Physics (status and plans)people.physics.tamu.edu/kamon/research/CMS/CMS... · D.D’Enterria O.Kodolova Super LHC D.Denegri QCD K.Rabbertz N.Varelas Top C.Campagnari J.D’Hondt

December 10, 2007CMS week -- collaboration meeting

1P. SphicasPhysics (status and plans)

Physics (status and plans)

Outline

News/updatephysics organization

analysis approval system

events/other actions since last CMS week

Physics objects: status

Physics analyses: examples

Planning, schedule

P.SphicasCMS week

December 10, 2007

News/update



CMS physics organization (from Jan 2008)

Physics CoordinatorP.SphicasDeputies:

J.Incandela, R.Tenchini

MC generatorsP.BartaliniR.Chierici

HiggsC.MariottiY.Sirois

SUSYO.Buchmuller

L.Pape

EWKJ.AlcarazS.Dasu

B physicsU.Langenegger

J.Olsen

b-taggingT.Speer

T.Boccali

Jets/MissETG.Dissertori

D.Elvira

MuonsN.AmapaneM.Mulders

e/γC.Seez

P.Vanlaer

ParticleFlow/τR.Cavanaugh

P.Janot

Forward PhysicsM.Grothe

Heavy IonsD.D’EnterriaO.Kodolova

Super LHCD.Denegri

QCDK.RabbertzN.Varelas

TopC.Campagnari

J.D’Hondt

ExoticsA.De Roeck

S.Eno



New physics organizationSUSY-BSM group split into “SUSY” and “Exotica”

Scope of SUSY-BSM group was far too large for a single groupDivision of topics not strictly thematic:SUSY includes “traditional” SUSY signatures with ETmiss; plus Universal Extra Dimensions, plus Little-Higgs models (with T-parity)Exotica includes remaining SUSY signatures (heavy stable charged particle, GMSB, R-parity violating SUSY)

and the remaining models Beyond the Standard Model

Diffractive physics group renamed to “Forward Physics”

Better reflect actual scope of the group’s activitiesA second convener will now be sought (given enlarged scope)



New analysis approval system (I)Starts this week; linked to new constitution (on publications)

Analysis Review Committee (ARC): ≥3 people, one from pub comm, one from “inside” group, one from collaboration at large

Appointed by Phys Coordinator and Pub Comm chairPre-approval in physics group: documentation must be available at least one week before pre-approval meeting

Standardized physics object ID must be applied in analysisusage of “standard objects” by an analysis constitutes “approval by default”. If an analysis makes changes to this, the code must go into CVS repository and get POG approval

After pre-approval: ARC decides whether to recommend (or not) proceeding with approval. Decision by phys coordinator.Subsequently: all documentation (Analysis Notes and PAS Web Page) frozen

Approval meeting announced two weeks ahead (full physics list)What gets approved: contents of PAS (Web) page.

PAS: 4-5 page summary with all relevant numbers and plots to be approved. Backed by one or more Analysis Notes.

Becomes public after approval.



New analysis approval system (II)

CMS Analysis Database (CAD)Holds all CMS physics analyses and relevant information

Contact people, Working group, links to Analysis Notes, PAS page, status (started, pre-app, scheduled for approval, etc), ARC, comments, etc

CMS Analysis Database Interface (CADI)Via iCMS: REQUIRES AFS (CMS) account

Log into iCMS (as normally). Access on left pane as “CADI”http://cms.cern.ch/iCMS/analysisadmin/analysismanagement

Thanks to Dirk Samyn (CERN, PH/CMC) for CAD/CADI

Instructions for new approval system on iCMS (Physics page Documents Approval procedure)

New system being field-tested using 2007 analyses.



Group on Analysis Software/AOD (I)PAGs (& also individuals): parallel and non-overlapping efforts towards a Physics Analysis Toolkit/Framework (PAT).

TQAF, SusyAnalyser, SusyTools, … diverging because of lack of coordinated common base for a CMS-wide PAT. Substantial, unnecessary duplication of work; user confusion

Analysis beginners (majority of CMS physicists at this point in time) do not know where to start from in setting up their analysis

Analysis of (first) data: without a unified PAT, analyses rely heavily on experts from various groups;

unnecessary delays between data taking and running of the analyses. Such delays will slow down tracking potential problems with the detector, the reconstruction chain, the analysis programs; could have very negative impact on our competitiveness



Group on Analysis Software/AOD (II)

Related issue: AOD content. AOD is the primary data format distributed to all the Tier-1 centers of CMS, i.e. should be most widely used input to physics analyses.

