H. Koru

Gazi University, Engüri, Ankara, Turkey

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Publications (19)44.29 Total impact

  • H.koru, M. P.rekalo
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    ABSTRACT: Charge symmetry of strong interaction results in a simplified spin structure of amplitude for n+p→d+η in "orthogonal" kinematics, where the η-production angle is equal to 90° in CMS. The presence of singlet and triplet amplitudes in such kinematics induces a rich set of different polarization observables, sensitive to the relative value of these amplitudes. This can be used to test a hypothesis of singlet enhancement of η-production in NN- and -collisions, due to a nonperturbative -component of the nucleon with special polarization properties.
    International Journal of Modern Physics E 01/2012; 07(01). · 0.63 Impact Factor
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    O. Çakir, E. Ateser, H. Koru
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    ABSTRACT: . We study scalar leptoquark production at TESLA and CLIC based colliders. Both direct and resolved contributions to the cross section are examined. We find that the masses of scalar leptoquarks can be probed up to about 0.9 TeV at TESLA and 2.6 TeV at CLIC.
    European Physical Journal C 01/2003; 28(3):381-388. · 5.25 Impact Factor
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    Hakan Ciftci, Engin Ateser, Hueyin Koru
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    ABSTRACT: In this study, we show that the energy eigenvalues and the eigenfunctions of the Schrodinger equation for the power-law and the logarithmic potential can be easily obtained by using variation technique for special type wave functions. The results are in very good agreement with exact numerical results. Comment: 13 pages, 5 figures
    Journal of Physics A General Physics 12/2002;
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    ABSTRACT: Main parameters of the FEL-RHIC collider are estimated. The physics search potential of this machine is illustrated using excitations of the ^{232}Th nucleus as an example. It is shown that, due to the tunability and monochromacity of FEL beam and high statistics, proposed collider will play an important role in the field of ''traditional'' nuclear physics. Comment: 12 pages, 2 Figures
    International Journal of Modern Physics E 01/2002; · 0.63 Impact Factor
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    ABSTRACT: The physics search potential of the FEL {gamma} - Nucleus colliders is analysed using excitations of the (232)Th nucleus. It is shown that, due to the monochromacity of FEL {gamma} beam and high statistics, proposed colliders will play an important role in the field of "traditional" nuclear physics.
    07/2001;
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    H. Ciftci, H. Koru
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    ABSTRACT: Leptonic decay widths and leptonic decay constants of light vector mesons and weak leptonic decay widths and weak decay constants of light and heavy pseudoscalar mesons have been studied in a field- theoretic framework based on the independent quark model with a scalar- vector power-law potential. The results are in very good agreement with the experimental data. Comment: 13 pages
    International Journal of Modern Physics E 05/2000; · 0.63 Impact Factor
  • O. Çakir, H. Koru, M. Ocak
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    ABSTRACT: We study single vector leptoquark production at future gammae and gammap colliders. The production cross sections are calculated for both gammae and gammap collisions. Analytical expressions are derived for the differential cross sections including the case of anomalous vector LQ coupling, a, to the photon. We find that the cross sections for single production of vector LQs have a rather weak dependence on the parameter a. The discovery limits for the masses of vector LQs are obtained for both cases.
    Journal of Physics G Nuclear and Particle Physics 01/1999; 25:1187-1203. · 5.33 Impact Factor
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    ABSTRACT: We establish the spin structure of matrix elements for processes, where P is a - or -meson, in terms of six scalar amplitudes. Isospin invariance of a strong interaction results in definite symmetry properties of these amplitudes relative to the change ; where is the P-meson production angle. We parametrize all possible polarization observables in using a formalism of structure functions and calculate these structure functions in terms of scalar amplitude. This allows us to establish symmetry properties of polarization observables relative to the transformation . Special attention is devoted to , where isospin invariance simplifies in particular spin structures of matrix elements.
