Abstract
In order to obtain the mass of \boldsymbol{\tau}𝛕 lepton at BESIII precisely, a beam energy measurement system was built at BEPCII. A scenario for high precision \boldsymbol{\tau}𝛕 mass measurement was put forth before data taken. More than 130 \boldsymbol{pb^{-1}}𝐩𝐛−1\boldsymbol{\tau}𝛕 mass scan data were collected in April 2018, and the uncertainty of \boldsymbol{m_{\tau}}𝐦𝛕 is expected to be less than 100 keV.
Highlights
The τ lepton is a fundamental particle in the standard model, and its mass is a fundamental parameter and should be given by experiment accurately
In order to decrease the systematical uncertainty related on the energy scale, beam energy measurement system was built at BEPCII
The beam energy measurement system (BEMS) at BEPCII is based on the Compton backscattering (CBS) principle
Summary
The τ lepton is a fundamental particle in the standard model, and its mass is a fundamental parameter and should be given by experiment accurately. According to PDG [1], the current world average value of the τ lepton mass is mτPDG = 1776.86 ± 0.12 MeV It is based mostly on BESIII [2], KEDR [3], BES [4], BABAR [5] and BELL [6]. The latter two experiments are performed at B factory using the pseudomass method, analysing the huge amount of data, they obtained good statistical accuracy, the systematic uncertainty is large for the absolute calibration of particle momentum measurements. In the spring of 2018, we took scan data near τ threshold, some analysis work and statistic uncertainty estimation are introduced in section 4, we give a short summary
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
