Transverse spin effects and light-quark dipole moments at lepton colliders
Xin-Kai Wen, Bin Yan, Zhite Yu, C.–P. Yuan
Abstract
We propose to probe light-quark dipole interactions at lepton colliders using the azimuthal asymmetry of a collinear dihadron pair <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mo stretchy="false">(</a:mo> <a:msub> <a:mi>h</a:mi> <a:mn>1</a:mn> </a:msub> <a:msub> <a:mi>h</a:mi> <a:mn>2</a:mn> </a:msub> <a:mo stretchy="false">)</a:mo> </a:math> produced in association with another hadron <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msup> <e:mi>h</e:mi> <e:mo>′</e:mo> </e:msup> </e:math> . This asymmetry, arising from quantum interference in the quark spin space, is exclusively sensitive to dipole interactions at the leading power of the new physics scale and simultaneously probes both the real and imaginary components of the dipole couplings. By combining all possible channels of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msup> <g:mi>h</g:mi> <g:mo>′</g:mo> </g:msup> </g:math> , this method allows for disentangling the up and down quark dipole moments and has the potential to significantly strengthen current constraints by one to two orders of magnitude.