At present: AOD size too large with respect to original plans.

Furthermore, we know neither whether this oversize is justified by physics needs nor whether the current content is adequate for “doing physics”.

A new group has been formed to tackle these two related issues

Chaired by Roberto Tenchini; open meetings: include representatives from Offline and physics groups

First report at dedicated workshop on Mon-Tue Jan 28-29 (right after Jan Physics Days to facilitate travel)



Physics/Trigger week (end October)

First half of the week: working group meetings.

Plenary Joint Physics-Trigger meeting on Wed;focused on activities of the new Trigger Studies Group (TSG) and trigger monitoring.

Both Physics and Trigger organizations now focused on readiness for early data-taking. Emphasis was on early trigger tables, preparations for calibrations and monitoring of trigger performance for fast feedback in early LHC running

Remainder of the week: devoted to plenary sessions covering the 2007 Analyses

In particular, plans for producing analysis notes on physics that can be accessed in 100 pb-1 or 10 pb-1 as may be obtained in the startup run of the LHC.



CSA07 and physicsMain Tier-0 output: ~150 Mevt

100pb-1 of data (not quite, e.g. not enough QCD jets)Reconstruct with calibration/alignment constants corresponding to “detector knowledge with 10pb-1 of data”

Tier-0 production ~200Mevt, have another 50Mevt to useAdd “10pb-1 of data”; reconstruct with startup calib/align precision

AOD crated and distributed to (all/multiple) Tier-1sRun skim jobs on AOD at Tier-1’s

Test re-reconstruction at Tier-1Same data, so this time run with 100pb-1 constants

At Tier-2’s: monitor incoming skim data; check/validateIn parallel: run on older samples (for 2007 analyses).

All analyses must migrate to Tier-2s. Note this is mimicking life (typically full analysis runs on data “version-1”.

Generate 50 Mevt Monte Carlo eventsCAF: first tests (data, code, organization) of “Express Line”

Three analyses: W/Z, Higgs and Z′. Would be nice to also inject signals (that go to the primary datasets at the Tier-2s as well). Currently in planning phase…



Physics plan and CSA07

The truth is we have been hurt by lack of dataWhen CSA07 was moved from Jun to Oct 07, it became apparent that only the early Spring07 data (CMSSW_1_3) could really be used for physics analyses.

Later, the excess production capacity was used to RECO the CSA07 data with CMSSW_1_5 ahead of time.

But no HLT in 1_5; also, perfect detector calibr/alignment

These data became available in September

Incompatible with 1_3 (e.g. geometry).

Further delays in the skimming made the CSA07 data available in mid November (beginning of appearance)

So impossible to use these samples

Most of what follows today is the result of work with 1_3 and 1_5 samples…

Physics Objects

Recent progress in physics objects



Physics Objects

Recall status at last CMS week: Current focus of work: definition of standard physics objects for “2007 analyses” and “CSA07 analyses”

By now: reconstruction algorithms well established

But ongoing improvements: e.g. use of mixed seeding for electron tracks

Emphasis of work:

Methods for measuring efficiency and fake rate from data

Beyond October (based on CSA07 samples): need physics object ID for start-up:

robust and simple to understand/measure efficiency with data



Electron Efficiency: Analysis NoteAN 2007/019: “Measuring Electron Efficiencies with Early Data”Tag + probe using Z→ee (C. Hill, G. Daskalakis, D. Evans, J. Jackson, J. Berryhill, J. Haupt, C. Timlin, D. Wardrope):

Tag electron defined using tight criteria. Z mass constraint used to identify a looser Probe electron - unbiased w.r.t efficiency to be measured.

Pre-approved at egamma POG meeting on Nov 12Approval presentation during physics plenary on FridayPAS: https://twiki.cern.ch/twiki/bin/view/CMS/TWikiTNPNote

Cumulative Efficiency(reconstruction, ID,isolation, trigger)

Electron trackreconstruction

efficiency



Electron IdentificationNew cut-based electron ID now available (M. Sani, J. Branson, R. Salerno)

Includes a simple “robust” electron ID provided suitable for startup conditionsDocumentation, including instructions for use with 13X, 16X, 17X:https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideElectronID

Reference performance plots (efficiency and fake rate from jets) provided here for PTDR electron ID (P. Ribeiro):

https://twiki.cern.ch/twiki/bin/view/CMS/ElectronPerformanceSimilar page for new electron ID will be available this week

