Jet charge: A new tool to probe the anomalous Zbb¯ couplings at the EIC

• Published in: Physics letters. B 2022-10, Vol.833, p.137300
• Main Authors: Li, Hai Tao, Yan, Bin, Yuan, C. -P.
• Format: Article
• Language: English
• Subjects: Atomic, Nuclear and Particle Physics; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 0370-2693
• DOI: 10.1016/j.physletb.2022.137300

We propose to probe the $Zb$$\overline{b}$ interactions at the Electron-Ion Collider (EIC) by utilizing the average jet charge weighted single-spin asymmetry ${A}^{bQ}_{e}$, which is induced by different cross sections of a left-handed and right-handed electron beam scattering off an unpolarized proton beam in the neutral current deeply-inelastic scattering processes with one observed $b$-tagged jet. This novel observable at the EIC is sensitive to the axial-vector component of the $Zb$$\overline{b}$ coupling, providing similar information as the $gg$ → $Zh$ cross section measurement at the high-luminosity Large Hadron Collider, and is complementary to the single-spin asymmetry measurement at the EIC which is sensitive to the vector component of the $Zb$$\overline{b}$ coupling. We show that the apparent degeneracy of the allowed $Zb$$\overline{b}$ coupling in its vector and axial-vector components, implied by the Large Electron Positron Collider (LEP) and the Stanford Linear Collider (SLC) precision electroweak data, can be broken by the ${A}^{bQ}_{e}$ measurement at the EIC. With a large enough integrated luminosity collected at the EIC, the measurement of ${A}^{bQ}_{e}$ could also resolve the long-standing discrepancy between bottom quark forward-backward asymmetry ${A}^{b}_{FB}$ at the LEP and the Standard Model prediction, with a strong dependence on the $b$-tagging efficiency.