12,961 research outputs found
Branching on multi-aggregated variables
open5siopenGamrath, Gerald; Melchiori, Anna; Berthold, Timo; Gleixner, Ambros M.; Salvagnin, DomenicoGamrath, Gerald; Melchiori, Anna; Berthold, Timo; Gleixner, Ambros M.; Salvagnin, Domenic
Intermediate integer programming representations using value disjunctions
We introduce a general technique to create an extended formulation of a
mixed-integer program. We classify the integer variables into blocks, each of
which generates a finite set of vector values. The extended formulation is
constructed by creating a new binary variable for each generated value. Initial
experiments show that the extended formulation can have a more compact complete
description than the original formulation.
We prove that, using this reformulation technique, the facet description
decomposes into one ``linking polyhedron'' per block and the ``aggregated
polyhedron''. Each of these polyhedra can be analyzed separately. For the case
of identical coefficients in a block, we provide a complete description of the
linking polyhedron and a polynomial-time separation algorithm. Applied to the
knapsack with a fixed number of distinct coefficients, this theorem provides a
complete description in an extended space with a polynomial number of
variables.Comment: 26 pages, 5 figure
Digging Deeper for New Physics in the LHC Data
In this paper we describe a novel, model-independent technique of
"rectangular aggregations" for mining the LHC data for hints of new physics. A
typical (CMS) search now has hundreds of signal regions, which can obscure
potentially interesting anomalies. Applying our technique to the two CMS
jets+MET SUSY searches, we identify a set of previously overlooked excesses. Among these, four excesses survive tests of inter- and
intra-search compatibility, and two are especially interesting: they are
largely overlapping between the jets+MET searches and are characterized by low
jet multiplicity, zero -jets, and low MET and . We find that resonant
color-triplet production decaying to a quark plus an invisible particle
provides an excellent fit to these two excesses and all other data -- including
the ATLAS jets+MET search, which actually sees a correlated excess. We discuss
the additional constraints coming from dijet resonance searches, monojet
searches and pair production. Based on these results, we believe the
wide-spread view that the LHC data contains no interesting excesses is greatly
exaggerated.Comment: 31 pages + appendices, 14 figures, source code for recasted searches
attached as auxiliary materia
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