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Search Results: 1 - 10 of 149233 matches for " Tarek F. Ibrahim Ibrahim "
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Periodicity and Solution of Rational Recurrence Relation of Order Six  [PDF]
Tarek F. Ibrahim Ibrahim
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.37107
Abstract: Difference equations or discrete dynamical systems is diverse field whose impact almost every branch of pure and ap- plied mathematics. Every dynamical system an+1=f(an) determines a difference equation and vise versa. We ob-tain in this paper the solution and periodicity of the following difference equation. xn+1=(xnxn-2xn-4)/(xn-1xn-3xn-5, (1) n=0,1,... where the initial conditions x-5,x-4,x-3,x-2,x-1 and x0 are arbitrary real numbers with x-1,x-3 and x-5 not equal to be zero. On the other hand, we will study the local stability of the solutions of Equation (1). Moreover, we give graphically the behavior of some numerical examples for this difference equation with some initial conditions.
Closed Form Solution of a Symmetric Competitive System of Rational Difference Equations
Tarek F. Ibrahim
Studies in Mathematical Sciences , 2012, DOI: 10.3968/j.sms.1923845220120501.1133
Abstract: In this paper, we will study a symmetric competitive three-dimensional system of difference equations in the form: $$ x_{n+1} = frac {x_n}{z_n y_n}~ & ~y_{n+1} = frac {y_n}{x_n z_n}~ & ~z_{n+1} = frac {z_n}{y_n x_n} eqno{(1)} $$ where the initial values $x_0$, $y_0$, and $z_0$ are nonzero real numbers. Moreover, we have studied periodicity of solutions for this system. Finally we will give some numerical examples as applications.
Self Organizing Map-based Document Clustering Using WordNet Ontologies
Tarek F. Gharib,Mohammed M. Fouad,Abdulfattah Mashat,Ibrahim Bidawi
International Journal of Computer Science Issues , 2012,
Abstract: With the rapid development of web content, retrieving relevant information is difficult task. The efficient clustering algorithms are needed to improve the results of the retrieval. Document clustering is a process of recognizing the similarity or dissimilarity among the given objects and forms subgroups sharing common characteristics. In this paper, we propose a semantic text document clustering approach that using WordNet lexical and Self Organizing Maps. The proposed approach uses the WordNet to identify the importance of the concepts in the document. The SOM is used to cluster the document. We use this approach to enhance the effectiveness of document clustering algorithms. The approach takes the advantages of the semantics available in knowledge base and the relationship between the words in the input documents. Some experiments are performed to compare efficiency of the proposed approach with the recently reported approaches. Experiments show advantage of the proposed approach over the others.
Effective Lagrangian for the $\chi^{+}_j \chi^{-}_kH^{0}_l$ interaction in the minimal supersymmetric standard model and neutral Higgs decays
Ibrahim, Tarek
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevD.76.075012
Abstract: We extend previous analyses of the supersymmetric loop correction to the neutral Higgs couplings to include the coupling $\chi^{+}_j \chi^{-}_kH^{0}_l$. The analysis completes the previous analyses where similar corrections were computed for the $\bar{\tau} \tau H^{0}_l$, $\bar{b} b H^{0}_l$, $\bar{c} c H^{0}_l$ and for $\bar{t} t H^{0}_l$ couplings within the minimal supersymmetric standard model. The effective one loop Lagrangian is then applied to the computation of the neutral Higgs decays. The sizes of the supersymmetric loop corrections of the neutral Higgs decay widths into $\chi^{+}_i \chi^{-}_j$ ($i=1,2$; $j=1,2$) are investigated and the supersymmetric loop correction is found to be in the range of $7\sim15%$ in significant regions of the parameter space. By including the loop corrections of the other decay channels $\bar{b} b$, $\bar{t} t$, $\bar{\tau} \tau$, $\bar{c} c$, and $\chi^0_i \chi^0_j$ ($i=1-4$; $j=1-4$), the corrections to branching ratios for $H^{0}_l\to \chi^{+}_i \chi^{-}_j$ can reach as high as 40%. The effects of CP phases on the branching ratio are also investigated.
Mixing of the CP Even and the CP Odd Higgs Bosons and the EDM Constraints
Tarek Ibrahim
Physics , 2001, DOI: 10.1103/PhysRevD.64.035009
Abstract: The mixing among the CP even and the CP odd neutral Higgs bosons of MSSM by one loop induced effects in the presence of CP phases is investigated using three different mechanisms to satisfy the EDM constraints, i.e., a fine tuning of phases, a heavy sparticle spectrum, and the cancellation mechanism. It is shown that if a mixing effect among the CP even and the CP odd Higgs bosons is observed experimentally, then it is only the cancellation mechanism that can survive under the naturalness constraint.
