2,851 research outputs found
Precursor of Color Superconductivity in Hot Quark Matter
We investigate possible precursory phenomena of color superconductivity in
quark matter at finite temperature T with use of a simple Nambu-Jona-Lasinio
model. It is found that the fluctuating pair field exists with a prominent
strength even well above the critical temperature T_c. We show that the
collective pair field has a complex energy located in the second Riemann sheet,
which approaches the origin as T is lowered to T_c. We discuss the possible
relevance of the precursor to the observables to be detected in heavy ion
collisions.Comment: 5 pages, 3 figures, version to appear in Phys. Rev. D. Discussions
are enlarged on the physical origin of the large fluctuation of the pair
field and its phenomenological consequences. References are adde
Chiral and Color-superconducting Phase Transitions with Vector Interaction in a Simple Model (Addenda)
In the preceding paper(Prog.Theor.Phys.108(2002)929 or hep-ph/0207255), we
have shown that the critical line of the first order chiral transition of QCD
can have two endpoints. In this addendum, we elucidate the mechanism to realize
the two-endpoint structure in the QCD phase diagram and argue the robustness
for the appearance of such an interesting phase structure
Spin 3/2 Penta-quarks in anisotropic lattice QCD
A high-precision mass measurement for the pentaquark (5Q) Theta^+ in
J^P=3/2^{\pm} channel is performed in anisotropic quenched lattice QCD using a
large number of gauge configurations as N_{conf}=1000. We employ the standard
Wilson gauge action at beta=5.75 and the O(a) improved Wilson (clover) quark
action with kappa=0.1210(0.0010)0.1240 on a 12^3 \times 96 lattice with the
renormalized anisotropy as a_s/a_t = 4. The Rarita-Schwinger formalism is
adopted for the interpolating fields. Several types of the interpolating fields
with isospin I=0 are examined such as (a) the NK^*-type, (b) the
(color-)twisted NK^*-type, (c) a diquark-type. The chiral extrapolation leads
to only massive states, i.e., m_{5Q} \simeq 2.1-2.2 GeV in J^P=3/2^- channel,
and m_{5Q} = 2.4-2.6 GeV in J^P=3/2^+ channel. The analysis with the hybrid
boundary condition(HBC) is performed to investigate whether these states are
compact 5Q resonances or not. No low-lying compact 5Q resonance states are
found below 2.1GeV.Comment: 15 pages, 6 figures, 4 table
Precursor of Color Superconductivity
We investigate possible precursory phenomena of color superconductivity at
finite temperature with an effective theory of QCD. It is found that the
fluctuation of the diquark pair field exists with a prominent strength even
well above the critical temperature . We show that such a fluctuaiton
forms a collective mode, the corresponding pole of which approaches the origin
as is lowered to in the complex energy plane. We discuss the possible
relevance of the precursor to the observables to be detected in heavy-ion
collisions.Comment: 4 pages, 5 figures, Talk presented at the XVIth International
Conference on Particles and Nuclei (PANIC02), Osaka, Japan, Sep.30 - Oct.4,
2002, Uses espcrc1.st
Protein-crystal growth experiment (planned)
To evaluate the effectiveness of a microgravity environment on protein crystal growth, a system was developed using 5 cubic feet Get Away Special payload canister. In the experiment, protein (myoglobin) will be simultaneously crystallized from an aqueous solution in 16 crystallization units using three types of crystallization methods, i.e., batch, vapor diffusion, and free interface diffusion. Each unit has two compartments: one for the protein solution and the other for the ammonium sulfate solution. Compartments are separated by thick acrylic or thin stainless steel plates. Crystallization will be started by sliding out the plates, then will be periodically recorded up to 120 hours by a still camera. The temperature will be passively controlled by a phase transition thermal storage component and recorded in IC memory throughout the experiment. Microgravity environment can then be evaluated for protein crystal growth by comparing crystallization in space with that on Earth
- …