3,209 research outputs found
Extracting Event Dynamics from Event-by-Event Analysis
The problem of eliminating the statistical fluctuations and extracting the
event dynamics from event-by-event analysis is discussed. New moments
(for continuous distribution), and (for anomalous distribution) are
proposed, which are experimentally measurable and can eliminate the Poissonian
type statistical fluctuations to recover the dynamical moments and
. In this way, the dynamical distribution of the event-averaged
transverse momentum \bar{\pt} can be extracted, and the anomalous scaling of
dynamical distribution, if exists, can be recovered, through event-by-event
analysis of experimental data.Comment: 15 pages, 2 eps figures, Phys. Rev. C accepte
Improved Simulation of the Mass Charging for ASTROD I
The electrostatic charging of the test mass in ASTROD I (Astrodynamical Space
Test of Relativity using Optical Devices I) mission can affect the quality of
the science data as a result of spurious Coulomb and Lorentz forces. To
estimate the size of the resultant disturbances, credible predictions of
charging rates and the charging noise are required. Using the GEANT4 software
toolkit, we present a detailed Monte Carlo simulation of the ASTROD I test mass
charging due to exposure of the spacecraft to galactic cosmic-ray (GCR) protons
and alpha particles (3He, 4He) in the space environment. A positive charging
rate of 33.3 e+/s at solar minimum is obtained. This figure reduces by 50% at
solar maximum. Based on this charging rate and factoring in the contribution of
minor cosmic-ray components, we calculate the acceleration noise and stiffness
associated with charging. We conclude that the acceleration noise arising from
Coulomb and Lorentz effects are well below the ASTROD I acceleration noise
limit at 0.1 mHz both at solar minimum and maximum. The coherent Fourier
components due to charging are investigated, it needs to be studied carefully
in order to ensure that these do not compromise the quality of science data in
the ASTROD I mission.Comment: 20 pages, 14 figures, submitted to International Journal of Modern
Physics
Gutzwiller Projected wavefunctions in the fermonic theory of S=1 spin chains
We study in this paper a series of Gutzwiller Projected wavefunctions for S=1
spin chains obtained from a fermionic mean-field theory for general S>1/2 spin
systems [Phys. Rev. B 81, 224417] applied to the bilinear-biquadratic (J-K)
model. The free-fermion mean field states before the projection are 1D paring
states. By comparing the energies and correlation functions of the projected
pairing states with those obtained from known results, we show that the
optimized Gutzwiller projected wavefunctions are very good trial ground state
wavefunctions for the antiferromagnetic bilinear-biquadratic model in the
regime K0). We find that different topological phases of the
free-fermion paring states correspond to different spin phases: the weak
pairing (topologically non-trivial) state gives rise to the Haldane phase,
whereas the strong pairing (topologically trivial) state gives rise to the
dimer phase. In particular the mapping between the Haldane phase and Gutwziller
wavefunction is exact at the AKLT point K=1/3. The transition point between the
two phases determined by the optimized Gutzwiller Projected wavefunction is in
good agreement with the known result. The effect of Z2 gauge fluctuations above
the mean field theory is analyzed.Comment: 10 pages,7 figure
Stereotactic radiotherapy: An alternative option for refractory ventricular tachycardia to drug and ablation therapy
Refractory ventricular tachycardia (VT) often occurs in the context of organic heart disease. It is associated with significantly high mortality and morbidity rates. Antiarrhythmic drugs and catheter ablation represent the two main treatment options for refractory VT, but their use can be associated with inadequate therapeutic responses and procedure-related complications. Stereotactic body radiotherapy (SBRT) is extensively applied in the precision treatment of solid tumors, with excellent therapeutic responses. Recently, this highly precise technology has been applied for radioablation of VT, and its early results demonstrate a favorable safety profile. This review presents the potential value of SBRT in refractory VT
N N bar,Delta bar N, Delta N bar excitation for the pion propagator in nuclear matter
The particle-hole and Delta -hole excitations are well-known elementary
excitation modes for the pion propagator in nuclear matter. But, the excitation
also involves antiparticles, namely, nucleon-antinucleon, anti-Delta-nucleon
and Delta-antinucleon excitations. These are important for high-energy momentum
as well, and have not been studied before, to our knowledge. In this paper, we
give both the formulas and the numerical calculations for the real and the
imaginary parts of these excitations.Comment: Latex, 3 eps file
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