Z→ee

No isolation



Muon Efficiency with Tag & Probe

Tag-And-Probe using Z→µµProbe: different categories (Golden, Matched, Unmatched, Tracker-only, Standalone)

Efficiency tables as a function of η&pT produced

Good agreement with MC expectationsGUGMGG

GMGG

GSGUGMGG

GUGMGG

GTGUGMGG

GUGMGG

NNN

NN

NNNN

NNN

NNNN

NNN

+++

=

+++++

=

+++++

=

2

2

2

2

2

2

matching

acktracker tr

muon standalone

ε

ε

ε

Global MuonTracker Track

TAG µ

PROBE µ



• pT correction as a function of muon kinematics (pT, η, φ, …) computed minimizing a likelihood

TWIKI page: https://twiki.cern.ch/twiki/bin/view/CMS/MuonScaleCalib

GLBMu

fit Lorentzian + decr. expo.

GLBMu

Muon Momentum Scale Calibration

• Modify muon pT to force the Z peak to be in the right position:

Tracker and Muon Syst. misaligned (10 pb-1 scenario)B field distortion

• Also biases from imprecise detector modeling considered:



Fast Simulation of Muon Hits

• Fast simulated hits (SimHits) now availableCan be fed into standard digitization and reconstruction

A ttbar event with 3 muons, from fast simulation(2 stand-alone muon tracks reconstructed)



First real HLT muons!

CosmicMuonReconstructor now producing the first real “Lvl-2” muons, on-line, in the filter farm



S. Esen, G. LandsbergType I JES Corrections

Raw MET

True MET, GeV

MET: recent results

High pT ZK. Terashiµ Corrections

Texas A&M τ Corrections

•W(eν)+jets Corrected MET



Measuring b-tag efficiency in data

Note on measuring b efficiency of lifetime-based b tags using data will be shown for approval on Friday. (C.Gerber et al)

Includes several methods, that exploit the small correlation between lifetime-based and b µ based b taggers.

Comparison of measured & true b tag efficiencies vs. jet Pt

Doesn’t show systematics of ~11%.

L ~ 14 pb-1



Measuring uds-Jet mistag rate in Data

Lifetime-based b tags: exploit the fact that B decays produce several tracks with significant +ve impact parameters.

One can use tracks with –ve impact parameters to estimate from how often light quark jets are tagged in real data:

Analysis Note should be complete by Jan (D.Bloch et al.)

Precision is dominated by systematics from uncertainty in B hadron flight direction, dependence on jet selection/event type & contribution to light quark tag rate from V0 decays.

Better than 10% relative for “medium” b tag with only 10 pb-1 !

⎥⎦

⎤⎢⎣

⎡−−

=)(

)()()(

ve

veudsuds

MC

DataMCData

εεεε



Primary Vertex Fitting

Primary vertex fit now uses measured beam-spot (BS) position, instead of (0,0,0). (W.Erdman, T.Speer)

Resolution transverse to beam improved by using beam constraint.

Equally good results when simulated beam is offset or tilted.

(9,16)(12, 17)140(500,250)

(9, 16)(12, 17)0(2000, 250)

(9, 16)(12, 16)0(0, 0)

With BS constraint

No BS constraint

Reconstructed primary vertex (x, z) resolution (µm)

Simulated beam

Tilt angle (µrads)

Simulated

BS

position

(x, y) (µm)

Vertex fit factor 2 faster due to change in matrix software (CLHEP SMatrix)



P-flow: Jet Performance StudiesPF Jet Resolution

Significantly better than “raw”CaloJets for pT < 120 GeVImprovements for high pT Jets

See next page!

PF Jet ResponseSignificantly better response than “raw” CaloJetsApproaches 1.0 for pT > 100 GeV

Improvements still possible for low pT Jets

Focus work to improve high pT Jet Resolution

high densityhigh multiplicity

QCD dijets

PFJet ResponsePFJet Response

QCD dijets

J-L. Agram

J-L. Agram



P-flow: recent algorithm Improvements at High pT

Improved separation of π0’s merged with charged hadrons

Before: γ’s from π0’s not separated from charged hadron

replaced by track lost energy

After: γ’ from π0’s identified and added to list of particles

Energy recovered Improved linking algorithm

Link track to cluster by Reco Hit associationRecover dispersed clusters

Before

After

500 GeV pT Jets

~10% improvementin resolution

Better jetresponse ∆ΕΤ/ΕΤ ∆ΕΤ/ΕΤ

∆ΕΤ/ΕΤ

200-500 GeV pT taus

200-500 GeV pT taus

Colin Bernet

Alex Zabi



p-flow: MET corrections (with JetMET)

QCD Jet corrections to MET inappropriate for tau-jets

For every (PFjet, CaloJet) matched pair, calculate a correction

Swap calo energy in cone 0.5 with the PF calculation

Improved MET response

Improved MET resolutionFirst time in CMSSW!

