arXiv subjects

A. Ozpineci

Publications and source records attributed to A. Ozpineci.

At least 19 recordsLinked to original sources

arXiv2026

Light cone QCD sum rules study of the rare radiative $\Xi^{*}_{bb}\to\Xi_b\gamma$ decay

The rare radiative decay $\Xi^{*}_{bb}\to\Xi_b\gamma$ is investigated within the light cone QCD sum rules approach. This decay proceeds through the flavor changing neutral current $b\to s$ transition in the Standard Model. The hadronic matrix element of the considered decay is parameterized in terms of four tensor form factors $T_1^{V}(q^2)$, $T_2^{V}(q^2)$, $T_1^{A}(q^2)$ and $T_2^{A}(q^2)$. The sum rules for these form factors describing the $\Xi^{*}_{bb}\to\Xi_b\gamma$ decay are derived at $q^2=0$ point using the $\Xi_b$ distribution amplitudes. The results of the form factors are employed to calculate the corresponding decay width. Our finding indicates that this weak radiative decay could be within reach of future high statistics studies of doubly heavy baryons at LHCb and upcoming facilities.

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arXiv2025

Multipole Moments of Double Heavy $J^P = \frac{3}{2}^+$ Baryons

In the present study, we calculate the multipole moments of spin-3/2 doubly heavy baryons within the light cone QCD sum rules. We compare our results on magnetic dipole moments with results existing in the literature. The results obtained in the present work may be useful for a deeper understanding of the properties of doubly heavy baryons as well as in the analysis of their strong and electromagnetic decays.

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arXiv2023

Re-analysis of rare radiative $Ξ_b^-\rightarrow Ξ^- γ$ decay in QCD

The upper limit of the branching ratio of the rare $Ξ_b^-\rightarrow Ξ^- γ$ decay is obtained as $BR(Ξ_b^-\rightarrow Ξ^- γ)<1.3\times10^{-4}$ by the LHCb. In the present work we study this decay within the light cone QCD sum rules employing the $Ξ_b$ distribution amplitudes. At first stage, the form factors entering the $Ξ_b^-\rightarrow Ξ^- γ$ decay are obtained. Next, using the results for the form factors the corresponding branching ratio for this decay is estimated to be $BR(Ξ_b^-\rightarrow Ξ^- γ)=(4.8\pm 1.3)\times 10^{-5}$. This value lies below the upper limit established by the LHCb collaboration. Our finding for the branching ratio is also compared with the results of the other theoretical approaches existing in the literature.

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arXiv2023

Radiative Decays of the Spin-$\nicefrac{3}{2}$ to Spin-$\nicefrac{1}{2}$ Doubly Heavy Baryons in QCD

The spin-$\nicefrac{3}{2}$ to spin-$\nicefrac{1}{2}$ doubly heavy baryon transition magnetic dipole $G_M$ and electric quadrupole $G_E$ formfactors are calculated in the framework of light cone sum rules method. Moreover, the decay widths of corresponding radiative transitions are estimated. Obtained results of magnetic dipole moments $G_M$ and decay widths are compared with the results present in the literature.

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arXiv2021

The effects of charmonium on the properties of the $1^{++}$ hidden charm poles in effective field theory

In this study, the properties of the $J^{PC}=1^{++}$ hidden charm poles are analyzed under the variation of the bare 2P charmonium mass within the effective field theory proposed in Ref.[1]. The main focus of the current work is on the pole trajectory of the $χ_{c1}(2P)$ charmonium dressed by the $D \bar{D}^*$ meson loops. It is shown that the trajectories of the pole change radically for values of the bare charmonium mass above a certain value and also depending on how close the pole is to the threshold.

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arXiv2019

$B \rightarrow T$ transition form factors in light-cone sum rules

We present a new calculation of the semileptonic tree-level and flavor-changing neutral current form factors describing $B$-meson transitions to tensor mesons $T=D_2^*,K_2^*,a_2,f_2$ ($J^{P}=2^{+}$). 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 ${B} \to K_2^{*}γ$ and semileptonic ${B} \to D_2^* \ell {\bar ν}_\ell$, ${B} \to K_2^{*}\ell^+\ell^-$ decays.

