\tt ee∈MC: Arbitrary Initial Spin States for the Production of \bf e⁺e^- → τ⁺τ^- (γ) Events and the Impact on Spin Correlations

2022/11/19 by Nugent, Ian M.
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)

paper · doi:10.48550/arxiv.2211.10548

Abstract

We present a modified spin algorithm, including spin correlations, which has been implemented in \tt ee∈MC for the simulation of e⁺e^- → τ⁺τ^- (γ) events with an arbitrary initial spin configuration. This algorithm is suitable for the proposed BELLE-II polarization upgrade to SuperKEKB, both for the ideal case and for the case where there are misalignments, radiative effects and allows for changing polarization conditions. The spin 1/2 states of the polarized beams are constructed in terms of a super-positioning of the helicity states corresponding to the polarimetric-vector describing the overall beam polarization and implemented both through a modification of the initial state in the modified Altrelli-Parsis Density Function as well as a change of basis of the helicity states.

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