Natural and Mathematical Sciences

Permanent URI for this collectionhttps://hdl.handle.net/10679/313

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Browsing by Institution Author "DAĞ, Hüseyin"

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    Conference ObjectPublicationOpen 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, Hüseyin
    In 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).
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    ArticlePublicationOpen Access
    B → T transition form factors in light-cone sum rules
    (American Physical Society, 2019-11-11) Aliev, T. M.; Dağ, Hüseyin; Kokulu, A.; Ozpineci, A.; Natural and Mathematical Sciences; DAĞ, Hüseyin
    We present a new calculation of the semileptonic tree-level and flavor-changing neutral current form factors describing B-meson transitions to tensor mesons T ¼ D2, K2, a2, f2 (JP ¼ 2þ). We employ the QCD light-cone sum rules approach with B-meson distribution amplitudes. We go beyond the leading-twist accuracy and provide analytically, for the first time, higher-twist corrections for the two-particle contributions up to twist-four terms. We observe that the impact of higher-twist terms to the sum rules is noticeable. We study the phenomenological implications of our results on the radiative B → K 2γ and semileptonic B → D 2lν¯l, B → K 2lþl− decays.
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    Exploratory study of χc1(4140) and like states in QCD sum rules
    (Elsevier, 2019-05) Türkan, Arzu; Dağ, Hüseyin; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, Hüseyin
    In this work, we chose three molecular and three diquark-antidiquark currents with the quark content c (c) over bars (s) over bar and J(PC) = 0(++), 1(++), 2(++), and estimated the masses and the meson coupling constants of the ground states coupling to these currents in the framework of QCD sum rules. In operator product expansion, we considered the terms including dimension eight, and we performed pole contribution tests carefully. According to our results, all of these currents couple to the ground states with degenerate masses which are in 10 MeV vicinity of chi(c1) (4140). Therefore, with a QCD sum rules analysis, it is not possible to conclude that chi(c1) (4140) has a dominant molecular or diquark-antidiquark content. However, there may be three states degenerate in mass, with positive charge conjugation and different isospins.
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    ArticlePublicationOpen Access
    Hidden-beauty broad resonance Yb(10890) in thermal QCD
    (Hindawi Limited, 2019) Süngü, J. Y.; Türkan, Arzu; Dağ, Hüseyin; Veliev, V.; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, Hüseyin
    In this work, the mass and pole residue of resonance Yb is studied by using QCD sum rules approach at finite temperature. Resonance Yb is described by a diquark-antidiquark tetraquark current, and contributions to operator product expansion are calculated by including QCD condensates up to dimension six. Temperature dependencies of the mass mYb and the pole residue Yb are investigated. It is seen that near a critical temperature (Tc similar or equal to 190MeV), the values of mYb and Yb decrease to 87% and to 44% of their values at vacuum.
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    Conference ObjectPublicationOpen Access
    Hot medium effects on pseudotensor K2(1820) meson
    (EDP Sciences, 2019) Türkan, Arzu; Dağ, Hüseyin; Süngü, J. Y.; Veliev, V.; Natural and Mathematical Sciences; Wronska, A.; Magiera, A.; Przygoda, W.; TÜRKAN, Arzu; DAĞ, Hüseyin
    The investigation of mesons in hot medium can give valuable information about the nature of QCD vacuum and deconfinement phase transitions. In this study, thermal properties of pseudotensor K-2(1820) meson is examined via QCD sum rules at finite temperature. The mass and the decay constant of K-2(1820) are estimated up to dimension-five by considering the new operators emerging at finite temperature. It is seen that after a certain temperature, the decay constant and the mass decrease significantly due to the hot medium effects.
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    Investigating the structure of X(4140) in QCD
    (EDP Sciences, 2017) Dağ, Hüseyin; Türkan, Arzu; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, Hüseyin
    In 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.
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    Investigation of the excited states in hidden charm hidden strange sector
    (2018) Dağ, Hüseyin; Türkan, Arzu; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, Hüseyin
    In 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).
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    ArticlePublicationOpen Access
    Light D-wave axial-tensor K2(1820) meson at finite temperature
    (IOP Publishing, 2019-06) Türkan, Arzu; Dağ, Hüseyin; Süngü, J. Y.; Veliev, V.; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, Hüseyin
    In this work the properties of the axial-tensor K-2(1820) meson in a hot medium are investigated. The mass and the decay constant of this state are calculated via thermal QCD sum rules considering QCD condensates up to dimension five. Our analysis show that both mass and decay constant stay almost monotonous up to certain temperatures and then they diminish with increasing temperature. The mass and decay constant estimated at zero temperature are in good agreement with the present experimental data and theoretical estimations.
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    Mass and pole residue of Yb(10890) state with JPC = 1−− at finite temperature
    (AIP Publishing, 2019) Süngü, J. Y.; Türkan, Arzu; Dağ, Hüseyin; Veliev, V.; Natural and Mathematical Sciences; TÜRKAN, Arzu; DAĞ, Hüseyin
    The status of the hidden beauty state Y-b is not clear up to now. The deviations from the expected behavior can provide a clue to consider it as an exotic meson candidate. Assuming the Y-b resonance as a tetraquark, we estimated its mass and pole residue, both at vacuum and T not equal 0 temperatures by calculating hot-medium contributions to hadronic parameters in the framework of Thermal QCD sum rules. Our results depict that the mass and pole residue values decrease dramatically at the vicinity of a critical temperature. Comparison of our results with the recent experimental data and theoretical results might be helpful in understanding the internal structure of bottomonium-like Y-b state.
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    Theoretical determination of K(1)(1270,1400) mixing angle in QCD
    (IOP Publishing, 2012) Dağ, Hüseyin; Ozpineci, A.; Çağıl, A.; Erkol, Güray; Natural and Mathematical Sciences; ERKOL, Güray; DAĞ, Hüseyin
    In quark model, the strange axial vector mesons K1(1270) and K1(1400) are defined as the mixtures of orbital angular momentum states K1A and K1B. In this work, by using the orthogonality of the mass eigenstates, we have estimated the K1(1270, 1400) mixing angle θK1, where we have found that θK1 sime −(39 ± 4)°.