)( τPFT

calojetTT EEE

rrr∑ −=/∆

Texas A&M Group: Alfredo Gurrola, et al

MET Resolution

τ-jets fromW(→τν) + 0jets

Status

Recent progress in physics analysisOnly a brief sketch here.

Note: numerous analyses will be presented at the Thursday and Friday plenary physics meetings for

approval

P. SphicasPhysics (status and plans)

Charged Hadron Spectra

Measurement of inclusive charged hadron production in pp collisions at 14 TeV;

scheduled for approval this week

Authors: F. Sikler, K. KrajczarARC: V. Chiochia, C. Lourenco,

F. Ambroglini

Algorithmic efficiency vs. transverse momentum for pions, kaons and protons

Comparison ofyields of chargedhadrons in rap. interval 0.4 – 0.6of simulation (hist.)and “data“ (symbols)

rel. deviation

AN 2007/021



γ*/Z→ee : 3662 events

di-jets&γ*/Z→ττ&Wjets : 53 evts

W/Z decays to electrons, muons

10pb-1

70.0<Me,e<110.0 GeV

di-jetWjetsγ*/Z ττ

γ*/Z ee

Signal+Background

(D. Wardrope, M.Malberti)

(A. Vilela)

(S. Goy)

QCDW→µν

W→µν

Take MET from ZMumu. Use template method to estimate QCD background.


Examples from Z→ττ decays

trigger: Iso Ele (12, 15 (L1,HLT)) Offline (main cuts):

Isolated electron (ET>16 GeV)Isolated taujet (ET>20 GeV)Electron veto

~138 events, ~50 bkg (mass 40-80 GeV/c2)

trigger: single, double leptonOffline (main cuts):

Isol. ele, mu (PT: 8, 7 GeV) cos Df>-0.1Vector (scalar) Pt sums < 120 (150) GeV/c

~700 events, background ~5.5% trigger: Iso Ele (12, 15 (L1,HLT))

Z−>ττ−>e+taujet (100pb-1)

emumasscut0Entries 2021Mean 37.31RMS 12.83

Invariant mass of leptons0 50 100 150 200 250 300 350 400 450 500

-1N

o o

f E

ven

ts/1

00 p

b

-210

-110

1

10

210

emumasscut0Entries 2021Mean 37.31RMS 12.83

emumasscut0

signal

WW

tt

W + Jets

Z−>ττ−>e+mu+X (100pb-1)

(K. A. Petridis,S. Greder)

(S. Bansal,K. Mazumdar)



IDEAL scenario, no PU Startup + PU

10 pb-1

Laura Ederaet al.

Top quark physicsσ~830pb (NLO) →very early physics; simple event selection:

At least four jets, ET > 30 GeV, |η| < 2.4One isolated muon (track<3, calo<5) , PT > 20 GeV, |η| < 2.4No other isolated lepton with PT > 10 GeV, |η| < 2.4

Jet combination which gives top quark with highest pT; among three jets require two in mW window

10 pb-1



currently on top of the MCJet correctionsapplying a Likelihood Ratio method to establish the correct jet combinationsever event selection to select the cleanest and most useful eventsmethod proven to be not sensitive to combinatorial and process backgroundmethod proven not to be biased

After pull correction: δ100/pb (∆E) ~0.6%

2σ contour

∆E(heavy)=-2.6 ± 1.2%

∆E(light)=-11.3 ± 1.2%

Petra Van Mulders

Jet Energy Scale from top events100 pb-1: obtain light and heavy quark residual Jet Energy Scale corrections via mW and mtop constraints in top quark events

This by applying an event-by-event kinematic fit

Dec 18: pre-approval of 5 top quark notes:early measurements, cross section, mttbar distribution, JES from top, flavour tagging performance from top

CMS Plenary - 21/06/200733


Natasha Ilina

Manuel Zeise

ττ→ll

ττ→l jet

2007 Analysis

H→ττ: Z→ττ bkg (shape) from data



SUSY: some (trigger) benchmarks

LM1

efficiency

Texas A&M: Tau+MET Trigger

HL

T B

and

wid

th

L1 Bandw

idth

Brown: e+jet Trigger Optimization

QCD rate

D. Mangeol: Acoplanar Jet Triggers

Planning & physics schedule



Broad-brush plan (I)“2008 papers”: we identified (early 2007) all the physics we will be doing in 2008 (if we were to get up to 1fb-1).

