We present recent results from CDF in the search for new phenomena appearing in the top quark samples. These results use data from p{bar p} collisions at {radical}s = 1.96 TeV corresponding to an integrated luminosity ranging from 195 pb{sup -1} to 760 pb{sup -1}. No deviations are observed from the Standard Model expectations, so upper limits on the size of possible new phenomena are set.
Twelve years after the discovery of the top quark at Fermilab's Tevatron, they are now finally beginning to shed light on this peculiarily massive quark. With 1-1.7 fb−1 of integrated luminosity collected by the CDF detector, they are able to probe the knowledge of the top quark physics, and to search for signals of physics beyond the Standard Model. In this paper, they present results of measurements of top quark properties, as well as tests for the production mechanism of the top quark. They also describe CDF latest searches for beyond Standard Model couplings of the top quark. Finally, they present the most recent searches for direct production of new particles in the collected data samples.
We present the results of the searches for new phenomena in pp collisions at[radical]s=1.8 TeV with the CDF detector using the full data sample of 110 pb[sup -1] collected between 1992 and 1995. We have searched for new physics in events with two photons, testing some of the hypotheses proposed to explain the appearance of the CDF ee[gamma][gamma] E[sub T] event. New results on the search for a heavy neutral scalar object, charged Higgs bosons (H[sup[+-]]) and the scalar top quark are presented. Finally we summarize the CDF results on the search for third generation leptoquarks.
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.
'Dorigo provides an engaging and insightful perspective on the pursuit of physics discoveries at CDF … Dorigo’s book is thus almost certainly going to be an important source for anyone interested in the history of CDF … It is a personal yet highly informative story of discovery and almost-discovery from the perspective of someone who saw the events firsthand.'Physics TodayFrom the mid-1980s, an international collaboration of 600 physicists embarked on the investigation of subnuclear physics at the high-energy frontier. As well as discovering the top quark, the heaviest elementary particle ever observed, the physicists analyzed their data to seek signals of new physics which could revolutionize our understanding of nature.Anomaly! tells the story of that quest, and focuses specifically on the finding of several unexplained effects which were unearthed in the process. These anomalies proved highly controversial within the large team: to some collaborators they called for immediate publication, while to others their divulgation threatened to jeopardize the reputation of the experiment.Written in a confidential, narrative style, this book looks at the sociology of a large scientific collaboration, providing insight in the relationships between top physicists at the turn of the millennium. The stories offer an insider's view of the life cycle of the 'failed' discoveries that unavoidably accompany even the greatest endeavors in modern particle physics.
Abstract: A search for new phenomena with top quark pairs in final states with one isolated electron or muon, multiple jets, and large missing transverse momentum is performed. Signal regions are designed to search for two-, three-, and four-body decays of the directly pair-produced supersymmetric partner of the top quark (stop). Additional signal regions are designed specifically to search for spin-0 mediators that are produced in association with a pair of top quarks and decay into a pair of dark-matter particles. The search is performed using the Large Hadron Collider proton-proton collision dataset at a centre-of-mass energy of s√ = 13 TeV recorded by the ATLAS detector from 2015 to 2018, corresponding to an integrated luminosity of 139 fb−1. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set in the stop-neutralino mass plane and as a function of the mediator mass or the dark-matter particle mass. Stops are excluded up to 1200 GeV (710 GeV) in the two-body (three-body) decay scenario. In the four-body scenario stops up to 640 GeV are excluded for a stop-neutralino mass difference of 60 GeV. Scalar and pseudoscalar dark-matter mediators are excluded up to 200 GeV when the coupling strengths of the mediator to Standard Model and dark-matter particles are both equal to one and when the mass of the dark-matter particle is 1 GeV
This book contains the proceedings of the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, SUSY06, held in Irvine, California, in June 2006. This conference took place just before the start of the Large Hadron Collider, widely anticipated to yield profound new results, and provided a focus for the growing excitement in high energy physics through over 250 plenary and parallel talks.
