Search

This study employs a first-principles approach to comprehensively examine the structural, electronic, optical, and magnetic properties of the thermodynamically stable scintillating double perovskite halides A 2 N a T a X 6 ( A = C s , R b ; X = C l , B r , I ). The dynamic stability of these materials were explained based on deduced phonon properties. Our analysis reveals that these compounds exhibit intriguing electronic behavior with spin polarization, demonstrating half-metallicity. In spin-up, the band gap is found to be zero, while in spin-down, it falls within the range of 3 to 4 eV with the incorporation of DFT+U corrections. Notably, the optical properties assessment highlights the exceptional UV and high-energy absorption capabilities of A 2 N a T a I 6 , making it a promising candidate for scintillation applications in particle detection. This research sheds light on the unique and versatile properties of these materials, with implications for various technological and scientific applications. [ABSTRACT FROM AUTHOR]

The two-body leptonic decays of both light and heavy-charged mesons X l 2 ± are investigated in the first Born approximation in the presence of a monochromatic and circularly polarized laser field. As a result of using Volkov functions, the analytic study of these processes has brought a change in the parameters associated with each decay process. The decay width, lifetime, and branching ratio of each decay process are affected by increasing the classical parameter ξ of the meson. A comparison between the matter decay X l 2 + and that of the anti-matter X l 2 - in the presence of a circularly polarized laser wave, indicates that increasing laser field strength (increasing the classical parameter ξ ) can induce a slight dominance of matter over antimatter or vise versa. [ABSTRACT FROM AUTHOR]

The Full Potential Linearised Augmented Plane Wave method (FP-LAPW) is used to design the structural, elastic-mechanical, electronic, magnetic, and thermoelectric prop-erties of new cubic double perovskite oxides X 2 C e V O 6 (X = S r , B a) . The tolerance factor and elastic parameters show and ensure the stability and formation of both perovskites in the cubic phase. Additionally, the predicted mechanical constants show that X 2 C e V O 6 (X = S r , B a) behave as stable ductile materials. Then, spin-polarized calculations show ferromagnetic and half-metallic behavior for both compounds with a total magnetic moment equal to 1 μ β . Thermoelectric parameters of both materials show high power factor and n-type conductivity, due to the multiple oxidation states of Vanadium. Therefore, these results show that the proposed perovskites X 2 C e V O 6 (X = S r , B a) can be promising materials for spintronic and thermoelectric applications. [ABSTRACT FROM AUTHOR]

In the center of mass frame, we have investigated the process of Higgs-strahlung production in association with a pair of fermions, e + e - → f f ¯ H , at the leading order in the presence of an intense electromagnetic field with circular polarization. Our analytical calculations are based on the narrow width approximation, which is valid in the leading order as Γ Z / M Z = 2 % . We have considered only the initial particles inside the laser field as a first step. In the second part, we have embedded both initial and final particles in the laser field. We have analyzed the angular distribution of the produced Higgs boson as a function of the laser parameters in both cases. We have found that the order of magnitude of the differential cross section of both processes e + e - → μ + μ - H and e + e - → b b ¯ H is reduced more significantly in the case where both initial and final particles are embedded in the laser field. [ABSTRACT FROM AUTHOR]

In this research paper, we consider the process of neutral Higgs production from e+e– annihilation in Inert Higgs Doublet Model (IHDM) in the absence and presence of an external field. The latter is assumed to be a plane and monochromatic wave with linear polarization. In the theoretical framework, we present the analytic calculation of the lowest order differential cross section by using the scattering matrix approach and Dirac–Volkov formalism for charged incident particles. The total cross section is computed by performing a numerical integration of the differential cross section over the solid angle. The results obtained are analyzed and discussed for different centre of mass energies and laser parameters. We found that inserting a laser wave with linear polarization is a suitable mechanism to enhance the total cross section of the process. Indeed, the probability of the process to occur increases with the presence of a linearly polarized laser field, especially with low frequency and high strength. [ABSTRACT FROM AUTHOR]

In this research paper, we investigate the decay of the proton into neutron, positron and electron neutrino in the presence of an external electromagnetic field with circular polarization. Different physical quantities related to this decay process, such as proton's decay rate and its lifetime, are calculated based on the S-matrix approach. The proton and positron are treated as Dirac–Volkov states, while the neutron and electron neutrino are free-states. We have found that, though it can not occur in vacuum, the proton's decay process into neutron, positron and electron neutrino becomes possible in the presence of laser field with high intensities near or close to the Schwinger limit. In addition, near this limit and for some frequencies, the proton's lifetime can be comparable to that of the neutron, and the required laser strength, from which this decay becomes possible, depends on the chosen laser source. [ABSTRACT FROM AUTHOR]

