Download or read book Looking for New Physics Search for Anomalous Gauge Couplings in WW and WZ Production in Lepton Jet Events in Proton proton Collisions at 13 TeV with the CMS Experiment written by Muhammad Ansar Iqbal and published by . This book was released on 2020* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Anomalous Triple Gauge Couplings in WW and WZ Production in Lepton Jet Events in Proton proton Collisions at s written by Albert M. Sirunyan and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Anomalous Couplings in Boosted mathrm WW WZ to ell nu mathrm Q bar q Production in Proton proton Collisions at sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Letter presents a search for new physics manifested as anomalous triple gauge boson couplings in WW and WZ diboson production in proton-proton collisions. The search is performed using events containing a W boson that decays leptonically and a W or Z boson whose decay products are merged into a single reconstructed jet. The data, collected at sqrt(s) =8 TeV with the CMS detector at the LHC, correspond to an integrated luminosity of 19 inverse femtobarns. No evidence for anomalous triple gauge couplings is found and the following 95% confidence level limits are set on their values: lambda ([-0.011,0.011]), Delta kappa[gamma] ([-0.044,0.063]), and Delta g[1,Z] ([-0.0087,0.024]). These limits are also translated into their effective field theory equivalents: c[WWW]/ Lambda^2, ([-2.7,2.7] TeV^{-2}), c[B]/ Lambda^2, ([-14,17] TeV^{-2}), and c[W]/ Lambda^2, ([-2.0,5.7] TeV^{-2}).
Download or read book Looking Inside Jets written by Simone Marzani and published by Springer. This book was released on 2019-05-11 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: This concise primer reviews the latest developments in the field of jets. Jets are collinear sprays of hadrons produced in very high-energy collisions, e.g. at the LHC or at a future hadron collider. They are essential to and ubiquitous in experimental analyses, making their study crucial. At present LHC energies and beyond, massive particles around the electroweak scale are frequently produced with transverse momenta that are much larger than their mass, i.e., boosted. The decay products of such boosted massive objects tend to occupy only a relatively small and confined area of the detector and are observed as a single jet. Jets hence arise from many different sources and it is important to be able to distinguish the rare events with boosted resonances from the large backgrounds originating from Quantum Chromodynamics (QCD). This requires familiarity with the internal properties of jets, such as their different radiation patterns, a field broadly known as jet substructure. This set of notes begins by providing a phenomenological motivation, explaining why the study of jets and their substructure is of particular importance for the current and future program of the LHC, followed by a brief but insightful introduction to QCD and to hadron-collider phenomenology. The next section introduces jets as complex objects constructed from a sequential recombination algorithm. In this context some experimental aspects are also reviewed. Since jet substructure calculations are multi-scale problems that call for all-order treatments (resummations), the bases of such calculations are discussed for simple jet quantities. With these QCD and jet physics ingredients in hand, readers can then dig into jet substructure itself. Accordingly, these notes first highlight the main concepts behind substructure techniques and introduce a list of the main jet substructure tools that have been used over the past decade. Analytic calculations are then provided for several families of tools, the goal being to identify their key characteristics. In closing, the book provides an overview of LHC searches and measurements where jet substructure techniques are used, reviews the main take-home messages, and outlines future perspectives.
Download or read book XXII DAE High Energy Physics Symposium written by Md. Naimuddin and published by Springer. This book was released on 2018-05-23 with total page 879 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings gather invited and contributed talks presented at the XXII DAE-BRNS High Energy Physics (HEP) Symposium, which was held at the University of Delhi, India, on 12–16 December 2016. The contributions cover a variety of topics in particle physics, astroparticle physics, cosmology and related areas from both experimental and theoretical perspectives, namely (1) Neutrino Physics, (2) Standard Model Physics (including Electroweak, Flavour Physics), (3) Beyond Standard Model Physics, (4) Heavy Ion Physics & QCD (Quantum Chromodynamics), (5) Particle Astrophysics & Cosmology, (6) Future Experiments and Detector Development, (7) Formal Theory, and (8) Societal Applications: Medical Physics, Imaging, etc. The DAE-BRNS High Energy Physics Symposium, widely considered to be one of the leading symposiums in the field of Elementary Particle Physics, is held every other year in India and supported by the Board of Research in Nuclear Sciences (BRNS), Department of Atomic Energy (DAE), India. As many as 400 physicists and researchers attended the 22nd Symposium to discuss the latest advances in the field. A poster session was also organized to highlight the work and findings of young researchers. Bringing together the essential content, the book offers a valuable resource for both beginning and advanced researchers in the field.