    Journal of Physics G Nuclear and Particle Physics 12/1998; 24(5):1003. · 5.33 Impact Factor
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    ABSTRACT: The general structure of electromagnetic currents for electrodisintegration of nuclei near threshold, e− + A → e− + A1 + A2 (A, A1 and A2 are arbitrary nuclei or hadrons with spins 0, 12 and 1), are established. Considering nuclei as elementary particles with the definite values of spin and space parity and using the conservation of hadronic electromagnetic current and P-invariance of hadron electromagnetic interaction, the spin structure of the amplitudes of the processes γ★ + A → A1 + A2 is derived in terms of threshold electromagnetic form factors. The present formalism is valid for any nuclear structure and any reaction mechanism. The structure functions, which characterize the scattering electrons on the polarized target, are calculated as quadratic combinations of the form factors. These structure functions are used for the analysis of the problem of complete experiment for the full determination of all threshold form factors. P-odd part of electromagnetic current, induced by P-odd nuclear forces, is parametrized also in terms of the corresponding form factors. The processes with the following combinations of spins of hadrons e− + 1 → e− + 0 + 0, e− + 1 → e− + 1 + 0, e− + 12 → e− + 12 + 1 and e− + 12 → e− + 12 + 12, and with different combinations of space parities of nuclei A, A1 and A2, are examined within this approach.
    Nuclear Physics A 01/1998; 635(3):387-407. · 2.50 Impact Factor
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    ABSTRACT: The decay width, forward-backward asymmetry and tau lepton longitudinal and transversal polarization for the exclusive (B -> K tau^+ tau^-) decay in a two Higgs doublet model are computed. It is shown that the forward-backward asymmetry and longitudinal polarization of the tau lepton are very effective tools for establishing new physics.
    Journal of Physics G Nuclear and Particle Physics 06/1997; · 5.33 Impact Factor
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    ABSTRACT: The decay width, forward-backward asymmetry and lepton longitudinal and transversal polarization for the exclusive B → K∗ℓ+ℓ− decay in a two Higgs doublet model are computed. It is shown that all these quantities are very effective tools for establishing new physics.
    Physics Letters B 04/1997; · 4.57 Impact Factor
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    ABSTRACT: We calculate the transition formfactors for the B -> Kl+ l- decay in the framework of the light cone QCD sum rules. The invariant dilepton mass distribution and the final lepton longitudinal polarization asymmetry are investigated. The comparison analysis of our results with traditional sum rules method predictions on the formfactors is performed.
    Physics Letters B 02/1997; · 4.57 Impact Factor
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    ABSTRACT: The polarization effects in processesγ+A→X,e−+A→e−+X,γ+A→h+X′ ande−+A→e−+h+X′ (Ais a target,-hadron or nuclei with spinJ;his the detected hadron,XandX′ are the undetected hadron systems) due to the collisions of polarized particles are analyzed using the structure functions formalism. The previously reported results for the spin 1/2 and 1 targets are generalized for any spinJ. For all the above mentioned processes the dependence ofP-odd effects on the polarization of initial particles is established. For thee−+A-interaction only the one-photon mechanism of the violation ofP-invariance is taken into account. The general properties ofT-odd polarization effects forγ+A-ande−+A-interactions are found without using the concretization of reaction mechanism or the structure of interacting particles.
    Annals of Physics 01/1997; 257(2):136-157. · 3.32 Impact Factor
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    ABSTRACT: The spin structure of the amplitudes for antiproton annihilation at rest, bar p+N-> P+V, P=pi, eta V=rho, omega, varphi, is established. The relation between symmetry properties of strong interaction (isospin invariance and the invariance relative to charge conjugation) and the polarization effects in such reactions are derived. It is demonstrated that the simplest polarization effects in bar p+N-> P+V, namely, the elements of V-meson density matrix, are sensitive to possible violation of the isospin invariance and C-invariance. The analysis of the spin structure of P-wave annihilation amplitudes is also presented.
