2005 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and The Physical Society of Japan
Sunday–Thursday, September 18–22, 2005;
Maui, Hawaii
Session KA: QCD Beyond Three Quarks
2:00 PM–5:00 PM,
Thursday, September 22, 2005
Ritz-Carlton Hotel
Room: Salon 4
Sponsoring
Units:
DNP JPS
Chair: Peter Bosted, Thomas Jefferson National Accelerator Facility
Abstract ID: BAPS.2005.HAW.KA.4
Abstract: KA.00004 : Hadronization within the Nuclear Environment
4:15 PM–5:00 PM
Preview Abstract
Abstract
Author:
Edward R. Kinney
(University of Colorado at Boulder)
Details of the hadronization process remain difficult to probe.
Experimentally one can only detect the fully formed hadron. Studies
of parton fragmentation from high energy collisions are explained by
semi-empirical models, but
are typically insensitive to details of the formation process. By
studying
the fragmentation process within the nuclear medium, one can hope to
explore the time-development of the hadronic state, that is, the
dynamics of
confinement.
Recent
high-energy experiments at RHIC have provided new measurements
of fragmentation within both cold and hot partonic matter. Since
the properties of the hot matter are deduced from the produced
hadrons,
a more detailed understanding of the hadronization process may
allow one to learn
more precise information about the state formed in the
heavy-ion collision. Measurements from $d-Au$ collisions are
forthcoming which test the modifcation of hadronization in cold
nuclear matter, and at the same time, the $B$-factories are
determining the
basic fragmentation functions to an unparalled precision.
Semi-inclusive
deep inelastic scattering of leptons from nuclei
provides a unique window on the hadronization process in
cold nuclear matter since the momentum of the initially struck
parton is
experimentally determined; in addition, initial state hadronic
effects
are largely suppressed.
The influence of the nuclear medium on the production of hadrons
has been recently studied in the Hermes experiment at DESY in
semi-inclusive
deep-inelastic scattering of 27.6~GeV positrons off deuterium,
helium, neon,
nitrogen and krypton targets. Differential multiplicities for the
heavier nuclei relative to deuterium have been determined for
$\pi^+$, $\pi^0$, $\pi^-$, $K^+$, $K^-$, $p$ and $\bar p$,
as a function of the virtual
photon energy $\nu$, the fraction $z$ of the energy transfered to the
hadron, the hadron transverse momentum squared, $p_T^2$, and the
four-momentum squared of the virtual photon, $-Q^2$. New
measurements of
two-hadron attenuation will also be presented.
Strong nuclear
effects are seen, which depend also on hadron identity and
nuclear size.
Results will be
compared to predictions of theoretical models which seek to explain
hadron formation within the nuclear medium, and compared with recent
results from RHIC.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.HAW.KA.4