相关论文: Flavour Changing Neutral Currents in Intersecting …
We consider extensions of the standard model inspired by intersecting D-brane constructions, in order to address flavor mass textures. We include additional anomalous gauge symmetries, and scalar fields to break them and to generate…
We present non-supersymmetric toroidal compactifications of type I string theory with both constant background NSNS two-form flux and non-trivial magnetic flux on the various D9-branes. The non-vanishing B-flux admits four-dimensional…
A popular approximation in lattice gauge theory is an extrapolation in the number of fermion species away from the four fold degeneracy natural with the staggered fermions formulation. I show that at finite lattice spacing and for an odd…
We study the restrictions imposed by cancellation of the tadpoles for two, three, and four-form gauge fields in string theory, M-theory and F-theory compactified to two, three and four dimensions, respectively. For a large class of…
We propose a spontaneous A4 flavor symmetry breaking scheme implemented in a warped extra dimensional setup to explain the observed pattern of quark and lepton masses and mixings. The main advantages of this choice are the explanation of…
In the present paper we examine, from the purely theoretical point of view and in a model-independent way, the case, when matter, gauge and Higgs fields are allowed to propagate in the bulk of five-dimensional brane world models with…
We re-examine the constraints on continuous family symmetries coming from flavour changing neutral current limits on the D-term contributions to squark and slepton masses. We show that, for a restricted choice of the familon sector,…
The branching ratio of the rare decay B->X_s gamma provides potentially strong constraints on models beyond the Standard Model. Considering a general scenario with new heavy neutral gauge bosons, present in particular in Z' and gauge…
There are theoretical and phenomenological motivations that there may exist additional heavy Z' bosons with family non-universal couplings. Flavor mixing in the quark and lepton sectors will then lead to flavor changing couplings of the…
We investigate the zero mode dimensional reduction of the Kaluza-Klein unifications in the presence of a single brane in the infinite extra dimension. We treat the brane as fixed, not a dynamical object, and do not require the orbifold…
We show that the recent anomalies in $b \to s \ell^+ \ell^-$ transitions observed by the LHCb collaboration can be accommodated within string motivated models with a low mass $Z^{\prime}$ gauge boson. Such $Z^{\prime}$ gauge boson can be…
We consider a model in which the third family fermions are subjected to an SU(2) interaction different from the first two family fermions. Constrained by the Z-pole data, the heavy gauge boson mass is bounded from below to be about 1.7 TeV…
D-branes, topological defects in string theory on which string endpoints can live, may give new insight into the understanding of the cosmological evolution of the Universe at early epochs. We analyze the dynamics of D-branes in curved…
We consider intersecting D-brane models which have two dimensional chiral fermions localized at the intersections. At weak coupling, the interactions of these fermions are described by generalized Gross-Neveu models. At strong coupling,…
The flipped trinification, a framework for unifying the 3-3-1 and left-right symmetries, has recently been proposed in order to solve profound questions, the weak parity violation and the number of families, besides the implication for…
A complete discussion of tree-level flavor-changing effects in the Randall-Sundrum (RS) model with brane-localized Higgs sector and bulk gauge and matter fields is presented. The bulk equations of motion for the gauge and fermion fields,…
We consider probe Dp-branes, p=3,5,7, in global AdS_5 x S^5, rotating along an internal direction in the S^5. These are dual to strongly interacting N=4 SYM on S^3 with massless fundamental flavours, in the presence of an R-symmetry…
We propose a new model of flavour chiral symmetry breaking in a (2+1)-dimensional defect gauge theory of strongly coupled fermions by introducing probe D5/anti-D5-flavour branes on the conifold. After working out the flavour brane…
We discuss the effect of the dynamics of D-branes on moduli stabilization in type IIB string theory compactifications, with reference to a concrete toy model of T6/Z3 orientifold compactification with fractional D3-branes and anti-D3-branes…
We study the membrane wrapping mode corrections to the Kaluza-Klein (KK) 6-brane in eleven dimensions. We examine the localized KK6-brane in the extended space in $E_{7(7)}$ exceptional field theory. In order to discuss the physical origin…