V. Bashiry

Cyprus International University, Cyprus

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Publications (51)100.06 Total impact

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    V. Bashiry
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    ABSTRACT: Exclusive $B_c^\ast \rightarrow D_{s}~\nu \bar{\nu}$ decay is studied in the framework of the three--point QCD sum rules approach. The two gluon condensate contributions to the correlation function are calculated and the form factors of this transition are found. The decay width and total branching ratio for this decay is also calculated.
    10/2014;
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    ABSTRACT: Rare exclusive $B_c^\ast \rightarrow D_{s}~l^+ l^-$ decays are analyzed in the framework of the three--point QCD sum rules approach. The two gluon condensate corrections to the correlation function are included and the form factors of this transition are evaluated. Using the form factors, the decay width and integrated decay rate for these decays are also calculated.
    10/2014;
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    V. Bashiry, A. Abbasi
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    ABSTRACT: The strong coupling constant g$_{h_{b}B_{c}^{PS}B_{c}^{V}}$ is calculated using the three-point QCD sum rules method. We use correlation functions to obtain these strong coupling constants with contributions of both B$_{c}^{PS} $ and B$_{c}^{V}$mesons as off-shell states. The contributions of two gluon condensates as a radiative correction are considered. The results show that g$_{h_{b}B_{c}^{PS}B_{c}^{V}}=8.80\pm 2.84 GeV^{-1}$and g$_{h_{b}B_{c}^{V} B_{c}^{PS}}=9.34\pm 3.12 GeV^{-1}$ in the $B_{c}^{PS}$ and $B_{c}^{V}$ off-shell state, respectively.
    01/2014;
  • A. Abbasi, V. Bashiry
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    ABSTRACT: The strong coupling constant $g_{\Upsilon B_c^{ps} B_c^V}$ is evaluated using the three-point QCD sum rules. The correlation functions used to calculate these strong coupling constants contain contributions of both $B_c^V$ and $B_c^{ps}$ mesons as off-shell states with contributions of two gluon condensates as a radiative corrections. The results, $g_{\Upsilon B_c^V B_c^{PS}}=1.67\pm 0.52 GeV^{-1}$ for $B_c^{Ps}$ off-shell and $g_{\Upsilon B_c^{PS}B_c^V}=(0.87\pm0.25) GeV^{-1}$ for $B_c^V$ off-shell are obtained for the relevant strong coupling constants
    European Physical Journal A 07/2013; · 2.42 Impact Factor
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    v. Bashiry
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    ABSTRACT: In this study we present the first theoretical calculation of the form factor of the $\chi_{c0}(1P) \rar J/\psi \gamma $ and $\chi_{b0}(1P) \rightarrow \Upsilon(1S) \gamma $ decays in the frame work of QCD sum rules. We also find branching ratio ${\cal B}_r(\chi_{c0}(1P) \rightarrow J/\psi \gamma)=(1.07\times \pm 0.14) \times 10^{(-2)} $ which is in agreement with the experimental data. Furthermore, we estimate the $\Gamma_{tot}(\chi_{b0}(1P)) =5.5\pm 0.5 $ MeV, where experimental bound for full width of $\chi_{b0}$ is $\Gamma_{tot}(\chi_{b0}(1P)) <6 $ MeV.
    05/2013;
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    ABSTRACT: Purpose ‐ The purpose of this paper is to describe a modified Hilbert-based fractal antenna for ultra wideband (UWB) wireless applications. Simulation results show excellent multi-band characteristics for UWB wireless applications. Design/methodology/approach ‐ A Hilbert curve-based fractal is optimised for self-replicating, space-filling and self-avoiding properties. In the proposed design, the Hilbert curve is applied to a rectangle as an initial iteration and maintained for the later iterations. Additionally, a Yagi-like strip is removed from the second iteration of the Hilbert patch and a hexagonal portion is removed from the substrate to achieve good optimization. The antenna feed is created through a micro-strip line with a feeding section. Finally, a partial ground plane technique is used for improved impedance matching characteristics. A finite element method (FEM) is used to simulate the modified Hilbert model with commercially available Ansoft HFSS software. Findings ‐ The proposed antenna is miniaturized (39?mm length×30?mm width) and has multi-band characteristics. The simulation results show that the antenna has a reflection coefficient characteristic of Originality/value ‐ The antenna shows promising characteristics for the full 7.5?GHz UWB bandwidth. In addition, the performance is achieved by using laceration techniques on the Hilbert patch and substrate, respectively. A partial ground plane ensures impedance matching of 50 over full UWB bandwidth. The simulation analysis of the modified Hilbert fractal antenna design constitutes the main contribution of the paper.
