HIC for FAIR logo Nuclear Physics Colloquium

Location: ITP, Science Campus Riedberg, Max-von-Laue-Str. 1, room 02.116 Time: Thursday, April 11, 2013, 4:30-5:30 pm (plus 10min for discussion)
Contact: hees@fias.uni-frankfurt.de

The relativistic distribution function for particles with spin at local thermodynamical equilibrium

Francesco Becattini (Università di Firenze, Florence)

We present an extension of relativistic single-particle distribution function for weakly interacting particles at local thermodynamical equilibrium including spin degrees of freedom, for massive spin-1/2 particles. We infer, on the basis of the global equilibrium case, that at local thermodynamical equilibrium particles acquire a net polarization proportional to the vorticity of the inverse temperature four-vector field. The obtained formula for polarization also implies that a steady gradient of temperature entails a polarization orthogonal to particle momentum. The single-particle distribution function in momentum space extends the so-called Cooper-Frye formula to particles with spin 1/2 and allows to predict their polarization in relativistic heavy ion collisions at the freeze-out.

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