Spin and chirality effects in antler-topology processes at high energy colliders

S. Y. Choi; N. D. Christensen; D. Salmon; X. Wang

doi:10.1140/epjc/s10052-015-3682-4

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2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2015) 75: 481
https://doi.org/10.1140/epjc/s10052-015-3682-4

Regular Article - Theoretical Physics

Spin and chirality effects in antler-topology processes at high energy $\varvec{e^+e^-}$ colliders

S. Y. Choi¹^,2, N. D. Christensen³, D. Salmon² and X. Wang²^*

¹ Department of Physics, Chonbuk National University, Jeonbuk, 561-756, Korea
² Department of Physics and Astronomy, Pittsburgh Particle physics, Astrophysics, and Cosmology Center, University of Pittsburgh, Pittsburgh, PA, 15260, USA
³ Department of Physics, Illinois State University, Normal, IL, 61790, USA

^* e-mail: xiw77@pitt.edu

Received: 16 March 2015
Accepted: 16 September 2015
Published online: 6 October 2015

Abstract

We perform a model-independent investigation of spin and chirality correlation effects in the antler-topology processes $e^+e^-\rightarrow \mathcal {P}^+\mathcal {P}^-\rightarrow (\ell ^+ \mathcal {D}^0) (\ell ^-\mathcal {\bar{D}}^0)$ at high-energy $$e^+e^-$$ colliders with polarized beams. Generally the production process $e^+e^-\rightarrow \mathcal {P}^+\mathcal {P}^-$ can occur not only through the s-channel exchange of vector bosons, $\mathcal {V}^0$ , including the neutral Standard Model (SM) gauge bosons, $\gamma$ and Z, but also through the s- and t-channel exchanges of new neutral states, $\mathcal {S}^0$ and $\mathcal {T}^0$ , and the u-channel exchange of new doubly charged states, $\mathcal {U}^{--}$ . The general set of (non-chiral) three-point couplings of the new particles and leptons allowed in a renormalizable quantum field theory is considered. The general spin and chirality analysis is based on the threshold behavior of the excitation curves for $\mathcal {P}^+\mathcal {P}^-$ pair production in $$e^+e^-$$ collisions with longitudinal- and transverse-polarized beams, the angular distributions in the production process and also the production-decay angular correlations. In the first step, we present the observables in the helicity formalism. Subsequently, we show how a set of observables can be designed for determining the spins and chiral structures of the new particles without any model assumptions. Finally, taking into account a typical set of approximately chiral invariant scenarios, we demonstrate how the spin and chirality effects can be probed experimentally at a high-energy $$e^+e^-$$ collider.