767 research outputs found
Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC
We present results from a harmonic decomposition of two-particle azimuthal
correlations measured with the STAR detector in Au+Au collisions for energies
ranging from GeV to 200 GeV. The third harmonic
, where is the
angular difference in azimuth, is studied as a function of the pseudorapidity
difference between particle pairs . Non-zero
{\vthree} is directly related to the previously observed large-
narrow- ridge correlations and has been shown in models to be
sensitive to the existence of a low viscosity Quark Gluon Plasma (QGP) phase.
For sufficiently central collisions, persist down to an energy of
7.7 GeV suggesting that QGP may be created even in these low energy collisions.
In peripheral collisions at these low energies however, is
consistent with zero. When scaled by pseudorapidity density of charged particle
multiplicity per participating nucleon pair, for central
collisions shows a minimum near {\snn} GeV.Comment: 7 pages, 4 figures, for submission to Phys. Rev. Let
Measurement of the mass difference and the binding energy of the hypertriton and antihypertriton
According to the CPT theorem, which states that the combined operation of
charge conjugation, parity transformation and time reversal must be conserved,
particles and their antiparticles should have the same mass and lifetime but
opposite charge and magnetic moment. Here, we test CPT symmetry in a nucleus
containing a strange quark, more specifically in the hypertriton. This
hypernucleus is the lightest one yet discovered and consists of a proton, a
neutron, and a hyperon. With data recorded by the STAR
detector{\cite{TPC,HFT,TOF}} at the Relativistic Heavy Ion Collider, we measure
the hyperon binding energy for the hypertriton, and
find that it differs from the widely used value{\cite{B_1973}} and from
predictions{\cite{2019_weak, 1995_weak, 2002_weak, 2014_weak}}, where the
hypertriton is treated as a weakly bound system. Our results place stringent
constraints on the hyperon-nucleon interaction{\cite{Hammer2002,
STAR-antiH3L}}, and have implications for understanding neutron star interiors,
where strange matter may be present{\cite{Chatterjee2016}}. A precise
comparison of the masses of the hypertriton and the antihypertriton allows us
to test CPT symmetry in a nucleus with strangeness for the first time, and we
observe no deviation from the expected exact symmetry
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
production at low transverse momentum in p+p and d+Au collisions at = 200 GeV
We report on the measurement of production in the dielectron
channel at mid-rapidity (|y|<1) in p+p and d+Au collisions at =
200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The
transverse momentum spectra in p+p for < 4 GeV/c and d+Au
collisions for < 3 GeV/c are presented. These measurements extend the
STAR coverage for production in p+p collisions to low .
The from the measured invariant cross section in
p+p and d+Au collisions are evaluated and compared to similar measurements at
other collision energies. The nuclear modification factor for is
extracted as a function of and collision centrality in d+Au and
compared to model calculations using the modified nuclear Parton Distribution
Function and a final-state nuclear absorption cross section
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