Search for Resonances in the Dijet Mass Spectrum from 7 TeV Pp Collisions at CMS.

Search for Resonances in the Dijet Mass Spectrum from 7 TeV Pp Collisions at CMS.
Author:
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Total Pages: 27
Release: 2011
Genre:
ISBN:

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A search for narrow resonances with a mass of at least 1 TeV in the dijet mass spectrum is performed using pp collisions at sqrt(s)=7 TeV corresponding to an integrated luminosity of 1 inverse femtobarn, collected by the CMS experiment at the LHC. No resonances are observed. Upper limits at the 95% confidence level are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, and gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% confidence level: string resonances with mass less than 4.00 TeV, E6 diquarks with mass less than 3.52 TeV, excited quarks with mass less than 2.49 TeV, axigluons and colorons with mass less than 2.47 TeV, and W' bosons with mass less than 1.51 TeV.

Search for Dijet Resonances in 7 TeV Pp Collisions at CMS.

Search for Dijet Resonances in 7 TeV Pp Collisions at CMS.
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Total Pages: 24
Release: 2011
Genre:
ISBN:

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A search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9 inverse pb collected by the CMS experiment at the LHC. Upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% CL: string resonances, with mass less than 2.50 TeV, excited quarks, with mass less than 1.58 TeV, and axigluons, colorons, and E_6 diquarks, in specific mass intervals. This extends previously published limits on these models.

New Physics Search in Dijet Mass Spectrum with Compact Muon Solenoid

New Physics Search in Dijet Mass Spectrum with Compact Muon Solenoid
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Total Pages: 134
Release: 2011
Genre:
ISBN:

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Many extensions of the SM predict the existence of new massive objects that couple to quarks and gluons and result in resonances in the dijet mass spectrum. In this thesis we present a search for narrow resonances in the dijet mass spectrum using data corresponding to an integrated luminosity of 1 fb$^{-1}$ collected by the CMS experiment at the LHC, at a proton-proton collision energy of $\sqrt{s}=7$ $TeV$. %This dijet analysis is searching for new particles in the dijet mass spectrum decaying to dijets. These new particles are predicted by new physics beyond Standard Model. This thesis presents a dijet analysis performed at the Compact Muon Solenoid (CMS) in pp collisions at $\sqrt{s}=7$ $TeV$ for an integrated luminosities of 1.0 fb$^{-1}$. The dijet mass distribution of two leading jets is measured and compared to QCD predictions, simulated by PYTHIA with the CMS detector simulation. We select events which have two leading jets with $\mid \Delta\eta \mid

Searches for Dijet Resonances

Searches for Dijet Resonances
Author: Lydia Audrey Beresford
Publisher: Springer
Total Pages: 175
Release: 2018-09-04
Genre: Science
ISBN: 331997520X

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This book addresses one of the most intriguing mysteries of our universe: the nature of dark matter. The results presented here mark a significant and substantial contribution to the search for new physics, in particular for new particles that couple to dark matter. The first analysis presented is a search for heavy new particles that decay into pairs of hadronic jets (dijets). This pioneering analysis explores unprecedented dijet invariant masses, reaching nearly 7 TeV, and sets constraints on several important new physics models. The two subsequent analyses focus on the difficult low dijet mass region, down to 200 GeV, and employ a novel technique to efficiently gather low-mass dijet events. The results of these analyses transcend the long-standing constraints on dark matter mediator particles set by several existing experiments.

Search for New Particles Decaying to Diject in 7 TeV Proton-proton Collisions at CMS.

Search for New Particles Decaying to Diject in 7 TeV Proton-proton Collisions at CMS.
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Total Pages: 150
Release: 2011
Genre:
ISBN:

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This thesis presents a measurement of the dijet invariant mass spectrum and search for new particles decaying to dijets at CMS in 7 TeV pp collisions using data corresponding to an integrated luminosity of 2.875 pb-1. The measured dijet mass distribution is compared to QCD prediction from PYTHIA . It is required the pseudorapidity separation of the two jets to satisfy.

Search for New Physics in the Dijet Mass Spectrum and Dijet Ratio in P P Collisions at S**1/2

Search for New Physics in the Dijet Mass Spectrum and Dijet Ratio in P P Collisions at S**1/2
Author:
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Total Pages: 4
Release: 2010
Genre:
ISBN:

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A search for new Physics is performed with inclusive dijet final states in pp collisions, using data corresponding to an integrated luminosity of 120 ± 13 nb−1 collected by the CMS experiment at LHC. Generic upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% CL: string resonances, with mass less than 1.67 TeV, excited quarks, with mass less than 0.59 TeV and axigluons and colorons with mass less than 0.52 TeV. A search for quark compositeness in the form of quark contact interactions is conducted using the dijet centrality ratio, which quantifies the angular distribution of the dijets. The measurement is found to agree with the predictions of the Standard Model and the statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions of 1.9 TeV at the 95% confidence level. The above results extend previously published limits on these models.

