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}
7752926
Possible dynamic effects in the particle decay of 59Cu compound nuclei.
The slopes of the energy spectra of {ital p}, {ital d}, {ital t}, and {alpha} particles emitted from {sup 59}Cu nuclei formed in the reaction of {sup 32}S+{sup 27}Al at a bombarding energy of 150 MeV are described by statistical-model calculations in which the deformation is frozen during the first two steps of the deexcitation chain. The resultant fits to the high-energy portions of the spectra are comparable to those previously obtained by modifying the spin dependence of the level density, suggesting that dynamic effects may be important in evaporation from light nuclei.
122764276
Excitations of two and three valence proton nuclei Te-134 and I-135
118027838
Structure of Co-65,Co-67 studied through the beta decay of Fe-65,Fe-67 and a deep-inelastic reaction
The neutron-rich isotopes {sup 65,67}Fe and {sup 65}Co have been produced at the LISOL facility, Louvain-La-Neuve, in the proton-induced fission of {sup 238}U. Beams of these isotopes have been extracted with high selectivity by means of resonant laser ionization combined with mass separation. Yrast and near-yrast levels of {sup 65}Co have also been populated in the {sup 64}Ni+{sup 238}U reaction at Argonne National Laboratory. The level structure of {sup 65}Co could be investigated by combining all the information from both the {sup 65}Fe and {sup 65}Co{beta} decay and the deep-inelastic reaction. The {sup 65}Fe, {sup 65}Co, and {sup 67}Fe decay schemes and the {sup 65}Co yrast structure are fully established. The {sup 65,67}Co level structures can be interpreted as resulting from the coexistence of core-coupled states with levels based on a low-energy proton-intruder configuration.
122206593
Observation of Octupole Structures in Radon and Radium Isotopes and Their Contrasting Behavior at High Spin
Multinucleon transfer reactions have been used, for the first time, to populate high-spin bands of alternating parity states in {sup 218,220,222}Rn and {sup 222,224,226}Ra. The behavior of the angular momentum alignment with rotational frequency for the Rn isotopes is very different when compared with Ra and Th isotopes with N{approx}134, indicating a transition from octupole vibrational to stable octupole deformation. Throughout the measured spin range the values of {vert_bar}D{sub 0}/Q{sub 0}{vert_bar} remain constant for {sup 222}Ra and {sup 226}Ra and have a very small value for {sup 224}Ra, suggesting that the charge and mass distributions are not affected appreciably by rotations. {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.
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.
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.
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.
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.