0000000000234620
AUTHOR
Jan Stern
Lepton-number violation and right-handed neutrinos in Higgs-less effective theories
Following previous work, we identify a symmetry S_nat that generalizes the concept of custodial symmetry, keeping under control deviations from the Standard Model (SM). To realize S_nat linearly, the space of gauge fields has to be extended. Covariant constraints formulated in terms of spurions reduce S_nat back to SU(2)_L x U(1)_Y. This allows for a covariant introduction of explicit S_nat-breaking parameters. We assume that S_nat is at play in a theory of electroweak symmetry-breaking without a light Higgs particle. We describe some consequences of this assumption, using a non-decoupling effective theory in which the loop expansion procedure is based on both momentum and spurion power cou…
Dispersive analysis ofKLμ3andKLe3scalar and vector form factors using KTeV data
Using the published KTeV samples of K{sub L} {yields} {pi}{sup {+-}}e{sup {-+}}{nu} and K{sub L} {yields} {pi}{sup {+-}}{mu}{sup {-+}}{nu} decays, we perform a reanalysis of the scalar and vector form factors based on the dispersive parameterization. We obtain phase space integrals I{sub K}{sup e} = 0.15446 {+-} 0.00025 and I{sub K}{sup {mu}} = 0.10219 {+-} 0.00025. For the scalar form factor parameterization, the only free parameter is the normalized form factor value at the Callan-Treiman point (C); our best fit results in ln C = 0.1915 {+-} 0.0122. We also study the sensitivity of C to different parametrizations of the vector form factor. The results for the phase space integrals and C a…