122032402
High-frequency Ramsey excitation in a Penning trap
The Ramsey excitation method for high-precision mass-measurements of highly-charged ions has been investigated and benchmarked using H2+ ions in the Penning-trap mass-spectrometer SMILETRAP. The reason for using H2+ ions are their high cyclotron frequency which is typical for the highly-charged ions usually used at SMILETRAP. Two-, three- and four-pulse Ramsey excitation data are analyzed with the help of recent theoretical work and are compared with the previously used single-pulse excitation data. An improvement factor of 2.9 in the statistical uncertainty is achieved. Furthermore the mass of 76Se, included in the previous Q-value measurement of the 76Ge neutrinoless double beta decay, is checked using 76Se25+ ions and a three-pulse Ramsey excitation. The results show a convincing agreement with the measurement when using single-pulse excitation and therefore our Q-value of 2039.006(50) keV, performed with single-pulse excitation, is confirmed.
10468219
High-accuracy Penning trap mass measurements with stored and cooled exotic ions
The technique of Penning trap mass spectrometry is briefly reviewed particularly in view of precision experiments on unstable nuclei, performed at different facilities worldwide. Selected examples of recent results emphasize the importance of high-precision mass measurements in various fields of physics.
53658744
Q value and half-life of double-electron capture in 184Os
The observation of neutrinoless double-beta transitionswould reveal physics beyond the Standard Model, asit would establish neutrinos to be Majorana particles,which implies a violation of the lepton number conserva-tion. Experiments searching for these transitions have fo-cused on the detection of neutrinoless double-beta decay(0 ) rather than neutrinoless double-electron capture(0). One reason among others is in general the sig-ni cantly shorter half-life of the 0 process. However,in the case of neutrinoless double-electron capture, thetransition is expected to be resonantly enhanced if theinitial and the nal state of the transition are degeneratein energy [1{3].In this work, we investigate neutrinoless double-electron capture in
96561563
Measurements of ground-state properties for nuclear structure studies by precision mass and laser spectroscopy
Atomic physics techniques like Penning-trap and storage-ring mass spectrometry as well as laser spectroscopy have provided sensitive high-precision tools for detailed studies of nuclear ground-state properties far from the valley of ?-stability. Mass, moment and nuclear charge radius measurements in long isotopic and isotonic chains have allowed extraction of nuclear structure information such as halos, shell and subshell closures, the onset of deformation, and the coexistence of nuclear shapes at nearly degenerate energies. This review covers experimental precision techniques to study nuclear ground-state properties and some of the most recent results for nuclear structure studies.
119242601
Direct mass measurements of cadmium and palladium isotopes and their double-β transition Q values
The Q-value of the double-electron capture in Cd-108 has been determined to be (272.04 +/- 0.55) keV in a direct measurement with the double-Penning trap mass spectrometer TRIGA-TRAP. Based on this result a resonant enhancement of the decay rate of Cd-108 is excluded. We have confirmed the double-beta transition Q-values of Cd-106 and Pd-110 recently measured with the Penning-trap mass spectrometers SHIPTRAP and ISOLTRAP, respectively. Furthermore, the atomic masses of the involved nuclides Cd-106, Cd-108, Cd-110, Pd-106, Pd-108 and Pd-110 have been directly linked to the atomic mass standard.
120165522
Mass measurements on stable nuclides in the rare-earth region with the Penning-trap mass spectrometer TRIGA-TRAP
The masses of 15 stable nuclides in the rare-earth region have been measured with the Penning-trap mass spectrometer TRIGA-TRAP. This is the first series of absolute mass measurements linking these nuclides to the atomic-mass standard {sup 12}C. Previously, nuclear reaction studies almost exclusively determined the literature values of these masses in the Atomic-Mass Evaluation. The TRIGA-TRAP results show deviations on the order of 3-4 standard deviations from the latest published values of the Atomic-Mass Evaluation 2003 for some cases. However, the binding-energy differences that are important for nuclear structure studies have been confirmed and improved. The new masses are discussed in the context of valence proton-neutron interactions using double differences of binding energies, {delta}V{sub pn}(Z,N).
36063309
THE MASS-RADIUS RELATION FOR STAR-FORMING GALAXIES AT z ∼ 1.5-3.0
We present early results from a Hubble Space Telescope WFC3/IR imaging survey of star-forming galaxies in the redshift range 1.5 < z < 3.0. When complete, this survey will consist of 42 orbits of F160W imaging distributed amongst 10 survey fields on the line of sight to bright background QSOs, covering 65 arcmin^2 to a depth of 27.9 AB with a point-spread function FWHM of 0".18. In this contribution, we use a subset of these fields to explore the evolution of the galactic stellar mass-radius relation for a magnitude-limited sample of 102 spectroscopically confirmed star-forming galaxies ((SFR) ~ 30 M_☉ yr^(–1)) with stellar mass M_* ~ 10^(10) M_☉. Although the light profile of these galaxies often has an irregular, multi-component morphology, it is typically possible to describe the brightest component with a Sersic profile of index n ~ 1. The circularized half-light radius r e of the brightest component is on average r_e = 1.66 ± 0.79 kpc (i.e., ~50%-70% the size of local late-type galaxies with similar stellar mass), consistent with recent theoretical models that incorporate strong feedback from star-forming regions. The mean half-light radius increases with stellar mass and, at fixed stellar mass, evolves with cosmic time as ~(1 + z)^(–1.42), suggesting that high-redshift star-forming galaxies may evolve onto the local stellar mass-radius relation by redshift z ~ 1.
