arXiv subjects

A. Türkan

Publications and source records attributed to A. Türkan.

13 recordsLinked to original sources

arXiv2026

Probing the $B^{0}$ meson in a hot medium with finite baryon chemical potential

We perform a quantitative analysis of the $B^{0}$ meson spectroscopic parameters in a hot and dense medium. Within the framework of QCD two-point sum rules, we calculate the mass and decay constant of the $B^{0}$ meson with the help of the perturbative spectral density and nonperturbative contributions up to mass dimension five as functions of temperature $T$ and baryon chemical potential $μ_B$. For various fixed values of the baryon chemical potential, our numerical results indicate that both the mass and decay constant of the $B^{0}$ meson initially increase with temperature, reach a maximum, and then gradually decrease before eventually vanishing at sufficiently high temperatures. The corresponding vanishing points are found to be in the temperature intervals $(0.182-0.273)~\mathrm{GeV}$ and $(0.118-0.173)~\mathrm{GeV}$, for the mass and decay constant, respectively. Moreover, these temperatures move toward lower values as the baryon chemical potential increases. On the other hand, for various fixed temperatures, both the mass and decay constant exhibit a slight initial increase with increasing baryon chemical potential, followed by a subsequent decrease, eventually vanishing at sufficiently high chemical potentials. The vanishing points for the decay constant is determined to be in baryon chemical potential interval $(0.23-0.83)~\mathrm{GeV}$. For the mass, the decrease at $T=0$ is much weaker than at finite temperatures; excluding this case, the vanishing points for the mass are determined to be in baryon chemical potential interval $(0.38-1.43)~\mathrm{GeV}$ for different fixed temperatures. It is further observed that the baryon chemical potential values corresponding to the vanishing of both the mass and decay constant move to lower values as the temperature increases. In the $T \to 0$ and $μ_B \to 0$ limit ...

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arXiv2026

Kaons in hot and dense QCD

We present a systematic QCD sum-rule analysis of the in-medium properties of the charged kaon doublet $K^{\pm}$ over the full $(T,ρ)$ plane relevant to current and forthcoming heavy-ion experiments. Working within the QCD sum-rule framework and incorporating temperature-and density-dependent quark, gluon, and mixed condensates, we derive Borel-transformed sum rules for the effective masses $m_{K^{\pm}}$, the pseudoscalar decay constants $f_{K^{\pm}}$, and the vector self-energy $Σ_{v}$ of both charged states simultaneously. Our vacuum results, $m_{K^{-}} = 494.6^{+4.9}_{-6.9}$~MeV and $f_{K^{-}} = 157.3^{+4.1}_{-2.9}$~MeV (with near-degenerate $K^{+}$ values), are in excellent agreement with Particle Data Group values at the sub-percent level. In the medium, $m_{K^{\pm}}$ decreases monotonically with increasing baryon density and temperature, signalling progressive partial restoration of chiral symmetry. A pronounced mass splitting $Δm = m_{K^{-}} - m_{K^{+}}$ develops in baryonic matter, driven by the opposite sign of the Weinberg--Tomozawa vector interaction for the two charge states; it reaches $|Δm| \sim 0.35$~GeV near $ρ\simeq 3.2\,ρ_{\rm sat}$ at $T = 0$ and is partially quenched by thermal fluctuations. A central outcome of this study is the extraction of the critical onset density $ρ_c$, defined as the threshold beyond which the in-medium modifications of $K^{-}$ properties signal the onset of the transition toward the chirally restored phase. We stress that $ρ_c(T)$ should not be interpreted as a precise determination of the QCD critical point-a task beyond the reach of any current effective framework-but rather as an indicator ....

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arXiv2023

Properties of kaon at non-zero temperature and baryon chemical potential

We investigate the spectroscopic properties of the strange particle kaon in the framework of hot and dense QCD. To this end, first, we find the perturbative spectral density, which is connected with both the temperature $T$ and the baryon chemical potential $μ_{B}$. We include the non-perturbative operators as functions of temperature and baryon chemical potential up to mass dimension five. We perform the calculations in momentum space and use the quark propagator in the hot and dense medium. The numerical results at non-zero temperature and baryon chemical potential demonstrate that the mass of the particle rises considerably by increasing the baryon chemical potential at a fixed temperature (for both the zero and non-zero temperatures) up to approximately $μ_{B}=0.4$ GeV. After this point, it starts to fall by increasing the baryon chemical potential and it apparently vanishes at $μ_{B}=(1.03-1.15)$ GeV for finite temperatures: The point of apparent vanishing moves to lower baryon chemical potentials by increasing the temperature. At zero temperature, the mass reaches to roughly a fixed value at higher baryon chemical potentials. On the other hand, the decay constant decreases considerably with respect to baryon chemical potential up to roughly $μ_{B}=0.4$ GeV, but after this point, it starts to increase in terms of the baryon chemical potential at finite temperatures. At $T=0$, the decay constant reaches to a fixed value at higher chemical potentials, as well. Regarding the dependence on the temperature we observe that, at fixed values of baryon chemical potentials, the mass and decay constant remain roughly unchanged up to $T=50$ MeV and $T=70$ MeV respectively, but after these points, the mass starts to fall and the decay constant starts to rise up to a critical temperature $T=155$ MeV, considerably.

