Lifting of superconformal descendants in the D1-D5 CFT

Abstract

Abstract We consider D1-D5-P states in the untwisted sector of the D1-D5 orbifold CFT where we excite one copy of the seed CFT with a left-moving superconformal descendant. When the theory is deformed away from this region of moduli space these states can ‘lift’, despite being BPS at the orbifold point. For descendants formed from the supersymmetry $${G}_{\dot{A},-s}^{\alpha }$$ and R-symmetry $${J}_{-n}^{a}$$ current modes we obtain explicit results for the expectation value of the lifts for various subfamilies of states at second order in the deformation parameter. A smooth ∼ $$\sqrt{h}$$ behaviour is observed in the lifts of these subfamilies for large dimensions. Using covering space Ward identities we then find a compact expression for the lift of the above $${J}_{-n}^{a}$$ descendant states valid for arbitrary dimensions. In the large-dimension limit this lift scales as ∼ $$\sqrt{h}$$, strengthening the conjecture that this is a universal property of the lift of D1-D5-P states. We observe that the lift is not simply a function of the total dimension, but depends on how the descendant level is partitioned amongst modes.