Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance
Author(s) -
K. Pitts
Publication year - 1994
Language(s) - English
Resource type - Reports
DOI - 10.2172/10114075
Subject(s) - bhabha scattering , physics , electroweak interaction , center (category theory) , luminosity , resonance (particle physics) , scattering , electron–positron annihilation , particle physics , coupling (piping) , weinberg angle , atomic physics , nuclear physics , electron , crystallography , hadron , lepton , chemistry , optics , mechanical engineering , quantum mechanics , galaxy , engineering
The cross section for Bhabha scattering (e{sup +}e{sup {minus}} {yields} e{sup +}e{sup {minus}}) with polarized electrons at the center of mass energy of the Z{sup 0} resonance has been measured with the SLD experiment at the Stanford Linear Accelerator Center during the 1992 and 1993 runs. The electroweak couplings of the electron are extracted. At small angles the measurement is done in the SLD Silicon/Tungsten Luminosity Monitor (LMSAT). A detailed description of the design, construction, commissioning and operation of the LMSAT is provided. The integrated luminosity for 1992 is measured to be L = 420.86{plus_minus}2.56 (stat){plus_minus}4.23 (sys) nb{sup {minus}1}. The luminosity asymmetry for polarized beams is measured to be A{sub LR}(LUM) = (1.7 {plus_minus} 6.4) {times} 10{sup {minus}3}. The large angle polarized Bhabha scattering reveals the effective electron vector and axial vector couplings to the Z{sup 0} through the measurement of the Z{sup 0} {yields} e{sup +}e{sup {minus}} partial width, {Gamma}{sub ee}, and the parity violation parameter, A{sub e}. From the combined 1992 and 1993 data the effective electron vector and axial vector couplings are measured to be {bar g}{sub v}{sup e} = {minus}0.0495{plus_minus}0.0096{plus_minus}0.0030, and {bar g}{sub {alpha}}{sup e} = {minus}0.4977{plus_minus}0.0035{plus_minus}0.0064 respectively. The effective weak mixing angle is measured tomore » be sin{sup 2}{theta}{sub W}{sup eff} = 0.2251{plus_minus}0.0049{plus_minus}0.0015. These results are compared with other experiments.« less
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