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arXiv2022

Dissociation of Pseudotensor Mesons through Critical Temperature

We have computed the masses and decay constants of isotriplet $π_2(1670)$, the isoscalar $η_2(1645)$ and $η_2(1870)$ states as the ground-state nonet of $1^1D_2$ case within the Thermal QCD sum rules framework. This method is applied to the spectral changes of pseudotensor mesons at high temperatures including quark, gluon, and mixed condensates up to the five dimensions. We found that their masses and decay constants are insensitive to temperature in low-temperature regions. At the near-critical temperature, we observed an exponential decrease of the masses of $π_2$, $η_2(1645)$, and $η_2(1870)$, but while the decay constant of $π_2$ is fallen, that of $η_2(1645)$ and $η_2(1870)$ is increased as a function of temperature. The modification of condensates at $T\neq 0$ is crucial to the change of considered mesons properties in a hot medium. We discuss and interpret the implications of the physical meaning of our results.

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arXiv2022

Impact of a thermal medium on newly observed $Z_{cs}(3985)$ resonance and its $ b $-partner

Motivated by the very recent discovery of the strange hidden-charm exotic state $Z_{cs}(3985)$ by the BESIII Collaboration, we study possible interpretation of this exotic state both at $ T= 0 $ and $ T\neq 0 $. We analytically compute the mass and meson-current coupling constant of this resonance with spin-parity $ J^{PC} = 1^{+-}$ at finite temperature approximation up to sixth order of the thermal operator dimension including non-perturbative contributions. Extracting thermal mass and meson-current coupling constant sum rules, the modifications on properties of $Z_{cs}(3985)$ state in hot medium is determined. As a by product, the hadronic parameters of the bottom partner of $Z_{cs}(3985)$ is estimated as well. Moreover the search of temperature effects on the hadronic parameters of hidden-charm meson $Z_{cs}(3985)$ and the bottom partner make us understand the phase transitions, chiral symmetry breaking and the properties of hot-dense matter in QCD.

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arXiv2021

Properties of spin-1/2 heavy baryons at nonzero temperature

The spectroscopic properties of single heavy spin-1/2 $Λ_{Q}$, $Σ_{Q}$, $Ξ^{(\prime)}_{Q}$ and $ Ω_{Q}$ baryons are investigated at finite temperature in the framework of thermal QCD sum rule. We discuss the behavior of the mass and residue of these baryons with respect to temperature taking into account contributions of non-perturbative operators up to dimension eight. We include additional operators coming from the Wilson expansion due to breaking the Lorentz invariance at non-zero temperature. The obtained results show that the mass of these baryons remain stable up to roughly $T=108$ MeV while their residue are unchanged up to $T=93$ MeV. After these points, the mass and residue start to diminish by increasing the temperature. The shifts in the mass and residue for both the bottom and charm channels are considerably large and we observe the melting of these baryons near to the pseudo-critical temperature determined by recent lattice QCD calculations. We present our results for the mass of these baryons with both the positive and negative parity at $ T\rightarrow 0 $ limit, which are consistent with the existing theoretical predictions as well as experimental data.

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arXiv2021

Newly observed resonance $ X(4685) $: diquark-antidiquark picture

In this work, the mass and pole residue of $ X(4685) $ state with spin-parity $J^P=1^+$ are computed by the QCD sum rule approaches up to operator dimension seven based on the diquark-antidiquark configuration. For its mass we get $ m_{X_{cs}}= 4607^{+36}_{-22} $ MeV and pole residue $ λ_{X_{cs}}= 6.19^{+0.32}_{-0.24}\times 10^{-2}~\mathrm{GeV^5}$, which may be checked via other nonperturbative approaches as well as future experiments. As a by product, the mass of the hidden-bottom partner state of the $ X(4685) $ is extracted to be both around $ m_{X_{bs}}= (10604-10924) $ MeV and $ λ_{X_{bs}}= (42.2-53.7)\times 10^{-2}~\mathrm{GeV^5}$, which can be searched in the $Υϕ$ invariant mass distribution.

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arXiv2021

Modifications on the Properties of $D^*_{s0}(2317)$ as Four-quark State in Thermal Medium

Since the low mass of $D^*_{s0}(2317)$ has still been a problem to the conventional quark model, one can consider other options regarding as multi-quark system. Therefore we investigate the scalar open-charm state $D^*_{s0}(2317)$ by Thermal QCD Sum Rules (TQCDSR) method using the two-point correlation function together with contributions of the non-perturbative condensates up to dimension six. Deriving and numerically analyzing thermal mass and pole residue sum rules, we accomplish the effects on the properties of $D^*_{s0}(2317)$ resonance in hot medium. Our numerical evaluations indicate that the variations in mass and pole residue values are stable through the growing temperature up to $T\cong100~\mathrm{MeV}$, but they begin to fall after this point. At critical temperature, the values of mass and pole residue change up to $91\%, 70\% $ of their values in vacuum in the molecular scenario and $ 91\%, 69\% $ in the diquark-antidiquark scenario. Our results does not give any definite information as to whether $D^*_{s0}(2317)$ resonance has molecular or diquark-antidiquark structure since they are very close to each other to differentiate them. Besides, we predict the hadronic parameters of the bottom partner of the $D^*_{s0}(2317)$ resonance in both molecular and diquark-antidiquark pictures. This bound state is worth investigating in future experiments. Also the detailed search of hot medium effects on the hadronic parameters of open-charm meson $D^*_{s0}(2317)$ and the bottom partner could have some implications to define the QCD phase diagram obtained from heavy-ion collision experiments. Moreover these results can be useful in distinguishing conventional quark model mesons from exotica.

