Abstract: Studying the glue which binds us all: the needs and requirements for an e+A collider
The surprisingly dominant role of gluons in nucleons that are viewed by a high-energy probe has
recently been found. Their density grows rapidly when one probes gluons which carry smaller fractions of
the proton's momentum, x, and when the target nucleons are in a nucleus. This is due
to a QCD cascade process. At high densities, soft gluons combine into harder ones and eventually
there is a saturation of gluons. This scale, Qs, depends on both x and the spatial
resolution with which the nucleon is probed. When Qs is large, the coupling is weak and
the large occupancy means the behavior is almost classical (CGC).
Performing DIS measurements in e+A collisions at high energies makes it uniquely possible to determine the
spatial and momentum distributions of gluons for x < 0.01. Studying the CGC is necessary to
quantitatively interpret RHI collisions, as this forms the initial conditions in A+A collisions at both RHIC
and the LHC.
In order to realise this, studies are underway to develop concepts of an e+A collider. In
this presentation, I will present the current status of the work at BNL towards an eRHIC
concept and associated requirements for an e+A detector.