944 research outputs found
New method of galactic axion search
An appealing candidate of the galactic dark matter is the axion, which was
postulated to solve the strong CP (Charge-conjugation Parity) violation problem
in the standard particle theory. A new experimental method is proposed to
determine the axion mass. The method uses collectively and coherently excited
atoms or molecules, the trigger laser inducing galactic axion absorption along
with signal photon emission to be detected.Comment: Finite size effect of target is incorporated. 5 pages, 3 figure
Determination of CP violation parameter using neutrino pair beam
Neutrino oscillation experiments under neutrino pair beam from circulating
excited heavy ions are studied. It is found that detection of double weak
events has a good sensitivity to measure CP violating parameter and distinguish
mass hierarchy patterns in short baseline experiments in which the
earth-induced matter effect is minimized.Comment: 9 pages, 6 figure
Dynamics of two-photon paired superradiance
We develop for dipole-forbidden transition a dynamical theory of two-photon
paired superradiance, or PSR for short. This is a cooperative process
characterized by two photons back to back emitted with equal energies. By
irradiation of trigger laser from two target ends, with its frequency tuned at
the half energy between two levels, a macroscopically coherent state of medium
and fields dynamically emerges as time evolves and large signal of amplified
output occurs with a time delay. The basic semi-classical equations in 1+1
spacetime dimensions are derived for the field plus medium system to describe
the spacetime evolution of the entire system, and numerically solved to
demonstrate existence of both explosive and weak PSR phenomena in the presence
of relaxation terms. The explosive PSR event terminates accompanying a sudden
release of most energy stored in the target. Our numerical simulations are
performed using a vibrational transition of
para-H molecule, and taking many different excited atom number densities
and different initial coherences between the metastable and the ground states.
In an example of number density close to cm and of high
initial coherence, the explosive event terminates at several nano seconds after
the trigger irradiation, when the phase relaxation time of ns is
taken. After PSR events the system is expected to follow a steady state
solution which is obtained by analytic means, and is made of many objects of
field condensates endowed with a topological stability.Comment: 31 pages, 15 figures. Revised for publication. Title slightly
changed, detailed explanation added, minor typos corrected. All equations and
figures unchange
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