Modern Physics Letters A

We introduce the new IR-improved Dokshitzer–Gribov–Lipatov–Altarelli–Parisi–Callan–Symanzik (DGLAP-CS) kernels recently developed by one of us into the HERWIG6.5 to generate a new MC, HERWIRI1.0(31), for hadron–hadron scattering at high energies. We use MC data to compare the parton shower generated by the standard DGLAP-CS kernels and that generated by the new IR-improved DGLAP-CS kernels. The seamless interface to MC@NLO, MC@NLO/HERWIRI, is illustrated. We show comparisons with FNAL data and discuss some possible LHC phenomenology implications.

Neutrino tribimaximal mixing is obtained from the breaking of A₄ to Z₃ in the charged-lepton sector and to Z₂ in the neutrino sector. To enforce this conflicting pattern, extra particles and symmetries are usually invoked, often accompanied by nonrenormalizable interactions and even extra dimensions. It is shown here in a specific renormalizable model how A₄ alone will accomplish this, with only the help of lepton number.

On the basis of postulates for the holographic description of gravity and the introduction of entropic force, for static sources we derive the universal law: the entropy of a holographic screen is equal to quarter of its area in the Planck system of units.

In this paper, we explore the parameter space for a Right-Handed (RH) sneutrino curvaton that can generate large non-Gaussianity without assuming any particular inflation sector. The mass of the RH sneutrino is suggested from a discussion on the initial condition of the curvaton field. It is shown that a small Yukawa coupling is generally required for a successful RH sneutrino curvaton. However, the Yukawa coupling can be larger if we consider the braneworld scenario. Some general discussion about the spectral index in curvaton scenario is also provided.

We consider a (2+1)-dimensional quantum superspace which has noncommuting coordinates in Manin sense and it was shown that this space has a Hopf algebra structure, i.e. the quantum supergroup, when it is extended by the inverse of the bosonic variable. Differential structures on this space were given by constructing the differential calculus in the sense of Woronowicz. Thus, we deduce that the corresponding quantum Lie superalgebra which as a commutation superalgebra appears classical, and as Hopf structure is non-cocommutative q-deformed. Finally, dual Hopf superalgebra was given.

We examine the possibility of determining the neutrino mass hierarchy in the limit θ₁₃=0 using atmospheric neutrinos as the source. In this limit, in which θ₁₃ driven matter effects are absent, independent measurements of Δ₃₁ and Δ₃₂ can, in principle, lead to hierarchy determination. Since the difference between these two is Δ₂₁, one needs an experimental arrangement where Δ₂₁ L/E ≳1 can be achieved. This condition can be satisfied by atmospheric neutrinos since they have a large range of energies and baselines. In spite of this, we find that hierarchy determination in the θ₁₃=0 limit with atmospheric neutrinos is not a realistic possibility, even in conjunction with an apparently synergistic beam experiment like T2K or NOνA. We discuss the reasons for this, and also in the process clarify the conditions that must be satisfied in general for hierarchy determination if θ₁₃=0.

The stability of de Sitter spacetime in Horava–Lifshitz theory of gravity with projectability but without detailed balance condition is studied. It is found that, in contrast to the case of the Minkowski background, the spin-0 graviton is now stable for any given ξ, and free of ghost for ξ ≤ 0 in the infrared limit, where ξ is the dynamical coupling constant.

We derive the different forms of BRST symmetry by using the Batalin–Fradkin–Vilkovisky formalism in a rigid rotor. The so-called "dual-BRST" symmetry is obtained from the usual BRST symmetry by making a canonical transformation in the ghost sector. On the other hand, a canonical transformation in the sector involving Lagrange multiplier and its corresponding momentum leads to a new form of BRST as well as dual-BRST symmetry.