arXiv subjects

M. Haghighat

Publications and source records attributed to M. Haghighat.

At least 19 recordsLinked to original sources

arXiv2026

Microscopic Interaction versus Purely Gravitational Coupling in Strange Quark Stars Admixed with Dark Matter: A One-Fluid and Two-Fluid Comparison

In this study, we investigate strange quark stars (SQSs) admixed with scalar dark matter (DM), focusing on the role of microscopic interactions versus purely gravitational coupling. Our results demonstrate that while the interacting one-fluid model yields viable configurations with M_TOV > 2M_sun that satisfy current pulsar M-R measurements alongside the tidal deformability (Lambda) constraints from GW170817, the noninteracting two-fluid model more robustly meets both existing GW170817 limits and the tighter Lambda bounds anticipated from next-generation gravitational-wave detectors.

astro-ph.HE↗

arXiv2026

Two fluid CFL strange quark stars with scalar dark matter: critical mass and mass gap implications

We investigate the structure of strange quark stars (SQSs) in the color--flavor--locked (CFL) phase in the presence of scalar bosonic dark matter within a two--fluid formalism employing perturbative QCD. By considering different dark matter masses and varying the pairing gap $\Delta$ and {the central dark matter pressure fraction} $f_r$, we analyze the impact of dark matter on the structural properties of SQSs, including the maximum gravitational mass $M_{\mathrm{TOV}}$, the ratio of dark matter to strange-quark-matter radii $R_{\mathrm{DM}}/R_{\mathrm{SQM}}$, and the dimensionless tidal deformability $\Lambda$. We further examine the compatibility of the resulting mass--radius relations with the recent NICER measurements of compact stars. Within the parameter space considered in this study, we find that $M_{\mathrm{TOV}}$ exhibits a non-monotonic dependence on the dark matter mass, with a critical value beyond which $M_{\mathrm{TOV}}$ decreases. We also show that some pure CFL strange quark star configurations, particularly those associated with very stiff EOSs and larger maximum masses, may not simultaneously remain compatible with the $\Lambda$ range inferred from GW170817 while occupying the lower mass--gap region. In contrast, the inclusion of dark matter allows two-fluid CFL strange quark star configurations to reproduce the observed properties of massive compact objects in the lower mass--gap region, such as the secondary component of GW190814, while remaining qualitatively compatible with the $\Lambda$ range inferred from GW170817. We note, however, that the GW170817 constraints were originally inferred within single-fluid compact-star frameworks and therefore provide only {qualitative guidance} for the present two-fluid halo configurations. Our results suggest that exotic compact-star configurations may populate part of the conventionally defined lower mass--gap region.

astro-ph.HE↗

arXiv2026

Constraints on a Light Singlet Scalar from Combined Exotic Higgs Decays

We investigate the phenomenology of the Standard Model extended by a real gauge-singlet scalar field, focusing on exotic Higgs decay channels. For a light scalar mass in the range $0 < m_{\phi} < 40$ GeV, the Higgs boson can decay to both two and three scalar final states. We derive analytical expressions for these decay rates and impose a global constraint on the model parameters by requiring that their sum does not exceed the total Standard Model Higgs boson decay width. This requirement translates into a fourth-order inequality with respect to the singlet vacuum expectation value, $v_{\phi}$. We demonstrate that satisfying this inequality imposes an upper bound of $\cos \theta < 0.12 - 0.13$ across the entire mass range, providing a complementary constraint to existing direct search limits. Utilizing stronger independent constraints on the mixing (e.g., $\cos \theta < 0.1$), we then predict upper bounds on the individual exotic decay rates as a function of $m_{\phi}$ as $\Gamma_{h \rightarrow \phi \phi} < 0.06$ MeV and $\Gamma_{h \rightarrow \phi \phi \phi} < 5 \times 10^{- 6}$ MeV, respectively.

