Download or read book Search for Massive Supersymmetric Particles Decaying to Many Jets Using the ATLAS Detector in Pp Collisions at u221A s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of a search for decays of massive particles to fully hadronic final states are presented. This search uses 20.3 fb-1 of data collected by the ATLAS detector in √s = 8 TeV proton-proton collisions at the LHC. Signatures based on high jet multiplicities without requirements on the missing transverse momentum are used to search for R-parity-violating supersymmetric gluino pair production with subsequent decays to quarks. The analysis is performed using a requirement on the number of jets, in combination with separate requirements on the number of b-tagged jets, as well as a topological observable formed from the scalar sum of the mass values of large-radius jets in the event. Results are interpreted in the context of all possible branching ratios of direct gluino decays to various quark flavors. No significant deviation is observed from the expected Standard Model backgrounds estimated using jet counting as well as data-driven templates of the total-jet-mass spectra. Gluino pair decays to ten or more quarks via intermediate neutralinos are excluded for a gluino with mass m-g 1TeV for a neutralino mass msubsup-/supX/subsubsup0/sup1/sub = 500 GeV. Direct gluino decays to six quarks are excluded for mgsubsup-/supg

Download or read book Search for Massive Supersymmetric Particles Decaying to Many Jets Using the ATLAS Detector in Pp Collisions at Root S written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of a search for decays of massive particles to fully hadronic final states are presented. This search uses 20.3 fb-1 of data collected by the ATLAS detector in [arrow]" TeV proton-proton collisions at the LHC. Signatures based on high jet multiplicities without requirements on the missing transverse momentum are used to search for R-parity-violating supersymmetric gluino pair production with subsequent decays to quarks. Our analysis was performed using a requirement on the number of jets, in combination with separate requirements on the number of b-tagged jets, as well as a topological observable formed from the scalar sum of the mass values of large-radius jets in the event. Results were interpreted in the context of all possible branching ratios of direct gluino decays to various quark flavors. No significant deviation is observed from the expected Standard Model backgrounds estimated using jet counting as well as data-driven templates of the total-jet-mass spectra. Gluino pair decays to ten or more quarks via intermediate neutralinos are excluded for a gluino with mass mg~

Download or read book Search for Massive Supersymmetric Particles Decaying to Many Jets Using the ATLAS Detector in Pp Collisions at arrow written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of a search for decays of massive particles to fully hadronic final states are presented. This search uses 20.3 fb-1 of data collected by the ATLAS detector in [arrow]" = 8 TeV proton-proton collisions at the LHC. Signatures based on high jet multiplicities without requirements on the missing transverse momentum are used to search for R-parity-violating supersymmetric gluino pair production with subsequent decays to quarks. The analysis is performed using a requirement on the number of jets, in combination with separate requirements on the number of b-tagged jets, as well as a topological observable formed from the scalar sum of the mass values of large-radius jets in the event. Results are interpreted in the context of all possible branching ratios of direct gluino decays to various quark flavors. No significant deviation is observed from the expected Standard Model backgrounds estimated using jet counting as well as data-driven templates of the total-jet-mass spectra. Gluino pair decays to ten or more quarks via intermediate neutralinos are excluded for a gluino with mass m~g

Download or read book Search for Pair produced Long lived Neutral Particles Decaying to Jets in the ATLAS Hadronic Calorimeter in Pp Collisions at u221A S written by and published by . This book was released on 2015 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3 fb-1 of data collected in proton–proton collisions at √s=8 TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeV to 900 GeV, and a long-lived neutral particle mass from 10 GeV to 150 GeV.

Download or read book Search for Pair produced Long lived Neutral Particles Decaying to Jets in the ATLAS Hadronic Calorimeter in Pp Collisions at 2 written by and published by . This book was released on 2015 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3 fb-1 of data collected in proton-proton collisions at [arrow]"=8 TeV. This research is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeV to 900 GeV, and a long-lived neutral particle mass from 10 GeV to 150 GeV.

Download or read book Search for New T Particles in Final States with Large Jet Multiplicities and Missing Transverse Energy in Pp Collisions at u221A s written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for a new particle T decaying to a top quark via T = t + X, where X goes undetected. We use a data sample corresponding to 5.7 fb-1 of integrated luminosity of pp collisions with √s = 1.96 TeV, collected at Fermilab Tevatron by the CDF II detector. Our search for pair production of T' is focused on the hadronic decay channel, pp = TT= tt+XX=bqqbqq + XX. We interpret our results in terms of a model where T is an exotic fourth generation quark and X is a dark matter particle. The data are consistent with standard model expectations. We set a limit on the generic production of TT = tt =+ XX, excluding the fourth generation exotic quarks T at 95% confidence level up to mT = 400 GeV/c2 for mX ≤ 70 GeV/c2.

