Modern Physics Letters A

A brief overview is presented of the progress made during the past few years on the general structure of local models of particle physics from string theory including: moduli stabilisation, supersymmetry breaking, global embedding in compact Calabi–Yau compactifications and potential cosmological implications. Type IIB D-brane constructions and the Large Volume Scenario (LVS) are discussed in some detail emphasising the recent achievements and the main open questions.

In this work, we have explored the possibilities of improving CP violation (CPV) discovery potential of newly planned Long-Baseline Neutrino Experiment (LBNE), USA, by combining with data from reactors. The third mixing angle θ₁₃ is now very precisely measured and this precise measurement of θ₁₃ helps in the measurement of CPV. Here, CPV is studied with and without data from reactors. The impact of placing a neutrino data (ND) is also studied. It is found that CPV discovery potential of LBNE with ND increases when combined with data from reactors. With a far detector of 35 kt, it is possible to obtain 5σ sensitivity of CPV when run for 5 years in ν and 5 years in mode. When normal hierarchy is assumed, CPV sensitivity is maximum. CPV discovery is possible by combining 5 years neutrino data from LBNE with 3 years anti-neutrino data from reactors. This study reveals that CPV can also be discovered at 5σ cl in inverted mass hierarchy (IH) mode when appearance measurement of LBNE is combined with reactors.

A dark sector containing a Higgs field and a dark photon coupled to visible photons via a small kinetic mixing is considered. The mass of the dark gauge boson becomes rescaled by the parameter involved in the kinetic mixing. We also calculate the total annihilation cross-section for scalar Higgs interacting with an external field and show that exhibits Sommerfeld enhancement. The model can be extended to a SU(3) × SU(2) × U(1) dark sector. The mass of the dark Z boson increases due to the kinetic mixing.

The paper is devoted to theoretical consideration of inclusive η_{c, b} meson production at LHC. It is shown that existing experimental data on η_c meson production at LHCb detector can be described in the framework of NRQCD formalism and color singlet component with phenomenological value of matrix element |R(0)|² gives main contribution. Using this model, we present theoretical prediction for integrated cross-sections and transverse momentum distributions for inclusive η_c production at other LHC detectors. The case of η_b meson production at LHC is also considered.

The three quantum groups dual to the generalized twist deformed Poincaré Hopf algebras are provided with use of FRT procedure. Their Galilean counterparts are obtained by nonrelativistic contraction scheme.

The response of fermionic system to external gauge fields is defined by current–current correlation function Π_μν(q, q₀). Transport properties of different physical quantities are determined by zero energy–momentum limit of it. As it is known close to half-filling the physics of graphene is described by (2+1)-dimensional Dirac theory. In this paper, we calculate current–current correlation function in Dirac theory in a presence of chemical potential η and gap m.

We have studied the effects of Lorentz-violation in the Bose–Einstein condensation (BEC) of an ideal boson gas, by assessing both the nonrelativistic and ultrarelativistic limits. Our model describes a massive complex scalar field coupled to a CPT-even and Lorentz-violating background. We first analyze the nonrelativistic case, at this level by using experimental data, we obtain upper-bounds for some LIV parameters. In the sequel, we have constructed the partition function for the relativistic ideal boson gas which to be able of a consistent description requires the imposition of severe restrictions on some LIV coefficients. In both cases, we have demonstrated that the LIV contributions are contained in an overall factor, which multiplies almost all thermodynamical properties. An exception is the fraction of the condensed particles.

We study a holographic superconductor model with Stückelberg mechanism in the four-dimensional AdS black hole background. We explore the effects of the model parameters on the scalar condensation and conclude that this new model allows first-order phase transitions to occur when the model parameter is above a threshold value. Finally, we examine the effects of the back-reaction parameters on the threshold values.