"Electromagnetic interaction of leptons and pions with heavy nuclei in ultra-peripheral ultra-relativistic collisions" (Kasia Mazurek, IFJ PAN, Krakow)

jeudi 25 nov. 2021, 10:45 → 12:00 Europe/Paris

salle de réunion (Batiment 27)

The photon-photon interaction in ultra-relativistic heavy-ion collision
is a source of the $(e^+,e^-)$ pairs.
The photon-photon fusion leads to lepton creation
in the broad configuration space around the ''collision'' point.
Those created close to heavy nuclei may undergo strong interaction with them.

The impact parameter space distribution of electrons and positrons are
calculated within the b-space EPA model of such collisions.
The evolution due to the electromagnetic interaction of $(e^+,e^-)$
with nuclei is studied, and the distortion of rapidity and transverse
momentum distributions are shown.
We show first exploratory results for the reaction Pb+Pb at
$\sqrt{s_{NN}}=$ 17.3~GeV (SPS) and 200~GeV (RHIC) energies.
We provide results for selected creation points and when integrating
over their position as dictated by the $b$-space EPA model.
We observe strong effects at low transverse momenta, so far not
measured regions of the phase space. In particular, we predict
a possible sizable accumulation of electrons with rapidities close
to the beam rapidity.
The EM effects lead to asymmetry in the production of electrons and
positrons when he previous calculation described only interaction of the spectator with charged pions.