Interacting Boson Research Articles

New Interacting Boson Fermion-Fermion Model results

We present a new application of the Interacting Boson Model (IBM) and its extensions for describing double charge exchange reactions. The study of double charge exchange reactions induced by heavy ions involving candidate nuclei for neutrinoless double beta decay is a complex task carried out by the NUMEN collaboration. This investigation faces the intricacies of complex oddodd intermediate nuclei in sequential double charge exchange processes. We will offer a comprehensive description of heavy odd-odd nuclei using the Interacting Boson Fermion-Fermion Model (IBFFM). Additionally, we will outline the methodology for describing transfer operators within this framework. Finally, we will explore the potential applications of our results for describing double charge exchange reactions.

Transitional character of Nd-Dy (N=90) isotones in IBM model

The Interacting Boson Model is used to study the level structure of ground state, beta, and gamma bands in150Nd, 152Sm, 154Gd and 156Dy (N = 90) isotones. The energy ratios R_((I+2)⁄2) and R_(0_2⁄2_1 ) are compared to the predictions of U(5), SU(3), and X(5) symmetry. The calculated reduced transition probabilities as well as quadrupoles moments were compared to experimental data. IBM-1 investigates the properties of the potential energy surface to determine the nuclear shape of the Nd-Dy (N=90) isotones.

A Study of Nuclear Structure of (Mo^96,98) by Using Interacting Boson Model-1

In this study, the interacting Boson Model (IBM-1) was used to find the best Hamiltonian structure for studying the (Mo^96,98) structure. For generating the Hamiltonian structure, the calculated energy levels (ground, beta, and gamma bands) and B(E2) transitions for (Mo^96,98) were explored using the optimal parameter values. According to this study and the IBM test findings, (Mo^96,98) are stable isotopes of Molybdenum, and their transition behaviors are close to the SU(5) limitations. When comparing the findings to the experimental data, they demonstrated a good agreement.

Quantum entanglement of SO(6)-U(5) transitional nuclei in the interacting boson model-2 (IBM-2)

The quantum shape phase transition between the spherical and deformed γ-unstable (U(5)−O(6)) even-even nuclei within the frameworks of Interacting Boson Model-1 and 2 (IBM-1,2) for low-lying states, using the “entanglement entropy” (S) has been studied. In both frameworks, the theoretical results showed that there exist minimum and maximum entanglement values between s bosons in the U(5) and O(6) limits, respectively. In order to confirmation of the theoretical results, we have calculated and analyzed the entanglement entropy of s−d bosons and proton (π) - neutron (ν) bosons in Cerium (C58122−136e) isotopes. The results indicate that the entanglement entropy correctly describes the transition from U(5) to O(6), for ground state (01+), but it cannot accurately determine the transitional nucleus.

Electric reduced transition probabilities of \(^{186}\text{W}\) and \(^{186}\text{Os}\) isobars through the interacting boson model-I

In this study, we applied the Interacting Boson Model (IBM-I) to compute the electric reduced transition probabilities B(E2)\(\downarrow\) of even-even neutron rich \(^{186}\text{W}\) and \(^{186}\text{Os}\) isobars. The ratio \(R_{4/2} = E(4_{1}^{+}) / E(2_{1}^{+})\) has also been calculated for those isobars and the SU(3) symmetry for those isobars has been reported. \(E(4_{1}^{+})\) and \(E(2_{1}^{+})\) indicate the energy level of \(4_{1}^{+}\) and \(2_{1}^{+}\), respectively. We have described the strength of B(E2) in W.u. for \(^{186}\text{W}\) and \(^{186}\text{Os}\) isobars of some of the low-lying quadrupole collective states in contrast to obtainable measured data. The electric reduced transition probabilities B(E2)\(\downarrow\) from yrast state gamma transition from \(12_1^{+} \rightarrow 10_1^{+}\), \(10_1^{+} \rightarrow 8_1^{+}\), \(8_1^{+} \rightarrow 6_1^{+}\), \(6_1^{+} \rightarrow 4_1^{+}\), \(4_1^{+} \rightarrow 2_1^{+}\) and \(2_1^{+} \rightarrow 0_1^{+}\) and other bands states and B(E2) ratio of \(^{186}\text{W}\) and \(^{186}\text{Os}\) isobars have been compared with obtainable measured data and other previous studies. Also calculated were the systematic strength of B(E2), intrinsic quadrupole moments, and deformation parameters of even-even \(^{186}\text{W}\) and \(^{186}\text{Os}\) isobars. The data from these calculations are in good matching with the obtainable measured data. The IBM-I model for the strength of B(E2) has been systematically deduced in SU(3) limit for a few yrasts states transitions in \(^{186}\text{W}\) and \(^{186}\text{Os}\) isobars.

