The KATRIN Experiment

The KArlsruhe TRitium Neutrino mass experiment, KATRIN, aims to search for the mass of the electron neutrino with a sensitivity of 0.2 eV/c^2 (90% C.L.) and a detection limit of 0.35 eV/c^2 (5 sigma). Both a positive or a negative result will have far reaching implications for cosmology and the standard model of particle physics and will give new input for astroparticle physics and cosmology. The major components of KATRIN are being set up at the Karlsruhe Institut of Technology in Karlsruhe, Germany, and test measurements of the individual components have started. Data taking with tritium is scheduled to start in 2012.Comment: 3 pages, 1 figure, proceedings of the TAUP 2009 International Conference on Topics in Astroparticle and Underground Physics, to be published in Journal of Physics, Conference Serie

Cluster-decay of hot 56^{56}Ni∗^* formed in 32^{32}S+24^{24}Mg reaction

The decay of $^{56}Ni^*$, formed in $^{32}S+^{24}Mg$ reaction at the incident energies $E_{cm}$=51.6 and 60.5 MeV, is calculated as a cluster decay process within the Preformed Cluster-decay Model (PCM) of Gupta et al. re-formulated for hot compound systems. The observed deformed shapes of the exit channel fragments are simulated by introducing the neck-length parameter at the scission configuration, which nearly coincides the $^{56}Ni$ saddle configuration. This is the only parameter of the model, which though is also defined in terms of the binding energy of the hot compound system and the ground-state binding energies of the various emitted fragments. The calculated s-wave cross sections for nuclear shapes with outgoing fragments separated within nuclear proximity limit (here $\sim$0.3 fm) can be compared with the experimental data, and the TKEs are found to be in reasonably good agreement with experiments for the angular momentum effects added in the sticking limit for the moment of inertia. Also, some light particle production (other than the statistical evaporation residue, not treated here) is predicted at these energies and, interestingly, $^4He$, which belongs to evaporation residue, is found missing as a dynamical cluster-decay fragment.Comment: 13 Pages, 12 figure

Simulations of the Galaxy Cluster CIZA J2242.8+5301 I: Thermal Model and Shock Properties

The giant radio relic in CIZA J2242.8+5301 is likely evidence of a Mpc sized shock in a massive merging galaxy cluster. However, the exact shock properties are still not clearly determined. In particular, the Mach number derived from the integrated radio spectrum exceeds the Mach number derived from the X-ray temperature jump by a factor of two. We present here a numerical study, aiming for a model that is consistent with the majority of observations of this galaxy cluster. We first show that in the northern shock upstream X-ray temperature and radio data are consistent with each other. We then derive progenitor masses for the system using standard density profiles, X-ray properties and the assumption of hydrostatic equilibrium. We find a class of models that is roughly consistent with weak lensing data, radio data and some of the X-ray data. Assuming a cool-core versus non-cool-core merger, we find a fiducial model with a total mass of $1.6 \times 10^{15}\,M_\odot$, a mass ratio of 1.76 and a Mach number that is consistent with estimates from the radio spectrum. We are not able to match X-ray derived Mach numbers, because even low mass models over-predict the X-ray derived shock speeds. We argue that deep X-ray observations of CIZA J2242.8+5301 will be able to test our model and potentially reconcile X-ray and radio derived Mach numbers in relics.Comment: 19 pages, 19 figure

Collective clusterization effects in light heavy ion reactions

The collective clusterization process, proposed for intermediate mass fragments (IMFs, 4$<$A$\le$28, 2$<$Z$\le$14) emitted from the hot and rotating compound nuclei formed in low energy reactions, is extended further to include also the emission of light particles (LPs, A$\le$4, Z$\le$2) from the fusion-evaporation residues. Both the LPs and IMFs are treated as the dynamical collective mass motion of preformed clusters through the barrier. Compared to IMFs, LPs are shown to have different characteristics, and the predictions of our, so-called, dynamical cluster-decay model are similar to those of the statistical fission model.Comment: 4 pages, 3 figures, Conferenc

Characterization of a microwave frequency resonator via a nearby quantum dot

We present measurements of a hybrid system consisting of a microwave transmission-line resonator and a lateral quantum dot defined on a GaAs heterostructure. The two subsystems are separately characterized and their interaction is studied by monitoring the electrical conductance through the quantum dot. The presence of a strong microwave field in the resonator is found to reduce the resonant conductance through the quantum dot, and is attributed to electron heating and modulation of the dot potential. We use this interaction to demonstrate a measurement of the resonator transmission spectrum using the quantum dot.Comment: 3 pages, 3 figure