    COMPEL International Journal of Computations and Mathematics in Electrical 11/2012; 31(6). · 0.44 Impact Factor
  • V Bashiry, K Azizi, S Sultansoy
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    ABSTRACT: The heavy fourth generation of quarks that have sufficiently small mixing with the three known SM families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from fourth family and the other from observed SM quarks, namely charm or bottom quark, in the framework of the QCD sum rules. In the calculations, the two gluon condensate diagrams as nonperturbative contributions are taken into account. The obtained numerical results are reduced to the known masses and decay constants of the b and c quarkonia, when the fourth family quark is replaced by the bottom or charm quark.
    Journal of Physics Conference Series 02/2012; 347(1):012027.
  • V. Bashiry, K. Azizi
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    ABSTRACT: Using form factors enrolled to the transition matrix elements and calculated via light-cone QCD sum rules including next-to-leading order corrections in the strong coupling constant, we provide a systematic analysis of the B s → f 0(980)ℓ +ℓ − both in the standard and universal extra dimension models. In particular, we discuss sensitivity of the differential branching ratio and various double lepton polarization asymmetries on the compactification factor of extra dimension and show how the results of the extra dimension model deviate from the standard model predictions. The order of branching ratio makes this decay mode possible to be checked at LHCb in near future.
    Journal of High Energy Physics 02/2012; 2012(2). · 6.22 Impact Factor
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    ABSTRACT: In this paper, the combination of concentric square loop and the Koch curve fractal geometries based microstrip antenna design for ultra wideband (UWB) applications is presented. This fractal structure is implemented on a empty square. Three progressively concentric square loop is applied inside the empty square and a full square is applied to the center for the first iteration. Then, a Koch curve fractal is applied to the lines of the first iteration. The proposed antenna is miniaturized (44 × 43 mm2) and has multi-band characteristics. Simulation results show that the presented antenna has a reflection coefficient characteristic < −15dB, 80% radiation efficiency, 4–6dBi antenna gain and omni-directional radiation pattern properties over the full UWB bandwidth (3.1 – 10.6 GHz) while showing the band-rejection performance in the frequency band of 4.75–6.75 GHz.
    01/2012;
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    V. Bashiry, K. Azizi
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    ABSTRACT: Using form factors enrolled to the transition matrix elements and calculated via light-cone QCD sum rules including next-to-leading order corrections in the strong coupling constant, we provide a systematic analysis of the $ B_s\rightarrow f_0 (980)\ell^+\ell^- $ both in the standard and universal extra dimension models. In particular, we discuss sensitivity of the differential branching ratio and various double lepton polarization asymmetries on the compactification factor of extra dimension and show how the results of the extra dimension model deviate from the standard model predictions. The order of branching ratio makes this decay mode possible to be checked at LHCb in near future.
    12/2011;
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    V.bashiry, M.bayar, K.azizi
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    ABSTRACT: In this paper, we compare the branching ratio and rate difference of electron channel to muon channel of and B →K*ℓ+ℓ- decays, where is the p-wave scalar meson, in the supersymmetric models. MSSM with R parity is considered since considerable deviation from the standard model predictions can be obtained in B→Xs ℓ-ℓ+. Taking CQ1 and CQ2 about one which is consistent with the B→K*μ+μ- rate at low dileptonic invariant mass region (1 ≤ q2 ≤ 6 GeV2). It is found that, firstly, the decay is measurable at LHC, secondly, in comparison with B →K*ℓ+ ℓ- decay a greater deviation in the decay can be seen. Measurement of these observables for the semileptonic rare , in particular, at low q2 region can give valuable information about the nature of interactions within Standard Model or beyond.
    Modern Physics Letters A 11/2011; 26(12). · 1.34 Impact Factor
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    V. Bashiry
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    ABSTRACT: The mass and decay constant of the ground state of spin singlet $b \bar{b}$ is calculated by using the QCD sum rules method. This meson is an axial vector $P$-wave named $h_b(1P)$ meson with $J^P =1^+$. It is found that the mass of this meson is $(m=9940\pm 37)$ MeV, which is consistent with the recent experimental data by Belle collaboration.
    Physical review D: Particles and fields 09/2011; 84.
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    V. Bashiry, K. Azizi, S. Sultansoy
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    ABSTRACT: The heavy fourth generation of quarks that have sufficiently small mixing with the three known SM families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from fourth family and the other from known third family SM quarks in the framework of the QCD sum rules. In the calculations, we take into account two gluon condensate diagrams as nonperturbative contributions. The obtained results reduce to the known masses and decay constants of the $\bar b b$ and $\bar c c$ quarkonia when the fourth family quark is replaced by the bottom or charm quark.
    Physical review D: Particles and fields 04/2011; 84.
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    ABSTRACT: A new combined fractal geometry based Monopole antenna design for ultra wideband (UWB) applications is presented in this paper. This fractal structure is implemented on square and Minkowski fractal is applied to the lines of a square. Then, a Sierpinski carpet fractal is formed on the first iteration of the Minkowski fractal. The proposed antenna is miniaturized (45 mm x 45 mm) and has multi-band characteristics. Simulation results show that the presented antenna has a reflection coefficient characteristic < -15dB, 80% radiation efficiency, 4-6dBi antenna gain and omni- directional radiation pattern properties over the UWB bandwidth (3.1 - 10.6 GHz). The gain variation is due to increased directivity at higher frequencies.