Production of massive W±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{\\pm }$$\\end{document} bosons and fermion–antifermion pairs from vacuum in the de Sitter Universe

In this paper we study the charged electro-weak interactions in the de Sitter geometry. We develop the reduction formalism for the Proca field with the help of the solutions for the interacting fields. Perturbation theory is used for obtaining the definition of the transition amplitudes in the first order. We apply our formalism to the study of spontaneous vacuum emission of fermions, anti-fermions and W±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{\\pm }$$\\end{document} bosons in the expanding de Sitter universe. Our results are generalizations of the Weinberg–Salam electro-weak theory to curved space-time, in the case of W±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{\\pm }$$\\end{document} boson interaction with leptons. The probability and transition amplitude are found to be a quantities which depend on the Hubble parameter. Our analytical and graphical results prove that such perturbative processes are possible only for the large expansion conditions of the early Universe. The total probability and rate of transition are obtained for the case of large expansion and we use dimensional regularization for the momenta integrals. In the end we recover the Minkowski limit, where our probabilities vanish, thus confirming the well known fact that spontaneous vacuum emission of W±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^{\\pm }$$\\end{document} bosons and fermions is forbidden in flat space-time due to energy–momentum conservation.

Quantum Coherence from a Few Incoherent Bosons

AbstractAn engineered hybrid interaction of a few incoherent bosons with a cooled discrete‐level system may give rise to substantial quantum coherence, an essential resource with diverse applications for quantum technology. This is in contrast to the expected requirement of intense and coherent external drives in current technologies. Substituting such external drives with internal hybrid processes stimulated by mere thermal energy may then contribute to reduced energy consumption in observing and using quantum phenomena. This low‐energy emergence of quantum coherence is then suitable for proof‐of‐principle exploration with recent experiments in platforms such as trapped ions and superconducting circuits.

Boson–Boson Interactions at the LHC

Vector boson scattering is a key production process to probe the electroweak symmetry breaking of the Standard Model and is one of the most important topics of the physics program for the HL-LHC since it involves both self-couplings of vector bosons and their coupling with the Higgs boson. If the Higgs mechanism is not the sole source of electroweak symmetry breaking, the scattering amplitude deviates from the Standard Model prediction at high scattering energy. Moreover, deviations may be detectable even if a New Physics scale is higher than the reach of direct searches. In this review, the most recent experimental measurements of the production cross sections of vector boson pairs in association with two jets in proton–proton collisions at [Formula: see text] TeV at the LHC are reported, using data sets recorded by the ATLAS and CMS detectors. Applications to searches for New Physics, as well as prospects for measuring the electroweak vector boson scattering processes with larger data samples, are also summarized.

A perturbative production of massive Z bosons and fermion–antifermion pairs from the vacuum in the de Sitter Universe

In this paper we study the problem of neutral electro-weak interactions in a de Sitter geometry. We develop the formalism of reduction for the Proca field with the help of the solutions for the interacting fields and by using perturbative methods we obtain the definition of the transition amplitudes in the first order of perturbation theory. As an application to our formalism we study the generation of massive fermions and Z bosons from vacuum in the expanding de Sitter universe. Our results are the generalization to the curved geometry of the Weinberg–Salam electro-weak theory for the case of Z boson interaction with leptons. The probability is found to be a quantity that depends on the Hubble parameter and we prove that such perturbative processes are possible only for large expansion regime of the early Universe. The total probability and rate of transition are obtained for the case of large expansion and we use the dimensional regularization for extract finite results from the momenta integrals. In the Minkowski limit we obtain that the probability of particle generation from vacuum is vanishing recovering the well known result that forbids particle production in flat space-time due to the momentum-energy conservation.

