jessica leonard, u. wisconsin, december 19, 2006 preliminary exam - 1 h-> jessica leonard...

Jessica Leonard, U. Wisconsin, December 19, 2006 Preliminary Exam - 1

H->H->

Jessica LeonardUniversity of Wisconsin -

MadisonPreliminary Examination


Standard modelStandard model


Higgs PhysicsHiggs PhysicsBackground on Why We Need the Higgs


The Higgs The Higgs tau tau tau tau signalsignal

Feynman diagramsWhy is it interesting? - Backgrounds: QCD 2 + 2/3j, EW 2 + 2j, t-tbar->WbWb, (b-bbar, Drell-Yan Z/* production,) W+jets


LHC!LHC!


Luminosity ProfileLuminosity Profile

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.


Experiments at the LHCExperiments at the LHC

First Collisions 2007Physics in 2008

27 Km ring 1232 dipoles B=8.3 T(NbTi at 1.9 K)

TOTEM

ATLAS and CMS :pp, general purpose

LHCb : pp, B-physics

ALICE : heavy ions,p-ions

• pp s = 14 TeV Ldesign = 1034 cm-2 s-1

• Heavy ions (e.g. Pb-Pb at s ~ 1000 TeV)


CMS detector (temp CMS detector (temp slide)slide)

Components with slides already:ECAL, HCAL, tracker, trigger, muon

Should other components have slides?magnet, preshower, . . .


CMS DetectorCMS Detector

MUON BARREL

CALORIMETERS

PixelsSilicon Microstrips210 m2 of silicon sensors9.6M channels

ECAL76k scintillating PbWO4 crystals

Cathode StripChambers (CSC)Resistive PlateChambers (RPC)

Drift Tube Chambers (DT)

Resistive Plate Chambers (RPC)

Superconducting Coil,4 Tesla

IRON YOKE

TRACKER

MUONENDCAPS

HCALPlastic scintillator/brasssandwich


ECALECAL

QuickTime™ and aTIFF (Uncompressed) decompressor




ECAL crystals are PbWO4 - high density - small Moliere radius


HCALHCAL




are needed to see this picture. HCAL sampling calorimeter:50 mm copper plates and 4 mm scintillator tiles

HF extends coverage to |h| = 5Steel plates and 300 m quartz fibers


Muon SystemMuon System

Largest chambers of drift tubes 4 x 2.5 m

Cathode strip chambers use wires and strips to measure r and , respectively

Resistive plate chambers capture avalanche charge on metal strips






TrackerTracker





Silicon strip detector used in barrel and endcaps

Silicon pixel detectorsused closest to the interactionregion


TriggerTrigger




Temp slideTemp slideSuggestions for text on detector component pages?

More detailed diagrams of different types of subcomponents, e.g. muon system? (RPC, DT, CSC)


H->H-> final states and final states and triggerstriggers

Note: Here “jet” means energy deposit consistent with

->jj•L1: single or double (93, 66 GeV) ???•HLT: double ???

->j•L1: single •HLT: single , + jet

->ej•L1: single isolated e, e + jet•HLT: single isolated e, e + jet


H->H->->l+->l++single-prong +single-prong event offline selectionevent offline selection

e and candidates identified•Additional electron requirements:•E/p > 0.9•Tracker isolation•Hottest HCAL tower Et < 2 GeV

Highest-pt lepton candidate with pt > 15 GeV chosen

Lepton track identifies the other tracks of interest: within z = 0.2 cm at vertex


H->H->->l+->l++single-prong +single-prong event offline selection event offline selection

(cont.)(cont.) candidates identified; jet formed around each and passed through t-tagging requirements

Require -jet charge opposite lepton charge

Hottest HCAL tower Et > 2 GeV if coincides with electron candidate

-jet Et > 30 GeV


H->H->->l+->l++single-prong +single-prong event offline selection event offline selection

(cont.)(cont.)Jets are the 2 highest-Et jets with Et > 40 GeV, not including e and candidate

Jets must be within || < 4.5, as well as having different signs in h

Require hj1j2 > 4.5, fj1j2 < 2.2, invariant mass Mj1j2 > 1 TeV

Require transverse mass of lepton-MisEt system < 40 GeV


H->H->->2 1-prong->2 1-prongBackgrounds: ttbar, Drell-Yan Z/*, W+jet, Wt, QCD multi-jet


H->H->->->+jet+jet


H->H->->e+jet->e+jet


Generate eventsGenerate events


My cutsMy cuts


PlotsPlots


What next?What next?


ConclusionsConclusions

jessica leonard, u. wisconsin, december 19, 2006 preliminary exam - 1 h-> jessica leonard...

Documents