2008 APS April Meeting and HEDP/HEDLA Meeting
Volume 53, Number 5
Friday–Tuesday, April 11–15, 2008;
St. Louis, Missouri
Session B14: Nucleon Spin Structure at High Energy
10:45 AM–11:45 AM,
Saturday, April 12, 2008
Hyatt Regency St. Louis Riverfront (formerly Adam's Mark Hotel),
Room: St. Louis G
Sponsoring
Unit:
DNP
Chair: Gerry Bunce, Brookhaven National Laboratory
Abstract ID: BAPS.2008.APR.B14.5
Abstract: B14.00005 : The STAR Forward GEM Tracker
11:33 AM–11:45 AM
Preview Abstract
Abstract
Author:
Bernd Surrow
(MIT)
Collaboration:
STAR
The STAR collaboration is preparing a tracking detector upgrade,
the Heavy Flavor Tracker (HFT) and
the Forward GEM Tracker (FGT) to further
investigate fundamental properties of the new state of strongly
interacting matter produced
in relativistic-heavy ion collisions at RHIC and to provide
fundamental studies of the
proton spin structure and dynamics in high-energy polarized
proton-proton collisions at RHIC.
The FGT will focus on novel spin physics measurements in
high-energy polarized proton-proton collisions,
determining the flavor dependence ($\Delta \bar{u}$ versus
$\Delta \bar{d}$) of the
polarized sea. These polarized parton distribution functions
(PDFs) are only weakly
constrained by polarized fixed target experiments, giving limited
insight into
the underlying mechanisms which produce the polarized sea. STAR
plans to probe these PDFs using parity violating
W production and decay.
The production of $W^{-(+)}$ bosons provides an ideal tool to study
the spin-flavor structure of the proton. $W^{-(+)}$ bosons are
produced in
$\bar{u}+d\,(\bar{d}+u)$ collisions and can be detected through
their leptonic decays, $e^{-}+\bar{\nu}_{e}\,(e^{+}+\nu_{e})$,
where only the respective charged lepton is measured.
The sensitivity of those measurements is enhanced in the forward
direction.
The discrimination of $\bar{u}+d (\bar{d}+u)$ quark combinations
requires distinguishing
between high $p_{T}$ $e^{-(+)}$ through their opposite charge
sign, which in turn requires
precise tracking information. An upgrade of the STAR forward
tracking system is
needed to provide the required tracking precision for charge sign
discrimination.
This upgrade will consist of six triple-GEM detectors with two
dimensional readout arranged
in disks along the beam axis.
The FGT design, the performance of triple-GEM prototype detectors
based on industrially produced GEM foils along with the status
of the FGT construction and the anticipated installation schedule
will be presented.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.APR.B14.5