W-pair production in the process e+e-→lνqq̄′ and measurement of the WWγ and WWZ couplings
We perform a detailed analysis of the process e+e-→lνqq̄′ where we include all tree level Feynman diagrams that contribute to this final state. We study the sensitivity of this process to anomalous trilinear gauge boson couplings of the WWγ and WWZ vertices using two popular parametrizations. We use a maximum likelihood analysis of a five-dimensional differential cross section based on the W and W decay product angular distributions. We concentrate on CERN LEP 200 energies, taking s =175 GeV, and energies appropriate to the proposed Next Linear Collider, a high energy e+e- collider with center-of-mass energies s =500 and 1 TeV. At 175 GeV, g1Z can be measured to about ±0.2, κZ to ±0.2, and κγ to ±0.3 λZ to ±0.2 and λγ to ±0.3 at 95% C.L. assuming 500 pb-1 integrated luminosity. Although these will be improvements of existing measurements they are not sufficiently precise to test the standard model at the loop level and are unlikely to see deviations from SM expectations. At 500 GeV with 50 fb-1 integrated luminosity, g1Z can be measured to about ±0.01, κZ and κγ to ±0.005 and λZ and λγ to ±0.003 at 95% C.L. while at 1 TeV with 200 fb-1 integrated luminosity, κV and λV can be measured to about ±0.005 and ±10-3, respectively. The 500 GeV measurements will be at the level of loop contributions to the couplings and may show hints of new physics while the 1 TeV should be sensitive to new physics at the loop level.
|Journal||Physical Review D|
Gintner, M. (Mikulá), Godfrey, S, & Couture, G. (Gilles). (1995). W-pair production in the process e+e-→lνqq̄′ and measurement of the WWγ and WWZ couplings. Physical Review D, 52(11), 6249–6263. doi:10.1103/PhysRevD.52.6249