47,914 research outputs found
Effects of the magnetic field on the spallation reaction implemented by BUU coupled with a phase-space coalescence afterburner
Based on the Boltzmann-Uehling-Uhlenbeck (BUU) transport model coupled with a
phase-space coalescence afterburner, spallation reaction of at the
incident beam energy of E= 800 MeV/nucleon is studied. We find that
the number of test particles per nucleon has minor effects on the neutron to
proton ratio (n/p) of the produced heavier fragments while it affects much on
their yields. The external strong magnetic field affects the production of
heavier fragments much than the n/p of produced fragments. The n/p of free
nucleons is greatly affected by the strong magnetic field, especially for the
nucleons with lower energies.Comment: 5 pages, 6 figures, revised, accepted by EP
Linear Relations of High Energy Absorption/Emission Amplitudes of D-brane
We calculate the absorption amplitudes of a closed string state at arbitrary
mass level leading to two open string states on the D-brane at high energies.
As in the case of Domain-wall scattering we studied previously, this process
contains only one kinematic variable. However, in contrast to the power-law
behavior of Domain-wall scattering, its form factor behaves as exponential
fall-off in the high energy limit. After identifying the geometric parameter of
the kinematic, we derive the linear relations (of the kinematic variable) and
ratios among the high energy amplitudes corresponding to absorption of
different closed string states for each fixed mass level by D-brane. This
result is consistent with the coexistence of the linear relations and
exponential fall-off behavior of high energy string/D-brane amplitudes.Comment: 9 pages,1 figur
Linear Relations and their Breakdown in High Energy Massive String Scatterings in Compact Spaces
We calculate high energy massive scattering amplitudes of closed bosonic
string compactified on the torus. For each fixed mass level with given
quantized and winding momenta ((m/R),(1/2)nR), we obtain infinite linear
relations among high energy scattering amplitudes of different string states.
For some kinematic regimes, we discover that linear relations with N_{R}=N_{L}
break down and, simultaneously, the amplitudes enhance to power-law behavior
instead of the usual expoential fall-off behavior at high energies. It is the
space-time T-duality symmetry that plays a role here. This result is consistent
with the coexistence of the linear relations and the softer exponential
fall-off behavior of high energy string scattering amplitudes as we pointed out
prevously. It is also reminiscent of our previous work on the power-law
behavior of high energy string/domain-wall scatterings.Comment: 18 pages, 1 figur
- …