hep-ph↗

arXiv2026

HyPCA-Net: Advancing Multimodal Fusion in Medical Image Analysis

Multimodal fusion frameworks, which integrate diverse medical imaging modalities (e.g., MRI, CT), have shown great potential in applications such as skin cancer detection, dementia diagnosis, and brain tumor prediction. However, existing multimodal fusion methods face significant challenges. First, they often rely on computationally expensive models, limiting their applicability in low-resource environments. Second, they often employ cascaded attention modules, which potentially increase risk of information loss during inter-module transitions and hinder their capacity to effectively capture robust shared representations across modalities. This restricts their generalization in multi-disease analysis tasks. To address these limitations, we propose a Hybrid Parallel-Fusion Cascaded Attention Network (HyPCA-Net), composed of two core novel blocks: (a) a computationally efficient residual adaptive learning attention block for capturing refined modality-specific representations, and (b) a dual-view cascaded attention block aimed at learning robust shared representations across diverse modalities. Extensive experiments on ten publicly available datasets exhibit that HyPCA-Net significantly outperforms existing leading methods, with improvements of up to 5.2% in performance and reductions of up to 73.1% in computational cost. Code: https://github.com/misti1203/HyPCA-Net.

cs.CV↗

arXiv2025

Influence of dark matter on the structure of strange quark stars in one-fluid model

This work studies the influence of scalar dark matter on the structural properties of strange quark stars (SQS) within a one-fluid framework, considering Yukawa interactions between dark matter and quark matter. Contributions from perturbative QCD, Yukawa interaction between scalar dark matter and quarks, and Bose-Einstein condensation of dark matter are included in the model. We first determine the allowable range of Yukawa interaction coupling by imposing the stability condition for strange quark matter (SQM). Using this range, we derive the equation of state (EOS) for different fractions of dark matter within the total pressure of SQS. These fractions are constrained by the tidal deformability limit from GW170817. The presence of dark matter alters the EOS, leading to changes in the mass-radius relationship, tidal deformability, and stability of SQS. We demonstrate that increasing the mass of dark matter softens the EOS, whereas higher fractions of dark matter lead to stiffer EOSs. We also explore the reasons behind this behavior. Our EOSs not only describe massive objects, such as PSR J0952-0607 and PSR J2215+5135, but also satisfy the tidal deformability constraint from GW170817. These results reveal that incorporating dark matter modifies the EOS, enabling the support of higher stellar masses while maintaining consistency with observational data.

hep-ph↗

arXiv2024

Impact of new particles on the ratio of Electromagnetic form factors

We consider the electromagnetic form factors ratio in the Rosenbluth and polarization methods. We explore the impact of adding new particles as the mediators in the electron-proton scattering on these ratios. Consequently, we find some bound on the scalar coupling as $\alpha_{sc}\sim 10^{-5}$ for $m_{sc}\sim 5 MeV-2 GeV$ and $\alpha_{sc}\sim 10^{-4}-10^{-3}$ for $m_{sc}\sim 2-10 GeV$. Meanwhile, the vector coupling is bounded as $\alpha_v\sim 10^{-5}$ for $m_v\sim 5 MeV-1.1 GeV$ and $\alpha_v\sim 10^{-4}-10^{-3}$ for $m_v\sim 1.2-10 GeV$. These constraints are in complete agreement with those which is found from other independent experiments.

hep-ph↗

arXiv2020

Circular polarization of cosmic photons due to their interactions with Sterile neutrino dark matter

In this paper, we explore the possibility of the polarization conversion of a wide energy range of cosmic photons to the circular polarization through their interactions with right handed Sterile neutrinos as a candidate for dark matter. By considering the Sterile neutrino in the seesaw mechanism framework and right-handed current model, we examine the Faraday conversion $Δϕ_\text{\tiny{FC}}$ of gamma ray burst (GRB) photons at both the prompt and afterglow emission levels as well as the radio photons emitted from our galaxy and extra-galactic sources interacting with the Sterile neutrinos. Consequently, for the Sterile neutrino with mixing angle $θ^2\lesssim 10^{-2}$ motivated by models with a hidden sector coupled to the sterile neutrino, the Faraday conversion can be estimated as $Δϕ_\text{\tiny{FC}}\lesssim 10^{-3}-10^{-18}$ rad for GRB, $Δϕ_\text{\tiny{FC}}\lesssim 10^{-6}-10^{-11}$ rad for radio emission source from our galaxy and $Δϕ_\text{\tiny{FC}}\lesssim 10^{-6}-10^{-15}$ rad for extra-galactic sources. We also examine the V-mode power spectrum $C_{Vl}$ of the cosmic microwave background (CMB) at the last scattering surface. We show that the circular polarization power spectrum at the leading order is proportional to the linear polarization power spectrum $C_{pl}$ and the mixing angle where for $θ^2\lesssim 10^{-2}$ leads to $C_{Vl}\lesssim 0.01$ Nano-Kelvin squared.

