Luminosity measurements for the R scan experiment at BESIII**Supported by National Key Basic Research Program of China (2015CB856700), National Natural Science Foundation of China (NSFC) (10935007, 11121092, 11125525, 11235011, 11322544, 11335008, 11375170, 11275189, 11079030, 11475164, 11475169, 11005109, 10979095, 11275211), Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (11179007, U1232201,

M Ablikim,C Q Feng,Z Y Zhang,M Wolke,X L Kang,H X Yang,Q J Xu,M Lara,K Y Liu,A Denig,T Li,G Chelkov,B X Zhang,D Liu,L L Wang,T Weber,J P Zheng,W D Li,Q Ouyang,S Q Zhang,X L Li,L Zhang,L Xia,Q N Xu,H J Li,J Pettersson,W M Song,M Shao,B C Ke,Z A Zhu,A Yuncu,Y Xia,A Zhemchugov,J M Bian,J Liu,J S Yu,K Li,Y N Zhang,J Y Zhao,L J Wu,X L Gao,C Li,K Zhang,I Denysenko,J Y Liu,J J Zhang,L Yan,W Wang,H M Liu,X Q Li,U Wiedner,W P Wang,J F Sun,J Z Zhang,J Zhang,D H Zhang,S H Zhu,X D Ruan,Z H Zhang,B Liu,Q Y Li,Z T Sun,B Y Zhang,S Han,Y Fang,Z Y Wang,C F Qiao,T C Zhao,D W Bennett,J L Zhang,H B Li,H H Liu,Y P Guo,J Q Zhang,S Chen,B Zheng,Y D Wang,F F An,W G Li,G S Huang,L W Jiang,T Luo,Y F Wang,F Y Li,P L Liu,B X Yu,M Savrié,N Berger,K Peters,J S Huang,P L Wang,M Wang,Z Zeng,Y B Chen,Y H Zhang,Z G Wang,P Wang,J Z Zhao,X N Li,M Ye,J Y Zhang,Z H Wang,Y Pan,Y B Liu,J W Zhao,Y J Sun,G Chen,S B Liu,D Wang,X Y Niu,C X Liu,X Y Jiang,L S Wang,J P Liu,Y Z Sun,X H Sun,X Liu,Y Wang,Y T Liang,G Rong,X R Lyu,Y B Li,F H Liu,B Wang,T Ma,Y T Zhang,J L Ping,J W Zhang,B J Liu,Y Q Wang,K Liu,H H Zhang,Q Ji,L D Liu,X L Ji,K Wang,X Chen,W Kühn,M L Chen,Y P Lu,H B Liu,Y Lu,X Q Hao,J B Jiao,S A Çetin ,T Hussain,R Farinelli,W B Yan,F Bianchi,Z P Mao,T Hu,I B Nikolaev,X R Chen,Q Gao,Y Zhu ,W J Zheng,Z Jiao,X Zhu ,Zhao Liu ,W X Gong,Z P Zhang,S S Fang,Xiang Zhou ,O B Kolcu,Q An,Y H Yan,X Tang,M Tiemens,Z Y Deng,Y Zheng ,H L Dai,J S Lange,J V Bennett,W Ikegami Andersson,H Muramatsu,M Pelizaeus,D H Wei,F Nerling,F E Maas,M Ripka,Lei Li,B Kopf,M Kavatsyuk,C D Fu,G X Sun,C Morales Morales,Q A Malik,T Holtmann,P Weidenkaff,J Z Bai,F A Harris,Y F Liang,X S Kang,C Schnier,L Yang,C J Tang,X Y ,J Zhuang,R Poling,X L Luo,F C ,N Yu Muchnoi,P X Shen,Y Hu,C Leng,T Held,H Y Zhang,Xiaozhong Huang ,D Ambrose ,J F Qiu,E H Thorndike,F De Mori,D Bettoni,Y Ding,H S Chen,J Fan ,M X Luo,Z A Liu,J G Messchendorp,Y J Mao,Gang Zhao ,I R Boyko ,C X Yu,C C Zhang,G Li,L Gong,R E Mitchell,J Fang,Q P Ji,O Albayrak,J B Liu,H M Hu,X Y Song,X Lou ,X Cai,Zhou Li ,S J Qian ,Fang Liu,Zhi Wang ,L B Guo,K Schoenning,G Mezzadri,X B Ji,Han Liu ,H J Lü ,Z Gao,I Uman,Ling Zhao,P R Li,K J Zhu,Dong Liu ,H Peng ,A Amoroso,Y Zeng,W Gradl,Yu Zhang,S P Wen,M Albrecht,X F Wang,M Bertani,I Garzia,S L Niu,Zhiqing Liu,C F Redmer,A Dbeyssi,Xin Fang ,Y Xie ,J P Dai,Feng Liu,F H Heinsius,M Qi,N Qin,J H Yin,V Prasad,H Loehner,R P Guo,L Zotti,C Z Yuan,Y J Mo,J Chai,K H Rashid,Z L Dou,A Q Guo,J F Hu,Q L Xiu,W Shan,S Sosio,C L Luo,Yifan Yang ,B S Zou,D X Lin,S Nisar,G Varner ,L Fava,T Johansson,X H Mo,X K Chu,R A Briere,T J Min,G Felici,Y B Zhao,Xu Li ,H Cai,R G Ping,Jin Li,J G Lü ,X Y Zhang,Z.r Wang ,O Çakır ,Z Haddadi,K L He,B Kloss,F Li,Cheng Li,A Calcaterra,B L Wang,M Kornicer,P Patterí ,S Spataro,D P Jin,Q M ,J Min,Y T Gu,Z B Li,C Dong,Xingyu Zhou ,М Н Ачасов ,H J Yang,Z J Xiao,Z H Qin,X T Huang,I Tapan,Y H Guan,L L ,J C Chen,X S Jiang,P Larin,A A Zafar,S X Du,Z Y You ,Z L Hou,J Dong,E Boger,Pengfei Duan ,R Kliemt,N Kalantar‐Nayestanaki ,S J Chen,G Cibinetto,K Goetzen,L H Wu,Y Zhang,F Feldbauer,B Zhong,H R Qi,D M Li,M G Zhao,P Musiol,X Y Shen,P Kiese,M Y Dong,J F Chang,H Xiao,E Fioravanti,C P Shen,H Leithoff,Hu Chen ,S J Zhao,G F Cao,A Julin,Yuan Gao ,M H Gu,A Hafner,X S Qin,Q Liu,G F Xu,M Greco,M Fritsch,Z J Sun,Y M ,S Marcello,G R Liao,S L Olsen,J C Li,X Ai ,Z Huang ,A Kupść ,S Ahmed,Y S Zhu,M H Ye,D Xiao,Q Zhao,Z Ning,D V Dedovich ,Y K Heng,X K Zhou,S Jin,Qin Liu ,M M ,Y Nefedov,J Xu ,X P Xu,Z Zhao ,Y Ban,S S Sun,M Destefanis,Ch Rosner,H L ,O Bakina,M Maggiora,Y Yuan,R Baldini Ferroli,X N ,S Pacetti,H Y Sheng,A Sarantsev,J H Zou

