Browsing by Author "Azizi, K."

Now showing 1 - 4 of 4

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Investigation of P-wave scalar and S-wave pseudo-scalar charmonia semileptonic transitions to the Ds(D) meson in QCD
(IOP Publishing, 2010) Dağ, Hüseyin; Azizi, K.; Bashiri, V.; Natural and Mathematical Sciences; DAĞ, Hüseyin
In this work, the semileptonic decays of the scalar charmonium state Xc0 and the pseudo scalar charmonia states ηc(1s) and ηc(2s) into Ds and D mesons are analyzed. The form factors of the transitions Xc0 → Ds(D)_ν and ηc(1s, 2s) → Ds(D)_ν are calculated within the framework of the threepoint QCD sum rules. The results of the form factors are used to estimate the decay widths of the charmonia states into Ds(D)eν¯e and Ds(D)μν¯μ.
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Properties of kaon at non-zero temperature and baryon chemical potential
(Springer, 2023-10-14) Bozkır, G.; Türkan, Arzu; Azizi, K.; Natural and Mathematical Sciences; TÜRKAN, Arzu
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 μB . 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 μB= 0.4 GeV. After this point, it starts to fall by increasing the baryon chemical potential and it apparently vanishes at μB= (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 μB= 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. It is also seen that the obtained results for the mass and decay constant at T= μB= 0 are in good consistency with the existing experimental data. The observations are consistent with the QCD phase diagram in the T- μB plane.
Open Access
Properties of spin-1=2 heavy baryons at nonzero temperature
(American Physical Society, 2021-11-18) Türkan, Arzu; Bozkır, G.; Azizi, K.; Natural and Mathematical Sciences; TÜRKAN, Arzu
The spectroscopic properties of single heavy spin-1/2 ΛQ, ςQ, ΞQ(′), and ωQ baryons are investigated at finite temperature in the framework of the 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 nonperturbative operators up to dimension eight. We include additional operators coming from the Wilson expansion due to breaking the Lorentz invariance at nonzero temperature. The obtained results show that the mass of these baryons remain stable up to roughly T=108 MeV while their residue is 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 pseudocritical 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 the T→0 limit, which are consistent with the existing theoretical predictions as well as experimental data.
Open Access
S-wave single heavy baryons with spin-3/2 at finite temperature
(Springer Nature, 2020-05-15) Azizi, K.; Türkan, Arzu; Natural and Mathematical Sciences; TÜRKAN, Arzu
The thermal behavior of the spectroscopic parameters of the S-wave single heavy baryons Sigma Q,Xi Q and Omega 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 -> 0 limit are compatible with the available experimental data and predictions of other theoretical studies.