5,371 research outputs found
Measuring the spectral running from cosmic microwave background and primordial black holes
We constrain the spectral running by combining cosmic microwave background
(CMB) data, baryon acoustic oscillation (BAO) data and the constraint from
primordial black holes (PBHs). We find that the constraint from PBHs has a
significant impact on the running of running of scalar spectral index, and a
power-law scalar power spectrum without running is consistent with
observational data once the constraint from PBHs is taken into account. In
addition, from the constraints on the slow-roll parameters, the derived tensor
spectral index in the single-field slow-roll inflation model is quite small,
namely which will be very difficult to be
measured by CMB data only in the future, and the absolute value of derived
running of tensor spectral index is not larger than at 95%
confidence level.Comment: 5 pages, 3 figure
Production of heavy isotopes in transfer reactions by collisions of U+U
The dynamics of transfer reactions in collisions of two very heavy nuclei
U+U is studied within the dinuclear system (DNS) model.
Collisions of two actinide nuclei form a super heavy composite system during a
very short time, in which a large number of charge and mass transfers may take
place. Such reactions have been investigated experimentally as an alternative
way for the production of heavy and superheavy nuclei. The role of collision
orientation in the production cross sections of heavy nuclides is analyzed
systematically. Calculations show that the cross sections decrease drastically
with increasing the charged numbers of heavy fragments. The transfer mechanism
is favorable to synthesize heavy neutron-rich isotopes, such as nuclei around
the subclosure at N=162 from No (Z=102) to Db (Z=105).Comment: 4 pages, 4 figure
Spin Correlations in top quark pair production near threshold at the Linear Collider
We investigate the spin correlations in top quark pair production near
threshold at the linear collider. Comparing with the results above
the threshold region, we find that near the threshold region the off-diagonal
basis, the optimized decomposition of the top quark spins above the threshold
region, does not exist, and the beamline basis is the optimal basis, in which
there are the dominant spin components: the up-down (UD) component for scattering and the down-up (DU) component for scattering can
make up more than 50% of the total cross section, respectively.Comment: 12 pages, 3 figures, minor modification
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