Download or read book Search for Neutral Long lived Particles in Pp Collisions at square Root s written by [Study Group] ATLAS Collaboration CERN and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A search for decays of pair-produced neutral long-lived particles (LLPs) is presented using 139 fb−1 of proton-proton collision data collected by the ATLAS detector at the LHC in 2015-2018 at a centre-of-mass energy of 13 TeV. Dedicated techniques were developed for the reconstruction of displaced jets produced by LLPs decaying hadronically in the ATLAS hadronic calorimeter. Two search regions are defined for different LLP kinematic regimes. The observed numbers of events are consistent with the expected background, and limits for several benchmark signals are determined. For a SM Higgs boson with a mass of 125 GeV, branching ratios above 10% are excluded at 95% confidence level for values of c times LLP mean proper lifetime in the range between 20 mm and 10 m depending on the model. Upper limits are also set on the cross-section times branching ratio for scalars with a mass of 60 GeV and for masses between 200 GeV and 1 TeV

Download or read book Search for Events with a Pair of Displaced Vertices from Long lived Neutral Particles Decaying Into Hadronic Jets in the ATLAS Muon Spectrometer in Pp Collisions at square Root S written by [Study Group] ATLAS Collaboration CERN and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A search for events with two displaced vertices from long-lived particle (LLP) pairs using data collected by the ATLAS detector at the LHC is presented. This analysis uses 139 fb−1 of proton-proton collision data at √s=13 TeV recorded in 2015-2018. The search employs techniques for reconstructing vertices of LLPs decaying to jets in the muon spectrometer displaced between 3 and 14 m with respect to the primary interaction vertex. The observed numbers of events are consistent with the expected background and limits for several benchmark signals are determined. For the Higgs boson with a mass of 125 GeV, the paper reports the first exclusion limits for branching fractions into neutral long-lived particles below 0.1%, while branching fractions above 10% are excluded at 95% confidence level for LLP proper lifetimes ranging from 4 cm to 72.4 m. In addition, the paper present the first results for the decay of LLPs into t ̄t in the ATLAS muon spectrometer

Download or read book Search for Long lived Weakly Interacting Particles that Decay to Displaced Hadronic Jets in Proton proton Collisions at arrow written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the decay of neutral, weakly interacting, long-lived particles using data collected by the ATLAS detector at the LHC is presented. This analysis uses the full data set recorded in 2012: 20.3 fb-1 of proton-proton collision data at [arrow]" = 8 TeV. The search employs techniques for reconstructing decay vertices of long-lived particles decaying to jets in the inner tracking detector and muon spectrometer. Signal events require at least two reconstructed vertices. No significant excess of events over the expected background is found, and limits as a function of proper lifetime are reported for the decay of the Higgs boson and other scalar bosons to long-lived particles and for Hidden Valley Z' and Stealth SUSY benchmark models. The first search results for displaced decays in Z' and Stealth SUSY models are presented. The upper bounds of the excluded proper lifetimes are the most stringent to date.

Download or read book A Search for Supersymmetric Phenomena in Final States with High Jet Multiplicity at the ATLAS Detector written by Matthew N.K. Smith and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Constraints on the properties of reclustered large-radius jets are used to improve the sensitivity. The main Standard Model backgrounds are removed using a template method that extrapolates background behavior from final states with fewer jets. No excess is observed over prediction, so limits are set on supersymmetric particle masses in the context of two different theoretical models. Gluino masses below 1500 and 1600 GeV, respectively, are excluded, a significant extension of the limits set by previous analyses.

Download or read book Search for Long lived Weakly Interacting Particles that Decay to Displaced Hadronic Jets in Proton proton Collisions at s written by Preema R. Pais and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many new physics models predict the existence of neutral, weakly interacting, long-lived particles that can decay within the detector volume, producing a distinctive experimental signature. A search is performed for a pair of such particles, using proton-proton collision data at √s = 8 TeV collected by the ATLAS detector in 2012, corresponding to a total integrated luminosity of 20.3 fb-1. Novel techniques are developed for the reconstruction of displaced decays to hadronic jets in the inner tracking detector and muon spectrometer. No significant deviation is found from the number of background events expected from Standard Model processes. The data are interpreted in terms of Hidden Valley scenarios with a Z' boson mediator. This dissertation presents the first results for a heavy Z' boson decaying to displaced hadronic jets.

