New Sum Rules for Nucleon Tensor Charges

Abstract

Two new sum rules for the quark tensor charges of the nucleon are proposed, based on a relation connecting the quark transversity distributions to the quark helicity distributions and the quark model spin distributions, and on the sum rules for the quark helicity distributions. The two sum rules are useful for an estimate of the values of the quark tensor charges $\delta U$ and $\delta D$ from the measured quantities of $\Gamma^p$, $\Gamma^n$, $g_A/g_V$ and $\Delta S$, and two model correction factors with limited uncertainties. We predict a small value for the sum of the quark tensor charges compared to most other predictions, in analogy to the unexpectedly small quark helicity sum which gave rise to the proton ``spin puzzle''.