A massive gauge theory à la Utiyama

Utiyama’s method is a deductive approach of building gauge theories for semi-simple groups of local transformations, including the Abelian U(1) case, the non-Abelian SU(N) group, and the gravitational interaction. Gauge theories à la Utiyama typically predict a massless gauge potential. This work brings a mass generation mechanism and Utiyama’s method together thus giving mass to the interaction boson without breaking the gauge symmetry. Herein we devote our attention to the Abelian case. Two gauge potentials are introduced: a vetor field A μ and a scalar field B. The associated gauge-invariant field strengths F μ ν and G μ are built from Utiyama’s technique. Gauge invariance requirement upon the total Lagrangian (including matter fields and gauge fields) yields the conserved currents. Finally, we study the simplest type of Lagrangian involving the field strengths and obtain the related field equation. By imposing appropriate constraints on this particular example, Stueckelberg model is recovered.

Measurement of the CP properties of Higgs boson interactions with tau -leptons with the ATLAS detector

A study of the charge conjugation and parity (textit{CP}) properties of the interaction between the Higgs boson and tau -leptons is presented. The study is based on a measurement of textit{CP}-sensitive angular observables defined by the visible decay products of tau -leptons produced in Higgs boson decays. The analysis uses 139 fb^{-1} of proton–proton collision data recorded at a centre-of-mass energy of sqrt{s}= 13 TeV with the ATLAS detector at the Large Hadron Collider. Contributions from textit{CP}-violating interactions between the Higgs boson and tau -leptons are described by a single mixing angle parameter phi _{tau } in the generalised Yukawa interaction. Without constraining the Hrightarrow tau tau signal strength to its expected value under the Standard Model hypothesis, the mixing angle phi _{tau } is measured to be 9^{circ } pm 16^{circ }, with an expected value of 0^{circ } pm 28^{circ } at the 68% confidence level. The pure textit{CP}-odd hypothesis is disfavoured at a level of 3.4 standard deviations. The results are compatible with the predictions for the Higgs boson in the Standard Model.

Renormalisation of SMEFT bosonic interactions up to dimension eight by LNV operators

We present the renormalisation group running of the bosonic operators of the Standard Model effective field theory (SMEFT) by the Lepton Number Violating operators (LNVs) at 1-loop order up to mathcal{O} (v4/Λ4), with v ∼ 246 GeV as the electroweak scale and Λ as the SMEFT cut-off. Using these relations with the positivity bounds on Wilson coefficients of ϕ4D4 class, we derive sign constraints on the Wilson coefficients of LNV operators, for models where ϕ4D4 operators do not appear at tree-level. We inspect these constraints for the LNV Wilson coefficients generated from matching the Type-I and III seesaw models to SMEFT up to dimension seven at tree-level. We also exhibit the unique bounds induced by the T-parameter on LNVs.

STUDY OF O(6) SYMMETRY IN 108,110,112Ru ISOTOPES BY IBM-1 CALCULATION

Interacting Boson Model (IBM-1) is very important for the low-lying combined state in even mass nuclei. We have described the O(6) limit in the 108,110,112Ru nuclei by IBM-1 model. The B(E2) strength and energy levels in different bands were established in good agreement theoretically and experimentally. The calculated potential energy surfaces (PES) of those nuclei were suggested O(6) characters.

Constraints on the Higgs boson self-coupling from single- and double-Higgs production with the ATLAS detector using pp collisions at [formula omitted] TeV

Constraints on the Higgs boson self-coupling are set by combining double-Higgs boson analyses in the bb¯bb¯, bb¯τ+τ− and bb¯γγ decay channels with single-Higgs boson analyses targeting the γγ, ZZ⁎, WW⁎, τ+τ− and bb¯ decay channels. The data used in these analyses were recorded by the ATLAS detector at the LHC in proton–proton collisions at s=13 TeV and correspond to an integrated luminosity of 126–139 fb−1. The combination of the double-Higgs analyses sets an upper limit of μHH<2.4 at 95% confidence level on the double-Higgs production cross-section normalised to its Standard Model prediction. Combining the single-Higgs and double-Higgs analyses, with the assumption that new physics affects only the Higgs boson self-coupling (λHHH), values outside the interval −0.4<κλ=(λHHH/λHHHSM)<6.3 are excluded at 95% confidence level. The combined single-Higgs and double-Higgs analyses provide results with fewer assumptions, by adding in the fit more coupling modifiers introduced to account for the Higgs boson interactions with the other Standard Model particles. In this relaxed scenario, the constraint becomes −1.4<κλ<6.1 at 95% CL.