hep-ph↗

arXiv2019

Impact of the vector dark matter on polarization of the CMB photon

We consider a vector dark matter (VDM) with a direct coupling with photon. We examine the effect of such an interaction on the CMB polarization to put new constrains on the properties of the DM particles. We show that a partially polarized VDM of the order of temperature fluctuation with a quadrupole distribution leads to a valuable CP for the CMB. In different DM-models the DM-masses range from few $eV$ to a few $TeV$. We show that the CP angular power spectrum depends on the mass of VDM as $C^{(S)}_{Vl}\propto 1/m_{_{V}}^6$ such that for $m_{_{V}}=10eV-1keV$, the CP angular power spectrum is $C^{(S)}_{Vl}\simeq 10^3- 10^{-11}{\rm nK^2}$. Therefore, the light VDM with masses less than $10 eV$ leads to an unexpected very large CP which can be excluded from the acceptable range of the VDM masses.

hep-ph↗

arXiv2018

Dipolar dark matter and CMB B-mode polarization

We consider dark matter as singlet fermionic particles which carrying magnetic dipole moment to explore its contribution on the polarization of cosmic microwave background (CMB) photons. We show that Dirac fermionic dark matter has no contribution on the CMB polarization. However, in the case of Majorana dark matter this type of interaction leads to the B-mode polarization in presence of primordial scalar perturbations which is in contrast with standard scenario for the CMB polarization. We numerically calculate the B-mode power spectra and plot $C_l^{BB}$ for different dark matter masses and the $r$-parameter. We show that the dark matter with masses less than 100MeV have valuable contribution on $C_l^{BB}$. Meanwhile, the dark matters with mass $m_d\leq50MeV$ for $r=0.07$ ( $m_d\leq80MeV$ for $r=0.09$) can be excluded experimentally. Furthermore, our results put a bound on the magnetic dipole moment about $M\leq 10^{-16} e\,\,cm$ in agreement with the other reported constraints.

hep-ph↗

arXiv2017

Muon anomalous magnetic moment in the standard model extension

We consider the standard model extension to explore the anomalous magnetic dipole moment of the muon. In the QED part of the theory for the CP and CPT-even Lorentz parameter $c_{μν}$, all independent electromagnetic form factors depend on a new scalar as $p'.c.p$. Therefore, the form factors, even in zero momentum transfer, can be energy dependent. We examine the magnetic form factor to find such an energy dependent up to the one loop level at the leading order of $c_{μν}$. We show that at the high energy limit (but low enough to satisfy $p^2/m^2\ll1$) there is an enhancement on the muon anomalous magnetic moment. For the first time, we find a bound on the $c_{μν}$ components for the muon as $[c_{TT}+0.35(c_{XX}+c_{YY})+0.28c_{ZZ}]$, which is about $10^{-11}$ in a terrestrial experiment

hep-ph↗

arXiv2017

Lorentz violation parameters and noncommutative scale

We consider the noncommutative Standard Model that contains Lorentz symmetry violation as a subset of the Standard Model extension. We introduce a constant electromagnetic field as a background to derive mutual relations between the free parameters of both theories. As the Lorentz violation parameters of the Standard Model extension are extensively explored in different experiments and many stringent bounds on these parameters are available, we can find new bounds on the scale of noncommutativity of the order of a few to tens of teraelectron volts.

hep-ph↗

arXiv2016

Using an intense laser beam in interaction with muon/electron beam to probe the Noncommutative QED

It is known that the linearly polarized photons can partly transform to circularly polarized ones via forward Compton scattering in a background such as the external magnetic field or noncommutative space time. Based on this fact we explore the effects of the NC-background on the scattering of a linearly polarized laser beam from an intense beam of charged leptons. We show that for a muon/electron beam flux $\bar\varepsilon_{μ,e}\sim 10^{12}/10^{10}\,{\rm TeV}\,{\rm cm}^{-2}\,{\rm sec}^{-1}$ and a linearly polarized laser beam with energy $k^0\sim $1 eV and average power $\bar{P}_{\rm laser}\simeq$1 MW, the generation rate of circularly polarized photons is about $R_{_V} \sim 10^4/{\rm sec}$ for Noncommutative energy scale $Λ_{\tiny{NC}}\sim 10$TeV. This is fairly large and can grow for more intense beams in near future.