    Modern Physics Letters A 01/1997; 12:479-487. · 1.11 Impact Factor
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    ABSTRACT: We analyzed the general form of all polarization effects in the 3H+3He→d2H+4He reaction. For this aim, we parametrized the spin structure of the full amplitude in terms of the transverse amplitudes which describe the different transitions between initial and final states, which in turn are differed by projections of nuclei spins along the normal to the reaction plane. The isospin invariance of the strong interaction generates definite symmetry properties of the transverse amplitudes relative to the change cosθ→-cosθ, where θ is the deuteron production angle in the c.m.s. We found all symmetry relations for the polarization observables in the 3H+3He→d2H+4He reaction, which are the generalized form of the well-known Barshay-Temmer theorem. We consider the one-, two-, and triple-spin correlations in 3H+3He→d2H+4He. For analysis of the triple-spin correlations, we focus on the structure functions formalism and show that a set of 41 structure functions describes all such correlations. Isospin invariance simplifies the spin structure of the full amplitude at θ=90°; therefore, we calculated all polarization observables for this special kinematics. © 1996 The American Physical Society.
    Physical Review C 06/1996; 53(6). · 3.72 Impact Factor
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    ABSTRACT: In134Cs uptake by the roots of orchard grass and beans planted in three different lands of soil has been studied. For this purpose, a134Cs radionuclide solution having 0.3086 Ci/pot radioactivity was added to Ando, Serpentine and Alluial and Clay soil which were fertilized by Standard, –K, +Ca, Water limited and Control for both orchard grass and bean groups. Thus, the above mentioned groups have been harvested and left to dry. The contamination levels these plants have been detected and measured by using an HPGe detector interactively working with MCA. Finally, it has been determined that the134Cs uptakes depend primarily on soil characteristics. Besides the decrease in the134Cs activity for the plants grown in soils to which the stable cesium or potassium was added 0.011–1.38 per cent activity for the root of plants grown in free K soils was observed. Moreover, highest134Cs activity has been determined for the plants grown in –K fertilized soil with respect to the other soil samples.
    Journal of Radioanalytical and Nuclear Chemistry 01/1993; 172(2):223-230. · 1.41 Impact Factor
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    ABSTRACT: The isotopic-spin impurity introduced to the ground state of an alpha-particle by the Coulomb plus specifically charge-dependent nuclear forces is investigated. The upper limit of the impurity is calculated by shell model wave functions. The sum of the squared amplitudes ofT=1,L≠0 states is found to be in the order of 10−4, which is one order of magnitude greater than earlier predictions.
    Il Nuovo Cimento A 01/1992; 105(5):703-709.
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    ABSTRACT: ZET Son yıllarda önerilmiş SEL (Serbest Elektron Lazeri) – Çekirdek çarpıştırıcıları nükleer fizik araştırmalarında yeni imkanlar sağlayacaktır. Bu yöntemde doğrusal elektron hızlandırıcısı bazında üretilen SEL demeti ile hadron halkalarında (RHIC, HERA, LHC) hızlandırılan çekirdek demetlerinin çarpıştırılması düşünülmektedir. Elde edilen keV enerjili SEL fotonları çekirdeğin durgun çerçevesinde MeV enerjili lazer demeti olarak görülecektir. Böylece çekirdeklerin uyarılmış seviyelerinin bugüne kadar ulaşılamamış bir hassasiyetle incelenmesi mümkün olacaktır. Bu çalışmada önerilen yöntem ile 232 Th çekirdeğinin uyarılmış seviyelerinin çeşitli özelliklerinin araştırılması için gereken parametre hesaplamaları yapılmıştır. SEL γ -Toryum çarpıştırıcılarında saniyede milyonlarca uyarılma gözleneceği gösterilmiştir. SEL demetinin özeliklerinden kaynaklanan bu yüksek istatistik (olay sayısı) sayesinde günümüzde çalışılan diğer deneysel yöntemlerle incelenmesi mümkün olmayan çekirdek özelliklerinin araştırılmasına imkan sağlanacaktır.
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    ABSTRACT: The physics s earch potential of the FEL γ - Nucleus colliders is analyzed u sing excitations of the 232Th n ucleus. It is s hown that, due to the monochromacity of FEL γ beam and high statistics, proposed colliders will play an important role in the field of "traditional" nuclear physics.