Modern Physics Letters A

We review on a recent construction of the on-shell supersymmetric brane action for the codimension-two branes with nonzero tension in the flux compactification of a 6D chiral gauged supergravity. On dimensionally reducing on 4D gauged supergravity for a new supersymmetric unwarped background with conical branes, we consider the modulus stabilization for determining the soft masses of the scalars localized on the branes and show that the bulk U(1)_R provides a new mechanism for mediating the SUSY breaking.

The simplest version of the daemon paradigm suggests the modulated 2–6-keV range events in DAMA/NaI and DAMA/LIBRA detectors are caused by the iodine ions knocked out elastically by the electrically neutral c-daemons moving with V = 30–50 km/s (c-daemon is a complex of negative daemon located in a remainder of formerly captured nucleus where the daemon decomposes nucleons one by one with ~ 10^-6 s mean interval). Furthermore, after the 2–6 keV event occurred, in subsequent ~ 10^-6 s, the c-daemon (which becomes negative during this time) recaptures new nucleus with resulting scintillations in ~ 10 MeV range! The last possibility was so far overlooked in the experiments as it did not stem from WIMP hypotheses. A modification of the NaI(Tl) experiments is suggested for revealing the effect described. Independently of the outcome, any obtained result will be important for refining the daemon paradigm further on.

We show systematically the relation between an N = 2 nonlinear supersymmetric (NLSUSY) model and an N = 2 SUSY QED theory by means of the superfield formulation in two-dimensional spacetime without imposing a priori any special gauge conditions for a gauge superfield.

Mass deformations of supersymmetric Yang–Mills theories in three spacetime dimensions are considered. The gluons of the theories are made massive by the inclusion of a nonlocal gauge and Poincaré invariant mass term due to Alexanian and Nair, while the matter fields are given standard Gaussian mass-terms. It is shown that the dimensional reduction of such mass-deformed gauge theories defined on R³ or R × T² produces matrix quantum mechanics with massive spectra. In particular, all known massive matrix quantum mechanical models obtained by the deformations of dimensional reductions of minimal super Yang–Mills theories in diverse dimensions are shown also to arise from the dimensional reductions of appropriate massive Yang–Mills theories in three spacetime dimensions. Explicit formulas for the gauge theory actions are provided.

We have analyzed the longitudinal momentum distribution of ²²Mg fragment coming from ¹²C(²³Al, ²²Mg)X reaction at 74 MeV/A beam energy within the framework of Glauber model. The comparison of data and predictions has revealed that the valence proton in ²³Al occupies d-orbital and suppresses the expected proton halo because of the presence of a strong centrifugal barrier.

The possibility to access the absolute neutrino mass scale through the measurement of the wrong helicity contribution of charged leptons is investigated in pion decay. Through this method, one may have access to the same effective mass extractable from the tritium beta decay experiments for electron neutrinos as well as the analogous effective mass for muon neutrinos. In the channel , the relative probability of producing an antineutrino with left helicity is enhanced if compared with the naive expectation (m_ν/2E_ν)². The possibility to constrain new interactions in the context of two-Higgs-Doublet models is also investigated.

It is well known that observers will be accelerated when they approach the planets. Thus, discussing the properties of accelerating observers in the Schwarzschild space is meaningful. For the sake of simplicity, we can construct these observers' world lines by comparing with the observers in the Hawking effect and Unruh effect, whose world lines are both hyperbolic curves in the appropriate coordinates. We do it after defining a certain special null hypersurface in the Kruskal coordinates. Our result shows that these accelerating observers defined in our paper can also detect the radiation with the analogy of the Unruh effect, though locally. Furthermore, we conjecture that, for any null hypersurface in any spacetime, the corresponding observers who can at least locally detect the radiation from it can be found.

Generally, in the presence of an antisymmetric tensor background field, the open string moving with mixed Neumann and Dirichlet boundary conditions will make the spacetime coordinates noncommutative. In this paper, comparing to the flat and static D-brane case studied in the literature, we first generalize the D-branes to be dynamical. And then by using the Hamiltonian approach, through a calculation of the classical Poisson brackets among the Fourier mode components of the string embedding coordinates and a consistent quantization procedure, we show that the spacetime coordinates of the string endpoints in the directions parallel and perpendicular to the D-branes both become noncommutative.