Speaker
Dr
Edmond Iancu
(Institut de Physique Théorique, Saclay)
Description
It is well known that the multiple interactions of a hard probe with
the dense quark-gluon plasma results in the "medium-induced" radiation
of soft gluon, responsible e.g. for jet energy loss. Such an emission
is computed using the BDMPS-Z formalism which has since been
generalised to include multiple medium-induced emissions. To get a
complete picture of the evolution of a jet in a dense medium, the main
missing ingredient is the inclusion of both medium-induced emissions
and "vacuum-like" emissions responsible for the parton shower from
large virtualities (of the order of the hard scale) down to the
hadronisation scale.
In this talk, we adopt a new approach and show that in a (leading)
double-logarithmic approximation, the time scales in the
evolution of a jet factorise. The vacuum-like parton cascades develop
at early times and exhibit angular ordering due to color coherence,
like the standard parton showers in the vacuum. The effect of the
medium can be simply formulated as a kinematic constraint which
limits the phase-space for vacuum-like radiation and thus reduces the parton
multiplicities. The gluons produced by these cascades lose their mutual
coherence via multiple scattering and thus act as independent sources
of energy loss via medium-induced radiation.
To the best of our knowledge, this is the first complete picture of jet
evolution in the medium derived from perturbative QCD. It has the
additional advantage of being well-suited for a Monte-Carlo
implementation. In the talk, we show how this simple evolution arise
and investigate its main properties.
Primary author
Dr
Edmond Iancu
(Institut de Physique Théorique, Saclay)
