Speaker
Description
With almost 8 fb−1, the KLOE and KLOE-2 data sample represents a
unique, physics-rich sample and the largest dataset ever sized at an electron-
positron collider operating at the φ peak resonance. It represents a collection
of about 24 billion of φ mesons, whose decays include about 8 billion pairs
of neutral K mesons and about 300 million η mesons. With this sample, the
KLOE-2 Collaboration carries out a complete, wide hadron physic program by
investigating rare meson decays, γγ interaction and dark forces.
Various models and theories, like VMD (Vector Meson Dominance) or ChPT
(Chiral Perturbation Theory) can be tested with the η → π0γγ golden channel,
which predicted Branching Ratio (BR) differs by far from the experimental
value. With a highly pure η sample produced in φ → ηγ, KLOE-2 has performed
a refined measurement of this BR.
Following a tradition on dark searches initiated by KLOE; KLOE-2 takes the
witness by testing an opposite model to the U boson or ”dark photon”, where
the dark force mediator is an hypothetical leptophobic B boson that could show
up in the φ → ηB → ηπ0γ , η → γγ channel. The analysis and the preliminary
upper limit on the αB coupling constant will be reported.
A very distinctive feature of KLOE-2 is to allow for the possibility to in-
vestigate π0 production from γγ scattering by tagging final-state leptons from
e+e− → γ∗γ∗e+e− → π0e+e− in coincidence with the π0 in the barrel calorime-
ter. The analysis status and preliminary counting of the γ∗γ∗ → π0 events will
be shown.
KLOE-2 is also performing the search for the double suppressed φ → η π+π−
and the conversion φ → η μ+μ− decays with both η → γγ and η → 3π0 reac-
tions. We will report clear signals, which are seen for the first time.
Lastly, the ω cross section measurement in the e+e− → π+π−π0γISR channel
using the Initial State Radiation (ISR) method will be also presented.
| speaker affiliation | Jagiellonian University |
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