doi:10.1088/1674-1137/41/6/063001

Abstract

By analyzing the large-angle Bhabha scattering events e+e− → (γ)e+e− and diphoton events e+e− → (γ)γγ for the data sets collected at center-of-mass (c.m.) energies between 2.2324 and 4.5900 GeV (131 energy points in total) with the upgraded Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider (BEPCII), the integrated luminosities have been measured at the different c.m. energies, individually. The results are important inputs for the R value and J/ψ resonance parameter measurements.

Highlights

Hadron production in e+e− annihilation is one of the most valuable testing grounds for Quantum Chromodynamics (QCD), and is an important input for precision tests of the Standard Model (SM)
The R value, which is defined as the lowest-level hadronic cross section normalized to the theoretical μ+μ− production cross section in e+e− annihilation, is an indispensable input for the determination of the non-perturbative hadronic contribution to the electromagnetic coupling constant evaluated at the Z pole (α(MZ2 )) [1, 2], and the anomalous magnetic moment aμ = (g−2)/2 of the muon [3]
We present the measurements of luminosities of the R scan data samples taken at BESIII from 2012 to 2014

Summary

Introduction

Hadron production in e+e− annihilation is one of the most valuable testing grounds for Quantum Chromodynamics (QCD), and is an important input for precision tests of the Standard Model (SM). The dominant uncertainties in both α(MZ2 ) and aμ measurements are due to the effects of hadronic vacuum polarization, which cannot be reliably calculated in the low energy region. Where is the number of observed hadronic events, background events, integrated luminosity, εhad is the detection efficiency for the hadron event selection, εtrig had is the trigger efficiency, 1+δ is the initial-state radiation (ISR) correction factor, and σ0 is the Born cross section of e+e− → μ+μ−. Quantum electrodynamics (QED) processes are usually applied to determine the integrated luminosity, due to larger production rates, simpler final-state topologies and more accurate cross section calculation in theory relative to the other processes. QED events observed in the experimental data, background events, σQED is the cross section of the selected QED process, detection efficiency and εtrig QED trigger efficiency. Carlo (MC) simulation at the J/ψ resonance is sensitive to the c.m. energy and is imperfect

Detector

Data sample and Monte Carlo simulation

Analysis

Systematic uncertainty

Findings

Summary