Old and new vacua of 5D maximal supergravity

We look for critical points with U(2) residual symmetry in 5-dimensional maximally supersymmetric gauged supergravity, by varying the embedding tensor, rather than directly minimizing the scalar potential. We recover all previously known vacua and we find four new vacua, with different gauge groups and cosmological constants. We provide the first example of a maximal supergravity model in D ≥ 4 having critical points with both positive and vanishing cosmological constant. For each vacuum we also compute the full mass spectrum. All results are analytic.

Development of a miniature time of flight mass spectrometer coupled with an improved substrate-enhanced laser-induced acoustic desorption source (SE-LIAD/TOF-MS)

A novel, compact and sensitive SE-LIAD/TOF-MS has been described. It facilitates the fast sample preparation and a full mass spectrum acquired efficiently and sensitively. More importantly, it features detection of...

MASS SPECTRUM OF THE JP=1/2- AND 3/2- PENTAQUARK ANTIDECUPLETS IN THE PERTURBATIVE CHIRAL QUARK MODEL

We study the recently discovered Θ+ baryon in the context of the perturbative chiral quark model. The basic configuration of the Θ+ is a pentaquark bound state, where the single particle wave functions are the ground state solutions of a confining potential. We classify the resulting pentaquark multiplets as the JP=1/2- and 3/2- flavor SU (3) antidecuplet. The full mass spectrum of the multiplets is determined by including the meson and gluon cloud contributions, which induce flavor SU (3) breaking. The resulting 3/2- antidecuplet is about 185 MeV heavier than the 1/2- one, mainly because of the semi-perturbative gluon effects. We assign the observed Θ+ baryon as a member of the 1/2- antidecuplet and discuss in particular its relation to the recent experimental signal for a Ξ-- baryon.