1,170 research outputs found
Probing dense QCD matter in the laboratory: The CBM experiment at FAIR
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt will provide
unique research opportunities for the investigation of fundamental open
questions related to nuclear physics and astrophysics, including the
exploration of QCD matter under extreme conditions, which governs the structure
and dynamics of cosmic objects and phenomena like neutron stars, supernova
explosions, and neutron star mergers. The physics program of the Compressed
Baryonic Matter (CBM) experiment is devoted to the production and investigation
of dense nuclear matter, with a focus on the high-density equation-of-state
(EOS), and signatures for new phases of dense QCD matter. According to the
present schedule, the CBM experiment will receive the first beams from the FAIR
accelerators in 2025. This article reviews promising observables, outlines the
CBM detector system, and presents results of physics performance studies.Comment: 16 pages, 13 figures. Physica Scripta 202
Studies of dense nuclear matter at NICA
Laboratory experiments with high-energetic heavy-ion collisions offer the
opportunity to explore fundamental properties of nuclear matter, such as the
high-density equation-of-state, which governs the structure and dynamics of
cosmic objects and phenomena like neutron stars, supernova explosions, and
neutron star mergers. A particular goal and challenge of the experiments is to
unravel the microscopic degrees-of-freedom of strongly interaction matter at
high density, including the search for phase transitions, which may feature a
region of phase coexistence and a critical endpoint. As the theory of strong
interaction is not able to make firm predictions for the structure and the
properties of matter high baryon chemical potentials, the scientific progress
in this field is driven by experimental results. The mission of future
experiments at FAIR and NICA, which will complement the running experimental
programs at GSI, CERN, and RHIC, is to explore new diagnostic probes, which
never have been measured before at collision energies, where the highest
net-baryon densities will be created. The most promising observables, which are
expected to shed light on the nature of high-density QCD matter, comprise the
collective flow of identified particles including multi-strange (anti-)
hyperons, fluctuations and correlations, lepton pairs, and charmed particles.
In the following, the perspectives for experiments in the NICA energy range
will be discussed.Comment: 23 pages, 21 figures, Physics introduction to the Technical Design
Report on the Inner Tracking System of the MPD experiment at NIC
Partition Statistics Equidistributed with the Number of Hook Difference One Cells
Let be a partition, viewed as a Young diagram. We define the hook
difference of a cell of to be the difference of its leg and arm
lengths. Define to be the number of cells of with
hook difference one. In the paper of Buryak and Feigin (arXiv:1206.5640),
algebraic geometry is used to prove a generating function identity which
implies that is equidistributed with , the largest part of a
partition that appears at least twice, over the partitions of a given size. In
this paper, we propose a refinement of the theorem of Buryak and Feigin and
prove some partial results using combinatorial methods. We also obtain a new
formula for the q-Catalan numbers which naturally leads us to define a new
q,t-Catalan number with a simple combinatorial interpretation
Strange Particles and Neutron Stars - Experiments at Gsi
Experiments on strangeness production in nucleus-nucleus collisions at SIS
energies address fundamental aspects of modern nuclear physics: the
determination of the nuclear equation-of-state at high baryon densities and the
properties of hadrons in dense nuclear matter. Experimental data and
theoretical results will be reviewed. Future experiments at the FAIR
accelerator aim at the exploration of the QCD phase diagram at highest baryon
densities.Comment: %Invited talk given at the International Invited talk given at the
International Symposium on Heavy Ion Physics (ISHIP 2006) April 3-6 2006,
FIAS, Frankfurt, Germany Frankfurt, German
Sγ3 switch sequences function in place of endogenous Sγ1 to mediate antibody class switching
Immunoglobulin heavy chain (IgH) class switch recombination (CSR) replaces the initially expressed IgH Cμ exons with a set of downstream IgH constant region (CH) exons. Individual sets of CH exons are flanked upstream by long (1–10-kb) repetitive switch (S) regions, with CSR involving a deletional recombination event between the donor Sμ region and a downstream S region. Targeting CSR to specific S regions might be mediated by S region–specific factors. To test the role of endogenous S region sequences in targeting specific CSR events, we generated mutant B cells in which the endogenous 10-kb Sγ1 region was replaced with wild-type (WT) or synthetic 2-kb Sγ3 sequences or a synthetic 2-kb Sγ1 sequence. We found that both the inserted endogenous and synthetic Sγ3 sequences functioned similarly to a size-matched synthetic Sγ1 sequence to mediate substantial CSR to IgG1 in mutant B cells activated under conditions that stimulate IgG1 switching in WT B cells. We conclude that Sγ3 can function similarly to Sγ1 in mediating endogenous CSR to IgG1. The approach that we have developed will facilitate assays for IgH isotype–specific functions of other endogenous S regions
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