I'm studying the [itex] \tau \rightarrow \rho \; \nu_{\tau} [/itex] decay. I'm asked to calculate the decay width, using a parameterization of the matrix element of the hadronic current. I actually find a matrix element of the form:(adsbygoogle = window.adsbygoogle || []).push({});

[tex] \left<\rho |\; \bar{u} \gamma^{\mu} \left( 1-\gamma^{5} \right ) d \; | 0\right> [/tex]

in which I have both the vector and the axial current (u and d are up and down quarks). The [itex] \rho [/itex] meson is a spin 1 vector meson, so I expect that only the term from the vector current survives. I've infact verified this statement in many articles which report:

[tex] \left<\rho |\; \bar{u} \gamma^{\mu} d \; | 0\right> = f_{\rho} m_{\rho} \epsilon ^{\mu} [/tex]

with [itex]\epsilon ^{\mu} [/itex] the polarization vector of the meson.

The problem is that I'm not able to demonstrate it. How can I formally demonstrate it? Is there any parity argument which allows me to exclude the axial term?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Vector Mesons decay constant

Loading...

Similar Threads for Vector Mesons decay |
---|

B Meson particles emitted from neutrons and protons |

I Excited hadrons v. fundamental particles |

B Can Leptons decay into mesons? |

I Feynman diagram of the Vector Boson Fusion |

**Physics Forums | Science Articles, Homework Help, Discussion**