Existence Theorem for a Nonlinear Functional Integral Equation and an Initial Value Problem of Fractional Order in L1(R+)  [PDF]
Ibrahim Abouelfarag Ibrahim, Tarek S. Amer, Yasser M. Aboessa
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.42060
Abstract:

The aim of this paper is to study the existence of integrable solutions of a nonlinear functional integral equation in the space of Lebesgue integrable functions on unbounded interval, L1(R+). As an application we deduce the existence of solution of an initial value problem of fractional order that be studied only on a bounded interval. The main tools used are Schauder fixed point theorem, measure of weak noncompactness, superposition operator and fractional calculus.

CP Violation From Standard Model to Strings
Ibrahim, Tarek;Nath, Pran
High Energy Physics - Phenomenology , 2007, DOI: 10.1103//RevModPhys.80.577
Abstract: A review of CP violation from the Standard Model to strings is given which includes a broad landscape of particle physics models, encompassing the non-supersymmetric 4D extensions of the standard model, and models based on supersymmetry, on extra dimensions, on strings and on branes. The supersymmetric models discussed include complex mSUGRA and its extensions, while the models based on extra dimensions include 5D models including models based on warped geometry. CP violation beyond the standard model is central to achieving the desired amount of baryon asymmetry in the universe via baryogenesis and leptogenesis. They also affect a variety of particle physics phenomena: electric dipole moments, $g-2$, relic density and detection rates for neutralino dark matter in supersymmetric theories, Yukawa unification in grand unified and string based models, and sparticle production cross sections, and their decays patterns and signatures at hadron colliders. Additionally CP violations can generate CP even-CP odd Higgs mixings, affect the neutral Higgs spectrum and lead to phenomena detectable at colliders. Prominent among these are the CP violation effects in decays of neutral and charged Higgs bosons. Neutrino masses introduce new sources of CP violation which will be explored in neutrino factories in the future. Such phases can also enter in proton stability in unified models of particle interactions. The current experimental status of CP violation is discussed and possibilities for the future outlined.
The Neutron and the Lepton EDMs in MSSM, Large CP violating Phases, and the Cancellation Mechanism
Tarek Ibrahim,Pran Nath
Physics , 1998, DOI: 10.1103/PhysRevD.60.099902
Abstract: An analysis of the electric dipole moment (EDM) of the neutron and of the leptons in the minimal supersymmetric standard model (MSSM) with the most general allowed set of CP violating phases without generational mixing is given. The analysis includes the contributions from the gluino, the chargino and the neutralino exchanges to the electric dipole operator, the chromoelectic dipole operator, and the CP violating purely gluonic dimension six operator. It is found that the EDMs depend only on certain combination of the CP phases. The independent set of such phases is classified. The analysis of the EDMs given here provides the framework for the exploration of the effects of large CP violating phases on low energy phenomena such as the search for supersymmetry at colliders, and in the analyses of dark matter consistent with the experimental limits on EDMs via the mechanism of internal cancellations.
The Neutron and the Electron Electric Dipole Moment in N=1 Supergravity Unification
Tarek Ibrahim,Pran Nath
Physics , 1997, DOI: 10.1103/PhysRevD.60.119901
Abstract: An analysis of the neutron EDM and of the electron EDM in minimal N=1 supergravity unification with two CP violating phases is given. For the neutron the analysis includes the complete one loop gluino, chargino, and neutralino exchange diagrams for the electric dipole and the chromoelectric dipole operators, and also the contribution of the purely gluonic dimension six operator. It is shown that there exist significant regions in the six dimensional parameter space of the model where cancellations between the gluino and the chargino exchanges reduce the electric and the chromoelectric contributions, and further cancellations among the electric, the chromoelectric, and the purely gluonic parts lead to a dramatic lowering of the neutron EDM sometimes below the electron EDM value. This phenomenon gives a new mechanism, i.e., that of internal cancellations, for the suppression of the neutron EDM in supersymmetric theories. The cancellation mechanism can significantly reduce the severe fine tuning problem associated with CP violating phases in SUSY and SUGRA unified models.
Slepton Flavor Nonuniversality, the Muon EDM and its Proposed sensitive Search at Brookhaven
Tarek Ibrahim,Pran Nath
Physics , 2001, DOI: 10.1103/PhysRevD.64.093002
Abstract: We analyze the electric dipole moment of the electron ($d_e$), of the neutron ($d_n$) and of the muon ($d_{\mu}$) using the cancellation mechanism in the presence of nonuniversalities of the soft breaking parameters. It is shown that the nonuniversalities in the slepton sector produce a strong violation of the scaling relation $d_{\mu}/d_e\simeq m_{\mu}/m_e$ in the cancellation region. An analysis of $d_e, d_n$ and $d_{\mu}$ under the constraints of the current experimental limits on $d_e$ and $d_n$ and under the constraints of the recent Brookhaven result on $g_{\mu}-2$ shows that in the non-scaling region $d_{\mu}$ can be as large as ($10^{-24}-10^{-23}$)ecm and thus within reach of the recently proposed Brookhaven experiment for a sensitive search for $d_{\mu}$ at the level of $10^{-24}$ ecm.
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