Download or read book Search for Decays of the W and Z Bosons Into Quark antiquark Pairs written by R. Ansari and published by . This book was released on 1987 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Pair Production of a New B Quark that Decays Into a Z Boson and a Bottom Quark with the ATLAS Detector at the LHC written by Andre Milton Bach and published by . This book was released on 2012 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search with the ATLAS detector for the pair production of a new b' quark in the Z boson plus b quark decay channel is reported. The pp collision data comprise 4.7 fb-1 of integrated luminosity at sqrt(s) = 7 TeV collected at the CERN Large Hadron Collider in 2011. This search complements recent searches for a b' decaying to a W boson and a top quark, and it is particularly important for new physics models containing vector-like quarks. From events containing both a Z boson reconstructed from electrons and a b tagged jet, any potential signal is enriched by selecting a subsample with large b' candidate pT. No evidence for a b' signal is found in this subsample; the invariant mass spectrum of the b' candidate agrees well with the Standard Model prediction. For the case of a b' that decays only to Z + b, masses mb'
Download or read book 60 Years Of Cern Experiments And Discoveries written by Herwig Schopper and published by World Scientific. This book was released on 2015-07-13 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a compilation of the most important experimental results achieved during the past 60 years at CERN - from the mid-1950s to the latest discovery of the Higgs particle. Covering the results from the early accelerators at CERN to those most recent at the LHC, the contents provide an excellent review of the achievements of this outstanding laboratory. Not only presented is the impressive scientific progress achieved during the past six decades, but also demonstrated is the special way in which successful international collaboration exists at CERN.
Download or read book Searches for New Quarks and Leptons in Z Boson Decays written by and published by . This book was released on 1990 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Story of the W and Z written by Peter Watkins and published by CUP Archive. This book was released on 1986-05-08 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a first-hand account of one of the most important scientific discoveries of the twentieth century. In 1983, two groups of scientists working at CERN near Geneva collected data, which were subsequently shown to be consistent with the W and Z bosons. This work earned two of those scientists the 1984 Nobel Prize in Physics. The author of this book, Peter Watkins, was a member of one of those groups. His book opens with a brief statement of the background, explaining in non-technical terms the theoretical developments that led to the prediction in the late 1960s of the existence of the W and Z bosons. He then moves on rapidly to describe the background to the experiments, explaining as he does so the problems that had to be overcome, and giving details of the accelerators, detectors and computers used in these very advanced- and difficult- experiments.
Download or read book Search for the Neutral Current Top Quark Decay T Zc Using Ratio of Z Boson 4 Jets to W Boson 4 Jets Production written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have used the Collider Detector at Fermilab (CDF II) to search for the flavor-changing neutral-current (FCNC) top quark decay t → Zc using a technique employing ratios of W and Z production, measured in p{bar p} data corresponding to an integrated luminosity of 1.52 fb−1. The analysis uses a comparison of two decay chains, p{bar p} → t{bar t} → WbWb → l[nu]bjjb and p{bar p} → t{bar t} → ZcWb → llcjjb, to cancel systematic uncertainties in acceptance, efficiency, and luminosity. We validate the modeling of acceptance and efficiency for lepton identification over the multi-year dataset using another ratio of W and Z production, in this case the observed ratio of inclusive production of W to Z bosons. To improve the discrimination against standard model backgrounds to top quark decays, we calculate the top quark mass for each event with two leptons and four jets assuming it is a t{bar t} event with one of the top quarks decaying to Zc. For additional background discrimination we require at least one jet to be identified as originating from a b-quark. No significant signal is found and we set an upper limit on the FCNC branching ratio Br(t → Zc) using a likelihood constructed from the llcjjb top quark mass distribution and the number of l[nu]bjjb events. Limits are set as a function of the helicity of the Z boson produced in the FCNC decay. For 100% longitudinally polarized Z bosons we find limits of 8.3% and 9.3% (95% C.L.) depending on the assumptions regarding the theoretical top quark pair production cross-section.
Download or read book Observation of Z Decays to B Quark Pairs at the Tevatron Collider written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for Z boson decays to pairs of b-quark jets has been performed in the full dataset collected with the CDF detector at the Tevatron p[anti p] collider. After the selection of a pure sample of b[anti b] events by means of the identification of secondary vertices from b-quark decays, we have used two kinematic variables to further discriminate the electroweak b[anti b] production from QCD processes, and sought evidence for the Z decay in the dijet invariant mass distribution. An absolute background prediction allows the extraction of an excess of events inconsistent with the background predictions by 3.23[sigma] but in good agreement with the amount and characteristics of the expected signal. We then fit the mass distribution with an unbinned likelihood technique, and obtain a Z[yields] b[anti b] signal amounting to 91[+-] 30[+-] 19 events.
Download or read book Scalar Boson Decays to Tau Leptons written by Cécile Caillol and published by Springer. This book was released on 2017-11-15 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a study of the scalar sector in the standard model (SM), as well as various searches for an extended scalar sector in theories beyond the SM (BSM). The first part of the thesis details the search for an SM Higgs boson decaying to taus, and produced by gluon fusion, vector boson fusion, or associated production with a vector boson, leading to evidence for decays of the Higgs boson to taus. In turn, the second part highlights several searches for an extended scalar sector, with scalar boson decays to taus. In all of the analyses presented, at least one scalar boson decays to a pair of taus. The results draw on data collected by the Compact Muon Solenoid (CMS) detector during proton–proton collisions with a center-of-mass energy of 7 or 8 TeV.
