Speaker
Description
Azimuthally differential HBT is a powerful tool for investigating the source shape at freeze out.
In heavy ion collisions, radial and anisotropic flow of the expanding medium have been observed.
These hydrodynamic expansions result in the deformation of the initial geometry.
Studying the deformation of the source shape is important for investigating the dynamics of the system evolution.
In the last decade, azimuthally differential femtoscopy with respect to the second order event plane has been measured.
The comparison between initial and final source eccentricities indicates the dilution of the source eccentricity by the expanding medium.
It is thought that initial density fluctuations generate higher order azimuthal anisotropy and it is expected
to be a good probe to constrain initial conditions and the viscosity of the QGP.
However it is not clear how the initial spatial fluctuations evolve to the geometry at freeze out.
Azimuthally differential femtoscopy with respect to the third order event plane provides new insights
into the medium expansion from the initial geometrical fluctuations to final anisotropies.
The azimuthal anisotropy flow coefficients vn fluctuate largely even in the same centrality class due to the fluctuations in the participant shape.
Recently event shape engineering(ESE) was suggested as a powerful tool to control event-by-event flow fluctuations
by selecting the magnitude of flow vectors $q_{2}$ and $q_{3}$.
Azimuthally differential HBT with ESE offers a detailed analysis of the relation between anisotropic flow and
the deformation of the source shape.
In this poster, we present azimuthally differential pion femtoscopy with respect to the second and the third order event plane and
the study of how the source eccentricity changes with $q_{2}$ and $q_{3}$ selections.
| Preferred Track | Collective Dynamics |
|---|---|
| Collaboration | ALICE |
