K±l3 AND K0l3 FORM FACTORS

• 来源期刊: 中国物理C（英文版）
• 年，卷（期）: 2016,（10）
• 页码范围: 706-707
• 页数: 2页
• 语种: 中文

摘要

Assuming that only the vector current contributes to K → πlν decays,we write the matrix element as M ∝f+(t) [(PK + Pπ)μ-lγμ(1 + γ5)ν] + f-(t) [ml-l(1 + γ5)ν],(1) where PK and Pπ are the four-momenta of the K and π mesons,me is the lepton mass,and f+ and f-are dimensionless form factors which can depend only on t =(PK-Pπ)2,the square of the four-momentum transfer to the leptons.If timereversal invariance holds,f+ and f-are relatively real.Kμ3 experiments,discussed immediately below,measure f+ and f-,while Ke3 experiments,discussed further below,are sensitive only to f+ because the small electron mass makes the f-term negligible.