Download or read book A Search for WW gamma and WZ gamma Triboson Production and Anomalous Quartic Gauge Couplings at sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis probing for the standard model production of three electroweak vector bosons, WV$\gamma$ with V = W or Z gauge boson, is presented. The W boson decays leptonically to an electron or muon, or their respective antiparticle, paired with the appropriate neutrino. The second boson V decays hadronically into two jets, and additionally a photon is required in the event. The data analyzed correspond to an integrated luminosity of 19.6~fb$^{-1}$ and 2.3~fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 8~TeV and 13~TeV, respectively, collected in 2012 and 2015 by the CMS detector at the Large Hadron Collider. The event selection criteria used in these analyses yields 322 and 46 observed events in data in 2012 and 2015, respectively, while the estimated background yield from theoretical predictions is 342.1~$\pm$~22.2 and 54.3~$\pm$~17.7. These observations are consistent with the standard model next-to-leading order QCD predictions. Given the limitation in statistics to measure the cross section for this production process, an upper limit of 3.4 times the standard model predictions is made at a 95\% confidence level for WV$\gamma$ with photon $p_{T}$ greater than 30~GeV and absolute pseudorapidity less than 1.44. Physics beyond the standard model, such as anomalous couplings between the gauge bosons at the quartic vertex, may lead to enhancement in the number of WV$\gamma$ events produced within high energy collisions. Such enhancements can be observed in kinematic distributions, particularly in the higher energy regions. No evidence of anomalous WW$\gamma\gamma$ and WWZ$\gamma$ quartic gauge boson couplings is found, while 95\% confidence level upper limits are obtained for various couplings.
Download or read book Lepton Dipole Moments written by B. Lee Roberts and published by World Scientific. This book was released on 2010 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a self-contained description of the measurements of the magnetic dipole moments of the electron and muon, along with a discussion of the measurements of the fine structure constant, and the theory associated with magnetic and electric dipole moments. Also included are the searches for a permanent electric dipole moment of the electron, muon, neutron and atomic nuclei. The related topic of the transition moment for lepton flavor violating processes, such as neutrinoless muon or tauon decays, and the search for such processes are included as well. The papers, written by many of the leading authors in this field, cover both the experimental and theoretical aspects of these topics. Sample Chapter(s). Chapter 1: Historical Introduction to Electric and Mangnetic Moments (367 KB). Contents: Historical Introduction (B L Roberts); Electromagnetic Dipole Moments and New Physics (A Czarnecki & W J Marciano); Lepton g OCo 2 from 1947 to Present (T Kinoshita); Analytic QED Calculations of the Anomalous Magnetic Moment of the Electron (S Laporta & E Remiddi); Measurements of the Electron Magnetic Moment (G Gabrielse); Determining the Fine Structure Constant (G Gabrielse); Helium Fine Structure Theory for the Determination of (K Pachucki & J Sapirstein); Hadronic Vacuum Polarization and the Lepton Anomalous Magnetic Moments (M Davier); The Hadronic Light-by-Light Contribution to a, e (J Prades et al.); General Prescriptions for One-loop Contributions to a e, (K R Lynch); Measurement of the Muon ( g OCo 2) Value (J P Miller et al.); Muon ( g OCo 2) and Physics Beyond the Standard Model (D StAckinger); Probing CP Violation with Electric Dipole Moments (M Pospelov & A Ritz); The Electric Dipole Moment of the Electron (E D Commins & D DeMille); Neutron EDM Experiments (S K Lamoreaux & R Golub); Nuclear Electric Dipole Moments (W C Griffith et al.); EDM Measurements in Storage Rings (B L Roberts et al.); Models of Lepton Flavor Violation (Y Okada); Search for the Charged Lepton-Flavor-Violating Transition Moments l OaAE l OC (Y Kuno). Readership: Researchers and graduate students in particle physics, atomic physics and nuclear physics, as well as experts working in the field
Download or read book Measurement of the Z gamma Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings written by and published by . This book was released on 2015 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cross section for the production of Z[gamma] in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb-1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. Furthermore, the differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. These observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. As a result, limits on anomalous triple gauge couplings of ZZ[gamma] and Z[gamma][gamma] are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson.
