Searches for Dijet Resonances

Searches for Dijet Resonances
Author: Lydia Audrey Beresford
Publisher: Springer
Total Pages: 175
Release: 2018-09-04
Genre: Science
ISBN: 331997520X

Download Searches for Dijet Resonances Book in PDF, Epub and Kindle

This book addresses one of the most intriguing mysteries of our universe: the nature of dark matter. The results presented here mark a significant and substantial contribution to the search for new physics, in particular for new particles that couple to dark matter. The first analysis presented is a search for heavy new particles that decay into pairs of hadronic jets (dijets). This pioneering analysis explores unprecedented dijet invariant masses, reaching nearly 7 TeV, and sets constraints on several important new physics models. The two subsequent analyses focus on the difficult low dijet mass region, down to 200 GeV, and employ a novel technique to efficiently gather low-mass dijet events. The results of these analyses transcend the long-standing constraints on dark matter mediator particles set by several existing experiments.

A Search for New Diboson Resonances in the Boosted Semi-leptonic Final State at √s

A Search for New Diboson Resonances in the Boosted Semi-leptonic Final State at √s
Author: Ryne Michael Carbone
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN:

Download A Search for New Diboson Resonances in the Boosted Semi-leptonic Final State at √s Book in PDF, Epub and Kindle

Models of a neutral, narrow scalar boson (spin-0), charged and neutral vector bosons (spin-1) coupling to the Standard Model gauge bosons, and a neutral Randall-Sundrum bulk graviton (spin-2) are considered. The search significantly improves the limits produced in recent searches.

Search for High-mass Diphoton Resonances in Proton-proton Collisions at 13 TeV and Combination with 8 TeV Search

Search for High-mass Diphoton Resonances in Proton-proton Collisions at 13 TeV and Combination with 8 TeV Search
Author:
Publisher:
Total Pages:
Release: 2016
Genre:
ISBN:

Download Search for High-mass Diphoton Resonances in Proton-proton Collisions at 13 TeV and Combination with 8 TeV Search Book in PDF, Epub and Kindle

The results of a search are presented for the resonant production of high-mass photon pairs, specifically spin-0 and spin-2 resonances with an invariant mass between 0.5 and 4.5 TeV, and with a width, relative to the mass, between 1.4E-4 and 5.6E-2. The data sample corresponds to an integrated luminosity of 12.9 inverse femtobarns of proton-proton collisions collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV. No significant excess is observed relative to the standard model expectation. The results of the search are combined statistically with those previously obtained in 2012 and 2015 at sqrt(s)=8 and 13TeV, respectively, corresponding to integrated luminosities of 19.7 and 3.3 inverse femtobarns, to derive exclusion limits on scalar resonances produced through gluon-gluon fusion, and on Randall-Sundrum gravitons. The lower mass limits for Randall-Sundrum gravitons range from 1.95 to 4.45 TeV for coupling parameters between 0.01 and 0.2. These are the most stringent limits on Randall-Sundrum graviton production to date.

Search for Massive Resonances in Dijet Systems Containing Jets Tagged as W Or Z Boson Decays in Pp Collisions at $ \sqrt{s} $

Search for Massive Resonances in Dijet Systems Containing Jets Tagged as W Or Z Boson Decays in Pp Collisions at $ \sqrt{s} $
Author:
Publisher:
Total Pages: 37
Release: 2014
Genre:
ISBN:

Download Search for Massive Resonances in Dijet Systems Containing Jets Tagged as W Or Z Boson Decays in Pp Collisions at $ \sqrt{s} $ Book in PDF, Epub and Kindle

Our search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of multijet events corresponding to an integrated luminosity of 19.7 fb-1, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. We found that the search uses novel jet-substructure identification techniques that provide sensitivity to the presence of highly boosted vector bosons decaying into a pair of quarks. Exclusion limits are set at a confidence level of 95% on the production of: (i) excited quark resonances q*decaying to qW and qZ for masses less than 3.2 TeV and 2.9 TeV, respectively, (ii) a Randall-Sundrum graviton GRS decaying into WW for masses below 1.2 TeV, and (iii) a heavy partner of the W boson W' decaying into WZ for masses less than 1.7 TeV. For the first time mass limits are set on W' → WZ and GRS → WW in the all-jets final state. The mass limits on q* → qW, q* → qZ, W' → WZ, GRS → WW are the most stringent to date. A model with a "bulk" graviton Gbulk that decays into WW or ZZ bosons is also studied.