Search for Anomalous Production of Events with a Photon, Jet, B-quark Jet, and Missing Transverse Energy

Search for Anomalous Production of Events with a Photon, Jet, B-quark Jet, and Missing Transverse Energy PDF Author:
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Languages : en
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Book Description
We present a signature-based search for anomalous production of events containing a photon, two jets, of which at least one is identified as originating from a b quark, and missing transverse energy (/E{sub T}). The search uses data corresponding to 2.0 fb−1 of integrated luminosity from p{bar p} collisions at a center-of-mass energy of √s = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. From 6,697,466 events with a photon candidate with transverse energy ET > 25 GeV, we find 617 events with /E{sub T} > 25 GeV and two or more jets with E{sub T} > 15 GeV, at least one identified as originating from a b quark, versus an expectation of 607 ± 113 events. Increasing the requirement on /E{sub T} to 50 GeV, we find 28 events versus an expectation of 30 ± 11 events. We find no indications of non-standard-model phenomena.

Search for Anomalous Production of Events with a Photon, Jet, B-quark Jet, and Missing Transverse Energy

Search for Anomalous Production of Events with a Photon, Jet, B-quark Jet, and Missing Transverse Energy PDF Author:
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ISBN:
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Languages : en
Pages :

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Book Description
We present a signature-based search for anomalous production of events containing a photon, two jets, of which at least one is identified as originating from a b quark, and missing transverse energy (/E{sub T}). The search uses data corresponding to 2.0 fb−1 of integrated luminosity from p{bar p} collisions at a center-of-mass energy of √s = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. From 6,697,466 events with a photon candidate with transverse energy ET > 25 GeV, we find 617 events with /E{sub T} > 25 GeV and two or more jets with E{sub T} > 15 GeV, at least one identified as originating from a b quark, versus an expectation of 607 ± 113 events. Increasing the requirement on /E{sub T} to 50 GeV, we find 28 events versus an expectation of 30 ± 11 events. We find no indications of non-standard-model phenomena.

Search for Anomalous Production of Photon + Jets + Missing Transverse Energy in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector

Search for Anomalous Production of Photon + Jets + Missing Transverse Energy in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector PDF Author: Samantha K. Hewamanage
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Languages : en
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Book Description
A model-independent signature-based search for physics beyond the Standard Model is performed in the photon + jets + missing transverse energy channel in proton-antiproton collisions at a center of mass energy of 1.96 TeV using the CDF II detector. Events with a photon + jets are predicted by the Standard Model and also by many theoretical models beyond the Standard Model. In the Standard Model, the main mechanisms for photon + jets production include quark-antiquark annihilation and quark-gluon scattering. No intrinsic missing transverse energy is present in any of these Standard Model processes. In this search, photon + [greater-than or equal to] 1 jet and photon + [greater-than or equal to] 2 jet events are analyzed with and without a minimum requirement on the missing transverse energy. Numerous mass distributions and kinematic distributions are studied and no significant excess over the background prediction is found. All results indicate good agreement with expectations of the Standard Model.

Search for Anomalous Production of Photon, B-jet, and Missing Transverse Energy at CDF.

Search for Anomalous Production of Photon, B-jet, and Missing Transverse Energy at CDF. PDF Author:
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ISBN:
Category :
Languages : en
Pages : 3

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Search for Anomalous Single Top Quark Production in Association with a Photon in Pp Collisions at {u221A}(s)

Search for Anomalous Single Top Quark Production in Association with a Photon in Pp Collisions at {u221A}(s) PDF Author:
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ISBN:
Category :
Languages : en
Pages : 34

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Book Description
We found the results of a search for flavor changing neutral currents (FCNC) through single top quark production in association with a photon is presented. The study is based on proton-proton collisions at a center-of-mass energy of 8 TeV using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb-1. The search for t? events where t → Wb andW → ?n is conducted in final states with a muon, a photon, at least one hadronic jet with at most one being consistent with originating from a bottom quark, and missing transverse momentum. Furthermore, there was no evidence of single top quark production in association with a photon through a FCNC is observed. Upper limits at the 95% confidence level are set on the tug and tcg anomalous couplings and translated into upper limits on the branching fraction of the FCNC top quark decays: B(t → u?) 1.3 x 10sup-4/sup and B(t →c?) 1.7 x 10

Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF.

Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 27

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Book Description
The authors present results of a search for anomalous production of two photons together with an electron, muon, [tau] lepton, missing transverse energy, or jets using p{bar p} collision data from 1.1-2.0 fb−1 of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs for new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy.