A long list

We split the time between “Physics-Org T0” and “LHC start” into two equal-time periods

So, starting in Feb 07, mid-point is ~Oct-Nov 07

“2007 analyses”: the subset of “2008 papers” that needs to be worked on already now, until Oct/Nov 07

Identified small number (2-6) topics per physics groupConcentrate all efforts on making these analyses as realistic aspossible

For each group, picked one analysis and currently walking through full analysis approval & pub committee procedure.

As soon as we finish this exercise, we will turn to the preparation for the arrival of collision data



Broad-brush plan (II)Dec 07 to May 08: prepare for real data. Goals:

Define all physics datasets and streamsEspecially Express Line

Have all of the HLT code in place (POGs; PAG tests)Have all the trigger monitoring system (code + people) in placeHave all the data-analysis organization (code + people) in place

For each physics group, well-defined data- and work-flow, from Tier-0 to Tier-1 to Tier-2

Have analyses geared for 10 pb-1 and 100 pb-1 ready to absorb the data; complete plans for up to 1000pb-1.

Complete the 2007 analyses, injecting even more realism (noise, dead channels, really bad miss-reconstruction)

Produce Monte Carlo samples in time for the startup

Ultimate goal: in May 2008 we should have analyses that are ready to absorb 100 pb-1 of data immediately. With some work, 1000pb-1.



Analysis plan: next step2007 analysis exercise approaching completion. As expected, a lot of work remains.

Now: enlarge scope to “2008 analyses”, i.e. full range of topics we expect to tackle in 2008 (and 2009)

Next step in all analyses: include CSA07 dataThis includes miscalib/misalignment in two scenarii: detector knowledge after 10pb-1 and after 100pb-1

April Physics/Trigger week: milestone for completing the 2007 and early 2008 analyses using CSA07 data

Software-wise: stay with CMSSW_1_6 until CMSSW_2 arrives (1_7 backwards incompatible with 1_6... There are ~400 Mevt events with 1_6…)

Planning on using fastsim for large samples. Need to decide on sample to be processed with full simu (and fastsim…) in time for startup

PS



Outgoing conveners

Many thanks indeed toDavid Futyan (egamma), Norbert Neumeister (muons), Nikos Varelas (JetMET), Ian Tomalin (btag), Roberto Tenchini (EWK), Sasha Nikitenko (Higgs), Maria Spiropulu (SUSY-BSM), Filip Moortgat (generators), Bolek Wyslouch (heavy ions)

for the energy and zest they invested into their responsibilities. They have led these nascent groups through the transition from the old PRS organization into the new physics organization of CMS, providing the necessary continuity.

Extras

Some details of current activities in physics groups



Electrons

Likelihood-based Electron ID now fully functional in CMSSW_16X (E. Di Marco, P. Govoni):

https://twiki.cern.ch/twiki/bin/view/CMS/LikelihoodElectronID

Electron Reconstruction:

Alternative track seeding for electrons using globalMixedSeeds implemented - will go in 180

(M. Sani, B. Mangano). Improved

efficiency at high η

Charge determination(D. Wardrope, W. Adam):

Charge mis-id rate can be improved using charge measurement obtained from ∆φ between pixel seed direction and SuperCluster position

electronspositrons



Electron and Photon IsolationNew tools available based on HLT egamma isolation (M. Mozer):

https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideEgammaIsolation

Ongoing studies to improve and optimize the algorithms (V. Sharma, M. LeBourgeois)

Systematic comparison of techniques - see talk at egamma meeting this week: http://indico.cern.ch/conferenceDisplay.py?confId=18242

Redefinition of Photon object (N. Marinelli, D. Futyan)Currently two physics objects; two photon collections (Photon and ConvertedPhoton). Will be combined into a single reco::PhotonDataFormat for 180 → Single photon collection stored in the event

analysis with photons simplified; AOD content reduced

Photon Identification (A. Kyriakis, D. Maletic)π0 rejection for unconverted photons now available as an analysis level tool https://twiki.cern.ch/twiki/bin/view/CMS/SWGuidePiZeroRejection

Requires only AOD information as input



Muon Reconstruction: Performance

Efficiency – ORCA vs CMSSW (16X)

BarrelEndcaps

pT resolution



Jets and Missing ET (JetMET)Analyses Notes:

