120 likes | 135 Views
Tests of the Standard Model and a (m Z ). 2. Bolek Pietrzyk LAPP, Annecy, IN2P3, CNRS International Workshop e + e - collisions from f to y February 27 – March 2 2006, Novosibirsk, Russia. effective couplings. Precision measurements at Z pole. (hep-ex/0509008) Phys. Reports acc.
E N D
Tests of the Standard Modeland a(mZ) 2 Bolek Pietrzyk LAPP, Annecy, IN2P3, CNRS International Workshop e+e- collisions from f to y February 27 – March 2 2006, Novosibirsk, Russia Standard Model and alpha
effective couplings Precision measurements at Z pole (hep-ex/0509008) Phys. Reports acc. Precision of ISR corrections ~10-4 Precision of measurements ~10-3 Natural size of genuine Electroweak corrections is Standard Model and alpha
3s Precise Electroweak Measurement all measurements are created equal but a and mt are more equal than others George Orwell, Animal Farm Standard Model and alpha
Electroweak Radiative Corrections ….. depend on , and … Summer 2005 Standard Model and alpha
Phys. Rev. D72:057501, 2005 Standard Model and alpha
from SM fits 114 GeV Standard Model and alpha
Predicting mH and … searching for it Predicting mt and finding top SM fits, winter 1994 B. Pietrzyk, proceedings Moriond EW 1994 Standard Model and alpha
174.3±-5.1 (mt ) 2003 178.0±4.3 (mt) 172.7±2.9 2004 (mt) 2005 Recent changes in blue band plot progress in mt measurement 95% CL upper limit Standard Model and alpha
- history … since 1989 Crystal Ball BES CMD2 and KLOE measurements very minor change Standard Model and alpha
- CMD2, KLOE and SND results – very minor change CMD2 and KLOE points integrated separately, results of integration combined, Previous measurements in the r region were already relatively precise R Adding SND results changes a(mZ) by less than 1/10 s 2 R/R(CMD2 parametrisation used in our 2001 paper) Standard Model and alpha
– possible improvements now 15% unct. in1.05-2 GeV region 5% unct. – total a(mZ) unct. 0.00035 0.00027 The change in the Higgs mass is small, but if the central value in 1-2 GeV region changes by +- 1s, the central value of the Higgs mass changes by -9+16 GeV more precise measurements are important. 2 Standard Model and alpha
Summary and conclusions Precise EW measurements at the Z pole are now published (hep-ex/0509008). mH varies with and mt • Two important changes in the history of a(mZ2) : Crystal Ball and BES results • Very minor change introduced by CMD2, KLOE and SND results • previous measurements in the r region were already relatively precise • Looking forward to see also BABAR results. • New R measurements in the low cms energy region • (particularly 1-2 GeV) will be important. LHC will start at 2007 – Will the prediction from the SM fits for mH be as successful as it was for mt? Standard Model and alpha