Explanations of the origin of ultra-high energy cosmic rays are severely constrained by the Greisen-Zatsepin-Kuz’min effect, which limits their propagation over cosmological distances. We argue that possible departures from strict Lorentz invariance, too small to have been detected otherwise, can affect elementary-particle kinematics so as to suppress or forbid inelastic collisions of cosmic-ra...

The spectra of strange hadrons have been measured in detail as a function of centrality for a variety of collision systems and energies at RHIC. Recent results are presented and compared to those measured at the SPS. The effects of the system size on strange particle production and kinematics are examined. I place specific emphasis on comparing A-A to p-p production and discuss how strangeness ...

In the presence of a cosmological constant, interpreted as a purely geometric entity, absence of matter is represented by a de Sitter spacetime. As a consequence, ordinary Poincaré special relativity is no longer valid and must be replaced by a de Sitter special relativity. By considering the kinematics of a spinless particle in a de Sitter spacetime, we study the geodesics of this spacetime, t...

We present a model calculation of the generalized parton distributions where the nucleon is described by a quark core surrounded by a mesonic cloud. In the one-meson approximation, we expand the Fock state of the physical nucleon in a series involving a bare nucleon and two-particle, meson-baryon, states. We discuss the role of the different Fock-state components of the nucleon by deriving a co...

3. Elementary processes in QED Scattering amplitudes and the differential cross-section Kinematics of binary processes, decay rate of an unstable particle The scattering e− e → μ− μ, the square of the scattering amplitude Unpolarized scattering and its differential cross-section The scattering e− μ− → e− μ−, the square of the scattering amplitude Crossing symmetry, Mandelstam variables, crossed...

Energy efficient communication is a plenary issue in Wireless Sensor Networks (WSNs). Contemporary energy efficient optimization schemes are focused on reducing power consumption in various aspects of hardware design, data processing, network protocols and operating system. In this paper, optimization of network is formulated by Cuckoo Based Particle Approach (CBPA). Nodes are deployed randomly...

The leading and next-to-leading threshold logarithms of the QCD corrections to electroproduction of heavy quarks in single-particle inclusive kinematics are resummed to all orders in perturbation theory. The resummed cross-section is used to derive the NLO and NNLO results near threshold and their numerical impact on the charm structure function is studied. Talk at the ‘6th International Worksh...

Abstract: In this paper we consider quantum walks whose evolution converges to the Dirac equation in the limit of small wave-vectors. We show exact Fast Fourier implementation of the Dirac quantum walks in one, two, and three space dimensions. The behaviour of particle states—defined as states smoothly peaked in some wave-vector eigenstate of the walk—is described by an approximated dispersive ...

Open charm production at HERA has developed as a precision testing ground for fixed order (FO) NLO pQCD calculations as well as for other QCD inspired models. The bulk of the available data is on inclusive charmed particle production cross sections for several species. I will focus on reviewing the status of the comparison of the data with FO NLO pQCD calculations trying to identify the open is...

We give a general treatment of twist-three effects in two-photon reactions. We address the issue of the gauge invariance of the Compton amplitude in generalized Bjorken kinematics and relations of twist-three 'transverse' skewed parton distributions to twist-two ones and interaction dependent three-particle correlation functions. Finally, we discuss leading order evolution of twist-three functi...