Search for Events with Leptonic Jets and Missing Transverse Energy in $\mathbf{p\bar{p}}$ Collisions at $\mathbf{\sqrt{s}

Search for Events with Leptonic Jets and Missing Transverse Energy in $\mathbf{p\bar{p}}$ Collisions at $\mathbf{\sqrt{s} PDF Author:
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ISBN:
Category :
Languages : en
Pages : 7

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Book Description
We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in p{bar p} collisions using 5.8 fb−1 of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above Standard Model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of 'dark-photon' mass, where the dark photon is produced in the decay of the lightest supersymmetric particle.

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? PDF Author: Roman Pasechnik
Publisher: Frontiers Media SA
ISBN: 2889639908
Category : Science
Languages : en
Pages : 180

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Book Description
This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Searching the Inclusive Lepton + Photon + Missing E(T) + B-quark Signature for Radiative Top Quark Decay and Non-Standard-Model Processes

Searching the Inclusive Lepton + Photon + Missing E(T) + B-quark Signature for Radiative Top Quark Decay and Non-Standard-Model Processes PDF Author:
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ISBN:
Category :
Languages : en
Pages : 9

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Book Description
In a search for new phenomena in a signature suppressed in the standard model of elementary particles (SM), we compare the inclusive production of events containing a lepton (l), a photon ([gamma]), significant transverse momentum imbalance (E{sub T}), and a jet identified as containing a b-quark, to SM predictions. The search uses data produced in proton-antiproton collisions at √s = 1.96 TeV corresponding to 1.9 fb−1 of integrated luminosity taken with the CDF detector at the Fermilab Tevatron. We find 28 l[gamma]bE{sub T} events versus an expectation of 31.0{sub -3.5}{sup +4.1} events. If we further require events to contain at least three jets and large total transverse energy, simulations predict that the largest SM source is top-quark pair production with an additional radiated photon, t{bar t} + [gamma]. In the data we observe 16 t{bar t}[gamma] candidate events versus an expectation from non-top-quark SM sources of 11.2{sub -2.1}{sup +2.3}. Assuming the difference between the observed number and the predicted non-top-quark total is due to SM top quark production, we estimate the t{bar t} cross section to be 0.15 ± 0.08 pb.

Search for New Physics in Events with High Jet Multiplicity and Low Missing Transverse Momentum in Proton-proton Collisions at $\sqrt{s}

Search for New Physics in Events with High Jet Multiplicity and Low Missing Transverse Momentum in Proton-proton Collisions at $\sqrt{s} PDF Author:
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Languages : en
Pages :

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Book Description
A dedicated search is presented for new phenomena in inclusive eight- and ten-jet final states with low missing transverse momentum, with and without identification of jets originating from b quarks. The analysis is based on data from proton-proton collisions corresponding to an integrated luminosity of 19.6 inverse femtobarns collected with the CMS detector at the LHC at sqrt(s) = 8 TeV. The dominant multijet background expectations are obtained from low jet multiplicity control samples. Data agree well with the standard model background predictions, and limits are set in several benchmark models. Colorons (axigluons) with masses between 0.6 and 0.75 (up to 1.15) TeV are excluded at 95% confidence level. Similar exclusion limits for gluinos in R-parity violating supersymmetric scenarios are from 0.6 up to 1.1TeV. These results comprise the first experimental probe of the coloron and axigluon models in multijet final states.

Search for $W'\to T B $ in Events with Large Missing Transverse Energy and Jets with the CDF Detector at the Fermilab Tevatron Collider

Search for $W'\to T B $ in Events with Large Missing Transverse Energy and Jets with the CDF Detector at the Fermilab Tevatron Collider PDF Author:
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Languages : en
Pages :

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Book Description
In the scope of the strong ongoing data analysis efforts of the CDF col- laboration at Fermilab, we present a search for the production of mas sive W1 bosons decaying to a top and a bottom quark in p$\bar{p}$ collisions at √s = 1.96 TeV. To perform this search, we select events with large Missing Transverse Energy plus two or three jets, in which the W generated from top decays leptonically, and either the e or μ is lost or the [tau] is reconstructed as a jet. A complete study of the selected sample is discussed, including the creation and subsequent optimization of a Neural Network-based multivariate tool to reject the QCD multijet background from the signal region. Finally, we perform a likelihood-based multichannel Bayesian fit procedure on the invariant transverse mass of the Missing Transverse Energy and jets to extract 95% CL limits on [sigma](p$\bar{p}$ . → W') × B(W' → tb) for MW' = 200 GeV/c2.