hep-ph↗

arXiv2016

Cosmic microwave background polarization in Noncommutative space-time

In the standard model of cosmology (SMC) the B-mode polarization of the CMB can be explained by the gravitational effects in the inflation epoch. However, this is not the only way to explain the B-mode polarization for the CMB. It can be shown that the Compton scattering in presence of a background besides generating a circularly polarized microwave, can leads to a B-mode polarization for the CMB. Here we consider the non-commutative (NC) space time as a background to explore the CMB polarization at the last scattering surface. We obtain the B-mode spectrum of the CMB radiation by scalar perturbation of metric via a correction on the Compton scattering in NC-space-time in terms of the circular polarization power spectrum and the non-commutative energy scale. It can be shown that even for the NC-scale as large as $10TeV$ the NC-effects on the CMB polarization and the r-parameter is significant. We show that the V-mode power spectrum can be obtained in terms of linearly polarized power spectrum in the range Micro to Nano-Kelvin squared for the NC-scale about $1TeV$ to $10TeV$, respectively.

hep-ph↗

arXiv2014

Hydrogen and muonic-Hydrogen Atomic Spectra in Non-commutative Space-Time

Comparing electronic Hydrogen with muonic Hydrogen shows that the discrepancy in measurement of the Lamb shift in the both systems are relatively of order of $(\frac{m_μ}{m_e})^{4-5}$. We explore the spectrum of Hydrogen atom in noncommutative $QED$ to compare the noncommutative effects on the both bound states. We show that in the Lorentz violating noncommutative QED the ratio of NC-corrections is $(\frac{m_μ}{m_e})^3$ while in the Lorentz conserving NCQED is $(\frac{m_μ}{m_e})^5$. An uncertainty about $1 \,Hz\ll 3\,kHz$ in the Lamb shift of Hydrogen atom leads to an NC correction about $10 \,MHz$ in the Lorentz violating noncommutative QED and about $400 \,GHz$ in the Lorentz conserving noncommutative QED.

hep-ph↗

arXiv2014

Higgs Couplings in NonCommutative Standard Model

We consider the Higgs and Yukawa parts of the Non-Commutative Standard Model (NCSM). We explore the NC-action to give all Feynman rules for couplings of the Higgs boson to electro-weak gauge fields and fermions.

hep-ph↗

arXiv2013

Charged lepton electric dipole moment enhancement in the Lorentz violated extension of the standard model

We consider the Lorentz violated extension of the standard model. In this framework, there are terms that explicitly violate CP-symmetry. We examine the CPT-even $d_{μν}$-term to find the electric dipole moment of charged leptons. We show that the form factors besides the momentum transfer, depend on a new Lorentz-scalar, constructing by $d_{μν}$ and the four momenta of the lepton, as well. Such an energy dependence of the electric dipole form factor leads to an enhancement of the lepton electric dipole moment at high energy, even at the zero momentum transfer. We show that at $\frac{|d|p^2}{m^2_l}\sim 1$ the electric dipole moment of the charged lepton can be as large as $10^{-14} e\,\,cm$.

hep-ph↗

arXiv2013

Lorentz Violation in the Higgs Sector and Noncommutative Standard Model

The noncommutative standard model apparently violates the Lorentz symmetry. We compare the Lorentz violating terms in the Higgs sector of the noncommutative standard model with their counterparts in the standard model extension. We show that the Lorentz violating parameters in the Higgs sector can be expressed directly in terms of the noncommutative parameter without any background field. The absence of the background field enhances the obtained bounds on the noncommutative parameter from the standard model extension.

hep-ph↗

arXiv2010

Nucleon-Nucleon Scattering in a Strong External Magnetic Field and the Neutrino Emissivity

The nucleon-nucleon scattering in a large magnetic background is considered to find its potential to change the neutrino emissivity of the neutron stars. For this purpose we consider the one-pion-exchange approximation to find the NN cross-section in a background field as large as $10^{15}\texttt{G}-10^{18}\texttt{G}$. We show that the NN cross-section in neutron stars with temperatures in the range 0.1-5 \texttt{MeV} can be changed up to the one order of magnitude with respect to the one in the absence of the magnetic field. In the limit of the soft neutrino emission the neutrino emissivity can be written in terms of the NN scattering amplitude therefore the large magnetic fields can dramatically change the neutrino emissivity of the neutron stars as well.

hep-ph↗