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 $W\to e \nu$ 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