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arXiv2020

Missing Member of the $J^{PC} = 2^{--}$ Nonet in Extreme Conditions

The isoscalar member of the axial-tensor family that should take place in the further states of the PDG is still absent. In this study, analyzes are made as to whether one of the X states whose quantum numbers are unknown in this group, is a candidate for the missing resonance under the assignment $ 2^3D_2 $. Moreover, replacing the time evolution operator with the thermal average one, we construct the modified correlator satisfying Thermal QCD sum rules approach. We determine that the hadronic parameters of the considered nonet member are sensitive to the increment of temperature. This knowledge can be helpful to complete the $J^{PC} = 2^{--}$ light meson nonet and also explore the hot medium behaviors at upcoming heavy-ion collision experiments.

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arXiv2020

Axial-tensor Meson Family at $T\neq0$

The mass and decay constant of the axial-tensor meson nonets $ρ_2,~ω_2$ and a missing member and also their first excited states are analyzed by the Thermal QCD sum rules model including QCD condensates up to dimension five. Mass and decay constant values in terms of variations of temperature are very well stable from $T=0$ up to ~$T \cong 120 ~\mathrm{MeV}$. However nearly after these threshold, our numerical analysis indicate that they begin to diminish with increasing temperature. Mass value of these mesons and their first excited states decrease about $(1-13\%)$ compared to vacuum values and $(10-26\%)$ for the decay constants according to PDG data and $(9-26\%)$ and $(2-34\%)$ respectively concerning Regge Trajectory Model in the corresponding Thermal QCD sum rules calculations. The experimental results are already copious, but expected to grow up at ongoing and future heavy-ion experimental programs allowing us to compare our results.

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arXiv2020

S-Wave Single Heavy Baryons with Spin-3/2 at Finite Temperature

The thermal behavior of the spectroscopic parameters of the S-wave single heavy baryons $ Σ_{Q}^{*}, Ξ_{Q}^{*}$ and $ Ω_{Q}^{*} $ with spin-3/2 are investigated in QCD at finite temperature. We analyze the variations of the mass and residue of these baryons taking into consideration the contributions of QCD thermal condensates up to dimension eight in Wilson expansion. At finite temperature, due to the breakdown of the Lorentz invariance by the choice of reference frame and presence of an extra $O(3)$ symmetry, some new four-dimensional operators come out in the form of the fermionic and gluonic parts of the energy momentum tensor that are taken into account in the calculations. Our analyses show that at lower temperatures, the parameters of baryons under consideration are not affected by the medium. These parameters, however, show rapid variations with respect to temperature at higher temperatures near to a pseudo-critical temperature, after which the baryons are melted. The results of the masses and residues at $ T\rightarrow 0 $ limit are compatible with the available experimental data and predictions of other theoretical studies.

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arXiv2019

In the Pursuit of $X(5568)$ and its Charmed Partner

The recent observation by the D$Ø$ collaboration of the first tetraquark candidate with four different quark flavors $(u, d, s$ and $ b)$ in the $B^0_sπ^{\pm}$ channel having a narrow structure, has still not been confirmed by other collaborations. Further independent experiments are required either to confirm the $X(5568)$ state or to set limits on its production. Though quantum numbers are not exactly clear, the results existing in the literature indicate that it is probably an axial-vector or scalar state candidate. In this study, mass and pole residue of the $X(5568)$ resonance assuming as a tightly bound diquark, with spin-parity both $J^{P}=1^{+}$ or $J^{PC}=0^{++}$ are calculated using two-point Thermal SVZ sum rules technique by including condensates up to dimension six. Moreover, its partner in the charm sector is also discussed. Investigations defining the thermal properties of $X(5568)$ and its charmed partner may provide valuable hints and information for the upcoming experiments such as CMS, LHCb and PANDA.

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arXiv2018

Hidden-Beauty Broad Resonance $Y_b(10890)$ in Thermal QCD

In this work, the mass and pole residue of resonance $Y_b$ is studied by using QCD sum rules approach at finite temperature. Resonance $Y_b$ 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 dependences of the mass $m_{Y_b}$ and the pole residue $λ_{Y_b}$ are investigated. It is seen that near a critical temperature $(T_c\simeq190~\mathrm{MeV})$, the values of $m_{Y_b}$ and $λ_{Y_b}$ are decreased to $87\%$, and to $44\%$ of their values at vacuum.

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