\gamma\gamma}$ approaches the experimental central value, while $\mu_{\tau\tau}$ reaches only $\sim0.5$ (about $1.4\sigma$ below the CMS central value) and remains within the $2\sigma$ interval---a good description of the di-photon excess but only a partial accommodation of the di-tau excess. The scenario predicts characteristic patterns in the singlet mixing and triplet vacuum expectation values and is highly testable at the HL-LHC and future lepton colliders via precision $\kappa_V$ measurements and direct exotic searches. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
Abstract Partial level schemes of $^{107,109,111}$Pd have been reported in literature, and antimagnetic rotational bands were recently predicted within the cranked shell model for the negative-parity bands of $^{107}$Pd and $^{109}$Pd, although lifetime data and semiclassical particle-rotor model studies are still unavailable. Electric quadrupole ($E2$) transitions have also been observed in the negative-parity band of $^{111}$Pd, where the rotational structure has not yet been investigated theoretically within the semiclassical particle-rotor framework. Over the past decade, the semiclassical particle-rotor model has been extensively applied to antimagnetic rotational bands in various nuclei, successfully explaining the generation of angular momentum through the shears mechanism and reproducing the observed systematics of excitation energies and $B(E2)$ transition rates. In the present work, the negative-parity bands of $^{107,109,111}$Pd are investigated within the semiclassical particle-rotor model, where angular momentum is generated through the closing of proton-hole shears towards the neutron-particle angular momentum vector involving high-$j$ orbitals. The calculated $B(E2)$ values decrease with increasing spin, while the ratio $\Im^{(2)}/B(E2)$ increases for the negative-parity bands of $^{107,109,111}$Pd, consistent with the characteristic signatures of antimagnetic rotation.
Abstract α decay plays a key role in the natural radioactivity of heavy and superheavy nuclei. In the present work, we systematically calculate the α decay half-lives of 177 even-even nuclei by applying the transfer matrix method within the clustering-formation model (CFM). Specifically, we employ both the phenomenological cosh potentialand the microscopic double-folding potential based on the density-dependent M3Y (DDM3Y) interaction to describethe a-daughter interaction. The quadrupole and hexadecapole deformation effects of daughter nuclei are taken intoaccount through orientation averaging. The calculated results are in good agreement with the experimental data, with the root-mean -square (RMS) deviations of 0.375 and 0.370 in thespherical and deformed cosh calculations, respectively, and 0.380 and 0.362 in the spherical and deformned DDM3Ycalculations. Furthermore, we extend this method to predict the α decay half-lives of 61 even-even nuclei with Z=120 and 122. For comparison, the universal decay law (UDL) proposed by Qi et al. [Phys. Rev. Lett. 103, 072501 (2009)] is utilized. These predicted results are consistent with each other.
Abstract The 237Np+48Ca reaction has been studied at the gas-filled separator DGFRS-2 at the SHE Factory at Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. We have observed three -decay chains of 282Nh and descendant nuclei 278Rg, 274Mt, 270Bh terminated by spontaneous fission of 266Db. The half-life T of isotopes 282Nh, 278Rg, and 270Bh correspond to the values expected from experimental systematics for odd-Z nuclei, but T for 274Mt exceeds this value by two orders of magnitude. These results are in agreement with those previously measured in Oganessian et al. [Phys. Rev. C 76, 011601(R) (2007); Phys. Rev. C 106, 064306 (2022)]. Such a significant difference in the measured T for 274Mt is observed for the first time for the heaviest nuclei with Z 107. The decay properties of some heavy odd-Z nuclei are compared with the predictions of a cluster model based on a dinuclear system approach and their corresponding decay schemes are proposed. The reaction cross section was measured to be 0.43■(+0.46@-0.25) pb, which is consistent with the expectation for the excitation functions of the 3n channel in 48Ca-induced reactions. The upper cross-section limit of the 4n reaction channel is 0.28 pb.
Abstract We prove a new spin-statistics theorem for a class of quantum field theory with pseudo-Hermitian Hamiltonians. Quantum fields with integer spin exhibit fermionic statistics, whereas those with half-integer spin exhibit bosonic statistics, opposite to the conventional case. This reversal arises from defining canonical field operators using pseudo-Hermitian conjugation rather than Hermitian conjugation, thereby circumventing the conventional spin-statistics theorem. The free fields retain locality, Lorentz covariance, and unitary evolution. However, interactions can violate unitarity due to the intrinsically non-Hermitian nature of pseudo-Hermitian Hamiltonians. We discuss the issues with unitarity for this quantum field theory and their potential applications to the $\text{dS}_{4}/\text{CFT}_{3}$ correspondence. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
