2026-02-22
BİRTEN BARSBAY İNAÇ
The scalar hybrid meson H bc , containing both heavy b and c quarks, represents an intriguing exotic state in QCD. In this article, we investigate its strong decay properties using three-point QCD sum rules. We focus on the two leading decay channels, H bc → B + D 0 and H bc → B 0 D + , which are expected to dominate the decay dynamics. The B and D mesons produced in these decays each consist of one heavy and one light quark. The strong coupling constants at the corresponding vertices are extracted, and the partial decay widths of both channels are found to be approximately equal, around (38.54 ± 9.80) MeV, with a total width of (77.08 ± 13.86) MeV for these dominant decays. Borel transformation and continuum subtraction are applied to ensure the convergence of the sum rules and to suppress higher resonance contributions. These results indicate that the two channels provide a substantial contribution to the decay of the H bc meson. Our findings provide a reliable quantitative description of its decay dynamics, shed light on the internal structure and interactions of scalar hybrid mesons, and advance the theoretical understanding of heavy hybrid meson spectroscopy. Furthermore, the results offer valuable guidance for future experimental searches at facilities such as LHCb and Belle II.
2026-02-22
CAN GÜNGÖR
We present a detailed analysis of the long-term X-ray light curve of 4U 1608–52, focusing on fast-rising exponential-decay (FRED) outbursts, low-intensity states, and quiescent intervals. By calibrating the onset times of the outbursts, we identify three distinct classes for the FRED-type events: (i) the long-high outbursts, exceeding ~50 d in duration with peak count rates above ~40 cnt s-1; (ii) the short-medium outbursts, with durations of ~20 d and peak count rates of ~30-50 cnt s-1; and (iii) the short-low outbursts, also lasting ~20 d but reaching only ~20-30 cnt s-1 at peak. Furthermore, we examine the relation between preoutburst duration and the peak and integrated count rates of the upcoming outburst. We show that outbursts following longer quiescent periods tend to be more energetic.
2026-02-22
NURLAN AMANGELDI et al.
New experimental data on the elastic scattering of the nuclear process 15N+11B at an energy of Elab=26.25 MeV were obtained on the DC-60 cyclotron of the INP RK. Based on a semi-microscopic analysis of the interaction of an accelerated 15N ion with 1p-shell nuclei 11B the effectiveness of the new B3Y-Fetal potential was studied. . The difference between the B3Y-Fetal potential and the traditional Yukawa potentials (M3Y-Reid and M3Y-Paris) is that its density-dependent parameters are determined from the saturation condition of nuclear matter at low energy. Analysis was performed on double folding optical model (DFOM) and so no for other acronyms. The real potential of semi-microscopic analysis was calculated on the matrix of effective NN - interactions by the density of nucleon distribution in the overlapping region of the colliding nuclei. The density C, α, β, γ - dependent parameters included in the effective NN interaction are calculated at the optimal K - incompressibility factor values. As a result of the analysis of the experimental data for the 15N+11B system, the optimal parameter values for the elastic scattering cross-section were determined. The effectiveness of the B3Y-Fetal potential used to increase the saturation property of the nuclear substance is determined by the Nr - renormalization factor of semi-microscopic analysis and the χ2/N - comparison factor with the experimental cross-section.
2026-02-22
GÖKHAN TORUN
Transforming nonorthogonal bases into orthogonal ones often compromises essential properties or physical meaning in quantum systems. Here, we demonstrate that Löwdin symmetric orthogonalization (LSO) outperforms the widely used Gram–Schmidt orthogonalization (GSO) in characterizing and quantifying quantum resources, with particular emphasis on coherence and superposition. We employ LSO both to construct an orthogonal basis from a nonorthogonal one and to obtain a nonorthogonal basis from an orthogonal set, thereby mitigating ambiguity related to the basis choice in defining quantum coherence. Unlike GSO, which depends on the ordering of input states, LSO applies a symmetric transformation that treats all vectors equally and minimizes deviation from the original basis. This procedure yields basis sets with enhanced stability, preserving the closest possible correspondence to the original physical states while satisfying orthogonality. Building on LSO, we also introduce Löwdin weights — probabilistic weights for nonorthogonal representations that provide a consistent measure of resource content. We explicitly contrast these with Chirgwin-Coulson weights, demonstrating that Löwdin weights ensure nonnegativity, a prerequisite for information-theoretic measures. These weights further enable the quantification of coherence and the characterization of superposition, providing a degree of superposition as a distinct measure, as well as facilitating the assessment of state delocalization through entropy and participation ratios. Our theoretical and numerical analyses confirm LSO’s superior preservation of quantum state symmetry and resource characteristics, underscoring the critical role of orthogonalization methods and Löwdin weights in resource theory frameworks involving nonorthogonal bases.
