The weak mixing angle has been measured from the charge asymmetry of hadronic events with two different approaches using the DELPHI detector at LEP. Both methods are based on a momentum-weighted charge sum to determine the jet charge in both event hemispheres. In a data sample of 247 300 multihadronic Z0 decays a charge asymmetry of [Q(F)] - [Q(B)] = -0.0076 +/- 0.0012(stat.) +/- O.0005(exp. syst.) +/- 0.0014(frag.) and a raw forward-backward asymmetry of A(FB)raw = 0.0109 +/- 0.0020(stat.) +/- 0.0010(exp.syst.) +/- 0.0017(frag.) have been measured. This result corresponds to a value of sin2-theta(eff) = 0.2345 +/- 0.0030(exp.) +/- 0.0027(frag.) +/- sin2-theta(MSBAR) = 0.2341 +/- 0.0030(exp.) +/- 0.0027(frag.) and to sin2-theta(w) = 1 -m(w)2/m(z)2 = 0.2299 +/- 0.0030(exp.) +/- 0.0027(frag.) +/- 0.0028 (theor.). The experimental error is the quadratic sum of the statistical and the experimental systematic error and the theoretical error originates from a value of m(t) = 130 +/- 40 GeV/c2 and a range of m(H) from 45 GeV/c2 to 100 GeV/c2.
A MEASUREMENT OF SIN2-THETA-W FROM THE CHARGE ASYMMETRY OF HADRONIC EVENTS AT THE Z0 PEAK
DE LOTTO, Barbara;SCURI, Fabrizio;
1992-01-01
Abstract
The weak mixing angle has been measured from the charge asymmetry of hadronic events with two different approaches using the DELPHI detector at LEP. Both methods are based on a momentum-weighted charge sum to determine the jet charge in both event hemispheres. In a data sample of 247 300 multihadronic Z0 decays a charge asymmetry of [Q(F)] - [Q(B)] = -0.0076 +/- 0.0012(stat.) +/- O.0005(exp. syst.) +/- 0.0014(frag.) and a raw forward-backward asymmetry of A(FB)raw = 0.0109 +/- 0.0020(stat.) +/- 0.0010(exp.syst.) +/- 0.0017(frag.) have been measured. This result corresponds to a value of sin2-theta(eff) = 0.2345 +/- 0.0030(exp.) +/- 0.0027(frag.) +/- sin2-theta(MSBAR) = 0.2341 +/- 0.0030(exp.) +/- 0.0027(frag.) and to sin2-theta(w) = 1 -m(w)2/m(z)2 = 0.2299 +/- 0.0030(exp.) +/- 0.0027(frag.) +/- 0.0028 (theor.). The experimental error is the quadratic sum of the statistical and the experimental systematic error and the theoretical error originates from a value of m(t) = 130 +/- 40 GeV/c2 and a range of m(H) from 45 GeV/c2 to 100 GeV/c2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
