Search for CP violation effects in the decay with colliders

Xin Chen; Yongcheng Wu

doi:10.1140/epjc/s10052-017-5258-y

EPJ

Search for CP violation effects in the $h\rightarrow \tau \tau$ decay with $$e^+e^-$$

colliders

Xin Chen¹^,2^,3 and Yongcheng Wu¹^,4^*

¹ Department of Physics, Tsinghua University, Beijing, 100084, China
² Collaborative Innovation Center of Quantum Matter, Beijing, 100084, China
³ Center for High Energy Physics, Peking University, Beijing, 100084, China
⁴ Ottawa-Carleton Institute for Physics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada

Received: 16 March 2017
Accepted: 25 September 2017
Published online: 23 October 2017

Abstract

A new method is proposed to reconstruct the neutrinos in the $e^+e^-\rightarrow Zh$ process followed by the $h\rightarrow \tau \tau$ decay. With the help of a refined Higgs momentum reconstruction from the recoiling system and the impact parameters, high precision in the determination of the momentum of neutrinos can be achieved. The prospect of measuring the Higgs CP mixing angle with the $h\rightarrow \tau \tau$ decay at $$e^+e^-$$

colliders is studied with the new method. The analysis is based on a detailed detector simulation of the signal and backgrounds. The fully reconstructed neutrinos and also other visible products from the tau decay are used to build matrix element (ME)-based CP observables. With 5 $ab^{-1}$ of data at $E_{\text {CM}}=250$ GeV, a precision of $2.9^\circ$ can be achieved for the CP mixing angle with three main one-prong decay modes of the taus. The precision is found to be about 35% better than the other methods.

12 Internat. Congress of the Balkan Physical Union
July 8-12, 2025
Bucharest, Romania

EPJ

Search for CP violation effects in the $h\rightarrow \tau \tau$ decay with colliders

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