Drell-Yan Scattering and the
Structure of Hadrons
Since it was first observed, the Drell-Yan reaction has
been an important tool, used to determine the substructure of
both the beam and target hadrons. Experimentally, we are now
working toward extending our knowledge of hadron structure
from a single dimension—longitudinal momentum described by xBj
include transverse degrees of freedom in the hadron as well.
Traditional deep inelastic scattering (DIS) experiments will
offer some answers about the transverse structure of the
hadron, but they will necessarily leave some questions
unanswered, with a complete answer requiring Drell-Yan
measurements as well. This workshop will focus on the future
theoretical and experimental work that is necessary to exploit
fully the upcoming Drell-Yan measurements that will take place
at Fermilab, CERN, Brookhaven and GSI-FAIR. A primary goal of
this workshop is to have theoreticians provide input to
experimentalists on what should be measured, and for
experimentalists to provide feedback to theoreticians on what
can be practically measured. Because the Drell-Yan
experiments will be collecting significant data samples in the
next few years, we believe that this is the time for this
workshop. The ability to measure the transverse structure of
hadrons in both DIS and Drell-Yan scattering is enabling a
test of the universality of transverse momentum dependent
parton distributions (TMD) and, more generally, of the present
understanding of (TMD) factorization theorems and color charge
flow in QCD. The Sivers’ function, f1T⊥
which arises from final-state interactions in DIS, but
initial-state interactions in Drell-Yan scattering, is
believed to change sign between the two processes.
Experimentalists have only recently been able to extract the
Sivers’ function from DIS scattering. Soon, a new generation
of Drell-Yan experiments will also be able to address this
Questions to be addressed at this
- What is the theoretical basis for expecting a change in
sign of the Sivers’ function when probed with Drell-Yan
scattering? Whatare the implications of an experimental
evidence for no sign change?
- Is there only a sign change, with a universal magnitude
for the Sivers’ function?
- How much do we know the shape of the Sivers’ function?
In order to reconcile the outcome of calculations in TMD-
and collinear-factorization, does the Sivers’ function
need to have a node?
- What do violations of the Lam-Tung relation for
Drell-Yan imply, in general and in terms of TMD?
- What can be measured about the structure of the pion and
kaon with Drell-Yan?
- How is the EMC effect manifest in Drell-Yan scattering?
- What is the underlying mechanism of the generation of
the hadron’s sea quark distributions?
While the first of these questions are focused on polarized
Drell-Yan experiments, it is important to remember that
there still remain issues of hadron structure that can only
be directly addressed with unpolarized (or polarization
averaged) Drell-Yan measurements.
Accommodations in Trento
Accomodations for registered participants will be handled by
ECT*. ECT* has obtained a discounted price at several hotels
in Trento. A single room costs between 63 and 71€.
Do not contact the hotels directly as you
will not receive the ECT* negotiated price.
These hotels include:
Please contact Gian Maria Ziglio
if you have questions or need
25 June 2012