Various properties of S r 2 M W O 6 (M = V , R h , R u) are investigated based on the DFT theory using the full-potential linearized augmented plane wave (FP-LAPW) method. Their magnetic properties show a half metallic bahavior for M = V and Rh with high magnetic moments. However, for S r 2 R u W O 6 , the bands for up and down spins are symmetric and thus this material is non-magnetic with an energy band gap of 1.4 e V . The presence of Ru and Rh in S r 2 M W O 6 structure increases the absorption of this material, especially in the visible light range. The elastic constants C α β for all studied compounds were obtained using Elastic1.1 and satisfy the Born stability criterion. This indicates that all the compounds are mechanically stable. Finally, electrical properties were determined using BoltzTraP package leading to interesting aspects. The obtained results are comparable with other perovskite phases. Therefore, these coupled features of the title compounds make them promising material for different applications. [ABSTRACT FROM AUTHOR]

In the framework of Higgs triplet model (HTM), we study the pair production process of doubly charged Higgs bosons via e + e - annihilation in the presence of a laser field with circular polarization. We begin our work by presenting the theoretical calculation of the differential cross section in the centre of mass frame including both Z and γ diagrams. Then, from the numerical analysis of the production cross section's dependence on the laser field parameters, we have shown that the laser-assisted total cross section decreases as far as the electromagnetic field intensity enhances or by decreasing its frequency. Finally, we analyse the variation of the total cross section versus the mass of the doubly charged Higgs boson by fixing the laser field parameters and the centre of mass energy, and we have found that the order of magnitude of the cross section decreases with the increment of M H ± ± . [ABSTRACT FROM AUTHOR]

Darwin wave functions, as a quasi-relativistic states describing the hydrogen atom, are used to calculate the differential cross section for inelastic excitation of 2p state hydrogen atom by electronic impact in various electron energy regions. The use of these wave functions gives interesting results so long as the condition z / c ≪ 1 is verified. The incident and scattered electrons are described by a free Dirac spinor. Relativistic spin effects are taken into account explicitly via the spinorial part. The computed results, in the first Born approximation, are given and discussed by analogy with the non-relativistic regime and the relativistic 1 s → 2 s . They are also compared with some other available theoretical models and with the experimental results of Williams (J Phys B At Mol Phys 14:1197, 1981). The general rule of optically allowed and forbidden transitions is also respected. [ABSTRACT FROM AUTHOR]

We analyse a light charged Higgs boson in the 2-Higgs Doublet Model (2HDM) Type-I, when its mass satisfies the condition MH±< Mt + Mb and the parameter space is consistent with theoretical requirements of self-consistency as well as the latest experimental constraints from Large Hadron Collider (LHC) and other data. Over such a parameter space, wherein the Standard Model (SM)-like state discovered at the LHC in 2012 is the heaviest CP-even state of the 2HDM, it is found that the decay modes of the charged Higgs boson are dominated by H±→ W±(∗)h. Furthermore, the light neutral Higgs boson h dominantly decays into two photons. Under these conditions, we find that the production and decay process pp → H±h → W±(∗)hh → ℓνℓ + 4γ (ℓ = e, μ) is essentially background free. However, since the W±(∗) could be largely off-shell and the h state is very light, so that both the lepton coming from the former and the photons coming from the latter could be rather soft, we perform here a full Monte Carlo (MC) analysis at the detector level demonstrating that such a W± + 4γ signal is very promising, as it would be yielding significant excesses at the LHC with an integrated luminosity of L = 300 fb−1 at both s = 13 and 14 TeV. [ABSTRACT FROM AUTHOR]

At the Large Hadron Collider (LHC), both the ATLAS and CMS Collaborations have been searching for light charged Higgs bosons via top (anti)quark production and decays channels, like pp → t t ¯ with one top (anti)quark decaying into a charged Higgs boson and a b (anti)quark, when the decay is kinematically open (i.e., when m H ± ≲ mt). In this paper, we propose new searches at the LHC involving light charged Higgs bosons via their pair production channels like pp → H±h/A and pp → H+H− in the 2-Higgs Doublet Model (2HDM) Type-I and -X scenarios. By focusing on the case where the heavy H state plays the role of the Standard Model (SM)-like Higgs boson with a mass near 125 GeV, we study the aforementioned Higgs boson pair production channels and investigate their bosonic decays, such as H± → W±h and/or H± → W±A. We demonstrate that for a light charged Higgs boson state, with m H ± ≲ mt, at the LHC, such di-Higgs production and decay channels can give rise to signatures with event rates much larger than those emerging from pp → t t ¯ → t b ¯ H− + c.c. We specifically study h/A → b b ¯ and τ+τ− decays. We, therefore, claim that the discussed combination of new production and decay modes can result in an alternative discovery channel for charged Higgs bosons lighter than the top (anti)quark at the LHC within the above two 2HDM Types. Finally, in order to motivate experimentalists in ATLAS and CMS to search for such signatures, we propose 16 Benchmark Points (BPs) which are compatible with both theoretical and experimental constraints. [ABSTRACT FROM AUTHOR]