We compute two-particle production in pA collisions and extract azimuthal harmonics, using the dilute-dense formalism in the Color Glass Condensate framework. The multiple scatterings of the partons inside the projectile proton on the dense gluons inside the target nucleus are expressed in terms of Wilson lines. They generate interesting correlations, which can be partly responsible for the signals of collectivity measured at RHIC and at the LHC. Most notably, while gluon Wilson loops yield vanishing odd harmonics, quark Wilson loops can generate sizable odd harmonics for two particle correlations. By taking both quark and gluon channels into account, we find that the overall second and third harmonics lie rather close to the recent PHENIX data at RHIC.

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In the Color Glass Condensate formalism, we evaluate the 3-dipole correlator up to the 1 N 4 c order with Nc being the number of colors, and compute the azimuthal cumulant c123 for 3-particle productions. In addition, we discuss the patterns appearing in the n-dipole formula in terms of 1 Nc expansions. This allows us to conjecture the Nc scaling of cn{m}, which is crosschecked by our calculation of c2{4} in the dilute limit. I. INTRODUCTIONExperimental data in deep inelastic scatterings (DIS) and proton-nucleus (pA) collisions indicates a sharp rise in the cross section at small Bjorken x, which is believed to be due to the fast growth of the gluon density in large nuclei. The gluon density increases steeply and tends to be saturated when going to a smaller x. The Color Glass Condensate (CGC) formalism [1-7] describes this gluon saturation regime by treating the fast-moving partons inside the dense nucleus as a classical color source of the soft gluons. In the McLerran-Venugopalan (MV) model [8], the small-x gluons are assumed as a classical Yang-Mills field. The soft gluons, whose color field A is associated with a random color source ρ, are radiated by the eikonal (high-energy and fixed at a transverse coordinate) partons [9].With the fact that the gluon density inside the nucleus is large, one can obtain a weak coupling constant g. Nevertheless, due to the strong nuclear field A ∼ 1 g , the high-density regime is nonlinear and cannot be handled perturbatively. The Jalilian-Marian-Iancu-McLerran-Weigert-Leonidov-Kovner (JIMWLK) renormalization group equation [10,11] governs the nonlinear evolution of the gluon distribution function in the saturation regime. In the dilute regime, this equation reduces to the linear BFKL equation, which describes the evolution of the unintegrated gluon density.Within the framework introduced above, multiparticle productions in high-energy collisions are represented by dipoles, quadrupoles, and higher-point functions. These multipoint functions are written in forms of the Gaussian average of Wilson lines in the fundamental representation for quarks and the adjoint representation for gluons. However, Ref. [12] shows that, in the large-N c limit, only dipoles and quadrupoles contribute to the particle production processes. The quadrupole corresponding to the Weiszäcker-Williams gluon distribution has been evaluated in Ref.[13] by the JIMWLK Hamiltonian method.The CGC formalism generates multiparticle correlations in dilute-dense scatterings (pA collisions) from the initial state . In order to study correlation observables, which include the nth moment of the m-particle cumulant c n {m} and the corresponding anisotropic flow v n {m}, one has to derive multidipole correlators. Some recent work has been done in Refs. [14,31,32,38]. In this paper, we evaluate the 3-dipole correlator up to the 1 N 4 c order by the color transition matrices method developed in Refs. [39][40][41][42]. It helps to obtain an n-dipole formula in forms of a power series at large N c . We calculate the 3-parti...

The dependency on combustion of coal, oil and gas for energy cannot be indefinite. Thus, the process of replacing fossil fuels with many energy technologies cannot be avoided in order to combat this high dependency. Nevertheless, we argue that in the long term, nuclear fission technology is the answer to the ever increasing demand for energy. This entails that nuclear fission has to play a major role in suppling energy in this age and beyond. In achieving this, the major aspect is in switching electrical energy generation from fossil fuels to nuclear fission. This cannot be achieved in a short period of time but in few decades citing France as an example.1 This energy transformation campaign is capable of reducing emissions of carbon dioxide as well as other greenhouse gases at a large scale. In view of this, replacement of coal-fired with gas-fired generating stations will not significantly reduce greenhouse gases emissions. What about the other energy sources such as wind and solar? These may not be an ultimate answer as they will be hard pressed in supply and may fall short in energy supply at very high scale. This is because they depend on backup power or energy storage hence not able to meet the ever growing high demand of energy. Therefore, this paper focuses on the current status of nuclear energy. It also discusses the future prospects of nuclear energy and the activities of the International Atomic Energy Agency (IAEA).

planned for construction as well as those at proposal stage. However, the ethics of nuclear power is increasingly under challenge due to the incidents at the Chernobyl and Fukushima Daiichi nuclear power plants, and concerns over radioactive discharges, safe management of radioactive waste and lack of an operational repository for spent nuclear fuel. Central to these concerns is the perceived unique radiological risk of nuclear power. But in a world where Climate Change presents a threat to the entire planet, is nuclear power and the associated radiological risk not ethical? Exploring the interplay between climate change ethics and the International Commission on Radiological Protection (ICRP)’s System of Radiological Protection, we consider the major contribution that new nuclear power stations can make to climate change mitigation, through decarbonisation of power systems, and finally unpick the case for nuclear power in this new world of climate change ethics.