Download or read book Searches for New Phenomena at the Tevatron written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present some of the latest updated results on searches for physics beyond the Standard Model at the Tevatron Collider using the full Run 1 data sample of p{anti p} collisions at √s = 1.8 TeV collected with the CDF and D0 detectors. Results are reported relative to searches for squarks and gluinos, scalar top and bottom quarks and superlight gravitino. 95% CL exclusion limits are presented for degenerate states of Technicolor particles [rho]T and [omega]T.
Download or read book Searches for New Phenomena with Lepton Final States at the Tevatron written by and published by . This book was released on 2007 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous searches for new phenomena have been carried out using data from proton-antiproton collisions at Fermilab's Tevatron. Final states with leptons give signatures which are relatively unique and generally have small backgrounds. We present many of the latest results from the CDF and D0 collaborations from 0.4-1.2 fb−1 of data. Topics include supersymmetry, extra gauge bosons, Randall-Sundrum gravitons, excited electrons and neutral, long-lived particles.
Download or read book Searches for New Phenomena at the Tevatron and at HERA written by Arnd Meyer and published by . This book was released on 2006 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results on searches for new physics at Run II of the Tevatron and highlights from HERA are reported. The searches cover many different final states and a wide range of models. All analyses have at this point led to negative results, but some interesting anomalies have been found.
Download or read book New Phenomena Searches at the Tevatron written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present here recent searches at the Tevatron for new phenomena. The superlight gravitino, scalar top and scalar bottom quarks searches are described in the framework of the supersymmetric models. We also discuss the new Tevatron limits on the second and third generations leptoquark masses.
Download or read book Non SUSY Searches at the Tevatron written by and published by . This book was released on 2011 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present recent results from searches for new physics beyond supersymmetry performed at the Tevatron accelerator at Fermilab. The CDF and D0 analyses presented here utilized data of integrated luminosity up to 6 fb−1. We cover leptonic and bosonic resonances interpreted in the Randall-Sundrum graviton and new-boson models, rare final states, and the search for vector-like quarks. The search for new phenomena beyond the weak-scale supersymmetry is a vital part of the Fermilab program. Both CDF and D0 experiments at the Tevatron collider actively look for signals not expected by the standard model (SM) or minimal supersymmetric models. The searches can be sorted in three categories: (a) searches for generic resonances that can be interpreted in several new-physics models; (b) searches for exotic combinations of final-state objects or abnormal kinematics (not necessarily predicted by current theories); and (c) model-dependent searches that test a particular theory. We present here latest results from all these categories: searches for new dilepton and diboson resonances (interpreted as gravitons and new gauge bosons), searches for anomalous [gamma] + E{sub T} + X production, and searches for vector-like quarks.
Download or read book Searches at the Run II Tevatron Collider written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some initial results based on 40-90 pb−1 of integrated luminosity from Run II are presented for searches for new phenomena beyond the Standard Model, conducted at the upgraded Tevatron CDF and D0 experiments.
Download or read book Searches for Exotics at the Tevatron written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fermilab Tevatron collider experiments CDF and D0 collected more than 100 pb−1 of data at (square root)(s) = 1.8 TeV during Run I (1992-1995). Results of searches for new phenomena (exotics) are presented, covering supersymmetry, leptoquarks, technicolor, and quark compositeness. In each case, no discrepancy with the Standard Model is observed, and stringent limits on new physics predicted by these models are extracted. Parameters for Run II of the Tevatron are given along with projections of search reaches for this upcoming run.
Download or read book Search for New Phenomena in CDF written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the most recent results and perspectives of the searches for new phenomena at the CDF experiment of the Tevatron collider.
Download or read book Beyond the Standard Model Physics Searches at the Tevatron written by and published by . This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent results on a number of searches performed at Tevatron for new phenomena beyond Standard Model are presented. The topics include the experimental tests of SUSY with mSUGRA and GMSB breaking scenarios. The latest analyses on large extra dimensions, new massive bosons are covered as well. The results are based on experimental data samples collected at the Tevatron with CDF and DO detectors and comprising a total integrated luminosity up to (almost equal to) 2.7 fb−1.
Download or read book Searches for New Physics at Tevatron written by and published by . This book was released on 2011 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most recent results obtained from searches of particles and phenomena beyond the Standard Model (new physics) in the D0 and CDF experiments at the Tevatron accelerator (FNAL, USA) on the basis of statistics corresponding to the integrated luminosity of up to 4 fb−1 in 2009 are considered. Particular attention is given to the most recent results on searches for a supersymmetric Higgs boson.
