# Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance

## Abstract

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 »

- Authors:

- Publication Date:

- Research Org.:
- Stanford Linear Accelerator Center, Menlo Park, CA (United States)

- Sponsoring Org.:
- USDOE, Washington, DC (United States)

- OSTI Identifier:
- 10114075

- Report Number(s):
- SLAC-446

ON: DE95006090;

- DOE Contract Number:
- AC03-76SF00515

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: PBD: Mar 1994

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Z NEUTRAL BOSONS; LEPTONIC DECAY; ELECTRON-POSITRON INTERACTIONS; BHABHA SCATTERING; ELECTRONS; WEINBERG-SALAM GAUGE MODEL; LINEAR COLLIDERS; CROSS SECTIONS; STANFORD LINEAR COLLIDER DETECTOR; BEAM LUMINOSITY; WEINBERG ANGLE; STANDARD MODEL; PARTICLE PRODUCTION; 662310; 662430; 662380; 662210; WEAK AND ELECTROMAGNETIC INTERACTIONS OF LEPTONS; PROPERTIES OF LEPTONS; DECAYS OF INTERMEDIATE BOSONS; UNIFIED THEORIES AND MODELS

### Citation Formats

```
Pitts, K.T..
```*Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance*. United States: N. p., 1994.
Web. doi:10.2172/10114075.

```
Pitts, K.T..
```*Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance*. United States. doi:10.2172/10114075.

```
Pitts, K.T.. Tue .
"Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance". United States. doi:10.2172/10114075. https://www.osti.gov/servlets/purl/10114075.
```

```
@article{osti_10114075,
```

title = {Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance},

author = {Pitts, K.T.},

abstractNote = {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 to 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.},

doi = {10.2172/10114075},

journal = {},

number = ,

volume = ,

place = {United States},

year = {1994},

month = {3}

}