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 |
V
us
| and allows us to perform several stringent tests of the Standard Model.
Upgrades to the LHCb computing infrastructure in the first long shutdown of the LHC have allowed for high quality decay information to be calculated by the software trigger making a separate offline ...event reconstruction unnecessary. Furthermore, the storage space of the triggered candidate is an order of magnitude smaller than the entire raw event that would otherwise need to be persisted. Tesla is an application designed to process the information calculated by the trigger, with the resulting output used to directly perform physics measurements.
The existence of a light dark force mediator has been tested with the KLOE detector at DAΦNE. This particle, called U, is searched for using the decay chain ϕ→ηU, η→π+π−π0, U→e+e−. No evidence is ...found in 1.5 fb−1 of data. The resulting exclusion plot covers the mass range 5<MU<470 MeV, setting an upper limit on the ratio between the U boson coupling constant and the fine structure constant, α′/α, of ⩽2×10−5 at 90% C.L. for 50<MU<420 MeV.
We have searched for a light vector boson U, the possible carrier of a “dark force”, with the KLOE detector at the DAΦNE e+e− collider, motivated by astrophysical evidence for the presence of dark ...matter in the Universe. Using e+e− collisions collected with an integrated luminosity of 239.3 pb−1, we look for a dimuon mass peak in the reaction e+e−→μ+μ−γ, corresponding to the decay U→μ+μ−. We find no evidence for a U vector boson signal. We set a 90% CL upper limit for the mixing parameter squared between the photon and the U boson of 1.6×10−5 to 8.6×10−7 for the mass region 520<mU<980 MeV.
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