M. M. Ettefaghi

University of Qom, Ghom, Qom, Iran

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Publications (12)24.07 Total impact

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    Zohreh Bagherian, Mohammad Mahdi Ettefaghi, Reza Moazzemi
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    ABSTRACT: We consider the standard model (SM) extended by a gauge singlet fermion as cold dark matter (SFCDM) and a gauge singlet scalar (singlet Higgs) as a mediator. The parameter space of the SM is enlarged by seven new ones. We obtain the total annihilation cross section of singlet fermions to the SM particles and singlet Higgs at tree level. Regarding the relic abundance constraint obtained by WMAP observations, we study the dependency on each parameter separately, for dark matter masses up to 1 TeV. In particular, the coupling of SFCDM to singlet Higgs $g_s$, the SFCDM mass $m_\psi$, the second Higgs mass $m_{h_2}$, and the Higgs bosons mixing angel $\theta$ are investigated accurately. Three other parameters play no significant role. For a maximal mixing of Higgs bosons or at resonances, $g_s$ is applicable for the perturbation theory at tree level. We also obtain the scattering cross section of SFCDM off nucleons and compare our results with experiments which have already reported data in this mass range; XENON100, LUX, COUPP and PICASSO collaborations.
    06/2014;
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    M.M. Ettefaghi, R. Moazzemi
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    ABSTRACT: We consider an extension of the standard model in which a singlet fermionic particle, to serve as cold dark matter, and a singlet Higgs are added. We perform a reanalysis on the free parameters. In particular, demanding a correct relic abundance of dark matter, we derive and plot the coupling of the singlet fermion with the singlet Higgs, gs, versus the dark matter mass. We analytically compute the pair annihilation cross section of singlet fermionic dark matter into two photons. The thermally averaged of this cross section is calculated for wide range of energies and plotted versus dark matter mass using gs consistent with the relic abundance condition. We also compare our results with the Fermi-Lat observations.
    Journal of Cosmology and Astroparticle Physics 02/2013; 2013(02):048. · 6.04 Impact Factor
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    M. M. Ettefaghi
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    ABSTRACT: Detecting the cosmic rays, in particular gamma-ray, coming from the dark matter annihilation or decay is an indirect way to survey the nature of the dark matter. In the commutative space-time, the annihilation of the dark matter candidates (WIMPs) to photons proceeds through loop corrections. However, it is possible for WIMPs as well as the other standard model singlet particles to couple with photons directly in the noncommutative space-time. In this paper, we study two-photon annihilation of singlet WIMPs in the noncommutative space-time. If the noncommutative interactions are relevant to the relic abundance, one can exclude some dark matter masses using Fermi-Lat data.
    Physical review D: Particles and fields 10/2012; 86(8).
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    M. M. Ettefaghi, T. Shakouri
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    ABSTRACT: Neutral particles can couple with the $U(1)$ gauge field in the adjoint representation at the tree level if the space-time coordinates are noncommutative (NC). Considering neutrino-photon coupling in the NC QED framework, we obtain the differential cross section of neutrino-electron scattering. Similar to the magnetic moment effect, one of the NC terms is proportional to $\frac 1 T$, where $T$ is the electron recoil energy. Therefore, this scattering provides a chance to achieve a stringent bound on the NC scale in low energy by improving the sensitivity to the smaller electron recoil energy.
    Journal of High Energy Physics 11/2010; 2010(11). · 5.62 Impact Factor
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    M M Ettefaghi, S M Fazeli
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    ABSTRACT: A Comment on the Letter by Saurya Das and Elias C. Vagenas, Phys. Rev. Lett. 101, 221301 (2008)10.1103/PhysRevLett.101.221301. The authors of the Letter offer a Reply.
    Physical Review Letters 03/2010; 104(11):119001; author reoly 119002. · 7.73 Impact Factor
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    M. M. Ettefaghi, M. Haghighat, R. Mohammadi
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    ABSTRACT: QED based on -unexpanded noncomutative space-time in contrast with the noncommutative QED based on -expanded U(1) gauge theory via the Seiberg-Witten map is one-loop renormalizable. Meanwhile it suffers from asymptotic freedom that is not in agreement with the experiment. We show that the QED part of the U{sub *}(3)xU{sub *}(1) gauge group as an appropriate gauge group for the noncommutative QED+QCD is not only one-loop renormalizable but also has a function that can be positive, negative and even zero. In fact the function depends on the mixing parameter as a free parameter and it will be equal to its counterpart in the ordinary QED for =0.367.
