119437909
A Survey of Open Clusters in the u'g'r'i'z' Filter System. 3. Results for the Cluster NGC 188
The authors continue the series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. The entire observed sample covered more than 100 clusters, but here they present data only on NGC 188, which is one of the oldest open clusters known in the Milky Way. They fit the Padova theoretical isochrones to the data. Assuming a solar metallicity for NGC 188, they find a distance of 1700 {+-} 100 pc, an age of 7.5 {+-} 0.7 Gyr, and a reddening E(B-V) of 0.025 {+-} 0.005. This yields a distance modulus of 11.23 {+-} 0.14.
118615935
Supersymmetric dark matter sectors
We investigate the properties of a dark matter sector where supersymmetry is a good symmetry. In this context we find that the stability of the dark matter candidate is possible even when R-parity is broken in the visible sector. In order to illustrate the idea we investigate a simple scenario where the dark matter candidate is the lightest scalar field in the dark sector which annihilates mainly into two sfermions when these channels are available. We study the relic density constraints and the predictions for the dark matter detection experiments.
34406165
Standard model with compactified spatial dimensions
We analyze the structure of the standard model coupled to gravity with spatial dimensions compactified on a three-torus. We find that there are no stable one-dimensional vacua at zero temperature, although there does exist an unstable vacuum for a particular set of Dirac neutrino masses.
119194544
Prospects and constraints for vector-like MFV matter at LHC
We examine the prospects for LHC discovery of SU(2)L singlet vector-like quarks that obey Minimal Flavour Violation (MFV) and are consistent with lower energy phenomenology. We study models where the vector-like quarks have the same quantum numbers as uR or dR, allowing mixing, which generally leads to significant low energy constraints. We find that at leading order in the MFV expansion there are two naturally phenomenologically viable MFV models of this type when the Weyl spinor components of the vector-like quarks are flavour triplets. We examine direct production bounds, flavour and electroweak precision data constraints for these models and determine the cross section for allowed values of the model parameters at LHC. For the models we identify as naturally phenomenologically viable, large amounts of parameter space afford a significant early discovery reach at LHC while being consistent with lower energy phenomenology.
1772638
Color octet scalars and high p_T four-jet events at the LHC
We study the effect of color octet scalars on the high transverse momenta four-jet cross section at the LHC. We consider both weak singlet and doublet scalars, concentrating on the case of small couplings to quarks. We find that a relatively early discovery at the LHC is possible for a range of scalar masses.
118379269
Finite temperature structure of the compactified standard model
We analyze the finite temperature structure of the standard model coupled to gravity with one and two dimensions compactified (on a circle and a torus). We find that finite temperature effects wash out any vacua which exist at zero temperature. We also discuss the possibility of transitions between the four-dimensional universe and the lower-dimensional spacetimes.
121561220
Proton-hole states in the N=30 neutron-rich isotope K-49
Excited states in the N=30 neutron-rich isotope {sup 49}K have been studied using multinucleon transfer reactions with thin targets and the PRISMA-CLARA spectrometer combined with thick-target {gamma}-coincidence data from Gammasphere. The d{sub 3/2} proton-hole state is located 92 keV above the s{sub 1/2} ground state, and the proton-particle f{sub 7/2} state is suggested at 2104 keV. Three other levels are established as involving the coupling to 2{sup +} of two neutrons above the N=28 shell. The measured or estimated lifetimes served to reinforce the interpretation of the observed level structure, which is found to be in satisfactory agreement with shell-model calculations.
12918880
Cross-shell excitation in two-proton knockout: Structure of Ca 52
Gade, A. Janssens, R. V. F. Bazin, D. Broda, R. Brown, B. A. Campbell, C. M. Carpenter, M. P. Cook, J. M. Deacon, A. N. Dinca, D. -C. Fornal, B. Freeman, S. J. Glasmacher, T. Hansen, P. G. Kay, B. P. Mantica, P. F. Mueller, W. F. Terry, J. R. Tostevin, J. A. Zhu, S.
121342637
Yrast states of neutron-rich N=83 nuclei from fission product gamma-ray studies
Prompt {gamma}-ray cascades in N=83 fission product nuclei near {sup 132}Sn have been studied at Eurogam II using a {sup 248}Cm source. Cross coincidences observed between {gamma} rays from complementary light and heavy fission fragments were vital for isotopic assignments. Yrast states in the N=83 isotones {sup 134}Sb, {sup 135}Te, and {sup 136}I are reported. The interpretation of the level schemes is based mainly on results of shell model calculations using empirical proton-proton interaction energies from {sup 134}Te, and proton-neutron interactions estimated from the well-known {sup 210}Bi level spectrum. {copyright} {ital 1997} {ital The American Physical Society}
120311197
Rotation-aligned coupling in Fe 61
New levels have been established above the 861-keV, $9/{2}^{+}$ isomeric state in $^{61}\mathrm{Fe}$. The observations can be reproduced satisfactorily by shell model calculations, but only after a significant lowering of the $\ensuremath{\nu}{g}_{9/2}$ single-particle energy with respect to the value determined empirically from levels outside a $^{48}\mathrm{Ca}$ core. The results are also described well within the scope of the particle-triaxial-rotor model assuming a deformation ${\ensuremath{\beta}}_{2}~0.24$. The present findings, together with the recently measured magnetic and quadrupole moments of this state, point toward a structure possibly associated with a prolate shape.
96468936
Collective oblate bands in Pb196
Evidence for collective oblate behavior in [sup 196]Pb is presented. One irregular and two regular bands of [ital M]1 transitions have been observed following the [sup 170]Er([sup 30]Si,4[ital n]) and [sup 176]Yb([sup 26]Mg,6[ital n]) reactions. Transitions linking the most intense regular band to the low-lying negative-parity yrast levels are observed, establishing excitation energies, spins, and probable parities of the band members. In contrast, no such transitions have been found for the irregular band and the weaker regular band. The bands are interpreted as corresponding to collective oblate rotation, arising mainly from deformation-aligned high-[ital j], shape-driving quasiproton excitations across the [ital Z]=82 shell gap, coupled to rotation-aligned quasineutrons.