15,489 research outputs found
meson production of high-energy nuclear collisions at NLO
The transverse momentum spectrum of meson in relativistic heavy-ion
collisions is studied at the next-to-leading-order (NLO) within the
perturbative QCD, where the jet quenching effect in the QGP is incorporated
with the effectively medium-modified fragmentation functions using the
higher-twist approach. We show that the theoretical simulations could give nice
descriptions of PHENIX data on meson in both and central collisions at the RHIC, and also provide numerical predictions of
spectra in central collisions with ~TeV at the
LHC. The ratios of in and in central
collisions at ~GeV are found to overlap in a wide region, which
matches well the measured ratio by PHENIX. We demonstrate that,
at the asymptotic region when the ratios of
in both and are almost determined only by
quark jets fragmentation and thus approach to the one in
scattering; in addition, the almost identical gluon (quark) contribution
fractions to and to result in a rather moderate variation of
distribution at intermediate and high region in
relative to that in ; while a slightly higher at small
in can be observed due to larger suppression of gluon
contribution fraction to as compared to the one to . The
theoretical prediction for at the LHC has also been presented.Comment: 7 pages, 8 figures, 2 typos corrected, revision for publicatio
NLO Productions of and with a Global Extraction of the Jet Transport Parameter in Heavy Ion collisions
In this work, we pave the way to calculate the productions of and
mesons at large in p+p and A+A collisions at the RHIC and
the LHC. The meson fragmentation functions (FFs) in vacuum at
next-to-leading order (NLO) are obtained by evolving NLO DGLAP evolution
equations with rescaled FFs at initial scale GeV from
a broken SU(3) model, and the FFs in vacuum are taken from AKK08
parametrization directly. Within the framework of the NLO pQCD improved parton
model, we make good descriptions of the experimental data on and
in p+p both at the RHIC and the LHC. With the higher-twist
approach to take into account the jet quenching effect by medium modified FFs,
the nuclear modification factors for meson and meson at
the RHIC and the LHC are presented with different sets of jet transport
coefficient . Then we make a global extraction of at the
RHIC and the LHC by confronting our model calculations with all available data
on 6 identified mesons: , , , , , and
. The minimum value of the total for productions of
these mesons gives the best value of for Au+Au
collisions with GeV at the RHIC, and for Pb+Pb collisions with TeV at the LHC
respectively, with the QGP spacetime evolution given by an event-by-event
viscous hydrodynamics model IEBE-VISHNU. With these global extracted values of
, the nuclear modification factors of , , ,
, , and in A+A collisions are presented, and
predictions of yield ratios such as and at
large in heavy-ion collisions at the RHIC and the LHC are provided.Comment: 9 pages, 13 figures, 1 tabl
Nuclear suppression of meson yields with large at the RHIC and the LHC
We calculate meson transverse momentum spectra in p+p collisions as
well as their nuclear suppressions in central A+A collisions both at the RHIC
and the LHC in LO and NLO with the QCD-improved parton model. We have included
the parton energy loss effect in hot/dense QCD medium with the effectively
medium-modified fragmentation functions in the higher-twist approach of
jet quenching. The nuclear modification factors of meson in central
Au+Au collisions at the RHIC and central Pb+Pb collisions at the LHC are
provided, and a nice agreement of our numerical results at NLO with the ALICE
measurement is observed. Predictions of yield ratios of neutral mesons such as
, and at large in relativistic
heavy-ion collisions are also presented for the first time.Comment: 7 pages, 8 figure
Comparison of the co-gasification of sewage sludge and food wastes and cost-benefit analysis of gasification- and incineration-based waste treatment schemes
The compositions of food wastes and their co-gasification producer gas were compared with the existing data of sewage sludge. Results showed that food wastes are more favorable than sewage sludge for co-gasification based on residue generation and energy output. Two decentralized gasification-based schemes were proposed to dispose of the sewage sludge and food wastes in Singapore. Monte Carlo simulation-based cost-benefit analysis was conducted to compare the proposed schemes with the existing incineration-based scheme. It was found that the gasification-based schemes are financially superior to the incineration-based scheme based on the data of net present value (NPV), benefit-cost ratio (BCR), and internal rate of return (IRR). Sensitivity analysis was conducted to suggest effective measures to improve the economics of the schemes
The Yin and Yang of centromeric cohesion of sister chromatids: mitotic kinases meet protein phosphatase 2A
Accurate chromosome segregation during meiosis and mitosis is essential for the maintenance of genomic stability. Defects in the regulation of chromosome segregation during division predispose cells to undergo mitotic catastrophe or neoplastic transformation. Cohesin, a molecular glue holding sister chromatids together, is removed from chromosomes in a stepwise fashion during mitosis and meiosis. Cohesin at centromeres but not on chromosome arm remains intact until anaphase onset during early mitosis and the initiation of anaphase II during meiosis. Several recent studies indicate that the activity of protein phosphatase 2A is essential for maintaining the integrity of centromeric cohesin. Shugoshin, a guardian for sister chromatid segregation, may cooperate with and/or mediate PP2A function by suppressing the phosphorylation status of centromeric proteins including cohesin
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