University of Iowa HEP Group CMS Analysis 1

2 Outline As University of Iowa HEP group, we are involved with several different physics analysis. Electroweak Symmetry Breaking qqH, H Forward Physics Majorana Neutrino Study Supersymmetry (SUSY) 1.m T2 (Separate background from signal) 2.A Data Driven Method to Estimate high E T miss tail in QCD Events New physics in dijet topology

EWK Symmetry Breaking 3 Vector boson fusion process has the second largest cross-section for Higgs particle production. This channel requires jet tagging in forward detector (HF). Our group members (Anthony Moeller and Alexi Mestvirishvili) study leptonic decay channels of Higgs particle with jets in the forward region within the Higgs group.

qqH, H 4 A study on Monte Carlo data for qqH leptonic decay is currently in progress. Mass reconstruction methods for Higgs and backgrounds are being studied for 115 and 130 GeV Higgs masses. Reconstruction only depends on E T miss and final state leptons. Anthony Moeller

Backgrounds and Forward Jet Cuts 5 qqH, H Without any cut: Backgrounds (W+jets, Z+jets, ttbar, etc.,) will dominate signal region. To eliminate background, a cut on forward tagging jets (HF) can be applied. Signal from Vector Boson Fusion (VBF) has a pair of forward jets whereas most common processes don’t. Background Distributions Anthony Moeller

Forward Physics 6 Centrally produced particles with low-x processes or jets in the forward regions require the use of HF detectors for trigger and tagging. Members at CERN (Taylan Yetkin, Kerem Cankocak and Sercan Sen) are sharing their detector and jet expertise with the forward groups and participating in analysis efforts.

Majorana Neutrino Study Mass Reconstruction 7 The Majorana nature of the neutrino allows for lepton number violation via di-lepton production without any E T miss. As the SM doesn’t allow for lepton number violation this is likely a discovery channel. Warren Clarida

Majorana Discovery & Exclusion Results 3 Sigma Exclusive 5 Sigma Discovery Discovery and Exclusion results for different Majorana Neutrino mass scales. Integrated Luminosity With only 100 pb -1 integrated luminosity neutrino masses lower than 180 GeV can be excluded. Warren Clarida

SUSY with m T2 9 Taylan Yetkin arXiv: v1 Alan J.Barr and Claire Gwenlan In decays where lightest supersymmetric particle(LSP) is pair produced and escaped the detector(E T miss ), it is not easy to determine the mass of the mother particle. m T2 (formed as transfer mass from 3 objects: jet, jet, E T miss ) is defined to put constrain on the mother particle mass.

A Data Driven Method to Estimate high E T miss tail in QCD Events 10 Estimating SM background for SUSY. Introduce an artificial imbalance by smearing p T of the jets. Smearing is done by using a response function. E. Asli Albayrak and Taylan Yetkin

Response Function The response function represents the effect of jet mismeasurements on E T miss and it is a combination of a Gaussian (R G ) and a non-Gaussian (R NG ) response.

Application of Response Function We form a multi-jet sample with low. p T of jets in this low MET sample is smeared by the response function as MET is recalculated for low MET events with the effect of smearing. 12 E. Asli Albayrak and Taylan Yetkin Smeared E T miss distribution

New Physics in Dijet Topology Discriminator Shape Efficiency Discriminator Cut mis-tagging b efficiency Study of efficiency and purity of CMS b-jet tagging algorithms (Colorado Reed) Dijet signal one of the early discovery topologies for CMS. Jane Nachtman is co-convenor of LPC Dijet Topology group which focuses Fermilab based effort. Analysis Control channel for VH with Di-boson signatures prove Higgs search viability Test or provide Jet Energy Scale calibration for b jets, mass resolution for Higgs Observation of di-boson process is an analysis in itself resonance as signature for new physics (Technicolor) Jane Nachtman, Kai Yi, Colorado Reed (undergrad), Scott Griffiths (grad, spring 2010) Summer 2009 work by Reed and K.E. Raghav (summer UG).

Meeting and Conferences study – qqH Task Force Meetings (LPC) – VBF Higgs Subgroup Meetings (CERN) – Meetings (CERN) – VBF Fermilab by A. Moeller, June 2009 Estimating E T miss tail in QCD Events – LPC JetMet Topology Group Meetings – SUSY All Hadronic Meetings (CERN) – JTerm Fermilab by E.A. Albayrak (January 09, August 09) – APS Prairie Meeting in Iowa City by E.A. Albayrak (November 09) Majorana Neutrino Study – Exotica Physics Meetings (CERN) – APS DPF meeting in Detroit by Warren Clarida (July 09) Forward Physics Studies – Forward Physics Meetings (CERN) Dijet Topology – LPC Dijet Topology Group Meetings 14