Download or read book Searches for New Physics at the Tevatron in Photon and Jet Final States written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of searches for non-standard model phenomena in photon and jet final states. These searches use data from integrated luminosities of 0.7-2.7 fb−1 of p{bar p} collisions at (square root)s = 1.96 TeV, collected with the CDF and D0 detectors at the Fermilab Tevatron. No significant excess in data has been observed. We report limits on the parameters of several models, including: large extra dimension, compositeness, leptoquarks, and supersymmetry.
Download or read book Search for New Particles in Multijet Final States at the Tevatron written by and published by . This book was released on 1997 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the latest results of the searches for new particles in hadronic final states performed in p{anti p} collisions at (square root)s=1.8 TeV. The large data samples collected with the CDF and D0 detectors at the Tevatron collider between 1992 and 1995 allow searches for low cross section phenomena in dijet and multijet events, despite the hindrance of the high background from normal QCD processes. However no signal for new physics is found, and the data show good agreement with QCD. Limits on the mass and on the cross section of the searched states can thus be set.
Download or read book New Phenomena Searches at CDF written by Aron Soha and published by . This book was released on 2006 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors report on recent results from the Collider Detector at Fermilab (CDF) experiment, which is accumulating data from proton-antiproton collisions with {radical}s = 1.96 TeV at Run II of the Fermilab Tevatron. The new phenomena being explored include Higgs, Supersymmetry, and large extra dimensions. They also present the latest results of searches for heavy objects, which would indicate physics beyond the Standard Model.
Download or read book New Phenomena I written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper summarizes results of recent searches for new phenomena with the CDF and D0 detectors at the Fermilab Tevatron. All results shown correspond to analysis from the past Run I data corresponding to a total integrated luminosity of (approximately) 100 pb−1 per experiment. In particular, the authors show new results from stop quark searches, neutral supersymmetric Higgs boson searches, a reinterpretation of the CDF second and third generation leptoquark searches in terms of leptoquark resonant production through technicolor interactions and, finally, they report a new D0 search for large extra space dimensions from high mass Drell-Yan dielectron and diphoton events.
Download or read book Challenging the Standard Model at the Tevatron Collider written by and published by . This book was released on 2011 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Even at a time where the world's eyes are focused on the Large Hadron Collider at CERN, which has reached the energy frontier in 2010, many important results are still being obtained from data analyses performed at the Tevatron collider at Fermilab. This contribution discusses recent highlights in the areas of B hadron, electroweak, top quark, and Higgs boson physics. The standard model (SM) of particle physics forms the cornerstone of our understanding of elementary particles and their interactions, and many of its aspects have been investigated in great detail. Yet it is generally suspected to be incomplete (e.g. by not allowing for the incorporation of gravity in a field theoretical setting) and un-natural (e.g. the mass of the Higgs boson is not well protected against radiative corrections). In addition, it does not explain the dark matter and dark energy content of the Universe. It is therefore of eminent importance to test the limits of validity of the SM. In the decade since its upgrade to a centre-of-mass energy √s = 1.96 TeV, the Tevatron p{bar p} collider has delivered an integrated luminosity of about 10 fb−1, up to 9 fb−1 of which are available for analysis by its CDF and D0 collaborations. These large datasets allow for stringent tests of the SM in two areas: direct searches for particles or final states that are not very heavy but that suffer from small production cross sections (e.g. the Higgs boson), and searches for indirect manifestations of beyond-the-standard-model (BSM) effects through virtual effects. The latter searches can often be carried out by precise measurements of otherwise known processes. This contribution describes such tests of the SM carried out by the CDF and D0 collaborations. In particular, recent highlights in the areas of B hadron physics, electroweak physics, top quark physics, and Higgs boson physics are discussed. Recent results of tests of QCD and of direct searches for new phenomena are described in another contribution.
Download or read book Top Quark Physics and Searches for New Phenomena at the Tevatron written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The CDF and D0 collaborations each have collected over 110 pb[sup -1] from top quark physics and searches for first generation leptoquarks (LQ), using the entire statistics of these large data sets. After careful selection, both collaborations have collected top quark data samples consisting of several dozen events each. From these events both experiments have measured the top quark mass and pair production cross section in a variety of decay channels, including the so-called dilepton, lepton plus jets, and all jets channels. The combined top quark mass from both experiments in the lepton plus jets channels is m[sub t]= 175.6[+-]5.5 GeV/c[sup 2]. CDF and D0 have also performed optimized searches for the pair production of first generation leptoquarks. No candidate events were found. Combining the results from the ee+jets, e[nu]+jets, and[nu][nu]+jets channels both experiments set 95% confidence level (CL) upper limits on the LQ pair production cross section as a function of mass and of[beta], the branching fraction to a charged lepton.
