2,381 research outputs found
Possible Cosmological Implications of the Quark-Hadron Phase Transition
We study the quark-hadron phase transition within an effective model of QCD,
and find that in a reasonable range of the main parameters of the model, bodies
with quark content between and 10 solar masses can have been formed
in the early universe. In addition, we show that a significant amount of
entropy is released during the transition. This may imply the existence of a
higher baryon number density than what is usually expected at temperatures
above the QCD scale. The cosmological QCD transition may then provide a natural
way for decreasing the high baryon asymmetry created by an Affleck-Dine like
mechanism down to the value required by primordial nucleosynthesis.Comment: 19 pages, LaTeX, 5 Postscript figures included. Submitted to Journal
of Physics
Partial purification and properties of the external NADH dehydrogenase from cuckoo-pint (Arum maculatum) mitochondria
Nucleon-nucleon interaction in the Skyrme model
We consider the interaction of two skyrmions in the framework of the sudden
approximation. The widely used product ansatz is investigated. Its failure in
reproducing an attractive central potential is associated with terms that
violate G-parity. We discuss the construction of alternative ans\"atze and
identify a plausible solution to the problem.Comment: 18 pages, 9 figure
Proteome Profiling of Breast Tumors by Gel Electrophoresis and Nanoscale Electrospray Ionization Mass Spectrometry
We have conducted proteome-wide analysis of fresh surgery specimens derived from breast cancer patients, using an approach that integrates size-based intact protein fractionation, nanoscale liquid separation of peptides, electrospray ion trap mass spectrometry, and bioinformatics. Through this approach, we have acquired a large amount of peptide fragmentation spectra from size-resolved fractions of the proteomes of several breast tumors, tissue peripheral to the tumor, and samples from patients undergoing noncancer surgery. Label-free quantitation was used to generate protein abundance maps for each proteome and perform comparative analyses. The mass spectrometry data revealed distinct qualitative and quantitative patterns distinguishing the tumors from healthy tissue as well as differences between metastatic and non-metastatic human breast cancers including many established and potential novel candidate protein biomarkers. Selected proteins were evaluated by Western blotting using tumors grouped according to histological grade, size, and receptor expression but differing in nodal status. Immunohistochemical analysis of a wide panel of breast tumors was conducted to assess expression in different types of breast cancers and the cellular distribution of the candidate proteins. These experiments provided further insights and an independent validation of the data obtained by mass spectrometry and revealed the potential of this approach for establishing multimodal markers for early metastasis, therapy outcomes, prognosis, and diagnosis in the future. © 2008 American Chemical Society
|Delta B|=1 Weak Effective Lagrangian in the Minimal Flavor Violation Supersymmetry
To evaluate the weak decays of b-hadrons, the weak effective
Lagrangian is the foundation. Any new physics beyond the standard model (SM)
would contribute to the effective Lagrangian through the loop integration at
the weak scale and evolution from the weak scale down to the hadronic scale. In
this work we present a systematic analysis on the effective Lagrangian which
mediates hadronic processes in the framework of the minimal
flavor violation supersymmetry as well as a numerical evaluation of the Wilson
coefficients in the effective theory.Comment: Latex,16 pages plus 5 figures, PRD versio
Spontaneous annihilation of high-density matter in the electroweak theory
In the presence of fermionic matter the topologically distinct vacua of the
standard model are metastable and can decay by tunneling through the sphaleron
barrier. This process annihilates one fermion per doublet due to the anomalous
non-conservation of baryon and lepton currents and is accompanied by a
production of gauge and Higgs bosons. We present a numerical method to obtain
local bounce solutions which minimize the Euclidean action in the space of all
configurations connecting two adjacent topological sectors. These solutions
determine the decay rate and the configuration of the fields after the
tunneling. We also follow the real time evolution of this configuration and
analyze the spectrum of the created bosons. If the matter density exceeds some
critical value, the exponentially suppressed tunneling triggers off an
avalanche producing an enormous amount of bosons.Comment: 38 pages, 6 Postscript figure
Electromagnetic Meson Production in the Nucleon Resonance Region
Recent experimental and theoretical advances in investigating electromagnetic
meson production reactions in the nucleon resonance region are reviewed.Comment: 75 pages, 42 figure
Quasi-Elastic Scattering in the Inclusive (He, t) Reaction
The triton energy spectra of the charge-exchange C(He,t) reaction
at 2 GeV beam energy are analyzed in the quasi-elastic nucleon knock-out
region. Considering that this region is mainly populated by the charge-exchange
of a proton in He with a neutron in the target nucleus and the final proton
going in the continuum, the cross-sections are written in the distorted-wave
impulse approximation. The t-matrix for the elementary exchange process is
constructed in the DWBA, using one pion- plus rho-exchange potential for the
spin-isospin nucleon- nucleon potential. This t-matrix reproduces the
experimental data on the elementary pn np process. The calculated
cross-sections for the C(He,t) reaction at to triton
emission angle are compared with the corresponding experimental data, and are
found in reasonable overall accord.Comment: 19 pages, latex, 11 postscript figures available at
[email protected], submitted to Phy.Rev.
Complete analysis on the next-to-leading order supersymmetric QCD corrections to mixing
We present a complete next-to-leading-order calculation of the QCD
corrections to () mixing in the framework of the
minimal flavor violating (MFV) supersymmetry. We take into account the
contributions from the gluino and find that the gluino-mediated corrections
modify the LO result obviously even when the mass of gluino . In general, one cannot neglect gluino contributions.Comment: 91 pages + 11 eps figures, publication version in PR
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