122190148
A mass-selecting apparatus to measure the energy loss of fission fragments in gases
Abstract We describe an apparatus combining solid-state and gas ionization chamber techniques to measure — for both fragments released in a fission event — the energy lost in a given gaseous range and the residual energy. This device allows to measure the energy loss in gases of fission fragments selecting their masses The performances of the apparatus are discussed referring to the data obtained by slowing down fission fragments from 252 Cf in gaseous argon.
122896950
Measurement of parity nonconserving neutron spin rotation in lanthanum
The rotation, phi/sub pnc/, of a neutron beam polarization vector due to parity nonconserving forces is measured in a lanthanum target. It is found that phi/sub pnc//l = -(21.9 +- 2.9) x 10- /sup 5/ rad/cm, where the negative sign corresponds to a left-handed rotation of the neutron spin about its momentum.
118381163
Holographic dark energy interacting with dark matter
We investigate a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cold dark matter coupled to a dark energy which is given by the modified holographic Ricci cutoff. The interaction used is linear in both dark energy densities, the total energy density and its derivative. Using the statistical method of $\chi^2$-function for the Hubble data, we obtain $H_0=73.6km/sMpc$, $\omega_s=\gamma_s -1=-0.842$ for the asymptotic equation of state and $ z_{acc}= 0.89 $. The estimated values of $\Omega_{c0}$ which fulfill the current observational bounds corresponds to a dark energy density varying in the range $0.25R < \ro_x < 0.27R$.
119112732
Comments on Unified Dark Energy and Dark Matter from a Scalar Field Different from Quintessence
In a recent paper by C. Gao, M. Kunz, A. Liddle and D. Parkinson [arXiv:0912.0949], the unification of dark matter and dark energy was explored within a theory containing a scalar field of non-Lagrangian type. This scalar field, different from the classic quintessence, can be obtained from the scalar field representation of an interacting two-fluid mixture described in the paper by L.P. Chimento and M. Forte [arXiv:0706.4142]