4,557 research outputs found
Support Vector Machine Classification on a Biased Training Set: Multi-Jet Background Rejection at Hadron Colliders
This paper describes an innovative way to optimize a multivariate classifier,
in particular a Support Vector Machine algorithm, on a problem characterized by
a biased training sample. This is possible thanks to the feedback of a
signal-background template fit performed on a validation sample and included
both in the optimization process and in the input variable selection. The
procedure is applied to a real case of interest at hadron collider experiments:
the reduction and the estimate of the multi-jet background in the
plus jets data sample collected by the CDF experiment. The training samples,
partially derived from data and partially from simulation, are described in
detail together with the input variables exploited for the classification. At
present, the reached performance is superior to any other prescription applied
to the same final state at hadron collider experiments.Comment: 24 pages, 8 figures, preprint of NIM pape
On the usage of the probability integral transform to reduce the complexity of multi-way fuzzy decision trees in Big Data classification problems
We present a new distributed fuzzy partitioning method to reduce the
complexity of multi-way fuzzy decision trees in Big Data classification
problems. The proposed algorithm builds a fixed number of fuzzy sets for all
variables and adjusts their shape and position to the real distribution of
training data. A two-step process is applied : 1) transformation of the
original distribution into a standard uniform distribution by means of the
probability integral transform. Since the original distribution is generally
unknown, the cumulative distribution function is approximated by computing the
q-quantiles of the training set; 2) construction of a Ruspini strong fuzzy
partition in the transformed attribute space using a fixed number of equally
distributed triangular membership functions. Despite the aforementioned
transformation, the definition of every fuzzy set in the original space can be
recovered by applying the inverse cumulative distribution function (also known
as quantile function). The experimental results reveal that the proposed
methodology allows the state-of-the-art multi-way fuzzy decision tree (FMDT)
induction algorithm to maintain classification accuracy with up to 6 million
fewer leaves.Comment: Appeared in 2018 IEEE International Congress on Big Data (BigData
Congress). arXiv admin note: text overlap with arXiv:1902.0935
Tevatron Top-Quark Combinations and World Top-Quark Mass Combination
Almost 20 years after its discovery, the top quark is still an interesting
particle, undergoing precise investigation of its properties. For many years,
the Tevatron proton antiproton collider at Fermilab was the only place to study
top quarks in detail, while with the recent start of the LHC proton proton
collider a top quark factory has opened. An important ingredient for the full
understanding of the top quark is the combination of measurements from the
individual experiments. In particular, the Tevaton combinations of single
top-quark cross sections, the ttbar production cross section, the W helicity in
top-quark decays as well as the Tevatron and the world combination of the
top-quark mass are discussed.Comment: 5 pages, 2 figures, to appear in the proceedings of Top2014, Cannes,
France (28th Sept - 3rd Oct 2014
QCD Physics at the Tevatron
Results on recent QCD measurements performed at the Tevatron ppbar Collider
at sqrt{s} = 1.96 TeV are here reported. The inclusive jet and dijet mass cross
sections are compared to NLO pQCD calculations and to Run I results. The
production rates and kinematic properties of W + jets production processes are
compared to ``enhanced'' LO theoretical predictions. Non-perturbative ``soft''
interactions leading to the underlying event are studied and compared to QCD
Monte Carlo phenomenological models.Comment: Presented at 18th Les Rencontres De Physique De La Vallee D'Aoste:
Results and Perspectives in Particle Physics, La Thuile, Aosta Valley, Italy,
Feb. 29 - March 6, 200
Top quark mass: Latest CDF results, Tevatron combination and electroweak implications
A summary of the most up-to-date top quark mass measurements at CDF is
presented. These analyses use top-antitop candidate events detected in the CDF
experiment at the Tevatron collider with an integrated luminosity of up to
~3/fb. The combination of all those measurements together with the
corresponding top mass measurements from the concurrently running D0 experiment
at the Tevatron yields a world average of M_t=[173.1+/-0.6(stat.)+/-1.1(syst.)]
GeV/c^2.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
\ttbar and single top cross sections at the Tevatron
We present a summary of the latest measurements of the top pair and single
top cross sections performed by the CDF and D0 collaborations at the Fermilab
Tevatron collider.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 4 pages, 8 figure
Searches for Low Mass Higgs Boson at the Tevatron
We present the result of the searches for a low mass Standard Model Higgs
boson performed at the Tevatron ppbar collider (sqrt(s) =1.96 TeV) by the CDF
and D0 experiments with an integrated luminosity of up to 8.5 fb^-1. Individual
searches are discussed and classified according to their sensitivity. Primary
channels rely on the associate production with a vector boson (WH or ZH) and
the H->bbbar decay channel (favored for M_H<135 GeV/c^2). Event selection is
based on the leptonic decay of the vector boson and the identification of
b-hadron enriched jets. Each individual channel is sensitive, for M_H=115
GeV/c^2, to less than 5 times the SM expected cross section and the most
sensitive channels can exclude a production cross section of 2.3 x sigma_H SM.
Secondary channels rely on a variety of final states. Although they are from 2
to 5 times less sensitive than any primary channel, they contribute to the
Tevatron combination and, in some cases, they pose strong constrains on exotic
Higgs boson models.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 4 pages, 5 figur
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