    01/2011;
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    ABSTRACT: As the demand for high bandwidth applications is increasing for wireless communication, the need for wideband antennas increases as well. In this paper, a new small fractal antenna design concept is proposed for ultra wideband (UWB) applications. UWB is a technology that high data rates (480Mb/s) and high bandwidth (0.528 - 7.5 GHz) with good signalling characteristics for wireless personal area networks (WPAN). First band group (BG:1, 3.1 - 4.752 GHz) of the UWB band is simulated and -41.3 dBm/MHz is observed. Fractal antenna geometry shows self-similarity characteristics that operates at multiple wavelengths with similar radiation patterns. Therefore, it is suitable to use for multi band orthagonal frequency division multiplexing (MB-OFDM) based UWB applications. Proposed fractal antenna design is analysed with less than -20dB return loss (S11) over whole UWB bandwidth (3.1 - 10.6 GHz). In addition to this, omni directional radiation pattern is observed for the BG:1 of the UWB band.
    01/2011;
  • H Daĝ, K Azizi, V Bashiry
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    ABSTRACT: In this work, the semileptonic decays of the scalar charmonium state Xc0 and the pseudo scalar charmonia states ηc(1s) and ηc(2s) into Ds and D mesons are analyzed. The form factors of the transitions Xc0 → Ds(D)ℓν and ηc(1s, 2s) → Ds(D)ℓν are calculated within the framework of the three-point QCD sum rules. The results of the form factors are used to estimate the decay widths of the charmonia states into and .
    Journal of Physics G Nuclear and Particle Physics 05/2010; 37(7):075005. · 2.84 Impact Factor
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    ABSTRACT: We present the first study of CP asymmetry in Λb → Λℓ+ ℓ− decay when a new weak phase comes through the extension of three-generation standard model to the four-generation standard model. Taking |Vt's* Vt'b| = 0.01, 0.02, 0.03 with phase {60° − 120°}, which is consistent with the b → sℓ+ℓ− rate and the Bs mixing parameter ΔmBs, we find out that CP asymmetry is quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, in particular, to search for the fourth generation quarks (t', b') via their indirect manifestations in loop diagrams.
    Chinese Physics Letters 03/2010; 27(4):041201. · 0.92 Impact Factor
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    T M Aliev, K Azizi, V Bashiry
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    ABSTRACT: The mass and decay constant of the ground state strange tensor meson K*2(1430) with I(JP) = 1/2(2+) are calculated using the QCD sum rules method. The results are consistent with the experimental data. It is found that SU(3) symmetry breaking effect constitutes about 20% of the decay constant.
    Journal of Physics G Nuclear and Particle Physics 01/2010; 37(2):025001. · 2.84 Impact Factor
  • V. Bashiry, K. Azizi
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    ABSTRACT: The mass eigen states K 1(1270) and K 1(1400) are mixture of the strange members of two axial-vector SU(3) octet, 3 P 1(K A 1) and 1 P 1(K B 1). Taking into account this mixture, the forward-backward asymmetry(A FB ), branching ratio(Br) and rate difference of electron channel to muon channel(R) of B → K 1(1270, 1400)ℓ+ℓ− transitions are studied in the framework of different supersymmetric models. MSSM with R parity is considered because considerable deviation from the standard model predictions can be obtained in B → X s ℓ−ℓ+. Taking C Q1 and C Q2 about one which is consistent with the B → K*μ+μ− rate at low dileptonic invariant mass region(1 ≤ q 2 ≤ 6GeV2), we obtain a size able deviation for A FB , Br and R with respect to the Standard Model results. Any measurement of physical observables and their comparison with the results obtained in this paper can gives useful information about the nature of interactions beyond the standard model.
    Journal of High Energy Physics 01/2010; 2010(1):1-18. · 6.22 Impact Factor
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    ABSTRACT: In this paper we present a study of CP asymmetry, single lepton polarization asymmetry and polarized CP asymmetry in B→K*ℓ+ℓ- decay within the four-generation standard model. Taking |Vt′s*Vt′b|=0.01, 0.02, 0.03 with phase {60°–120°}, which is consistent with the b→sℓ+ℓ- rate and the Bs mixing parameter ΔmBs, we find that CP asymmetry, single lepton polarization asymmetry and polarized CP asymmetry are sensitive to the existence of the fourth generation. This can serve as an indirect method to search for new physics effects, in particular, to search for the fourth-generation quarks(t′,b′) via their indirect manifestations in loop diagrams.
    Physical review D: Particles and fields 07/2009; 80(1).