26 research outputs found

    The Beta Generalized Exponential Distribution

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    We introduce the beta generalized exponential distribution that includes the beta exponential and generalized exponential distributions as special cases. We provide a comprehensive mathematical treatment of this distribution. We derive the moment generating function and the rrth moment thus generalizing some results in the literature. Expressions for the density, moment generating function and rrth moment of the order statistics also are obtained. We discuss estimation of the parameters by maximum likelihood and provide the information matrix. We observe in one application to real data set that this model is quite flexible and can be used quite effectively in analyzing positive data in place of the beta exponential and generalized exponential distributions

    Efficacy of whole-body vibration training on brain-derived neurotrophic factor, clinical and functional outcomes, and quality of life in women with fibromyalgia syndrome: a randomized controlled trial

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    Whole-body vibration (WBV) is an exercise modality or treatment/prophylaxis method in which subjects (humans, animals, or cells) are exposed to mechanical vibrations through a vibrating platform or device. The vibrations are defined by their direction, frequency, magnitude, duration, and Biology 2021, 10, 965. https://doi.org/10.3390/biology10100965 https://www.mdpi.com/journal/biology Biology 2021, 10, 965 2 of 30 the number of daily bouts. Subjects can be exposed while performing exercises, hold postures, sitting, or lying down. Worldwide, WBV has attracted significant attention, and the number of studies is rising. To interpret, compare, and aggregate studies, the correct, complete, and consistent reporting of WBV-specific data (WBV parameters) is critical. Specific reporting guidelines aid in accomplishing this goal. There was a need to expand existing guidelines because of continuous developments in the field of WBV research, including but not limited to new outcome measures regarding brain function and cognition, modified designs WBV platforms and attachments (e.g., mounting a chair on a platform), and comparisons of animal and cell culture studies with human studies. Based on Delphi studies among experts and using EQUATOR recommendations, we have developed extended reporting guidelines with checklists for human and animal/cell culture research, including information on devices, vibrations, administration, general protocol, and subjects. In addition, we provide explanations and examples of how to report. These new reporting guidelines are specific to WBV variables and do not target research designs in general. Researchers are encouraged to use the new WBV guidelines in addition to general design-specific guideline

    Measurement of inclusive and differential cross sections for single top quark production in association with a W boson in proton-proton collisions at s \sqrt{s} = 13 TeV

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    International audienceMeasurements of the inclusive and normalised differential cross sections are presented for the production of single top quarks in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data used were recorded with the CMS detector at the LHC during 2016–2018, and correspond to an integrated luminosity of 138 fb1^{−1}. Events containing one electron and one muon in the final state are analysed. For the inclusive measurement, a multivariate discriminant, exploiting the kinematic properties of the events is used to separate the signal from the dominant tt \textrm{t}\overline{\textrm{t}} background. A cross section of 79.2±0.9(stat)8.0+7.7(syst)±1.2(lumi) 79.2\pm 0.9{\left(\textrm{stat}\right)}_{-8.0}^{+7.7}\left(\textrm{syst}\right)\pm 1.2\left(\textrm{lumi}\right) pb is obtained, consistent with the predictions of the standard model. For the differential measurements, a fiducial region is defined according to the detector acceptance, and the requirement of exactly one jet coming from the fragmentation of a bottom quark. The resulting distributions are unfolded to particle level and agree with the predictions at next-to-leading order in perturbative quantum chromodynamics.[graphic not available: see fulltext

    Search for pair production of vector-like quarks in leptonic final states in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search is presented for vector-like T \mathrm{T} and B \mathrm{B} quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016-2018, with an integrated luminosity of 138 fb1 ^{-1} . Events are separated into single-lepton, same-sign charge dilepton, and multilepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T \mathrm{T} quark masses up to 1.54 TeV and B \mathrm{B} quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for TT \mathrm{T} \overline{\mathrm{T}} production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for BB \mathrm{B} \overline{\mathrm{B}} production with B \mathrm{B} quark decays to tW.A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016–2018, with an integrated luminosity of 138 fb1^{−1}. Events are separated into single-lepton, same-sign charge dilepton, and multi-lepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for TT \textrm{T}\overline{\textrm{T}} production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for BB \textrm{B}\overline{\textrm{B}} production with B quark decays to tW.[graphic not available: see fulltext]A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016-2018, with an integrated luminosity of 138 fb1^{-1}. Events are separated into single-lepton, same-sign charge dilepton, and multilepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for TT\mathrm{T\overline{T}} production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for BB\mathrm{B\overline{B}} production with B quark decays to tW

    Measurement of the Higgs boson inclusive and differential fiducial production cross sections in the diphoton decay channel with pp collisions at s \sqrt{s} = 13 TeV

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    International audienceThe measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb1^{−1}. The inclusive fiducial cross section is measured to be σfid=73.45.3+5.4(stat)2.2+2.4(syst) {\sigma}_{\textrm{fid}}={73.4}_{-5.3}^{+5.4}{\left(\textrm{stat}\right)}_{-2.2}^{+2.4}\left(\textrm{syst}\right) fb, in agreement with the standard model expectation of 75.4 ± 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed.[graphic not available: see fulltext

    Probing heavy Majorana neutrinos and the Weinberg operator through vector boson fusion processes in proton-proton collisions at s=\sqrt{s} = 13 TeV

