121766040
Supermembrane monopole vacua
Abstract The supermembrane classical solutions with non-trivial circle bundles, i.e. supermembrane monopole vacua, are derived. The hamiltonian of the fermion fluctuations about the monopole vacuum configuration is weakly hermitian, in contrast with the same problem in QED. The electrically charged and dyon analogues to the monopole vacua are also discussed.
124596353
DOES THE RUBAKOV EFFECT EXIST IN AN SU(2) MODEL
In an spontaneously broken gauge theory with a Higgs triplet, the mass effect of an isospin 1/2 fermion on the fermion-monopole bound states is discussed. It is shown that when the direct coupling between fermion and Higgs field approaches zero, but the Dirac mass remains finiteness, the necessary condition of the fermion-monopole bound state cannot be satisfied. This result means that the Rubakov effect is absent for monopole because of the Dirac mass.
117665288
Instantons in grand unification
SummaryA class of instantons in four-dimensional Euclidean grand unification is discussed. These solutions in the classical limit have nonzero Lagrangian density at only one single point. These instantons can generate proton decay processes, whose rate has an extremely feeble effect in theSU5 model. However, it can be observable in unification with technifermions that embedded instantons induce technifermions decay to ordinary fermion. We also consider the instantons in aSO10 model.RiassuntoSi discute una classe di instantoni nella grande unificazione euclidea a quattro dimensioni. Queste soluzioni nel limite classico hanno densità lagrangiana non nulla solo in un singolo punto. Questi istantoni possono generare processi di decadimento protonico, il cui valore ha un effetto molto debole nel modelloSU5. Tuttavia, si può osservare che, nella unificazione con i tecnifermioni, gli istantoni inclusi inducono decadimenti dei tecnifermioni a fermioni ordinari. Si considerano anche gli istantoni in un modelloSO10.РезюмеОбсуждается класс инстантонов в четырехмерном эвклидовом великом объединении. Эти решения в классическом пределе имеют ненулевую плотность Лагранжиана только в одной изолированной точке. Эти инстантоны могут генерировать процессы распада протона. Интенсивность этих процессов представляет чрезвычайно малый эффект в моделиSU5. Однако, этот процесс может быть наблюдаем при объединении с технифермионом, когда внедренный инстантон индуцирует распад технифермионов в обыкновенные фермионы. Мы также рассматриваем инстантоны в моделиSO10.
121018905
A class of generalized monopole solutions in Kaluza-Klein theories
Abstract We present a new class of generalized monopole solutions in Kaluza-Klein theories. Both the Gross-Perry-Sorkin solution and the Bais-Batenburg solutions are contained as special cases of the general solutions.
121291742
A six-dimensional cosmology solution with GUT and monopole-induced spontaneous compactification
In this paper, the authors present a cosmological solution of a six-dimensional Einstein-gauge unification theory to which is added a matter term. This exact solution appears that cosmology of the very early universe may differ considerably from the usually contemplated scenarios.
120212512
The mass matrix of neutral fermions and application in some SUSY E6-GUT
The fermion mass spectrum remains one of the outstanding problems of grand unification. The authors discuss the mass matrix of neutral fermions, which arises in three SUSY E6-breaking patterns by including the contributions of the five-dimensional superpotential terms. The solar neutrino puzzle is solved in the breakdown through SU3C*SU3L*SU3R. The model is shown to lead naturally to large oscillations of the doublet neutrino into a sterile fermion leading to the possibility of substantial depletion of the solar electron neutrino flux.
53695340
Exclusive radiative B-meson decays within the aligned two-Higgs-doublet model
A bstractIn the aligned two-Higgs-doublet model, the alignment of Yukawa matrices in flavour space guarantees the absence of tree-level flavour-changing neutral currents, while allowing at the same time for new sources of CP violation, implying potentially large effects in many low-energy processes. In this work we study the constraints from exclusive radiative B → V γ decays, where V denotes a light vector meson. The current experimental data on the CP-averaged branching ratios and the direct CP and isospin asymmetries are analyzed. It is found that, while the branching ratios and direct CP asymmetries do not constrain the parameter space much further compared to the inclusive B → Xs,d γ decays, complementary constraints can be obtained from the isospin asymmetries Δ(K*γ) and Δ(ργ). In addition, correlations between the various observables in exclusive B → V γ and inclusive B → Xs,d γ decays are investigated in detail, and predictions are made for several so far unmeasured observables.
14104948
Two particle states in an asymmetric box and the elastic scattering phases
The exact two-particle energy eigenstates in a generic asymmetric rectangular box with periodic boundary conditions in all three directions are studied. Their relations with the elastic scattering phases of the two particles in the continuum are obtained for both ${D}_{4}$ and ${D}_{2}$ symmetries. These results can be viewed as a generalization of the corresponding formulas in a cubic box obtained by L\"uscher before. In particular, the s-wave scattering length is related to the energy shift in the finite box. Possible applications of these formulas are also discussed.
119191019
The effects of a family non-universal Z-prime boson on B--->pipi decays
Motivated by the measured large branching ratio of (the so-called ππ puzzle), we investigate the effects of a family nonuniversal Z′ model on the tree-dominated B → ππ decays. We find that the Z′ coupling parameter with a nontrivial new weak phase , which is relevant to the Z′ contributions to the QCD penguin sector △C5, is needed to reconcile the observed discrepancy. Combined with the recent fitting results from B → πK, πK* and ρK decays, the Z′ parameter spaces are severely reduced but still not excluded entirely, implying that both the "ππ" and "πK" puzzles could be accommodated simultaneously within such a family nonuniversal Z′ model.
43493679
Precision benchmark calculations for four particles at unitarity
The unitarity limit describes interacting particles where the range of the interaction is zero and the scattering length is infinite. We present precision benchmark calculations for two-component fermions at unitarity using three different ab initio methods: Hamiltonian lattice formalism using iterated eigenvector methods, Euclidean lattice formalism with auxiliary-field projection Monte Carlo methods, and continuum diffusion Monte Carlo methods with fixed and released nodes. We have calculated the ground-state energy of the unpolarized four-particle system in a periodic cube as a dimensionless fraction of the ground-state energy for the noninteracting system. We obtain values of 0.211(2) and 0.210(2) using two different Hamiltonian lattice representations, 0.206(9) using Euclidean lattice formalism, and an upper bound of 0.212(2) from fixed-node diffusion Monte Carlo methods. Released-node calculations starting from the fixed-node result yield a decrease of less than 0.002 over a propagation of 0.4E{sub F}{sup -1} in Euclidean time, where E{sub F} is the Fermi energy. We find good agreement among all three ab initio methods.
2525683
Two particle states in an asymmetric box
The exact two-particle energy eigenstates in an asymmetric rectangular box with periodic boundary conditions in all three directions are studied. Their relation with the elastic scattering phases of the two particles in the continuum are obtained. These results can be viewed as a generalization of the corresponding formulae in a cubic box obtained by Luscher before. In particular, the s-wave scattering length is related to the energy shift in the finite box. Possible applications of these formulae are also discussed.