3,062 research outputs found
Search for Anomalous Top--Quark Interaction at LEP-2 Collider
We show that a search for
events at LEP--2 collider provide a possibility to improve significantly the
modern constraints on coupling constants of anomalous --quark interaction
via flavor--changing neutral currents.Comment: 12 pages, LaTeX, epsfig, 4 figures. Corrected typo
An evaluation of |Vus| and precise tests of the Standard Model from world data on leptonic and semileptonic kaon decays
We present a global analysis of leptonic and semileptonic kaon decay data,
including all recent results published by the BNL-E865, KLOE, KTeV, ISTRA+ and
NA48 experiments. This analysis, in conjunction with precise lattice
calculations of the hadronic matrix elements now available, leads to a very
precise determination of |Vus| and allows us to perform several stringent tests
of the Standard Model.Comment: LaTeX, 25 pages, 12 figures, 16 tables. Submitted to EPJC. v2: Minor
changes for accepted version. No numerical results change
Precision tests of the Standard Model with leptonic and semileptonic kaon decays
We present a global analysis of leptonic and semileptonic kaon decays data,
including all recent results by BNL-E865, KLOE, KTeV, ISTRA+, and NA48.
Experimental results are critically reviewed and combined, taking into account
theoretical (both analytical and numerical) constraints on the semileptonic
kaon form factors. This analysis leads to a very accurate determination of Vus
and allows us to perform several stringent tests of the Standard Model
Observation of the radiative kaon decay K- --> mu-pi0gammanu
Using data collected with the ISTRA+ spectrometer during the 2001 run of the
U-70 proton synchrotron in Protvino, we report the first observation of the
radiative kaon decay K- -->mu-pi0gammanu. We find Br(Kmu3g)/Br(Kmu3) for two
regions 5<Eg<30 and 30<Eg<60 MeV consistent with theoretical predictions. The
measured angular distribution asymmetry for the first region,
0.093+/-0.141, is two standard deviations away from the theoretical
prediction of 0.354. The measured asymmetry in the T-odd variable is
-0.03+/-0.13.Comment: 15 pages, 8 figurs, submitted to Yadernaya Fizik
- …