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    The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision data set recorded at s=\sqrt{s} = 13 TeV, collected with the CMS detector and corresponding to a total integrated luminosity of 138 fb1^{-1}. The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV-25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μμ\mu\mu Majorana neutrino mass of 10.8 GeV.The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision dataset recorded at s=13  TeV, collected with the CMS detector and corresponding to a total integrated luminosity of 138  fb−1. The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV–25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μμ Majorana neutrino mass of 10.8 GeV.The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision data set recorded at s\sqrt{s} = 13 TeV, collected with the CMS detector and corresponding to a total integrated luminosity of 138 fb1^{-1}. The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV-25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μμ\mu\mu Majorana neutrino mass of 10.8 GeV

    Measurement of the top quark pole mass using tt \textrm{t}\overline{\textrm{t}} +jet events in the dilepton final state in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A measurement of the top quark pole mass mtpole{{m_{\mathrm{t}}} ^{\text{pole}}} in events where a top quark-antiquark pair (ttˉ\mathrm{t\bar{t}}) is produced in association with at least one additional jet (ttˉ\mathrm{t\bar{t}}+jet) is presented. This analysis is performed using proton-proton collision data at s=\sqrt{s} = 13 TeV collected by the CMS experiment at the CERN LHC, corresponding to a total integrated luminosity of 36.3 fb1^{-1}. Events with two opposite-sign leptons in the final state (e+^{+}e^{-}, μ+μ\mu^{+}\mu^{-}, e±μ^{\pm}\mu^{\mp}) are analyzed. The reconstruction of the main observable and the event classification are optimized using multivariate analysis techniques based on machine learning. The production cross section is measured as a function of the inverse of the invariant mass of the ttˉ\mathrm{t\bar{t}}+jet system at the parton level using a maximum likelihood unfolding. Given a reference parton distribution function (PDF), the top quark pole mass is extracted using the theoretical predictions at next-to-leading order. For the ABMP16NLO PDF, this results in mtpole={{m_{\mathrm{t}}} ^{\text{pole}}} = 172.94 ±\pm 1.37 GeV.A measurement of the top quark pole mass mtpole {m}_{\textrm{t}}^{\textrm{pole}} in events where a top quark-antiquark pair (tt \textrm{t}\overline{\textrm{t}} ) is produced in association with at least one additional jet (tt \textrm{t}\overline{\textrm{t}} +jet) is presented. This analysis is performed using proton-proton collision data at s \sqrt{s} = 13 TeV collected by the CMS experiment at the CERN LHC, corresponding to a total integrated luminosity of 36.3 fb1^{−1}. Events with two opposite-sign leptons in the final state (e+^{+}e^{−}, μ+^{+}μ^{−}, e±^{±}μ^{∓}) are analyzed. The reconstruction of the main observable and the event classification are optimized using multivariate analysis techniques based on machine learning. The production cross section is measured as a function of the inverse of the invariant mass of the tt \textrm{t}\overline{\textrm{t}} +jet system at the parton level using a maximum likelihood unfolding. Given a reference parton distribution function (PDF), the top quark pole mass is extracted using the theoretical predictions at next-to-leading order. For the ABMP16NLO PDF, this results in mtpole {m}_{\textrm{t}}^{\textrm{pole}} = 172.93 ± 1.36 GeV.[graphic not available: see fulltext]A measurement of the top quark pole mass mtpolem_\mathrm{t}^\text{pole} in events where a top quark-antiquark pair (ttˉ\mathrm{t\bar{t}}) is produced in association with at least one additional jet (ttˉ\mathrm{t\bar{t}}+jet) is presented. This analysis is performed using proton-proton collision data at s\sqrt{s} = 13 TeV collected by the CMS experiment at the CERN LHC, corresponding to a total integrated luminosity of 36.3 fb1^{-1}. Events with two opposite-sign leptons in the final state (e+^+e^-, μ+μ\mu^+\mu^-, e±μ^\pm\mu^\mp) are analyzed. The reconstruction of the main observable and the event classification are optimized using multivariate analysis techniques based on machine learning. The production cross section is measured as a function of the inverse of the invariant mass of the ttˉ\mathrm{t\bar{t}}+jet system at the parton level using a maximum likelihood unfolding. Given a reference parton distribution function (PDF), the top quark pole mass is extracted using the theoretical predictions at next-to-leading order. For the ABMP16NLO PDF, this results in mtpolem_\mathrm{t}^\text{pole} = 172.93 ±\pm 1.36 GeV

    Search for resonant and nonresonant production of pairs of dijet resonances in proton-proton collisions at s \sqrt{s} = 13 TeV

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    International audienceA search for pairs of dijet resonances with the same mass is conducted in final states with at least four jets. Results are presented separately for the case where the four jet production proceeds via an intermediate resonant state and for nonresonant production. The search uses a data sample corresponding to an integrated luminosity of 138 fb1^{−1} collected by the CMS detector in proton-proton collisions at s \sqrt{s} = 13 TeV. Model-independent limits, at 95% confidence level, are reported on the production cross section of four-jet and dijet resonances. These first LHC limits on resonant pair production of dijet resonances via high mass intermediate states are applied to a signal model of diquarks that decay into pairs of vector-like quarks, excluding diquark masses below 7.6 TeV for a particular model scenario. There are two events in the tails of the distributions, each with a four-jet mass of 8 TeV and an average dijet mass of 2 TeV, resulting in local and global significances of 3.9 and 1.6 standard deviations, respectively, if interpreted as a signal. The nonresonant search excludes pair production of top squarks with masses between 0.50 TeV to 0.77 TeV, with the exception of a small interval between 0.52 and 0.58 TeV, for supersymmetric R-parity-violating decays to quark pairs, significantly extending previous limits. Here, the most significant excess above the predicted background occurs at an average dijet mass of 0.95 TeV, for which the local and global significances are 3.6 and 2.5 standard deviations, respectively.[graphic not available: see fulltext
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