Feasibility study of measuring photon polarisation in at STCF

Yu-Lan Fan; Xiao-Dong Shi; Xiao-Rong Zhou; Liang Sun

doi:10.1140/epjc/s10052-021-09841-y

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 1068
https://doi.org/10.1140/epjc/s10052-021-09841-y

Regular Article - Experimental Physics

Feasibility study of measuring $b \to s γ$ $b\rightarrow s\gamma$ photon polarisation in $D^{0} \to K_{1} {(1270)}^{-} e^{+} ν_{e}$ $D^0\rightarrow K_1(1270)^- e^+\nu _e$ at STCF

Yu-Lan Fan¹, Xiao-Dong Shi²^,3, Xiao-Rong Zhou²^,3^c and Liang Sun¹^d

¹ School of Physics and Technology, Wuhan University, 430072, Wuhan, People’s Republic of China
² State Key Laboratory of Particle Detection and Electronics, 230026, Hefei, People’s Republic of China
³ School of Physical Sciences, University of Science and Technology of China, 230026, Hefei, People’s Republic of China

^c zxrong@ustc.edu.cn
^d sunl@whu.edu.cn

Received: 14 July 2021
Accepted: 17 November 2021
Published online: 4 December 2021

Abstract

We report a sensitive study of measuring $b \to s γ$ $b\rightarrow s\gamma$ photon polarisation in $D^{0} \to K_{1} {(1270)}^{-} e^{+} ν_{e}$ $D^{0}\rightarrow K_1(1270)^-e^+\nu _e$ with an integrated luminosity of $L$ $\mathscr {L}$ = 1 ab $^{- 1}$ $^{-1}$ at a center-of-mass energy of 3.773 GeV at a future Super Tau Charm Facility. More than 61,000 signals of $D^{0} \to K_{1} {(1270)}^{-} e^{+} ν_{e}$ $D^{0}\rightarrow K_1(1270)^-e^+\nu _e$ are expected. Based on a fast simulation software package, the statistical sensitivity for the ratio of up-down asymmetry is estimated to be $1.5 \times 10^{- 2}$ $1.5\times 10^{-2}$ by performing a two-dimensional angular analysis in $D^{0} \to K_{1} {(1270)}^{-} e^{+} ν_{e}$ $D^{0}\rightarrow K_1(1270)^-e^+\nu _e$ . Combining with measurements of up-down asymmetry in $B \to K_{1} γ$ $B\rightarrow K_1\gamma$ , the photon polarisation in $b \to s γ$ $b\rightarrow s\gamma$ can be determined model-independently.

© The Author(s) 2021

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