    Physical review D: Particles and fields 01/2010; 82(10):105017-105017.
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    M. M. Ettefaghi
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    ABSTRACT: We extend the noncommutative (NC) standard model to incorporate singlet particles as cold dark matter. In the NC space-time, the singlet particles can be coupled to the U(1) gauge field in the adjoint representation. We Study the relic density of the singlet particles due to the NC induced interaction. Demanding either the singlet fermion or the singlet scalar to serve as cold dark matter and the NC induced interactions to be relevant to the dark matter production, we obtain the corresponding relations between the NC scale and the dark matter masses, which are consistent with some existing bounds. Comment: 14 pages, to appear in Phys. Rev. D
    Physical review D: Particles and fields 03/2009;
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    M. M. Ettefaghi, M. Dehghani
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    ABSTRACT: We consider the unparticle physics introduced by Georgi and show that if the standard model is extended to include a singlet scalar as a dark matter candidate, there is a channel which leads to its decay to photon and unparticle. We calculate the decay rate for this new channel and find a lower bound on unparticle physics scale by demanding the stability of this candidate of the dark matter.
    06/2008;
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    M. M. Ettefaghi, M. Haghighat
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    ABSTRACT: We consider the noncommutative standard model based on SU(3)×SU(2)×U(1). We study the gauge transformation of right-handed neutrinos and its direct interaction with photons in the noncommutative space-time. We show that the massive Dirac neutrinos, through the Higgs mechanism, cannot accommodate this extension of the standard model, while the massive Majorana neutrinos are consistent with the gauge symmetry of the model. The electromagnetic properties and the dispersion relations for the neutrino in the noncommutative standard model is examined. We also compare the results with the noncommutative standard model based on U(3)×U(2)×U(1).
    Physical Review D 03/2008; 77(5). · 4.69 Impact Factor
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    M. M. Ettefaghi, M. Haghighat
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    ABSTRACT: We consider Lorentz conserving noncommutative field theory to construct the Lorentz conserving noncommutative standard model based on the gauge group $SU(3)\times SU(2)\times U(1)$. We obtain the enveloping algebra-valued of Higgs field up to the second order of the noncommutativity parameter $\th_{\mu\nu}$. We derive the action at the leading order and find new vertices which are absent in the ordinary Standard Model as well as the minimal noncommutative standard model. We briefly study the phenomenological aspects of the model.
    Physical review D: Particles and fields 04/2007;
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    M. Haghighat, M. M. Ettefaghi, M. Zeinali
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    ABSTRACT: We extend the non-commutative standard model based on the minimal $SU(3)\times SU(2)\times U(1)$ gauge group to include the interaction of photon with neutrino. We show that, in the gauge invariant manner, only the right handed neutrino can directly couple to the photon. Consequently, we obtain the Feynman rule for the $\gamma\nu\bar\nu$-vertex which does not exist in the minimal extension of non-commutative standard model (mNCSM). We calculate the amplitude for $\gamma\nu\to\gamma\nu$ in both the nonminimal non-commutative standard model (nmNCSM) and the extended version of mNCSM. The obtained cross section grows in the center of mass frame, respectively, as $(\theta_{NC})^2{M}_Z^{-4}E^6$ and $(\theta_{NC})^4E^6$ which can exceed the cross section for $\gamma\nu\to\gamma\gamma\nu$ and $\gamma\nu\to\gamma\nu$ in the high energy limit in the commutative space. Comment: 12 pages, 3 figures, to appear in Phys. Rev. D
    Physical review D: Particles and fields 11/2005;
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    M. Haghighat, M. M. Ettefaghi
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    ABSTRACT: We consider the Lorentz invariant noncommutative QED and complete the Feynman rules for the theory up to the order theta2. In the Lorentz invariant version of the noncommutative QED the particles with fractional charges can be also considered. We show that in the parton model, even at the lowest order, the Bjorken scaling violates as ˜theta2Q4.
    Physical review D: Particles and fields 01/2004; 70(3).