Accurate determination of the enhancement factor <i>X</i> for the nuclear Schiff moment in ²⁰⁵TlF molecule based on the four-component relativistic coupled-cluster theory

Studies of parity (<i>P</i>) and time-reversal (<i>T</i>) symmetry violations using molecules are important and attractive because they are complementary to the high-energy tests of physics beyond the Standard Model of elementary particles. The focus of our present work is to surpass the current accuracies of the quantity <i>X</i>, an enhancement factor for the nuclear Schiff moment (<i>Q</i>), and the nucleon electric dipole moments for the ²⁰⁵TlF molecule. We obtain <i>X</i> = 6856 a.u. using a relativistic coupled-cluster singles and doubles and perturbative triples (CCSD(T)) approach. This new value of <i>X</i> improves the upper limits for <i>Q</i> and the proton EDM by about ten percent over the previous ones.