Special features of nuclear structure of [formula omitted]Xe

The special spectral features of valence neutron hole deficient (N=74, 76, 78) 128-132Xe isotopes are studied, with respect to the shape phase changes with N. Besides the study of the excited 02+, 03+ states, vis-a-vis the critical point symmetry E(5), the study of the ground band and K=π2+γ-vibrational band provides a wholesome view of the nuclear structure of these isotopes. An in-depth analysis of the spectral features is presented. Comparison is made with the Interacting boson model-1 predictions.

Measuring CP properties of Higgs boson interactions with τ leptons with the ATLAS detector

Measuring CP properties of Higgs boson interactions with τ leptons with the ATLAS detector

Investigation of the radiative decay $b \to s \gamma$ in the 3-4-1-1 model

We investigate the branching ratio of the radiative decay $b\to s \gamma$ in the 3-4-1-1 model with arbitrary charge parameters $p,q$. We show that the new Higgs bosons, $\mathcal{H}_1^\pm$, and the new gauge bosons $W_{13,14 }^{\pm p,q}, Z_{2,3}$ contribute to this decay. Of these sources, the main contribution comes from the interaction of the singly-charged Higgs boson. If the spontaneous breaking of the enlarged gauge group symmetry down to the electroweak group is around a few TeVs, the predictions for the branching ratio Br($b\to s \gamma$) and meson mixing are both consistent with experimental constraints.

New pattern in regular nuclei based on their experimental quadrupole transition rates and some new candidates

In this paper, we tried to get a new signature of regular nuclei based on their quadrupole transition rates. We have analyzed the experimental electric quadrupole transition probabilities of well-known "regular nuclei". The results indicate finding specific repetition patterns for E2 transition rates, similar to what has been reported for the energy levels of these nuclei. We also tested the existence of this observed repetition scheme for all known isotopes whose experimental transition rates are available and introduced several new candidates as regular nuclei. Then, the energy spectra (Experimental) of these new suggested "regular nuclei" are investigated in the framework of the Interacting Boson Model, in which the parameters of Hamiltonian confirm the placement of these nuclei in the "Alhassid-Whelan arc of regularity" region. In order to further study the statistical distribution of experimental energy levels related to the electromagnetic transitions we are considering, we studied using the random matrix theory. The results confirmed their regularity.

A + 2n compound nuclei and the unitary limit in nuclear physics

This contribution discusses a new perception of the structure of compound nuclei by introducing intermediate states of the Feshbach formalism of nuclear reactions in the Interacting Boson Model of nuclear structure. The stake is to explore the manifestation of the unitary limit in heavy, even-even nuclei. Interactions that govern Feshbach resonances of cold and dilute atomic gases suggest the formulation of an IBM-compound Hamiltonian for scattering two neutrons (2n) from a heavy, even-even target (A). The solutions of the corresponding coupled channel equations host a 2n-IBM state resonance. It turns out that the unitary limit is measurable in a heavy A + 2n compound nucleus at low temperatures. That measurement is feasible through the fluctuations of the cross-sections that tune the 2n-A scattering length.

Relationship between two-particle topology and fractional Chern insulator

Lattice generalizations of fractional quantum Hall (FQH) systems, called fractional Chern insulators (FCIs), have been extensively investigated in strongly correlated systems. Despite many efforts, previous studies have not revealed all of the guiding principles for the FCI search. In this paper, we investigate a relationship between the topological band structure in the two-particle problem and the FCI ground states in the many-body problem. We first formulate the two-particle problem of a bosonic on-site interaction projected onto the lowest band of a given tight-binding Hamiltonian. We introduce a reduced Hamiltonian whose eigenvalues correspond to the two-particle bound-state energies. By using the reduced Hamiltonian, we define the two-particle Chern number and numerically check the bulk-boundary correspondence that is predicted by the two-particle Chern number. We then propose that a nontrivial two-particle Chern number of dominant bands roughly indicates the presence of bosonic FCI ground states at filling factor $\ensuremath{\nu}=1/2$. We numerically investigate this relationship in several tight-binding models with Chern bands and find that it holds well in most of the cases, albeit two-band models being exceptions. Although the two-particle topology is neither a necessary nor a sufficient condition for the FCI state as other indicators in previous studies, our numerical results indicate that the two-particle topology characterizes the degree of similarity to the FQH systems.