Constraints on the new particle in Σ→ pμμ

Yu-Kuo HsiaoWith the collaborator C.Q. Geng

National Tsing-Huang University, TaiwanBased on ph/0509175, to appear in PLB.

• Experiment• Constraints from other modes• Summary• Comparison

New particles with different masses?

Dark matter particle with mass of (ph/0508572)

Axion-like particle with mass of 0.7 meV-2 meV from PVLAS Collaboration. (ex/0507107)

A light scalar boson of mass 1-10 MeV, accounting for the fluxes of 511 keV gamma ray.(PLB 624, 162)

Intermediate boson with mass of 214.3 MeV from HyperCP Collaboration. (PRL94, 021801)

ExperimentExperiment

The effective Hamiltonian

The Amplitude

The form factors

The Form FactorsThe Form Factors

Constraints from K→ Constraints from K→ ππμμμμ

ConstraintsConstraints from KL→ from KL→μμμμ

Constraints from KL→μμ

The models?

The models?

Comparison

Summary