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arXiv2019

Radiative decay of the $X(3872)$ as a mixed molecule-charmonium state in effective field theory

Assuming that $X(3872)$ is a mixture between $2P$ charmonium and $\bar{D}D^{*}$ molecular states with $J^{PC}=1^{++}$, an analysis of $X(3872)$ radiative decays into $J/ψγ$ and $ψ(2S)γ$ is presented. The modification of the radiative branching ratio due to possible constructive or destructive interferences between the meson-loop and the short-distance contact term, which is modeled by a charm quark loop, is shown. The model predictions are shown to be compatible with the experimentally determined ratio of the mentioned branching fractions for a wide range of the $X(3872)$ charmonium content. In the case of the destructive interference, a strong restriction on the charmonium admixture is found.

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arXiv2016

Tensor form factors of the octet hyperons in QCD

Light-cone QCD sum rules to leading order in QCD are used to investigate the tensor form factors of the $Σ-Σ$, $Ξ-Ξ$ and $ Σ-Λ$ transitions in the range $1 GeV^2 \leq Q^2 \leq 10 GeV^2$. The DAs of $Σ$, $Ξ$ and $Λ$ baryon have been calculated without higher order terms. Then, study including higher order corrections have been done for $Σ$ and $Λ$ baryon. The result of form factors are obtained using these two DAs. We make a comparison with the predictions of the chiral quark soliton model.

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arXiv2016

Axial vector transition form factors of $N \rightarrow Δ$ in QCD

The isovector axial vector form factors of $N \rightarrow Δ$ transition are calculated by employing Light-cone QCD sum rules. The analytical results are analysed by both the conventional method, and also by a Monte Carlo based approach which allows one to scan all of the parameter space. The predictions are also compared with the results in the literature, where available. Although the Monte Carlo analysis predicts large uncertainties in the predicted results, the predictions obtained by the conventional analysis are in good agreement with other results in the literature.

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arXiv2016

Quarkonium Contribution to Meson Molecules

Starting from a molecular picture for the X(3872) resonance, this state and its J^{PC}=2++ HQSS partner [X2(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium states. Since it is reasonable to expect the bare chi_{c1}(2P) to be located above the D\bar D* threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to bind the X(3872), but it will not appear in the 2++ sector. Indeed in this latter sector, the chi_{c2}(2P) should provide an effective small repulsion, because it is placed well below the D*\bar D* threshold. We show how the 1++ and 2++ bare charmonium poles are modified due to the D(*)\bar D(*) loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the 1++ dressed charmonium state. On the other hand, the X(3872) and X2(4012) start developing some charmonium content, which is estimated by means of the compositeness Weinberg sum-rule. We also show that for X(3872) molecular probabilities of around 70-90 %, the X2 resonance destabilizes and disappears from the spectrum, becoming either a virtual state or being located deep into the complex plane, with decreasing influence in the D* \bar D* scattering line.

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arXiv2016

Light Cone Distribution Amplitudes of Excited P-Wave Heavy Quarkonia at the Leading Twist

Leading twist light cone distribution amplitudes (LCDAs) are key ingredients in calculating various hadronic amplitudes using light cone QCD sum rules. This work concentrates on calculating the leading twist LCDAs of P-wave heavy quarkonia. Quark model wavefunctions for the ground, first and second excited states of P-wave charmonia and bottomonia have been calculated, and are used for calculating the relevant LCDAs and leptonic decay constants.

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arXiv2015

The axial charge of Δbaryon in QCD

The iso-vector axial-vector form factors of the Δ-Δtransition are calculated in the framework of the Light-cone QCD sum rules method. Also, axial charge of Δbaryon is predicted.

