Family Gauge Boson Mass Estimated from $K^{+}\to {\pi }^{+}\nu \bar{\nu }$

Abstract

It is emphasized that a rare decay $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ becomes promising in a future search for a new particle, because the theoretical treatment is well established and the value of the branching ratio $Br(K^{+}\to {\pi }^{+}\nu \bar{\nu })$ is sensitive to a search for a new particle with a TeV scale mass. As an example, according to a U(3) family gauge boson model which predicts the lowest family gauge boson with a few TeV mass $M_{11}$, the branching ratio $Br(K^{+}\to {\pi }^{+}\nu \bar{\nu })$ is discussed. If we can obtain, in future, a slightly lower value $B{r}^{obs}\sim 0.9\times 10^{-10}$ compared with the present observed value $B{r}^{obs}=(1.7\pm 1.1)\times 10^{-10}$, we can conclude $M_{11}\sim$ a few TeV.

Comments: 9 pages, 2 figures