The PHOBOS experiment at RHIC - physics and capabilities. Page: 4 of 12
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Chromodynamics (QCD) predicts that the nature of the QCD vacuum will
change, resulting in a deconfined, chirally symmetric phase where the partons
are no longer bound within color-singlet mesons or hadrons 1. Many possible
signatures for such transitions have been suggested, such as the suppression (or
enhancement) of the production of strange or charmed mesons, fluctuations in
the numbers of emitted charged particles, or the modification of the free-space
properties of various mesons propagating through the highly excited region
produced in the Au-Au collisions.
2 PHOBOS Philosophy
Although several signatures for the Quark-Gluon Plasma (QGP) phase tran-
sition have been suggested, it remains unclear which, if any of these alone
would provide the strongest experimental evidence for new physics from rela-
tivistic heavy ion collisions. It is likely that a preponderance of circumstantial
evidence, with the concurrent anomalous behavior of several observables, will
point to the experimental verification of the existence of these new states of
matter. To study this behavior, the PHOBOS experiment is designed to com-
bine measurements of global properties, such as the charged-particle multiplic-
ity N, with detailed studies aimed at characterizing the microscopic aspects
of the collisions. Furthermore, the experiment will concentrate on performing
measurements at low pT, where the physics will be dominated by elementary
interactions rather than hard, parton-parton scattering events. It is in this
regime that particles produced from long range, long time-scale collective phe-
nomena are expected. Since the events which signify new physics are likely to
be quite rare, PHOBOS is designed to obtain minimum-bias data at the full
luminosity and event rate. The aim is to obtain a data sample which is initially
as unbiased as possible, so that trends in many observables may be followed.
3 RHIC Environment and PHOBOS
RHIC will provide a very challenging environment for any experiment. Al-
though it is not known exactly what this environment will be like, all models of
relativistic heavy-ion collisions suggest that it will be inhospitable. The RHIC
design luminosity of 2x1026 cm-2sec-1 is expected to yield approximately
600 minimum-bias collisions per second. Current models predict between 5000
and 10000 charged particles to be produced for each central collision, with this
number decreasing as the collisions become more peripheral. For minimum
bias events, the event rate coupled with the number of produced particles very
roughly suggests a charged particle flux on the order of 3 x 106 particles per2
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Back, B. B. The PHOBOS experiment at RHIC - physics and capabilities., article, November 17, 1998; Illinois. (https://digital.library.unt.edu/ark:/67531/metadc626711/m1/4/: accessed March 28, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.