skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC

Abstract

This document describes the work achieved under the OJI award received May 2008 by Peter Wittich as Principal Investigator. The proposal covers experimental particle physics project searching for physics beyond the standard model at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research.

Authors:
Publication Date:
Research Org.:
Cornell University, Ithaca, NY
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1045792
Report Number(s):
DOE/08ER41558
TRN: US1204100
DOE Contract Number:
FG02-08ER41558
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CERN; HADRONS; PHYSICS; STANDARD MODEL; CMS Trigger; CMS data taking

Citation Formats

Wittich, Peter. Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC. United States: N. p., 2011. Web. doi:10.2172/1045792.
Wittich, Peter. Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC. United States. doi:10.2172/1045792.
Wittich, Peter. Fri . "Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC". United States. doi:10.2172/1045792. https://www.osti.gov/servlets/purl/1045792.
@article{osti_1045792,
title = {Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC},
author = {Wittich, Peter},
abstractNote = {This document describes the work achieved under the OJI award received May 2008 by Peter Wittich as Principal Investigator. The proposal covers experimental particle physics project searching for physics beyond the standard model at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research.},
doi = {10.2172/1045792},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Oct 14 00:00:00 EDT 2011},
month = {Fri Oct 14 00:00:00 EDT 2011}
}

Technical Report:

Save / Share:
  • The results obtained in the CMS experiment at the LHC from searches for various physics phenomena beyond the Standard Model in proton-proton interactions at the c.m. energy of 7 TeV are presented. The respective analysis is based on data measured in the CMS experiment over the period spanning 2010 and 2011.
  • A data sample of events from proton-proton collisions with two isolated same-sign leptons, missing transverse momentum, and jets is studied in a search for signatures of new physics phenomena by the CMS Collaboration at the LHC. The data correspond to an integrated luminosity of 35.9 inverse femtobarns, and a center-of-mass energy of 13 TeV. The properties of the events are consistent with expectations from standard model processes, and no excess yield is observed. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos, squarks, and same-sign top quarks, as well as top-quark associatedmore » production of a heavy scalar or pseudoscalar boson decaying to top quarks, and on the standard model production of events with four top quarks. The observed lower mass limits are as high as 1500 GeV for gluinos, 830 GeV for bottom squarks. The excluded mass range for heavy (pseudo)scalar bosons is 350-360 (350-410) GeV. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results.« less
  • A search for physics beyond the standard model in events with one or more high-momentum Higgs bosons, H, decaying to pairs of b quarks in association with missing transverse momentum is presented. The data, corresponding to an integrated luminosity of 35.9 fbmore » $$^{-1}$$, were collected with the CMS detector at the LHC in proton-proton collisions at the center-of-mass energy $$\sqrt{s}=$$ 13 TeV. The analysis utilizes a new b quark tagging technique based on jet substructure to identify jets from H$$\to$$bb. Events are categorized by the multiplicity of H-tagged jets, jet mass, and the missing transverse momentum. No significant deviation from standard model expectations is observed. In the context of supersymmetry (SUSY), limits on the cross sections of pair-produced gluinos are set, assuming that gluinos decay to quark pairs, H (or Z), and the lightest SUSY particle, LSP, through an intermediate next-to-lightest SUSY particle, NLSP. With large mass splitting between the NLSP and LSP, and 100% NLSP branching fraction to H, the lower limit on the gluino mass is found to be 2010 GeV.« less
  • Dimuon and dielectron mass spectra, obtained from data resulting from proton-proton collisions at 8 TeV and recorded by the CMS experiment, are used to search for both narrow resonances and broad deviations from standard model predictions. The data correspond to an integrated luminosity of 20.6 (19.7) fb –1 for the dimuon (dielectron) channel. No evidence for non-standard-model physics is observed and 95% confidence level limits are set on parameters from a number of new physics models. The narrow resonance analyses exclude a Sequential Standard Model Z SSM ' resonance lighter than 2.90 TeV, a superstring-inspired Z ψ ' lighter thanmore » 2.57 TeV, and Randall-Sundrum Kaluza-Klein gravitons with masses below 2.73, 2.35, and 1.27 TeV for couplings of 0.10, 0.05, and 0.01, respectively. A notable feature is that the limits have been calculated in a model-independent way to enable straightforward reinterpretation in any model predicting a resonance structure. The observed events are also interpreted within the framework of two non-resonant analyses: one based on a large extra dimensions model and one based on a quark and lepton compositeness model with a left-left isoscalar contact interaction. Lower limits are established on MS, the scale characterizing the onset of quantum gravity, which range from 4.9 to 3.3 TeV, where the number of additional spatial dimensions varies from 3 to 7. Thus lower limits on Λ, the energy scale parameter for the contact interaction, are found to be 12.0 (15.2) TeV for destructive (constructive) interference in the dimuon channel and 13.5 (18.3) TeV in the dielectron channel.« less
  • A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 fbmore » $$^{-1}$$. No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeV at a 95% confidence level for a W$$^{\prime}$$ boson with the same couplings as that of the standard model W boson are determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza-Klein W$$^{(2)}_{{\rm KK}}$$ states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W$$^{\prime}$$ boson and the standard model W boson, and for a compositeness model.« less
    Cited by 38