International Journal of Modern Physics A

This paper describes how to perform model-independent searches for new pair-produced color octet particles that each subsequently decay into two jets plus missing energy. The details of this analysis are focussed on the Tevatron, however, all of the lessons can be carried over to the LHC. Current searches are not sensitive to all regions of parameter space because they employ CMSSM-motivated cuts. Optimizing the H_T and cuts expands the sensitivity of searches for all kinematically allowed decays.

Spin measurement is crucial in distinguishing major scenarios of TeV scale new physics once it is discovered at the Large Hadron Collider (LHC). We give a brief survey of methods of measuring the spin of new physics particles at the LHC. We focus on the case in which a long lived massive neutral particle is produced at the end of every cascade decay and escape detection. This is the case for R-parity preserving supersymmetry, Little Higgs models with T-parity, extra-dimensional models with KK-parity, and a large class of similar models and scenarios. After briefly commenting on measuring spin by combining mass and rate information, we concentrate on direct measurement by observing angular correlations among decay products of the new physics particles. We survey a wide range of possible channels, discuss the construction of possible correlation variables, and outline experimental challenges. We also briefly survey the Monte Carlo tools which are useful in studying such correlations.

The nuclear physics and particle physics researches in China have a long tradition. BEPC is a milestone of the particle physics in China. The many interesting physics results were obtained from BEPC. Beijing Synchrotron Radiation Facility based on BEPC became the major synchrotron radiation facility in China. The upgrade of BEPC, which will increase the luminosity by two orders of magnitude, is going smoothly. The nonaccelerator based experiments were promoted also. Professor Yang made very important contribution to Chinese physics, especially to promote the large science facilities for the multiple discipline researches. The particle physics faces the great challenges, and meets the great opportunities in the 21st century. The medium-term plan of the particle physics in China was discussed.

We count the number of independent structures which can arise in expressions for radiation friction force in different even space–time dimensions and demonstrate that their number is too big at d ≥ 8 to allow determination of this force from the transversality condition alone, as was done by B. Kosyakov in 6d. This implies that in general one cannot bypass a tedious calculation involving explicit regularization and evaluation of emerging counterterms. However, simple Kosyakov's method works nicely in any dimension for the special case of circular motion with constant angular velocity.

Energy is among the characteristics of Ultra High Energy Cosmic Rays (E > 5 ×10¹⁹eV) which could be estimated experimentally based on simulations. This paper attempts to estimate the energy of an UHECR proton by applying a Monte Carlo simulation code. A number of extensive air showers, vertical and inclined, are simulated to derive the lateral distribution functions of the shower particles. The scenario of simulations is adapted to the P. Auger Observatory site.

The basic concepts and mathematical constructions of the Maxwell–Lorentz electrodynamics in flat space–time of an arbitrary even dimension d = 2n are briefly reviewed. We show that the retarded field strength due to a point charge living in a 2n-dimensional world can be algebraically expressed in terms of the retarded vector potentials generated by this charge as if it were accommodated in 2m-dimensional worlds nearby, 2 ≤ m ≤ n+1. With this finding, the rate of radiated energy–momentum of the electromagnetic field takes a compact form.

We calculate the second-order corrections to vacuum polarization tensor of photons at low temperatures, i.e. T ≪ 10¹⁰K(T ≪ m_e). The thermal contributions to the QED coupling constant are evaluated at temperatures below the electron mass that is T < m_e. Renormalization of QED at these temperatures has explicitly been checked. The electromagnetic properties of such a thermal medium are modified. Parameters like electric permittivity and magnetic permeability of such a medium are no more constant and become functions of temperature.

Cross-couplings between a massless spin-two field (described in the free limit by the Pauli–Fierz action) and an Abelian three-form gauge field in D = 11 are investigated in the framework of the deformation theory based on local BRST cohomology. These consistent interactions are obtained on the grounds of smoothness in the coupling constant, locality, Lorentz covariance, Poincaré invariance, and the presence of at most two derivatives in the interacting Lagrangian. Our results confirm the uniqueness of the 11-dimensional interactions between a graviton and a three-form prescribed by general relativity.