Download or read book A Measurement of the W Z Production Cross Section and Limits on Anomalous Trilinear Gauge Couplings in Proton proton Collisions at s written by Advait Neel Nagarkar and published by . This book was released on 2012 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: I present a measurement of the W±Z production cross section in the leptonic final states in pp collisions at √s = 7 TeV and limits on anomalous trilinear gauge couplings, using 4.64 fb-1 of data collected using the ATLAS experiment at the LHC. The production cross section has been determined to be 19.0+1.4-1.3(stat.)±0.9(syst.)±0.4(lumi.) pb, in agreement with the Standard Model (SM) expectation of 17.6+1.1-1.0 pb. A search for anomalous trilinear gauge couplings has been conducted and limits have been set at the 95% confidence level; the result is consistent with the SM couplings.
Download or read book Measurement of the Pp 2 ZZ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four lepton Final States at arrow written by and published by . This book was released on 2014 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton-proton collisions at [arrow]" = 8 TeV are presented. The analysis is based on a data sample, corresponding to an integrated luminosity of 19.6 fb−1, collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ 2!lll'l', where l = e, [mu] and l' = e, [mu], [tau]. The measured total cross section [sigma](pp 2!ZZ) = 7.7 " 0.5 (stat)-0.4+0.5 (syst) " 0.4 (theo) " 0.2 (lumi) pb, for both Z bosons produced in the mass range 60
Download or read book Elementary Particle Theory written by and published by . This book was released on 1968 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Higgs Boson Decays into a Pair of Bottom Quarks written by Cecilia Tosciri and published by Springer Nature. This book was released on 2021-10-22 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery in 2012 of the Higgs boson at the Large Hadron Collider (LHC) represents a milestone for the Standard Model (SM) of particle physics. Most of the SM Higgs production and decay rates have been measured at the LHC with increased precision. However, despite its experimental success, the SM is known to be only an effective manifestation of a more fundamental description of nature. The scientific research at the LHC is strongly focused on extending the SM by searching, directly or indirectly, for indications of New Physics. The extensive physics program requires increasingly advanced computational and algorithmic techniques. In the last decades, Machine Learning (ML) methods have made a prominent appearance in the field of particle physics, and promise to address many challenges faced by the LHC. This thesis presents the analysis that led to the observation of the SM Higgs boson decay into pairs of bottom quarks. The analysis exploits the production of a Higgs boson associated with a vector boson whose signatures enable efficient triggering and powerful background reduction. The main strategy to maximise the signal sensitivity is based on a multivariate approach. The analysis is performed on a dataset corresponding to a luminosity of 79.8/fb collected by the ATLAS experiment during Run-2 at a centre-of-mass energy of 13 TeV. An excess of events over the expected background is found with an observed (expected) significance of 4.9 (4.3) standard deviation. A combination with results from other \Hbb searches provides an observed (expected) significance of 5.4 (5.5). The corresponding ratio between the signal yield and the SM expectation is 1.01 +- 0.12 (stat.)+ 0.16-0.15(syst.). The 'observation' analysis was further extended to provide a finer interpretation of the V H(H → bb) signal measurement. The cross sections for the VH production times the H → bb branching ratio have been measured in exclusive regions of phase space. These measurements are used to search for possible deviations from the SM with an effective field theory approach, based on anomalous couplings of the Higgs boson. The results of the cross-section measurements, as well as the constraining of the operators that affect the couplings of the Higgs boson to the vector boson and the bottom quarks, have been documented and discussed in this thesis. This thesis also describes a novel technique for the fast simulation of the forward calorimeter response, based on similarity search methods. Such techniques constitute a branch of ML and include clustering and indexing methods that enable quick and efficient searches for vectors similar to each other. The new simulation approach provides optimal results in terms of detector resolution response and reduces the computational requirements of a standard particles simulation.
