95039655
Lifetime measurements of unbound nuclear states
A Differential Plunger device for measuring the lifetimes of Unbound Nuclear States (DPUNS) is currently being built at the University of Manchester. The plunger has been designed to be able to work with the proton-, alpha-, beta- and isomer-tagging methods using the JUROGAM II - RITU - GREAT setup at the University of Jyvaskyla, Finland. Valuable nuclear-structure information can be investigated from the measurement of lifetimes in proton-and alpha-unbound nuclei. To date, nuclear structure information from proton emission has been obtained from a comparison of the experimentally measured half-life with that predicted from various tunnelling calculations. A crucial parameter required to perform these calculations is the deformation of the parent nucleus involved in the decay, which in all cases to date, has only ever been estimated or calculated from theory. DPUNS aims to address this logical weakness through the measurement of the lifetimes of excited states in these unbound nuclei. The first measurement of a lifetime in a proton-unbound nucleus was recently obtained for 109I. The results from this measurement were discussed along with the future physics programme that can be performed with DPUNS.
94646277
The nature of subvalent gallium and indium in aqueous media
Subvalent gallium can exist in aqueous solutions as Ga-Ga bonded gallium(II) species stabilised by halide ligands in the form of the complex anions Ga2X62- (X = Cl, Br or I) whose formation and rea ...
207879155
Isospin purity of T = 1 states in the A = 38 nuclei studied via lifetime measurements in 38
The Doppler Shift Attenuation Method has been used to measure lifetimes for levels in K at excitation energies of 1698, 2404, 2830, 2996 and 3671 keV, populated using the Ca(d,α)K reaction at a beam energy of 4.5 MeV. Values of 109(29), 95(22), 457(63), 130(40) and 160(50) fs respectively were measured and are compared with previous values obtained using different stopping powers. The matrix element for the transition between the Jπ = 2+T=1 and 0 + T=1 states in this Tz=0 nucleus is compared with the analogous transition in the other nuclei in the T=1 triplet, Ca (Tz=-1) and Ar (Tz=+1), and with the results of shell-model calculations. PACS numbers: 21.10.-k, 21.10.Tg, 21.60.Cs, 23.20.Js,27.30.+t Current address: Department of Physics, University of York, Heslington, York, YO10 5DD, UK. Current address: Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA. Current address: Department of Physics, University of Richmond, Richmond, VA 23173, USA.
120317800
First {$\gamma$}-ray spectroscopy of Fe49 and Ni53: Isospin-breaking effects at large proton excess
Isospin-breaking effects have been studied for the first time in T=(3/2) isobaric analog states. Gamma decays have been observed from T{sub z}=-(3/2) nuclei, {sup 49}Fe and {sup 53}Ni, presented here in new level schemes, and mirror energy differences have been computed following observation of analog states in {sup 49}V and {sup 53}Mn, respectively. Shell-model calculations in the fp shell are in good agreement with the data and reveal the importance of non-Coulomb isospin-breaking effects in T=(3/2) isobaric analog states. A two-step fragmentation process was developed to allow access to highly proton-rich nuclei and to produce each member of a mirror pair via mirrored fragmentation of a {sup 56}Ni secondary beam. This work represents the first study using this technique and demonstrates the power of this approach for future studies of isobaric analog states in very proton-rich systems.
122430943
Spectroscopy of Nuclei Approaching the Proton Drip-line Using a Secondary-fragmentation Technique with the RISING Detector Array
An experiment utilizing a double fragmentation reaction was performed to study isobaric analogue states in A similar to 50 nuclei approaching the proton drip-line. gamma-ray spectroscopy will be used to identify excited states in the neutron-deficient nuclei produced in the second fragmentation reaction. Excited state level schemes will be obtained, through comparison with states in their well-known mirror partners, along with information on Coulomb effects through measurements of the Coulomb energy differences between isobaric analogue excited states. The validity of isospin symmetry for nuclei approaching the proton drip-line can also be investigated and the information gained will aid in testing and improving fp shell model calculations. The analysis of the collected data is at a preliminary stage and current status of this work is reported.
14611363
General 2 charge geometries
Two charge BPS horizon free supergravity geometries are important in proposals for understanding black hole microstates. In this paper we construct a new class of geometries in the NS1-P system, corresponding to solitonic strings carrying fermionic as well as bosonic condensates. Such geometries are required to account for the full microscopic entropy of the NS1-P system. We then briefly discuss the properties of the corresponding geometries in the dual D1-D5 system.
3319486
Lifshitz as a deformation of Anti-de Sitter
A bstractWe consider holography for Lifshitz spacetimes with dynamical exponent z = 1+ϵ2, where ϵ is small. We show that the holographically dual field theory is a specific deformation of the relativistic CFT, corresponding to the z = 1 theory. Treating ϵ as a small expansion parameter we set up the holographic dictionary for Einstein-Proca models up to order ϵ2 in three and four bulk dimensions. We explain how renormalization turns the relativistic conformal invariance into non-relativistic Lifshitz invariance with dynamical exponent z = 1 + ϵ2. We compute the two-point function of the conserved spin two current for the dual two-dimensional field theory and verify that it is Lifshitz invariant. Using only QFT arguments, we show that a particular class of deformations of CFTs generically leads to Lifshitz scaling invariance and we construct examples of such deformations.
35115472
A consistent truncation of IIB supergravity on manifolds admitting a Sasaki-Einstein structure
We present a consistent truncation of IIB supergravity on manifolds admitting a Sasaki-Einstein structure, which keeps the metric and five real scalar fields. This theory can be further truncated to a constrained one-parameter family that depends on only the metric and one scalar, as well as to a theory with a metric and three scalars. The reduced theory admits supersymmetric and non-supersymmetric AdS5 and $ Ad{S_4} \times \mathbb{R} $ solutions. We analyze the spectrum around the AdS critical points and identify the dual operators.
52263753
Inhomogeneity simplified
We study models of translational symmetry breaking in which inhomogeneous matter field profiles can be engineered in such a way that black-brane metrics remain isotropic and homogeneous. We explore novel Lagrangians involving square root terms and show how these are related to massive gravity models and to tensionless limits of branes. Analytic expressions for the DC conductivity and for the low frequency scaling of the optical conductivity are derived in phenomenological models, and the optical conductivity is studied in detail numerically. The square root Lagrangians are associated with linear growth in the DC resistivity with temperature and also lead to minima in the optical conductivity at finite frequency, suggesting that our models may capture many features of heavy fermion systems.
1437149
Holographic Coulomb branch vevs
We compute holographically the vevs of all chiral primary operators for supergravity solutions corresponding to the Coulomb branch of = 4 SYM and find exact agreement with the corresponding field theory computation. Using the dictionary between 10d geometries and field theory developed to extract these vevs, we propose a gravity dual of a half supersymmetric deformation of = 4 SYM (on Mink4) by certain irrelevant operators.