Download or read book Searches for New Physics at Colliders written by My Phuong Thi Le and published by Stanford University. This book was released on 2011 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: The turning-on of the Large Hadron Collider is the momentous milestone in our quest for new physics beyond the Standard Model. Soon, we will be presented with the task of detecting, identifying, and studying the possibly large parameter space of the underlying model. In this thesis, we will look at some possible extensions to the SM, their signatures at colliders, and possible search strategies to explore the new physics in a model-independent way. In chapter 2, we study the extended neutral gauge sector of the Littlest Higgs model at the 500 GeV e+e- collider using the fermion pair production and Higgs associate production channel. We find that these channels can provide an accurate determination of the fundamental parameters and thus allows the verification of the little Higgs mechanism designed to cancel the Higgs mass quadratic divergence. In chapter 3, we study the ATLAS supersymmetry searches proposed for the 14 TeV pp collider using the $\sim$ 70k models of the phenomenological Minimal Supersymmetric Model (pMSSM) moldel set, that have survived many theoretical and experimental constraints. Since pMSSM does not make any simplifying assumptions about its SUSY-breaking mechanism at high scale, this encompasses a broad class of Supersymmetric models. We find that even though these searches were optimized mostly for mSUGRA signals, they are relatively robust in observing the more general pMSSM models. For the case of models in which squarks and gluinos have mass below 1 TeV, essentially all of these models ($> 99\%$) were observable in at least one of these searches, with 1 $fb^{-1}$ of integrated luminosity allowing for an uncertainty of 50\% in the SM background. We found that 0-lepton searches are the most powerful searches, while searches with 1-2 leptons do not have coverage as good as has been shown for mSUGRA. We then study possible reasons why a model could not be observed. These difficult models mostly include those with long-lived charginos which lead to small Missing Tranverse Energy (MET) and models with squeezed spectra which lead to soft jets that fail the jet cuts. In chapter 4, we study similar searches that have been carried out by ATLAS at the 7 TeV LHC. We found that systematic uncertainty again plays an important role in determining the coverage of the searches. This is especially true for searches with a large SM background, such as $n$-jet 0 lepton searches. We study the implication of a null result from the 7 TeV LHC. We find that the degree of fine-tuning in the pMSSM depends on the prior in which we scan our 19-dimensional space, but overall it is not as large as in mSUGRA. We find that a null result at the 7 TeV with $10 fb^{-1}$ and 20\% systematic errors would imply a need for a higher energy e+e- machine than the 500 GeV ILC to study Supersymmetry. Continuing on along the line of Supersymmetry, in chapter 5 we explore the possibility of adding one more generation to the MSSM (4GMSSM). We find that the CP-odd A boson can be very light due to the contribution of the heavy 4th generation fermion loops while all other Higgs particles (including the CP-even {\it h}) are all quite heavy. The parameter $tan(\beta)$ is strongly constrained to be between 0.5 and 2 due to perturbativity requirements on Yukawa couplings. We study the electroweak constraints as well as collider signatures on the possibility of a light A of mass $\sim$115 GeV. As for an LHC discovery, we find that this light A can be seen in the standard 2-photon Higgs search channel with cross-section more than an order of magnitude greater than that of the SM Higgs. In the last two chapters, we study possible search strategies to explore the new physics in a model-independent way. In chapter 6, we attempt to show how one could be largely agnostic about the underlying model in exploring the complete kinematically-allowed parameter space of pair-produced color octet particles (with mass $m_{\tilde{g}}$) that each directly decay into two jets plus a neutral stable particle (with mass $m_{\tilde{B}}$) that would escape the detectors and appear as MET. The kinematics of this process can be completely described by two parameters $m_{\tilde {g}}$ and $m_{\tilde {B}}$ , and in particular their splitting determines the softness or hardness of jets from the decay products. In order to cover the whole parameter space, one would need separate searches for different regions. We show that optimizing the final cuts for every ($m_{\tilde {g}}$, $m_{\tilde {B}}$) point, and combining all searches, can extend the coverage significantly. Since this is just based on the kinematics of the decay, this result can be easily interpreted for any model with this decay topology. In chapter 7, we carry this model-independent approach further in jets plus missing energy searches, by proposing that one should bin the measured data (or simulated SM background) differentially in MET and $H_T$ (scalar sum of invisible energy) for each search, and use them to set limits on any model of interest. We demonstrate this technique by carrying out a search similar to that studied in chapter 6, with one added decay step for the color octet particle, mainly it decays to 2 jets and another particle (with mass $m_{\tilde {W}}$) and it in turn decays to the neutral stable particle and 2 jets. We study different kinematic regions and set bounds in this 3-dimensional parameter space ($m_{\tilde {g}}$, $m_{\tilde {W}}$, $m_{\tilde {B}}$).
