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

The spectroscopic properties of single heavy spin-$1/2{\mathrm{\Lambda }}_Q$, ${\mathrm{\Sigma }}_Q$, ${\mathrm{\Xi }}_Q^{(\prime )}$, and ${\mathrm{\Omega }}_Q$ 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 $T=108\mathrm{MeV}$ while their residue is unchanged up to $T=93\mathrm{MeV}$. 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 $T\to 0$ limit, which are consistent with the existing theoretical predictions as well as experimental data.

Figure 1

The mass of the positive parity ${\mathrm{\Sigma }}_b$ baryon as functions of $M^2$ and $s_0$ at $T=0$.

Figure 2

The ratio $m(T)/m(0)$ as functions of $M^2$ and $T/T_{pc}$ for positive parity ${\mathrm{\Lambda }}_b$, ${\mathrm{\Xi }}_b$, ${\mathrm{\Sigma }}_b$, ${\mathrm{\Xi }}_b^{\prime }$, and ${\mathrm{\Omega }}_b$ baryons at the average value of $s_0$.

Figure 3

The ratio $\lambda (T)/\lambda (0)$ as functions of $M^2$ and $T/T_{pc}$ for positive parity ${\mathrm{\Lambda }}_b$, ${\mathrm{\Xi }}_b$, ${\mathrm{\Sigma }}_b$, ${\mathrm{\Xi }}_b^{\prime }$, and ${\mathrm{\Omega }}_b$ baryons at the average value of $s_0$.