Hi everybody :)(adsbygoogle = window.adsbygoogle || []).push({});

A lagrangian of the u and d quarks where they don't have a mass, shares chiral SU(2) and U(1) symmetries.

In the vacuum, we write

[itex] <0| \bar{Q} Q | 0 > = \eta [/itex]

where Q is the douplet of u and d quarks. In such a way we break chiral symmetries.

The current associated with the three axial broken symmetries creates three goldstone bosons, the pions, and in the approximation where d and u are massless, the pions are massless too.

Now I just don't understand the following point: breaking the symmetry, we give a mass to u and d quarks, as Peskin says in pag. 669.

How can these quarks and their relative antiquarks form the pions, which we said to be massless?

**Physics Forums - The Fusion of Science and Community**

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

# Quarks effective masses and the pions

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

Loading...

Similar Threads - Quarks effective masses | Date |
---|---|

I Question about gauge invariance and the A-B effect | Mar 3, 2018 |

B How did we measure the mass of Quarks? | Jun 1, 2017 |

I What mediates the exchange force? | Feb 18, 2017 |

I Beta radiation | Apr 9, 2016 |

How do quarks determine which quarks to pair with? | Sep 29, 2015 |

**Physics Forums - The Fusion of Science and Community**