Download or read book Hadrons Quarks and Gluons written by J. Thanh Van Tran and published by Atlantica Séguier Frontières. This book was released on 1987 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Searches for New Quarks and Leptons in Z Boson Decays written by Richard James Van Kooten and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 1990 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phenomena Beyond the Standard Model What Do We Expect for New Physics to Look Like written by Roman Pasechnik and published by Frontiers Media SA. This book was released on 2020-09-03 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Searches for New Particles Produced in Z Boson Decay written by and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Searches for events with new particle topologies in 455 hadronic Z decays with the Mark 2 detector at SLC are presented. 95% confidence level lower limits of 40.7 GeV/c2 for the top quark mass and 42.0 GeV/c2 for the mass of a fourth generation charge - 1/3 quark, regardless of decay mode, are obtained. For a fourth generation sequential Dirac neutrino?4 mass up to 43 GeV/c2. Decays of the Z boson to a pair of non-minimal Higgs bosons (Z → H{sub s}°H{sub p}°), where one of them is relatively light ({approx lt} 10 GeV/c2), are also considered. Limits are obtained on the ZH{sub s}°H{sub p}° coupling as a function of the Higgs boson masses. 11 refs., 2 figs., 2 tabs.
Download or read book Higgs boson potential at colliders status and perspectives written by Biagio Di Micco and published by Roma TrE-Press. This book was released on 2020-12-18 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Questo documento riassume lo stato attuale degli ricerche studi, teorici e sperimentali, sulla produzione di coppie di bosoni di Higgs, e sui vincoli, sia diretti che indiretti, al valore del termine di auto-interazione del bosone di Higgs, con l’intento di servire da referenza per i prossimi anni. Il documento discute lo stato degli studi teorici, includendo le più recenti stime della sezione di produzione di coppie di bosoni di Higgs, sviluppi sulle teorie di campo efficaci, e studi su specifici scenari di nuova fisica che possono contribuire alla produzione di due bosoni di Higgs. Sono presentati i più recenti risultati sperimentali sulle ricerche di coppie di bosoni di Higgs e sui limiti diretti e indiretti al termine di auto-interazione, ottenuti al Large Hadron Collider di Ginevra, con una panoramica delle tecniche sperimentali. Infine, sono discusse le capacità dei collisionatori futuri di determinare il termine di auto-interazione del bosone di Higgs. Questo lavoro è iniziato come raccolta di contributi della conferenza “Di-Higgs ai Colliders”, che ha avuto luogo a Fermilab dal 4 al 9 settembre 2018, ma gli argomenti discussi vanno al di là di quelli presentati alla conferenza, includendo ulteriori sviluppi.
Download or read book Measurement of the Z boson Branching Fraction Into Hadrons Containing Bottom Quarks written by and published by . This book was released on 1990 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use the Mark II detector to study Z decays into bottom quark-anti-quark pairs, leading to the production of bottom hadrons. The Z bosons are formed in ee− annihilation at the SLC at center-of-mass energies between 89 and 93 GeV. We identify events containing semileptonic decays of bottom hadrons by detecting isolated leptons, i.e leptons with high transverse momenta relative to the nearest hadronic jet. Using isolated electrons and muons, we measure the B-hadron semileptonic branching ratio times the fraction of hadronic Z decays which contain bottom hadrons, B(B 2!Xl[nu]){center dot}[Gamma](Z 2!b{bar b})/[Gamma](Z 2!had) = 0.025 {sub -0.009}{sup +0.100} {plus minus} 0.005, where we have listed the statistical errors followed by the systematic error. Assuming B(B 2!X(ell)[nu]) = 11% {plus minus} 1%, we measure [Gamma](Z 2!b{bar b})/[Gamma](Z 2!had) = 0.23 {sub -0.09}{sup +0.11}, in good agreement with the standard-model prediction of 0.22. We find [Gamma](Z 2!b{bar b}) = 0.40 {sub -0.16}{sup +0.19} GeV. 83 refs., 34 figs., 19 tabs.
Download or read book The Ideas of Particle Physics written by James E. Dodd and published by Cambridge University Press. This book was released on 2020-09-24 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fourth edition of this popular book is a comprehensive introduction to particle physics, including the latest ideas and discoveries.
Download or read book Search for tt H Production in the H bb Decay Channel written by Marcel Rieger and published by Springer Nature. This book was released on 2021-02-25 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1964, a mechanism explaining the origin of particle masses was proposed by Robert Brout, François Englert, and Peter W. Higgs. 48 years later, in 2012, the so-called Higgs boson was discovered in proton-proton collisions recorded by experiments at the LHC. Since then, its ability to interact with quarks remained experimentally unconfirmed. This book presents a search for Higgs bosons produced in association with top quarks tt̄H in data recorded with the CMS detector in 2016. It focuses on Higgs boson decays into bottom quarks H → bb̅ and top quark pair decays involving at least one lepton. In this analysis, a multiclass classification approach using deep learning techniques was applied for the first time. In light of the dominant background contribution from tt̄ production, the developed method proved to achieve superior sensitivity with respect to existing techniques. In combination with searches in different decay channels, the presented work contributed to the first observations of tt̄H production and H → bb̅ decays.
Download or read book QCD and Beyond written by J. Thanh Van Tran and published by Atlantica Séguier Frontières. This book was released on 1985 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