2025-10-21
KADİR SAYGIN
The paper presents for the first time a phenomenological assessment which focuses on the charge asymmetry phenomenon for the W γ production process with subsequent leptonic decay modes W + γ → l + ν l γ and W − γ → l − ν l ¯ γ in proton-proton (pp) collisions. Charge asymmetry for the leptonic W γ process is predicted by the inclusion of genuine next-to-next-to-leading order (NNLO) corrections in the QCD perturbation theory. NNLO predictions of asymmetry distributions are assessed for the key observables, including the decay lepton and photon pseudorapidities η l and η γ , respectively, and the lepton-photon pseudorapidity correlation Δη(l, γ). The predictions are presented by focusing on realistic fiducial phase-space definitions in comparison at various pp-collision energies of 13 TeV, 14 TeV, and 100 TeV. The sensitivity of the predicted asymmetry distributions to an important observation known as radiation amplitude zero in the W γ process is reported. The asymmetry distribution for the Δη(l, γ) is shown to be important for probing the radiation-zero effect in the presence of high-transverse momentum photons. The impact of imposing jet veto for the final state of the W γ process on the asymmetry distributions is reported for future pp-collision energies. Prospects of phase-space definitions including a jet veto and harder-photon recoil are discussed to compensate for the negative impact of increasing collision energy on the asymmetry distributions. The charge asymmetry distributions are proposed as sensitive observables that offer a unique opportunity for stringent tests of the SM and represent a novel method for probing departure from the SM in indirect searches for new-physics effects, independently from the existing direct searches for anomalous WW γ coupling regarding the W γ final state.
2025-10-21
ÇAĞIL KADEROĞLU
In this study, DFT calculations were carried out in order to reveal the adsorption properties of chrysene molecule on the Si(001)−(2×1) surface. For this purpose, structural, electronic, and optical properties were calculated for five different adsorption configurations. The results show that the electronic and optical properties vary depending on the adsorption configuration of the molecule. In general, the chrysene molecule was found to reduce the work function of the Si(001)−(2×1) surface and affect its optical absorption and reflection properties in the IR and UV regions. These results indicate that the Chrysene + Si(001) hybrid could be quite useful in molecular electronics design. Furthermore, the changes in the optical and electronic properties of the Si(001) surface upon adsorption indicate that this surface may also be a good substrate for the detection of toxic PAHs.
2025-10-21
GIUSEPPE ORLANDO
The exact explicit solution of a stigmatic two-reflector optical system under Herschel’s condition is presented Details of how the solution is calculated are reported. A comparison of caustics between an aplanatic optical system and the relevant system meeting Herschel’s condition is also presented. Ray tracing verification on different optical systems validates the obtained results.
2025-10-21
ÇİÇEK BOZTUĞ
On-chip optical sensors have been attracting significant attention of the researchers due to their portability, low cost, and in-situ detection compatibility. The realization of these compact and mass-producible sensors will be possible if all required optical and electronic components are fully integrated on the same chip. However, the main obstacle here is the lack of the room-temperature on-chip light source; therefore, an external source has been utilized for optical sensing applications. Our work introduces a germanium-based optical sensing structure, specifically designed to operate at low refractive indices, with all required optical components integrated on silicon in a CMOS-compatible manner. The structure features germanium laser cavity as light source, a germanium waveguide to laterally direct lasing output, and a multiple slot waveguide to function as the sensing region. 3-dimensional (3D) finite difference time domain (FDTD) simulations are carried out to estimate waveguide sensitivities, effective indices of the optical modes and the transmission spectra of the lasing output through the sensing region as a function of the refractive index of the sample varying in the range of 1 – 1.032. Our results demonstrate 27% difference in the intensity of the lasing output transmitted to the exit of the three parallel slots when the refractive index of the sensing region is increased from 1 to 1.032. Furthermore, we analyze the potential feasibility of our proposed design for gas sensing applications since the studied refractive index range covers refractive indices of several different gases. A figure of merit (FOM) of 11 RIU-1 has been achieved through this design within the refractive index range of 1 to 1.0015. Moreover, future directions are outlined to enhance the FOM, paving the way for the potential development of fully integrated gas sensors with embedded light source.
2025-08-13
BİLDANE ÇAMUKA et al.
In this study, the generation of additional electrical energy through the temperature gradient across photovoltaic (PV) panel surfaces was investigated using thermoelectric (Peltier) modules. The experimental setup was conducted in three stages, each focusing on voltage output and thermal behavior under varying configurations. The results showed that Peltier modules can successfully convert thermal differences into electrical energy, and that output voltage increases with greater temperature differentials and active cooling. Among all configurations, the system with a 12 V fan demonstrated the highest voltage generation. This study highlights the potential of integrating thermoelectric elements into PV systems for improved energy efficiency, particularly in environments where temperature gradients are present.