Natural and Mathematical Sciences
Permanent URI for this collectionhttps://hdl.handle.net/10679/313
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Conference ObjectPublication Open Access Analysis of X(4140) like states and their radial excitations in QCD(Sissa Medialab Srl, 2017) Türkan, Arzu; Dağ, Hüseyin; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, HüseyinIn this work, we investigated the X(4140) and like states and their radial excitations by using molecular and diquark-antidiquark currents which couple to scalar, axial vector and tensor states via QCD sum rules. In operator product expansion, we considered quark, gluon and mixed vacuum condansates up to dimension eight. For the ground states coupling to these currents, we found that masses are almost degenerate with X(4140). For the excited states, we found that scalar and tensor currents are coupling to D∗ sD∗ s threshold. However for the axial vector currents, the mass of the first excited state is compatible with X(4274). Thus we conclude that, X(4274) might be the first radial excitation of X(4140).
Conference ObjectPublication Metadata only Electromagnetic structure of charmed baryons(Proceedings of Science, 2013) Can, K. U.; Oka, M.; Erkol, Güray; Işıldak, Bora; Takahashi, T. T.; Natural and Mathematical Sciences; ERKOL, Güray; IŞILDAK, BoraWe compute the electromagnetic form factors of charmed baryons (∑ c, (ξcc, ω c and ω cc) in 2+1 Lattice QCD and extract their electric and magnetic charge radii as well as their magnetic mo-ments. Such observables are important to understand the structure and the inner dynamics of the hadrons. We find that the existence of the heavy quarks drive the charge radii and magnetic moments to smaller values as compared to those of, e.g., proton.Conference ObjectPublication Metadata only Electromagnetic structure of charmed hadrons(IOP Publishing, 2014) Erkol, Güray; Can, K. U.; Işıldak, Bora; Oka, M.; Ozpineci, A.; Takahashi, T. T.; Natural and Mathematical Sciences; ERKOL, Güray; IŞILDAK, BoraWe compute the electromagnetic structures of D and D* mesons, the singly charmed Σc, Ωc and the doubly charmed Ξcc, Ωcc baryons in 2+1 flavor Lattice QCD. We extract the charge radii and the magnetic moments of these hadrons. In general, charmed hadrons are found to be more compact as compared to light hadrons. The magnetic moments of the singly charmed baryons are found to be dominantly determined by the light quark and the role of the charm quark is significantly enhanced when it is doubly represented.Conference ObjectPublication Metadata only First lattice calculation of charmed hadrons' electromagnetic form factors(IOP Publishing, 2014) Can, K. Utku; Erkol, Güray; Işıldak, Bora; Oka, M.; Takahashi, T. T.; Natural and Mathematical Sciences; ERKOL, Güray; IŞILDAK, Bora; Can, K. UtkuElectromagnetic form factors of D and D* mesons and Ξcc, Σc, Ωc and Ωcc baryons are calculated in 2+1 flavor lattice QCD. As a by product of this calculation electric/magnetic charge radii and magnetic moments are extracted. Compared to the PDG values of the light- sector, i.e. pion and proton, charmed hadron results are systematically smaller.Conference ObjectPublication Metadata only Investigating the structure of X(4140) in QCD(EDP Sciences, 2017) Dağ, Hüseyin; Türkan, Arzu; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, HüseyinIn this work, the masses of the ground states coupling to molecular or tetraquark currents with JPC = 0++, 1++, 2++ are studied to investigate the structure of X(4140) exotic meson observed at J/ψφ invariant mass spectrum. We found that all currents predict ground states with masses of the same magnitude, which might be inter-pereted as the existance of at least three exotic structures with degenerate mass.Conference ObjectPublication Metadata only Investigation of the excited states in hidden charm hidden strange sector(2018) Dağ, Hüseyin; Türkan, Arzu; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, HüseyinIn this work, we studied the radial excitations of X(4140) and like states within QCD sum rules. We chose three molecular and three diquark-antidiquark currents with the quark content cc‾ss‾ and JPC = 0++, 1++, 2++, and estimated the masses and the meson coupling constants of the first excited states coupling to these currents in the framework of QCD sum rules. The ground states coupling to these currents were analyzed in a previous work and we have shown that all of these ground states have degenerate masses within 10 MeV neighborhood of exotic meson X(4140). For the excited states, the masses are not found to be degenerate. We found that scalar and tensor currents are coupling to Ds ⁎D‾s ⁎ threshold. However for the axial vector currents, the first excited states found to have mass compatible with X(4274), which was measured in the same decay with X(4140). Thus we conclude that X(4274) could be a radial excitation of X(4140).Book PartPublication Metadata only Molecular modeling of MOF membranes for gas separations(World Scientific Publishing Co., 2017-01-01) Fındıkçı, İlknur Eruçar; Keskin, S.; Mechanical Engineering; FINDIKÇI, Ilknur EruçarMetal organic frameworks (MOFs) have received significant attention as membrane materials in the last decade. MOFs typically have high porosities, tunable pore sizes, large surface areas, reasonable thermal and mechanical stabilities. These properties make them ideal membrane materials for gas separations. Considering the very large number of available MOF structures, it is not practically possible to test membranebased gas-separation performance of MOFs using purely experimental means. Molecular modeling methods are highly useful to complement experimental studies by providing insights into the gas-separation mechanisms of MOFs. Molecular simulation studies have been recently used to screen large numbers of MOFs for gas separation applications to identify the most promising MOF membranes. In this way, experimental efforts, time, and resources can be directed to the materials with the highest separation performance. The aim of this chapter is to review the recent advances in molecular modeling of MOF membranes for gas-separations and address the current opportunities and challenges in using molecular simulations for MOF membranes.Conference ObjectPublication Metadata only Size dependent change of mean square displacement in gold nanocrystals: A molecular dynamics simulation(Wiley, 2023-11-01) Batyrow, Merdan; Fındıkçı, İlknur Eruçar; Öztürk, Hande; Mechanical Engineering; FINDIKÇI, Ilknur Eruçar; KAYMAKSÜT, Hande Öztürk; Batyrow, MerdanThermally activated atomic vibrations significantly decrease the x-ray diffraction intensities of nanocrystalline powders. Hence their quantification is critical for accurate structural characterization of small nanocrystals by x-ray diffraction. In this study, atomic vibrations in the form of mean square displacements (MSDs) in 5, 10, 15, 20, and 30 nm diameter spherical gold nanocrystals were computed by molecular dynamics (MD) simulations at room temperature and below. A strong size and temperature dependency of MSD was observed from spherical gold nanocrystals. Moreover, these displacements increased radially from the center of the nanocrystals and reached a maximum at the surface layers due to the presence of undercoordinated surface atoms and their relatively unrestricted motions. High temperature simulations were performed to investigate the evolution of structural stability of nanoparticles with increasing temperature. Surface melting was observed before complete melting of nanocrystals. Results of this work will be useful to understand the effect of nanocrystal size on the amplitude of thermally activated atomic vibrations and their quantification in measured intensities by x-ray diffraction experiments.