A simple method to calculate the total annihilation cross section of massive cold relics is presented. Exact expressions for arel, brel, and crel of σvrel = arel + brelv 2 rel + crelv 4 rel are obtained from simple derivatives of the squared annihilation amplitude. Three examples are given. In one example, the computed annihilation cross section of massive Dirac neutrinos confirms recent correc...

Enhanced positron annihilation on polyatomic molecules is a long-standing and complex problem. We report the results of calculations of resonant positron annihilation on methyl halides. A free parameter of our theory is the positron binding energy. A comparison with energy-resolved annihilation rates measured for CH3F, CH3Cl, and CH3Br [L. D. Barnes, Phys. Rev. A 74, 012706 (2006)10.1103/PhysRe...

Assuming that ρ -mesons exist in a quark-gluon plasma at temperatures close to the QCD phase transition, we calculate the dilepton production rate from q-q̄ annihilation via a ρ -meson state using Vector Meson Dominance. The result is compared to the rates from direct q-q̄ annihilation and from π-π annihilation. Furthermore we discuss the suppression of low mass dileptons if the quarks assume an ...

The collimation C of a hadronic event in the e + e −-annihilation is defined as the average of cos θ, C =< cos θ >, where θ is the angle of each hadron measured from the thrust axis, and the average is over all the hadrons produced in an event. It is an infrared-stable event-shape parameter. 1−C, the difference between the unity and the average collimation at a given energy, is proportional to ...

This paper develops an ontologically rich explanation of the inner mechanics of the annihilation process, starting from a non-local hidden-variable (NLHV) design. This explains the process in terms of the handedness of matter and antimatter, the interaction of the electron and antielectron as they approach, the collapse of their discrete force structures and their reformation into photon struct...

We present evidence for a 0 (1450) decaying to KK in pp annihilation at rest in liquid hydrogen in the nal state K L K. This reaction is important for the study of the KK decay mode of scalar resonances, in particular the isovectors a 0 (980) and a 0 (1450). The determination of the a 0 (1450) production also xes the KK coupling of the isoscalar f 0 (1500). We

. We combine the creation and annihilation operators of a scalar field in Minkowski spacetime to obtain the generators of the SU(1,1). We show that the transformation between Minkowski and Rindler vacua can be represented by (pseudo)rotation in the space of the SU(1,1) group. The root of this fact originates from the coordinate transformation between Minkowski and Rindler manifolds that can als...

Random walk simulations of exciton trapping and annihilation on binary and ternary lattices are presented. Single walker visitation efficiencies for ordered and random binary lattices are compared. Interacting multiple random walkers on binary and ternary random lattices are presented in terms of trapping and annihilation efficiencies that are related to experimental observables. A master equat...

With the aid of the creation operators introduced in our previous works, we show how to construct a basis of the space of quasi-local operators for the homogeneous XXZ chain.