Download or read book Measurements of ZZ Production Cross Section Using Four lepton Events and Constraints on Anomalous Triple Gauge Couplings at squareroot s written by Usama Hussain and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of four-lepton production in proton-proton collisions, pp → (Z/[gamma]*)(Z/[gamma]*)→ 4l, where l = e or [mu], using data collected during 2016-2018 (Run II) are presented. The dataset corresponds to an integrated luminosity of 137 fb^(−1) at a center-of-mass energy of 13 TeV, collected by the CMS detector at the LHC. All reported measurements use the 2l2l' final states, where l,l' = e or [mu]. The total ZZ cross section for all events with two Z bosons in the mass range 60-120 GeV is measured and found to be [sigma](pp → ZZ) = 17.2 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (theo) ± 0.3 (lumi) pb. Differentialcross sections are measured as functions of a number of kinematic observables. Allthese results agree with standard model predictions. Searches for anomalous triplegauge couplings are performed, and the four-lepton invariant mass distributions areused to set the most stringent limits to date on a number of parameters affectingneutral gauge boson interactionsl
Download or read book Measurement of the Pp u2192 ZZ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four lepton Final States at u221A s written by and published by . This book was released on 2014 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton–proton collisions at √s = 8 TeV are presented. The analysis is based on a data sample, corresponding to an integrated luminosity of 19.6 fb−1, collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ → lll'l', where l = e,? and l' = e,?,?. The measured total cross section ?(pp → ZZ) = 7.7 ± 0.5 (stat)-0.4+0.5 (syst) ± 0.4 (theo) ± 0.2 (lumi) pb, for both Z bosons produced in the mass range 60 msubZ/sub 120 GeV, is consistent with standard model predictions. Differential cross sections are measured and well described by the theoretical predictions. As a result, the invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ? couplings at the 95% confidence level: –0.004 fsub4/subsupZ/sup 0.004, –0.004 fsub5/subsupZ/sup 0.004, –0.005 fsub4
Download or read book Evidence for Exclusive u2192 W W u2013 Production and Constraints on Anomalous Quartic Gauge Couplings in Pp Collisions at sqrt s written by and published by . This book was released on 2016 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for exclusive or quasi-exclusive ?? → W${̂+}$ W${̂–}$ production, via pp → p${̂(*)}$ W${̂+}$ W${̂–}$ p${̂(*)}$ → p${̂(*)}$ ?${̂±}$e${̂∓}$ p${̂(*)}$ at $ sqrt{s}=8 $ TeV, is reported using data corresponding to an integrated luminosity of 19.7 fb${̂–1}$. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum p$_{T}$(?${̂±}$e${̂∓}$) > 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 fb${̂–1}$ of data). In the signal region, 13 (2) events are observed over an expected background of 3.9 ± 0.6 (0.84 ± 0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4? over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive ?? → W${̂+}$ W${̂–}$ production. Here, upper limits on the anomalous quartic gauge coupling operators a$_{0,C}{̂W}$ (dimension-6) and f$_{M0,1,2,3}$ (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.
Download or read book Search for New Physics in Events with High Jet Multiplicity and Low Missing Transverse Momentum in Proton proton Collisions at sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Search for Anomalous Couplings in WW and WZ Measurements at the Tevatron D0 and CDF Results written by and published by . This book was released on 1995 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The search for WW and WZ production in p{anti p} collisions at √s = 1.8 TeV using the CDF and D0 detectors is presented. Three analyses, one concentrating on the leptons + jets decay channels and two concentrating on the dilepton decay channels are described in detail. Limits on anomalous WW[gamma] and WWZ trilinear gauge boson couplings are presented. Prospects for further study of diboson production and anomalous couplings with the Upgraded Tevatron are also presented.
