Search for Heavy Gauge W' Boson in Events with an Energetic Lepton and Large Missing Transverse Momentum at Sqrt(s)


Book Description

A search is presented for W' bosons in events with an electron or muon and large missing transverse momentum, using proton-proton collision data at sqrt(s) = 13 TeV collected with the CMS detector in 2015 and corresponding to an integrated luminosity of 2.3 inverse femtobarns. No evidence of an excess of events relative to the standard model expectations is observed. For a W' boson described by the sequential standard model, upper limits at 95% confidence level are set on the product of the production cross section and branching fraction and lower limits are established on the new boson mass. Masses below 4.1 TeV are excluded combining electron and muon decay channels, significantly improving upon the results obtained with the 8 TeV data. Exclusion limits at 95% confidence level on the product of the W' production cross section and branching fraction are also derived in combination with the 8 TeV data. Finally, exclusion limits are set for the production of generic W' bosons decaying into this final state using a model-independent approach.




The Physics Associated with Neutrino Masses


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.




Search for a Heavy Gauge Boson W' in the Final State with an Electron and Large Missing Transverse Energy in Pp Collisions at Sqrt(s)


Book Description

A search for a heavy gauge boson W has been conducted by the CMS experiment at the LHC in the decay channel with an electron and large transverse / energy imbalance, E T, using proton-proton collision data corresponding to an integrated luminosity of 36 pb[-]1 . No excess above standard model expectations / is seen in the transverse mass distribution of the electron-E T system. Assuming standard-model-like couplings and decay branching fractions, a W boson with a mass less than 1.32 TeV/c2 is excluded at the 95% confidence level.




Search for a Heavy Gauge Boson $W$ ' in the Final State with an Electron and Large Missing Transverse Energy in $pp$ Collisions at $\sqrt{s}


Book Description

A search for a heavy gauge boson W' has been conducted by the CMS experiment at the LHC in the decay channel with an electron and large transverse energy imbalance, using proton-proton collision data corresponding to an integrated luminosity of 36 inverse picobarns. No excess above standard model expectations is seen in the transverse mass distribution of the electron-(missing E_T) system. Assuming standard-model-like couplings and decay branching fractions, a W' boson with a mass less than 1.36 TeV/c2̂ is excluded at 95% confidence level.




Search for New Heavy Charged Bosons and Measurement of High-Mass Drell-Yan Production in Proton—Proton Collisions


Book Description

This book presents two analyses, the first of which involves the search for a new heavy charged gauge boson, a so-called W' boson. This new gauge boson is predicted by some theories extending the Standard Model gauge group to solve some of its conceptual problems. Decays of the W' boson in final states with a lepton (l± = e± , μ±) and the corresponding (anti-)neutrino are considered. Data collected by the ATLAS experiment in 2015 at a center of mass energy of √s =13 TeV is used for the analysis. In turn, the second analysis presents a measurement of the double-differential cross section of the process pp->Z/gamma^* + X -> l^+l^- + X, including a gamma gamma induced contribution, at a center of mass energy of sqrt{s} = 8 TeV. The measurement is performed in an invariant mass region of 116 GeV to 1500 GeV as a function of invariant mass and absolute rapidity of the l^+l^-- pair, and as a function of invariant mass and pseudorapidity separation of the l^+l^-- pair. The data analyzed was recorded by the ATLAS experiment in 2012 and corresponds to an integrated luminosity of 20.3/fb. It is expected that the measured cross sections are sensitive to the PDFs at very high values of the Bjorken-x scaling variable, and to the photon structure of the proton.




Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\sqrt{s} with the ATLAS Detector


Book Description

The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W′,W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb−1. No excess beyond standard model expectations is observed. A W′ with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.







Search for New Phenomena in Events with a Photon and Missing Transverse Momentum in Pp Collisions at $$ \sqrt{s}


Book Description

In this paper, results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the Large Hadron Collider are reported. The data were collected in proton-proton collisions at a centre-of-mass energy of 13 TeV and correspond to an integrated luminosity of 3.2 fb-1. The observed data are in agreement with the Standard Model expectations. Exclusion limits are presented in models of new phenomena including pair production of dark matter candidates or large extra spatial dimensions. In a simplified model of dark matter and an axial-vector mediator, the search excludes mediator masses below 710 GeV for dark matter candidate masses below 150 GeV. In an effective theory of dark matter production, values of the suppression scale M * up to 570 GeV are excluded and the effect of truncation for various coupling values is reported. Finally, for the ADD large extra spatial dimension model the search places more stringent limits than earlier searches in the same event topology, excluding M D up to about 2.3 (2.8) TeV for two (six) additional spatial dimensions; the limits are reduced by 20-40% depending on the number of additional spatial dimensions when applying a truncation procedure.







Search for a W' Boson Decaying to a Muon and a Neutrino in Pp Collisions at Sqrt(s)


Book Description

A new heavy gauge boson, W', decaying to a muon and a neutrino, is searched for in pp collisions at a centre-of-mass of 7 TeV. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 36 inverse picobarns. No significant excess of events above the standard model expectation is found in the transverse mass distribution of the muon-neutrino system. Masses below 1.40 TeV are excluded at the 95% confidence level for a sequential standard-model-like W'. The W' mass lower limit increases to 1.58 TeV when the present analysis is combined with the CMS result for the electron channel.