Download or read book Search for Long lived Neutral Particles Decaying to Quark antiquark Pairs in Proton proton Collisions at u221A s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for long-lived massive neutral particles decaying to quark-antiquark pairs. The experimental signature is a distinctive topology of a pair of jets, originating at a secondary vertex. Events were collected with the CMS detector at the CERN LHC in proton-proton collisions at a center-of-mass energy of 8 TeV. The data analyzed correspond to an integrated luminosity of 18.5 fb–1. No significant excess is observed above standard model expectations. Upper limits at 95% confidence level are set on the production cross section of a heavy neutral scalar particle, H, in the mass range of 200 to 1000 GeV, decaying promptly into a pair of long-lived neutral X particles in the mass range of 50 to 350 GeV, each in turn decaying into a quark-antiquark pair. For X with mean proper decay lengths of 0.4 to 200 cm, the upper limits are typically 0.5–200 fb. The results are also interpreted in the context of an R-parity-violating supersymmetric model with long-lived neutralinos decaying into a quark-antiquark pair and a muon. For pair production of squarks that promptly decay to neutralinos with mean proper decay lengths of 2–40 cm, the upper limits on the cross section are typically 0.5–3 fb. As a result, the above limits are the most stringent on these channels to date.

Download or read book Search for Supersymmetric Particles in Final States with Leptons Jets and Missing Transverse Energy with the ATLAS Detector written by Peter Tornambè and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Massive Resonances in Dijet Systems Containing Jets Tagged as W Or Z Boson Decays in Pp Collisions at sqrt s written by and published by . This book was released on 2014 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of multijet events corresponding to an integrated luminosity of 19.7 fb-1, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. We found that the search uses novel jet-substructure identification techniques that provide sensitivity to the presence of highly boosted vector bosons decaying into a pair of quarks. Exclusion limits are set at a confidence level of 95% on the production of: (i) excited quark resonances q*decaying to qW and qZ for masses less than 3.2 TeV and 2.9 TeV, respectively, (ii) a Randall-Sundrum graviton GRS decaying into WW for masses below 1.2 TeV, and (iii) a heavy partner of the W boson W' decaying into WZ for masses less than 1.7 TeV. For the first time mass limits are set on W' → WZ and GRS → WW in the all-jets final state. The mass limits on q* → qW, q* → qZ, W' → WZ, GRS → WW are the most stringent to date. A model with a "bulk" graviton Gbulk that decays into WW or ZZ bosons is also studied.

Download or read book Searches for Supersymmetric Particles with the ATLAS Detector Using Boosted Decay Tree Topologies written by Daniel Bullock and published by . This book was released on 2016 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: The existence of a scalar Higgs particle poses a challenge to the Standard Model through an unnatural hierarchy problem with quadratic divergence. A supersymmetric framework, proposing heavy partners to every Standard Model particle, can solve this problem by introducing new loop diagrams that involve a new fermion-boson symmetry. The LHC has the potential to probe the energy scale necessary for creation of these particles and the ATLAS experiment is poised for discovery. The detected particles are studied by reconstructing the detected events in boosted frames that approximate each decay frame of the interaction with pairs of heavy, invisible particles. This Razor method was used in the analysis of data from 2011 and 2012 and then generalized to the Recursive Jigsaw method in 2015.

Download or read book Search for Top squark Pairs Decaying Into Higgs Or Z Bosons in Pp Collisions at u221A s written by and published by . This book was released on 2014 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search for supersymmetry through the direct pair production of top squarks, with Higgs (H) or Z bosons in the decay chain, is performed using a data sample of proton–proton collisions at √s= 8TeV collected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 fb-1. The search is performed using a selection of events containing leptons and bottom-quark jets. No evidence for a significant excess of events over the standard model background prediction is observed. The results are interpreted in the context of simplified supersymmetric models with pair production of a heavier top-squark mass eigenstate t̃/sup2 source decaying to a lighter top-squark mass eigenstate t̃/sup2 via either t̃/sup2 → Ht̃/sup1 or tsup̃/sup2 →Ztsup̃/sup1, followed in both cases by tsup̃/sup1→ t?sup0̃1, where ?sup0̃1 source is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between the tsup̃/sup1 and ?sup0̃1 states is approximately equal to the top-quark mass (mt1-msup?01≃mt), which is not probed by searches for direct tsup̃/sup1 squark pair production. This analysis excludes top squarks with mass mt1 575 GeVand msubt2

Download or read book A Search for Long Lived Charged Supersymmetric Particles Using Ionization with the ATLAS Detector written by Bradley Dean Axen and published by . This book was released on 2016 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several extensions of the Standard Model predict the existence of charged, very massive, and long-lived particles. Because of their high masses these particles would propagate non-relativistically through the ATLAS pixel detector and would therefore be identifiable through a measurement of large specific energy loss. Measuring heavy, long-lived particles through their track parameters in the pixel detector allows sensitivity to particles with lifetimes in the nanosecond range and above. This dissertation presents an inner detector driven method for identifying such particles in proton-proton collisions at 13 TeV with the 2015 LHC dataset corresponding to an integrated luminosity of 3.5 pb-1.