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arXiv2014

Isovector Axial Vector Form Factors of Octet-Decuplet Hyperon Transition in QCD

We calculate the isovector axial vector form factors of the octet-decuplet hyperon transitions within the framework of the light-cone QCD sum rules (LCSR) to leading in QCD and including higher-twist corrections. In particular, we motivate the most recent version of the $Σ$ baryon distribution amplitudes which are examined up to twist-6 based on conformal symmetry of the massless QCD Lagrangian.

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arXiv2014

Isovector axial vector and pseudoscalar transition form factors of $Δ$ in QCD

We investigate the isovector axial vector and pseudoscalar form factors of $Δ$ baryon by employing light-cone QCD sum rules. Numerical calculations show that the form factors can be well fitted by the exponential form. We make a comparison with the predictions of Lattice QCD, Chiral Perturbation Theory and Quark Model.

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arXiv2014

Hidden charm and bottom molecular states

We investigate heavy quark symmetries for heavy light meson-antimeson systems in a contact-range effective field theory. In the SU(3) light flavor limit, the leading order Lagrangian respecting heavy quark spin symmetry contains four independent counter-terms. Neglecting $1/m_Q$ corrections, three of these low energy constants can be determ1ined by theorizing a molecular description of the $X(3872)$ and $Z_b(10610)$ states. Thus, we can predict new hadronic molecules, in particular the isovector charmonium partners of the $Z_b(10610)$ and the $Z_b(10650)$ states. We also discuss hadron molecules composed of a heavy meson and a doubly-heavy baryon, which would be related to the heavy meson-antimeson molecules thanks to the heavy antiquark-diquark symmetry. Finally, we also study the $X(3872) \to D^0\bar D^0π^0$ decay, which is not only sensitive to the short distance part of the $X(3872)$ molecular wave function, as the $J/ψππ$ and $J/\psi3π$ $X(3872)$ decay modes are, but it is also affected by the long-distance structure of the resonance. Furthermore, this decay might provide some information on the interaction between the $D\bar D$ charm mesons.

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arXiv2014

Long-distance structure of the X(3872)

We investigate heavy quark symmetries for heavy meson hadronic molecules, and explore the consequences of assuming the X(3872) and $Z_b(10610)$ as an isoscalar $D\bar D^*$ and an isovector $B\bar B^*$ hadronic molecules, respectively. The symmetry allows to predict new hadronic molecules, in particular we find an isoscalar $1^{++}$ $B\bar B^*$ bound state with a mass about 10580 MeV and the isovector charmonium partners of the $Z_b(10610)$ and the $Z_b(10650)$ states. Next, we study the $X(3872) \to D^0 \bar D^0π^0$ three body decay. This decay mode is more sensitive to the long-distance structure of the X(3872) resonance than its $J/ψππ$ and $J/\psi3π$ decays, which are mainly controlled by the short distance part of the X(3872) molecular wave function. We discuss the $D^0 \bar D^0$ final state interactions, which in some situations become quite important. Indeed in these cases, a precise measurement of this partial decay width could provide precise information on the interaction strength between the $D^{(*)}\bar D^{(*)}$ charm mesons.

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arXiv2013

Hidden beauty molecules within the local hidden gauge approach and heavy quark spin symmetry

Using a coupled channel unitary approach, combining the heavy quark spin symmetry and the dynamics of the local hidden gauge, we investigate the meson-meson interaction with hidden beauty and obtain several new states. Both I=0 and I=1 states are analyzed and it is shown that in the I=1 sector, the interactions are too weak to create any bound states within our framework. In total, we predict with confidence the existence of 6 bound states, and weakly bound 6 more possible states. The existence of these weakly bound states depend on the influence of the coupled channel effects.

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arXiv2013

X(3872) and its Partners in the Heavy Quark Limit of QCD

In this letter, we propose interpolating currents for the X(3872) resonance, and show that, in the Heavy Quark limit of QCD, the X(3872) state should have degenerate partners, independent of its internal structure. Magnitudes of possible I=0 and I=1 components of the X(3872) are also discussed.

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