Properties of nucleon in nuclear matter: once more

We calculate the mass and residue of the nucleon in nuclear matter in the framework of QCD sum rules using the nucleon's interpolating current with an arbitrary mixing parameter. We evaluate the effects of the nuclear medium on these quantities and compare the obtained results with the existing theoretical predictions. The results are also compared with those obtained in vacuum to find the shifts in the quantities under consideration. Our calculations show that these shifts in the mass and residue are about $32\%$ and $15\%$, respectively.Comment: 18 Pages, 2 Tables and 7 Figures, To be appear in EPJ

QCD nature of dark energy at finite temperature: cosmological implications

The Veneziano ghost field has been proposed as an alternative source of dark energy whose energy density is consistent with the cosmological observations. In this model, the energy density of QCD ghost field is expressed in terms of QCD degrees of freedom at zero temperature. We extend this model to finite temperature to search the model predictions from late time to early universe. We depict the variations of QCD parameters entering the calculations, dark energy density, equation of state, Hubble and deceleration parameters on temperature from zero to a critical temperature. We compare our results with the observations and theoretical predictions existing at different eras. It is found that this model safely defines the universe from quark condensation up to now and its predictions are not in tension with those of the standard cosmology. The EoS parameter of dark energy is dynamical and evolves from $-1/3$ in the presence of radiation to $-1$ at late time. The finite temperature ghost dark energy predictions on the Hubble parameter well fit to those of $\Lambda$CDM and observations at late time.Comment: 10 Pages and 6 Figures. Some references were rearrange

Positive and negative parity hyperons in nuclear medium

The effects of nuclear medium on the residue, mass and self energy of the positive and negative parity $\Sigma$, $\Lambda$ and $\Xi$ hyperons are investigated using the QCD sum rule method. In the calculations, the general interpolating currents of hyperons with an arbitrary mixing parameter are used. We compare the results obtained in medium with those of the vacuum and calculate the shifts in the corresponding parameters. It is found that the shifts on the residues in nuclear matter are over all positive for both the positive and negative parity hyperons, except for the positive parity $\Sigma$ hyperon that the shift is negative. The shifts on the masses of these baryons are obtained to be negative. The shifts on the residues and masses of negative parity states are large compared to those of positive parities. The maximum shift belongs to the residue of the negative parity $\Lambda$ hyperon. The vector self-energies gained by the positive parity baryons are large compared to the negative parities' vector self-energies. The maximum value of the vector self-energy belongs to the positive parity $\Sigma$ hyperon. The numerical values are compared with the existing predictions in the literature.Comment: 20 Pages, 9 Figures and 7 Table

More about the BB and DD mesons in nuclear matter

We calculate the shifts in decay constants of the pseudoscalar $B$ and $D$ mesons in nuclear medium in the frame work of QCD sum rules. We write those shifts in terms of the $B-N$ and $D-N$ scattering lengths and an extra phenomenological parameter entered to calculations. Computing an appreciate forward scattering correlation function, we derive the QCD sum rules for the $B-N$ and $D-N$ scattering lengths and the extra phenomenological parameter in terms of various operators in nuclear medium. We numerically find the values of the shifts in the decay constants compared to their vacuum values. Using the sum rules obtained, we also determine the shifts in the masses of these particles due to nuclear matter and compare the results obtained with the previous predictions in the literature.Comment: 16 Pages, 4 Figures and 3 Table

Scalar and vector self-energies of heavy baryons in nuclear medium

The in-medium sum rules are employed to calculate the shifts in the mass and residue as well as the scalar and vector self-energies of the heavy $\Lambda_Q, \Sigma_Q$ and $\Xi_Q$ baryons, with Q being $b$ or $c$ quark. The maximum shift in mass due to nuclear matter belongs to the $\Sigma_c$ baryon and it is found to be $\Delta m_{\Sigma_{c}}=-936 ~ MeV$. In the case of residue, it is obtained that the residue of $\Sigma_b$ baryon is maximally affected by the nuclear medium with the shift $\Delta \lambda_{\Sigma_b} = -0.014 ~ GeV^3$. The scalar and vector self-energies are found to be $\Sigma^{S}_{\Lambda_b} = 653 ~ MeV$, $\Sigma^{S}_{\Sigma_b} = -614 ~ MeV$, $\Sigma^{S}_{\Xi_b} = -17 ~ MeV$, $\Sigma^{S}_{\Lambda_c} = 272 ~ MeV$, $\Sigma^{S}_{\Sigma_c} = -936 ~ MeV$, $\Sigma^{S}_{\Xi_c} = -5 ~ MeV$ and $\Sigma^{\nu}_{\Lambda_b} = 436 \pm 148 ~ MeV$, $\Sigma^{\nu}_{\Sigma_b} = 382 \pm 129 ~MeV$, $\Sigma^{\nu}_{\Xi_b} =15 \pm 5 ~ MeV$, $\Sigma^{\nu}_{\Lambda_c} = 151 \pm 45 ~ MeV$, $\Sigma^{\nu}_{\Sigma_c} = 486 \pm 144 ~ MeV$ and $\Sigma^{\nu}_{\Xi_c} = 1.391 \pm 0.529 ~ MeV$.Comment: 13 Pages, 11 Figures and 5 Table

Properties of Ds2∗(2573)D_{s2}^*(2573) charmed-strange tensor meson

The mass and current coupling constant of the $D_{s2}^* (2573)$ charmed-strange meson is calculated in the framework of two-point QCD sum rule approach. Although the quantum numbers of this meson is not exactly known, its width and decay modes are consistent with $I(J^P)=0(2^+)$, which we consider to write the interpolating current used in our calculations. Replacing the light strange quark with up or down quark we also compare the results with those of $D_{2}^*$ charmed tensor meson and estimate the order of SU(3) flavor symmetry violation.Comment: 9 Pages, 2 Figures and 1 Table, Some misprints are correcte

Subcritical and supercritical fluid extraction a critical review of its analytical usefulness

Subcritical R134a is suggested as a low-pressure alternative to supercritical CO2 in the supercritical fluid extraction technology in particular of palm oil application. Therefore, a measurement of solubility of palm oil in subcritical Rl34a will be carried out at temperatures of 40, 60, 70 and 80°C and pressures up to 300 bar. The solubility of carotene are also will be measured using UV Spectrophotometer. Results obtained from this study will be compared with the previous work and for the first time, simulation for the SFE process of palm oil will be performed using Artificial Neural Network (ANN) and it will be implemented in comparisons as well when the operating conditions of the previous findings are different from this study. It is expected that the solubility of the palm oil in subcritical Rl34a is much higher than SC-C02, and it is expected that R134a could be a viable alternative solvent to supercritical carbon dioxide as R134a could be perform well at a lower pressure used whereas can achieved a higher solubility compared to SC-C0