Search for New Physics in the Dijet Mass Spectrum and Dijet Ratio in P P Collisions at S**ư

Search for New Physics in the Dijet Mass Spectrum and Dijet Ratio in P P Collisions at S**ư
Author:
Publisher:
Total Pages: 4
Release: 2010
Genre:
ISBN:

Download Search for New Physics in the Dijet Mass Spectrum and Dijet Ratio in P P Collisions at S**ư Book in PDF, Epub and Kindle

A search for new Physics is performed with inclusive dijet final states in pp collisions, using data corresponding to an integrated luminosity of 120 ± 13 nb−1 collected by the CMS experiment at LHC. Generic upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% CL: string resonances, with mass less than 1.67 TeV, excited quarks, with mass less than 0.59 TeV and axigluons and colorons with mass less than 0.52 TeV. A search for quark compositeness in the form of quark contact interactions is conducted using the dijet centrality ratio, which quantifies the angular distribution of the dijets. The measurement is found to agree with the predictions of the Standard Model and the statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions of 1.9 TeV at the 95% confidence level. The above results extend previously published limits on these models.

Search for Low-mass and High-mass Narrow Dijet Resonances with the CMS Detector at Sqrt(s)

Search for Low-mass and High-mass Narrow Dijet Resonances with the CMS Detector at Sqrt(s)
Author: David Gruft Sheffield
Publisher:
Total Pages: 131
Release: 2017
Genre: Large Hadron Collider (France and Switzerland)
ISBN:

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A search for narrow resonances decaying to the dijet final state at the CMS experiment. The data consists of 12.9 fb^( -1) of proton-proton collisions. Data scouting is used to extend the search to lower masses. The dijet mass spectra at low and high masses are well parametrized by smoothly falling functions. No significant evidence of a resonance is observed. Upper limits on the product of cross section, branching fraction, and experimental acceptance at the 95% confidence level are set on resonances with masses between 0.6 and 7.5 TeV. The limits exclude benchmark models for string resonances below 7.4 TeV, scalar diquarks below 6.9 TeV, axigluons and colorons below 5.5 TeV, excited quarks below 5.4 TeV, color-octet scalars below 3.0 TeV, W' bosons below 2.7 TeV, Z' bosons below 2.1 TeV and from 2.3 to 2.6 TeV, vector and axial-vector DM mediators below 2.0 TeV, and RS gravitons below 1.9 TeV. These limits expand the excluded region beyond past searches and are the first limits set on DM mediators by the dijet channel.

Search for Dijet Resonances in Proton-proton Collisions at $\sqrt{s}

Search for Dijet Resonances in Proton-proton Collisions at $\sqrt{s}
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Total Pages:
Release: 2016
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ISBN:

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A search is presented for narrow resonances decaying to dijet final states in proton-proton collisions at sqrt(s)=13 TeV using data corresponding to an integrated luminosity of 12.9 inverse femtobarns. The dijet mass spectrum is well described by a smooth parameterization and no significant evidence for the production of new particles is observed. Upper limits at 95% confidence level are reported on the production cross section for narrow resonances with masses above 0.6 TeV. In the context of specific models, the limits exclude string resonances with masses below 7.4 TeV, scalar diquarks below 6.9 TeV, axigluons and colorons below 5.5 TeV, excited quarks below 5.4 TeV, color-octet ascalars below 3.0 TeV, W' bosons below 2.7 TeV, Z' bosons below 2.1 TeV and between 2.3 and 2.6 TeV, and RS gravitons below 1.9 TeV. These extend previous limits in the dijet channel. Vector and axial-vector mediators in a simplified model of interactions between quarks and dark matter are excluded below 2.0 TeV. The first limits in the dijet channel on dark matter mediators are presented as functions of dark matter mass and are compared to the exclusions of dark matter in direct detection experiments.

Search for Narrow Resonances Decaying to Dijets in Proton-proton Collisions at {u221A}s

Search for Narrow Resonances Decaying to Dijets in Proton-proton Collisions at {u221A}s
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Total Pages:
Release: 2016
Genre:
ISBN:

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In this study, a search for narrow resonances in proton-proton collisions at √s = 13 TeV is presented. The invariant mass distribution of the two leading jets is measured with the CMS detector using a data set corresponding to an integrated luminosity of 2.4 fb–1. The highest observed dijet mass is 6.1 TeV. The distribution is smooth and no evidence for resonant particles is observed. Upper limits at 95% confidence level are set on the production cross section for narrow resonances with masses above 1.5 TeV. When interpreted in the context of specific models, the limits exclude string resonances with masses below 7.0 TeV, scalar diquarks below 6.0 TeV, axigluons and colorons below 5.1 TeV, excited quarks below 5.0 TeV, color-octet scalars below 3.1 TeV, and W' bosons below 2.6 TeV. These results significantly extend previously published limits.