4 research outputs found
A Forward Branching Phase-Space Generator
We develop a forward branching phase-space generator for use in
next-to-leading order parton level event generators. By performing 2 -> 3
branchings from a fixed jet phase-space point, all bremsstrahlung events
contributing to the given jet configuration are generated. The resulting
phase-space integration is three-dimensional irrespective of the considered jet
multiplicity. In this first study, we use the forward branching phase-space
generator to calculate in the leading-color approximation next-to-leading order
corrections to fully differential gluonic jet configurations.Comment: 35 pages, 5 figures, 1 tabl
Non-perturbative proton stability
Proton decay is a generic prediction of GUT models and is therefore an
important channel to detect the existence of unification or to set limits on
GUT models. Current bounds on the proton lifetime are around 10^33 years, which
sets stringent limits on the GUT scale. These limits are obtained under
`reasonable' assumptions about the size of the hadronic matrix elements. In
this paper we present a non-perturbative calculation of the hadronic matrix
elements within the chiral bag model of the proton. We argue that there is an
exponential suppression of the matrix elements, due to non-perturbative QCD,
that stifles proton decay by orders of magnitude -- potentially O(10^-10). This
suppression is present for small quark masses and is due to the chiral symmetry
breaking of QCD. Such a suppression has clear implications for GUT models and
could resuscitate several scenarios
Thread-Scalable Evaluation of Multi-Jet Observables
A leading-order, leading-color parton-level event generator is developed for
use on a multi-threaded GPU. Speed-up factors between 150 and 300 are obtained
compared to an unoptimized CPU-based implementation of the event generator. In
this first paper we study the feasibility of a GPU-based event generator with
an emphasis on the constraints imposed by the hardware. Some studies of Monte
Carlo convergence and accuracy are presented for PP -> 2,...,10 jet observables
using of the order of 1e11 events.Comment: 16 pages, 5 figures, 3 table