53550841
An octonionic formulation of the M-theory algebra
A bstractWe give an octonionic formulation of the N=1$$ \mathcal{N}=1 $$ supersymmetry algebra in D = 11, including all brane charges. We write this interms of a novel outer product, which takes a pair of elements of the division algebra A$$ \mathbb{A} $$ and returns a real linear operator on A$$ \mathbb{A} $$. More generally, with this product comes the power to rewrite any linear operation on ℝn$$ {\mathbb{R}}^n $$ (n =1, 2, 4, 8) in terms of multiplication in the n-dimensional division algebra A$$ \mathbb{A} $$. Finally, we consider the reinterpretation of the D =11 supersymmetry algebra as an octonionic algebra in D =4 and the truncation to division subalgebras.
11500580
Renormalization-group analysis of layered sine-Gordon type models
Abstract We analyze the phase structure and the renormalization group (RG) flow of the generalized sine-Gordon models with nonvanishing mass terms, using the Wegner–Houghton RG method in the local potential approximation. Particular emphasis is laid upon the layered sine-Gordon (LSG) model, which is the bosonized version of the multi-flavour Schwinger model and approaches the sum of two “normal”, massless sine-Gordon (SG) models in the limit of a vanishing interlayer coupling J . Another model of interest is the massive sine-Gordon (MSG) model. The leading-order approximation to the UV (ultraviolet) RG flow predicts two phases for the LSG as well as for the MSG, just as it would be expected for the SG model, where the two phases are known to be separated by the Coleman fixed point. The presence of finite mass terms (for the LSG and the MSG) leads to corrections to the UV RG flow, which are naturally identified as the “mass corrections”. The leading-order mass corrections are shown to have the following consequences: (i) for the MSG model, only one phase persists, and (ii) for the LSG model, the transition temperature is modified. Within the mass-corrected UV scaling laws, the limit of J → 0 is thus nonuniform with respect to the phase structure of the model. The modified phase structure of general massive sine-Gordon models is connected with the breaking of symmetries in the internal space spanned by the field variables. For the LSG, the second-order subleading mass corrections suggest that there exists a cross-over regime before the IR scaling sets in, and the nonlinear terms show explicitly that higher-order Fourier modes appear in the periodic blocked potential.
5513253
A HST/WFC3-IR Morphological Survey of Galaxies at z = 1.5-3.6. II. The Relation between Morphology and Gas-phase Kinematics
We analyze rest-frame optical morphologies and gas-phase kinematics as traced by rest-frame far-UV and optical spectra for a sample of 204 star-forming galaxies in the redshift range z ~ 2-3 drawn from the Keck Baryonic Structure Survey. We find that spectroscopic properties and gas-phase kinematics are closely linked to morphology: compact galaxies with semimajor axis radii r ≾ 2 kpc are substantially more likely than their larger counterparts to exhibit Lyα in emission. Although Lyα emission strength varies widely within galaxies of a given morphological type, all but one of 19 galaxies with Lyα equivalent width W_(Lyα) > 20 A have compact and/or multiple-component morphologies with r ≤ 2.5 kpc. The velocity structure of absorption lines in the galactic continuum spectra also varies as a function of morphology. Galaxies of all morphological types drive similarly strong outflows (as traced by the blue wing of interstellar absorption line features), but the outflows of larger galaxies are less highly ionized and exhibit larger optical depth at the systemic redshift that may correspond to a decreasing efficiency of feedback in evacuating gas from the galaxy. This v ~ 0 km s^(–1) gas is responsible both for shifting the mean absorption line redshift and attenuating W_(Lyα) (via a longer resonant scattering path) in galaxies with larger rest-optical half-light radii. In contrast to galaxies at lower redshifts, there is no evidence for a correlation between outflow velocity and inclination, suggesting that outflows from these puffy and irregular systems may be poorly collimated. Our observations are broadly consistent with theoretical models of inside-out growth of galaxies in the young universe, in which typical z ~ 2-3 star-forming galaxies are predominantly unstable, dispersion-dominated, systems fueled by rapid gas accretion that later form extended rotationally supported disks when stabilized by a sufficiently massive stellar component.
85464497
Functional renormalization group for quantized anharmonic oscillator
Abstract Functional renormalization group methods formulated in the real-time formalism are applied to the O ( N ) symmetric quantum anharmonic oscillator, considered as a 0 + 1 dimensional quantum field-theoric model, in the next-to-leading order of the gradient expansion of the one- and two-particle irreducible effective action. The infrared scaling laws and the sensitivity-matrix analysis show the existence of only a single, symmetric phase. The Taylor expansion for the local potential converges fast while it is found not to work for the field-dependent wavefunction renormalization, in particular for the double-well bare potential. Results for the gap energy for the bare anharmonic oscillator potential hint on improving scheme-independence in the next-to-leading order of the gradient expansion, although the truncated perturbation expansion in the bare quartic coupling provides strongly scheme-dependent results for the infrared limits of the running couplings.