Papers by renato campanini
A measurement is presented of the exclusive and semi-exclusive production of charged pion pairs i... more A measurement is presented of the exclusive and semi-exclusive production of charged pion pairs in proton-proton collisions, pp → p(p *) + π + π − + p(p *), where the π + π − pair is emitted at central rapidities, and the scattered protons stay intact (p) or diffractively dissociate (p *) without detection. The measurement is performed with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 450 µb −1 collected at a center-of-mass energy of 7 TeV. The dipion cross section, measured for single-pion transverse momentum p T > 0.2 GeV/c and rapidity |y| < 2, is 26.5 ± 0.3 (stat) ± 5.0 (syst) ± 1.1 (lumi) µb. The differential cross sections measured as a function of the invariant mass, p T , and y of the pion pair, and as a function of single-pion p T , are compared to phenomenological predictions.
Physics Letters B, 2018
A search is presented for single production of a vector-like quark (T) decaying to a Z boson and ... more A search is presented for single production of a vector-like quark (T) decaying to a Z boson and a top quark, with the Z boson decaying leptonically and the top quark decaying hadronically. The search uses data collected by the CMS experiment in protonproton collisions at a center-of-mass energy of 13 TeV in 2016, corresponding to an integrated luminosity of 35.9 fb −1. The presence of forward jets is a particular characteristic of single production of vector-like quarks that is used in the analysis. For the first time, different T quark width hypotheses are studied, from negligibly small to 30% of the new particle mass. At the 95% confidence level, the product of cross section and branching fraction is excluded above values in the range 0.26-0.04 pb for T quark masses in the range 0.7-1.7 TeV, assuming a negligible width. A similar sensitivity is observed for widths of up to 30% of the T quark mass. The production of a heavy Z boson decaying to Tt, with T → tZ, is also searched for, and limits on the product of cross section and branching fractions for this process are set between 0.13 and 0.06 pb for Z boson masses in the range from 1.5 to 2.5 TeV.
International Journal of Modern Physics C, 2000
In this paper, we investigate the performance of a Computer Aided Diagnosis (CAD) system for the ... more In this paper, we investigate the performance of a Computer Aided Diagnosis (CAD) system for the detection of clustered microcalcifications in mammograms. Our detection algorithm consists of the combination of two different methods. The first, based on difference-image techniques and gaussianity statistical tests, finds out the most obvious signals. The second, is able to discover more subtle microcalcifications by exploiting a multiresolution analysis by means of the wavelet transform. We can separately tune the two methods, so that each one of them is able to detect signals with similar features. By combining signals coming out from the two parts through a logical OR operation, we can discover microcalcifications with different characteristics. Our algorithm yields a sensitivity of 91.4% with 0.4 false positive cluster per image on the 40 images of the Nijmegen database.
International Journal of Modern Physics C, 2000
In this paper, we investigate the performance of a Computer Aided Diagnosis (CAD) system for the ... more In this paper, we investigate the performance of a Computer Aided Diagnosis (CAD) system for the detection of clustered microcalcifications in mammograms. Our detection algorithm consists of the combination of two different methods. The first, based on difference-image techniques and gaussianity statistical tests, finds out the most obvious signals. The second, is able to discover more subtle microcalcifications by exploiting a multiresolution analysis by means of the wavelet transform. We can separately tune the two methods, so that each one of them is able to detect signals with similar features. By combining signals coming out from the two parts through a logical OR operation, we can discover microcalcifications with different characteristics. Our algorithm yields a sensitivity of 91.4% with 0.4 false positive cluster per image on the 40 images of the Nijmegen database.
Journal of High Energy Physics, 2017
A search for strongly produced supersymmetric particles using signatures involving multiple energ... more A search for strongly produced supersymmetric particles using signatures involving multiple energetic jets and either two isolated same-sign leptons (e or μ), or at least three isolated leptons, is presented. The analysis relies on the identification of b-jets and high missing transverse momentum to achieve good sensitivity. A data sample of proton-proton collisions at $$ \sqrt{s}=13 $$ s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016, corresponding to a total integrated luminosity of 36.1 fb−1, is used for the search. No significant excess over the Standard Model prediction is observed. The results are interpreted in several simplified supersymmetric models featuring R-parity conservation or R-parity violation, extending the exclusion limits from previous searches. In models considering gluino pair production, gluino masses are excluded up to 1.87 TeV at 95% confidence level. When bottom squarks are pair-produced and decay to a chargino and ...
The European Physical Journal C, 2016
A search for new physics is performed using events with two isolated same-sign leptons, two or mo... more A search for new physics is performed using events with two isolated same-sign leptons, two or more jets, and missing transverse momentum. The results are based on a sample of proton-proton collisions at a center-of-mass energy of 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 2.3 fb 1. Multiple search regions are defined by classifying events in terms of missing transverse momentum, the scalar sum of jet transverse momenta, the transverse mass associated with a W boson candidate, the number of jets, the number of b quark jets, and the transverse momenta of the leptons in the event. The analysis is sensitive to a wide variety of possible signals beyond the standard model. No excess above the standard model background expectation is observed. Constraints are set on various supersymmetric models, with gluinos and bottom squarks excluded for masses up to 1300 and 680 GeV, respectively, at the 95 % confidence level. Upper limits on the cross sections for the production of two top quark-antiquark pairs (119 fb) and two same-sign top quarks (1.7 pb) are also obtained. Selection efficiencies and model independent limits are provided to allow further interpretations of the results.
Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013
A search for nonresonant new phenomena, originating from either contact interactions or large ext... more A search for nonresonant new phenomena, originating from either contact interactions or large extra spatial dimensions, has been carried out using events with two isolated electrons or muons. These events, produced at the LHC in proton-proton collisions at ffiffi ffi s p ¼ 7 TeV, were recorded by the ATLAS detector. The data sample, collected throughout 2011, corresponds to an integrated luminosity of 4.9 and 5:0 fb À1 in the e þ e À and þ À channels, respectively. No significant deviations from the Standard Model expectation are observed. Using a Bayesian approach, 95% confidence level lower limits ranging from 9.0 to 13.9 TeV are placed on the energy scale of ''qq contact interactions in the left-left isoscalar model. Lower limits ranging from 2.4 to 3.9 TeV are also set on the string scale in large extra dimension models. After combining these limits with results from a similar search in the diphoton channel, slightly more stringent limits are obtained.
Digital Mammography, 2003
The aim of this paper is to investigate the properties of a clinical FFDM unit (Giotto-Image MD, ... more The aim of this paper is to investigate the properties of a clinical FFDM unit (Giotto-Image MD, IMS Italy). The digital detector consists of a flat panel using the amorphous selenium technology (ANRAD Corporation, Canada). The active area of the imager is 17.4 cm × 23.9 cm (2048×2816 pixels) with a pixel pitch of 85 µm. The direct conversion of X-rays into charge provides excellent imaging performance. In this work we present an objective and complete characterization of such system: detector response, MTF, NPS and DQE calculation will be presented. MTF and DQE at Nyquist frequency (5.88 lp/mm) are equal to 38% and 15%, respectively. The detector linearity is very good under the typical mammographic tested exposure conditions.
Physical Review Letters, 2007
Journal of Physics: Conference Series, 2013
A search is presented for single production of heavy vector-like quarks (B) that decay to a Higgs... more A search is presented for single production of heavy vector-like quarks (B) that decay to a Higgs boson and a b quark, with the Higgs boson decaying to a highly boosted bb pair reconstructed as a single collimated jet. The analysis is based on data collected by the CMS experiment in proton-proton collisions at √ s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb −1. The data are consistent with background expectations, and upper limits at 95% confidence level on the product of the B quark cross section and the branching fraction are obtained in the range 1.28-0.07 pb, for a narrow B quark with a mass between 700 and 1800 GeV. The production of B quarks with widths of 10, 20 and 30% of the resonance mass is also considered, and the sensitivities obtained are similar to those achieved in the narrow width case. This is the first search at the CERN LHC for the single production of a B quark through its fully hadronic decay channel, and the first study considering finite resonance widths of the B quark.
The European Physical Journal C, 2013
A search for physics beyond the standard model is performed with events having one or more hadron... more A search for physics beyond the standard model is performed with events having one or more hadronically decaying τ leptons, highly energetic jets, and large transverse momentum imbalance. The data sample corresponds to an integrated luminosity of 4.98 fb −1 of proton-proton collisions at √ s = 7 TeV collected with the CMS detector at the LHC in 2011. The number of observed events is consistent with predictions for standard model processes. Lower limits on the mass of the gluino in supersymmetric models are determined.
Physics Letters B, 2011
We deduce approximate equations of state from experimental measurements in pp and pp collisions. ... more We deduce approximate equations of state from experimental measurements in pp and pp collisions. Thermodynamic quantities are estimated combining the measure of average transverse momentum p T vs pseudorapidity density dN ch dη with the estimation of the interaction region size from measures of Bose Einstein correlation, or from a theoretical model which relates dN ch dη to the impact parameter. The results are very similar to theory predictions in case of crossover from hadron gas to quark gluon plasma. According to our analysis, the possible crossover should start at dN ch dη ≃ 6 and end at dN ch dη ≃ 24.
In this work, we present a novel approach to mass detection in digital mammograms. The great vari... more In this work, we present a novel approach to mass detection in digital mammograms. The great variability of the masses appearance is the main obstacle of building a mass detection method. It is indeed demanding to characterize all the varieties of masses with a reduced set of features. Hence, in our approach we have chosen not to extract any feature, for the detection of the region of interest; on the contrary, we exploit all the information available on the image. A multiresolution overcomplete wavelet representation is performed, in order to codify the image with redundancy of information. The vectors of the very-large space obtained are then provided to a first SVM classifier. The detection task is here considered as a two-class pattern recognition problem: crops are classified as suspect or not, by using this SVM classifier. False candidates are eliminated with a second cascaded SVM. To further reduce the number of false positives, an ensemble of experts is applied: the final suspect regions are achieved by using a voting strategy. The sensitivity of the presented system is nearly 80% with a false-positive rate of 1.1 marks per image, estimated on images coming from the USF DDSM database.
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Papers by renato campanini