4,957 research outputs found
Fission fragment mass reconstruction from Si surface barrier detector measurement
A method for plasma delay and pulse-height defect corrections for Si surface
barrier detectors (SBD) is presented. Based on known empirical formulae, simple
approximations involving the measured time-of-flight (TOF) and energy of the
ions were found and a mass reconstruction procedure was developed. The
procedure was applied for obtaining the fission fragment mass and angular
distributions from the Ni+Au reaction at 418 MeV and 383 MeV
incident energy using an array of eight SBDs.Comment: 3 pages, 1 table, 3 figures, submitted to NIM A ; 4 pages, 1 table, 5
figures, added discussion and figure
Flow fluctuations and long-range correlations: elliptic flow and beyond
These proceedings consist of a brief overview of the current understanding of
collective behavior in relativistic heavy-ion collisions. In particular, recent
progress in understanding the implications of event-by-event fluctuations have
solved important puzzles in existing data -- the "ridge" and "shoulder"
phenomena of long-range two-particle correlations -- and have created an
exciting opportunity to tightly constrain theoretical models with many new
observables.Comment: 10 pages, 2 figures, Proceedings for the 22nd International
Conference On Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter
2011), Annecy, France, May 23 - 28, 2011; includes Fig. 2 which was omitted
from journal submission for lack of spac
Sensitivity of Azimuthal Jet Tomography to Early Time Energy-Loss at RHIC and LHC
We compute the jet path-length dependence of energy-loss for higher azimuthal
harmonics of jet-fragments in a generalized model of energy-loss that can
interpolate between pQCD and AdS/CFT limits and compare results with Glauber
and CGC/KLN initial conditions. We find, however, that even the high-pT second
moment is most sensitive to the poorly known early-time evolution during the
first fm/c. Moreover, we demonstrate that quite generally the energy and
density-dependence leads to an overquenching jet fragments relative to the
first LHC -data, once the parameters of the energy-loss model are fixed
from -data at RHIC.Comment: 4 pages, 2 figures, version accepted for publication in J. Phys. G:
Nucl. Part. Phys. as conference proceedings for Quark Matter 2011, May 23 -
May 28, Annecy, Franc
Overview of experimental results in PbPb collisions at sqrt{s_NN} = 2.76 TeV by the CMS Collaboration
The CMS experiment at the LHC is a general-purpose apparatus with a set of
large acceptance and high granularity detectors for hadrons, electrons, photons
and muons, providing unique capabilities for both proton-proton and ion-ion
collisions. The data collected during the November 2010 PbPb run at sqrt{s_NN}
= 2.76 TeV was analyzed and multiple measurements of the properties of the hot
and dense matter were obtained. Global event properties, detailed study of jet
production and jet properties, isolated photons, quarkonia and weak bosons were
measured and compared to pp data and Monte Carlo simulations.Comment: 8 pages, 10 figures, proceedings for Quark Matter 2011, Annecy,
France, May 23-28, 201
Hadron Production at Intermediate at RHIC
Large proton and antiproton enhancement with respect to pions has been
observed at intermediate transverse momentum 2-5 GeV/ in Au+Au
collisions at RHIC. To investigate the possible source of this anomaly, the
production of mesons and two particle angular correlations triggered by
mid- baryons or mesons are studied. We also present the first measurement
of proton and antiproton production at GeV in Au+Au
collisions, which aims to study the energy dependence of the observed baryon
enhancement.Comment: 7 pages, 5 figures, proceedings of Hot Quarks 2004 workshop, Taos
Valley, New Mexico, 18-24 Jul 2004,, to be published in J. Phys.
Strangeness Report
The paper provides a short report on strangeness production in
ultrarelativistic nucleus-nucleus collision, with the main stress on strange
particle abundances.Comment: Proceedings of Quark Matter 200
Strange particle production at RHIC in a single-freeze-out model
Strange particle ratios and pT-spectra are calculated in a thermal model with
single freeze-out, previously used successfully to describe non-strange
particle production at RHIC. The model and the recently released data for phi,
Lambda, anti-Lambda, and K*(892) are in very satisfactory agreement, showing
that the thermal approach can be used to describe the strangeness production at
RHIC.Comment: We have added the comparison of the model predictions to the newly
released Lambda and K*(892) pT-spectra from STA
Event Reconstruction in the PHENIX Central Arm Spectrometers
The central arm spectrometers for the PHENIX experiment at the Relativistic
Heavy Ion Collider have been designed for the optimization of particle
identification in relativistic heavy ion collisions. The spectrometers present
a challenging environment for event reconstruction due to a very high track
multiplicity in a complicated, focusing, magnetic field. In order to meet this
challenge, nine distinct detector types are integrated for charged particle
tracking, momentum reconstruction, and particle identification. The techniques
which have been developed for the task of event reconstruction are described.Comment: Accepted for publication in Nucl. Instrum. A. 34 pages, 23 figure
Bulk properties and flow
In this report, I summarize the experimental results on {\bf bulk properties
and flow} presented at Quark Matter 2004. It is organized in four sections: 1)
Initial condition and stopping; 2) Particle spectra and freeze-outs; 3)
Anisotropic flow; 4) Outlook for future measurements.Comment: 10 pages, 4 figures, "Rapporteur-Conference Highlights", Quark Matter
2004, Oakland, January 11-1
Manifestation of transient effects in fission induced by relativistic heavy-ion collisions
We examine the manifestation of transient effects in fission by analysing
experimental data where fission is induced by peripheral heavy-ion collisions
at relativistic energies. Available total nuclear fission cross sections of
238U at 1 A GeV on gold and uranium targets are compared with a
nuclear-reaction code, where transient effects in fission are modelled using
different approximations to the numerical time-dependent fission-decay width: a
new analytical description based on the solution of the Fokker-Planck equation
and two widely used but less realistic descriptions, a step function and an
exponential-like function. The experimental data are only reproduced when
transient effects are considered. The deduced value of the dissipation strength
depends strongly on the approximation applied for the time-dependent
fission-decay width and is estimated to be of the order of 2x10**21 s**(-1). A
careful analysis sheds severe doubts on the use of the exponential-like
in-growth function largely used in the past. Finally, we discuss which should
be the characteristics of experimental observables to be most sensitive to
transient effects in fissionComment: 18 pages, 2 figures, background information on
http://www-w2k.gsi.de/kschmidt
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