909 research outputs found
Nuclear matrix element for two neutrino double beta decay from 136Xe
The nuclear matrix element for the two neutrino double beta decay (DBD) of
136Xe was evaluated by FSQP (Fermi Surface Quasi Particle model), where
experimental GT strengths measured by the charge exchange reaction and those by
the beta decay rates were used. The 2 neutrino DBD matrix element is given by
the sum of products of the single beta matrix elements via low-lying (Fermi
Surface) quasi-particle states in the intermediate nucleus. 136Xe is the
semi-magic nucleus with the closed neutron-shell, and the beta + transitions
are almost blocked. Thus the 2 neutrino DBD is much suppressed. The evaluated 2
neutrino DBD matrix element is consistent with the observed value.Comment: 7 pages 6 figure
Solar Neutrinos as Background in Direct Dark Matter Searches
The coherent contribution of all neutrons in neutrino nucleus scattering due
to the neutral current is examined considering the boron solar neutrinos. These
neutrinos could potentially become a source of background in the future dark
matter searches aiming at nucleon cross sections in the region well below the
few events per ton per year.Comment: 6 pages, 5 figures, Submitted for the DSU proceedings to be published
by the American institute of Physics (AIP). References adde
Isentropic thermodynamics in the PNJL model
We discuss the isentropic trajectories on the QCD phase diagram in the
temperature and the quark chemical potential plane using the
Nambu--Jona-Lasinio model with the Polyakov loop coupling (PNJL model). We
impose a constraint on the strange quark chemical potential so that the strange
quark density is zero, which is the case in the ultra relativistic heavy-ion
collisions. We compare our numerical results with the truncated estimates by
the Taylor expansion in terms of the chemical potential to quantify the
reliability of the expansion used in the lattice QCD simulation. We finally
discuss the strange quark chemical potential induced by the strangeness
neutrality condition and relate it to the ratio of the Polyakov loop and the
anti-Polyakov loop.Comment: 9 pages, 9 figure
On the existence of the critical point in finite density lattice QCD
We propose a method to probe the nature of phase transitions in lattice QCD
at finite temperature and density, which is based on the investigation of an
effective potential as a function of the average plaquette. We analyze data
obtained in a simulation of two-flavor QCD using p4-improved staggered quarks
with bare quark mass , and find that a first order phase transition
line appears in the high density regime for \mu_q/T \simge 2.5. We also
discuss the difference between the phase structures of QCD with non-zero quark
chemical potential and non-zero isospin chemical potential.Comment: 17 pages, 9 figure
Coherent photonuclear reactions for isotope transmutation
Coherent photonuclear isotope transmutation (CPIT) produces exclusively
radioactive isotopes (RIs) by coherent photonuclear reactions via E1 giant
resonances. Photons to be used are medium energy photons produced by laser
photons backscattered off GeV electrons. The cross sections are as large as 0.2
- 0.6 b, being independent of individual nuclides. A large fraction of photons
is effectively used for the photonuclear reactions, while the scattered GeV
electrons remain in the storage ring to be re-used. CPIT with medium energy
photons provides specific/desired RIs with the high rate and the high density
for nuclear science, molecular biology and for nuclear medicines.Comment: 8 pages, 2 figure
Numerical study of the equation of state for two flavor QCD at finite density
We discuss the equation of state for 2 flavor QCD at non-zero temperature and
density. Derivatives of with respect to quark chemical potential
up to fourth order are calculated, enabling estimates of the pressure,
quark number density and associated susceptibilities as functions of
via a Taylor series expansion. It is found that the fluctuations in the quark
number density increase in the vicinity of the phase transition temperature and
the susceptibilities start to develop a pronounced peak as is
increased. This suggests the presence of a critical endpoint in the plane.Comment: 5 pages, 4 figures, Talk at Confinement 200
- …