Scalar glueball mass reduction at finite temperature in SU(3) anisotropic lattice QCD

We report the first study of the glueball properties at finite temperatures below $T_c$ using SU(3) anisotropic lattice QCD with $\beta =6.25,$ the renormalized anisotropy $\xi \equiv a_s{/a}_t=4\mathrm{}$ and ${20}^3\times N_t{(N}_t=35,36,37,38,40,43,45,50,72)$ at the quenched level. From the temporal correlation analysis with the smearing method, about 20% mass reduction is observed for the lowest scalar glueball as $m_G\mathrm{}\left(T\right)=1250\mathrm{}\pm 50\hspace{0.5em}\mathrm{MeV}$ for ${0.8T}_c<T<\mathrm{}{T}_c$ in comparison with $m_G\simeq 1500–1700$ MeV at $T\simeq 0.$