Speaker
Description
The transverse spin effects can be measured at upcoming Electron-Ion Collider (EIC) and proposed Electron-Ion Collider at China (EicC) with polarized electrons or/and protons. The corresponding observables, single-spin asymmetry (SSA)/double-spin asymmetry (DSA), are suppressed in the Standard Model. We investigate the enhancement of DSA under new physical effects. We parameterize such contributions of new physics in the framework of standard model effective field theory (SMEFT). Assume the electrons and protons are polarized in the same direction, we demonstrate that the interference between the scalar/tensor type four-fermion operators and SM leads to nontrival azimuthal $\cos2\phi$ and $\sin2\phi$ distributions and are linearly dependent on the Wilson coefficients associated with these operators at the ${\cal O}(1/\Lambda^2)$, without any suppression from the electron and quark masses. Furthermore, the results are not significantly affected by the presence of other NP operators in DIS process.
