Within the framework of the constituent quark model, it is shown that the single hadron fragmentation function of a parton can be expressed as a convolution of shower diquark or triquark distribution function and quark recombination probability, if the interference between amplitudes of quark recombination with different momenta is neglected. The recombination probability is determined by the h...

We review the main aspects of the fragmentation of bottom quarks in top quark decay. The NLO b-quark energy spectrum presents large mass logarithms ln(mt/m 2 b), which can be resummed by the use of the approach of perturbative fragmentation functions. Large soft contributions in both coefficient function and initial condition of the perturbative fragmentation function have been resummed as well...

We study consistent collections of random fragmentation trees with random integervalued edge lengths. We prove several equivalent necessary and sufficient conditions under which Geometrically distributed edge lengths can be consistently assigned to a Markov branching tree. Among these conditions is a characterization by a unique probability measure, which plays a role similar to the dislocation...

We discuss perturbative and non{perturbative strong interaction eeects in the pair production of stop squarks (~ t 1) at e + e ? colliders. Events with an additional hard gluon allow to detect or exclude ~ t 1 ~ t 1 production even in scenarios with very small mass splitting between ~ t 1 and an invisible lightest supersymmetric particle (LSP). Such events can also help to establish that ~ t 1 ...

We study fragmentation of a random recursive tree into a forest by repeated removal of nodes. The initial tree consists of N nodes and it is generated by sequential addition of nodes with each new node attaching to a randomly-selected existing node. As nodes are removed from the tree, one at a time, the tree dissolves into an ensemble of separate trees, namely, a forest. We study statistical pr...

The Λ baryons with a single heavy flavor which transfer the quark polarization, have been studied both theoretically and experimentally. The Ξ’s with two heavy constituents are well treated in quark-diquark model. In this work we study the production of triply heavy baryons in the perturbative QCD regime and calculate the fragmentation functions for Ωccc and Ωbbb in the c and b quark fragmentat...

We prove the existence of a stationary solution of any given mass to the coagulationfragmentation equation without assuming a detailed balance condition, but assuming instead that aggregation dominates fragmentation for small particles while fragmentation predominates for large particles. We also show the existence of a self similar solution of any given mass to the coagulation equation and to ...

I present new results on the quark distribution in an on-shell heavy quark in perturbative QCD and explore its all–order relations with heavy–quark fragmentation. I first compute the momentum distribution function to all orders in the large–β0 limit and show that it is identical to the perturbative heavy–quark fragmentation function in the same approximation. I then analyze the Sudakov limit of...

The potential consequences of anthropogenic habitat fragmentation on species diversity and extinction have drawn considerable attention in recent decades. In many cases, traditional island biogeography theory has been applied to explain the observed patterns. Here, we propose that habitat fragmentation as a selective force can be traced in mammalian body length changes. By exploring historical ...

The fragmentation dynamics of aggregate of non-Brownian particles in shear flow is investigated numerically. The breakup behaviors of aggregates having the same connectivity but the different space-filling properties are examined. The Lagrangian particle simulation in a linear flow field is performed. The effect of surrounding fluid on the motion of multiple particles is estimated by Stokesian ...