Performance of MET: CMS AN-2007/041 (v.4)Editors: Greg Landsberg and Albert De RoeckPre-approved by JetMET; presented for approval this weekARC: Mayda Velasco, Luc Page, Philipp Schieferdecker

Performance of (All) Jet AlgorithmsEditors: Philipp Schieferdecker and Marek ZielinskiStatus: Draft available

Plans for Jet Energy Scale CorrectionsEditor: Robert HarrisStatus: Released for comments

Completed Internal Notes:Jet and MET Performance in CMSSW_1.2.0: CMS IN-2007/053Performance of the KT Jet Algorithm in CMSSW: CMS IN-2007/062

Upcoming Notes:Jet Energy Resolutions from dijet balance - data-driven method: draft stageSISCone performance: draft available



TGEN p

10 210 310

GE

N

T/p

RE

CT

p

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Jet Response

|<1.4GEN

η0.0<|

ICone R=0.7MCone R=0.7SISCone R=0.7

D=0.6Tk

Jet Response

(GeV/c)T

genp0 20 40 60 80 100

ma

tch

ing

eff

icie

nc

y (

%)

0

20

40

60

80

100

Iterative Cone 0.5

Midpoint Cone 0.5

Seedless Cone 0.5

Fast KT 0.4

5≤| η |≤ 0 •R < 0.5 ∆

CaloJetEt(GeV)10 210 310

MC

Jet

Co

rrecti

on

1

1.5

2

2.5

3

3.5

4

|<0.226η0.000<|

iterativeCone5midPointCone5sisCone5fastjet4

|<0.226η0.000<|

Z. Qi

Jet response

A. Smoron

Jet pT resolutions from

MC-truth and dijet balance

C. Dragoiu

Jet efficiencies

K. Kousouris

152 MCJet corrections

P. Schieferdecker

Top mass resolution

r/0.70 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

(r/0

.7)

ρ

-510

-410

-310

-210

-110

1

Towers

MCone7

ICone7

SisCone7

kT D=0.6

< 120 GeV/cJetT 80 < P

P. Kurt

Jet shapes

Recent Jet Results for AN Note



Jet Correction Plan (near term)MCJet is now the standard correction; factorized corrections becoming available; will become standard early in 2008

L1 (Offset); Zero suppression corrections available; next: pile-up correctionsL2 (η); Data-driven dijet balance correction to replace MC truth soonL3(pT); Data-driven γ / Z + jet balance studies underway

L4(EMF)Studies using 1_5_2 and integration with L2 & L3 corrections

L5(Flavour)h dependence, integration with prior corrections and with parton level corrections

L6-L7 (Parton)First release expected early in 2008



b Tag POG: Analysis Notes near completion



Particle Flow Activites: TrackingTogether with the Tracker DPG

Progress continues on multiple fronts!Iterative Tracking

Faster, more efficient,

same (low) fake rate

Internal Note now exists,

Michele Pioppi

Nuclear Interactions

Identification & reconstruction,

Vincent Roberfroid

V0’s

ORCA code now ported to

CMSSW,

Brian Drell



EWK status

AN 2007/26 “Towards a W±→e±ν & γ*/Ζ→e+e- cross section measurement” (Physics Plenary in January)

AN 2007/31 “Towards a W±→m±ν & γ*/Ζ→m+m-cross section measurement” (this Week at Physics Plenary)

AN 2007/28 “Tau production from W and Ζ decays”(Physics Plenary in January)

Meanwhile: multiboson studies are continuing (e.g. QCD/EWK/TOP tomorrow)

measurements useful for PDF fits are progressing (PDF Workshop on Wed)



EWK: examples from theory studiesNLO/NNLO: MC@NLO+PHOTOS OK (agreement with NNLO generator RESBOS)

(N. Adam et al.)

QED: PHOTOS is OK (agreement with 2nd order QED/EW generator HORACE)

PDF uncertainties: 1% (variations) ⊕1.3% (MRST-CTEQ comparisons)



First results: after previous selection signal rate is factor 10smaller than QCD multi-jet bkg rate (simulated with PYTHIA!)Factorizing the selection cuts between lepton and jets the following is obtained

(4 jets ET>30 GeV & isolated muon pT>20 GeV + acceptance cuts)

MET or HT cuts will not help in reducing this background significantlyNeed to investigate topological observables eg. sphericity, centrality, etc…

160240*300*ttbar (muon decay)

1706701670QCD

≥2 loose b-tag’s≥1 loose b-tag≥0 loose b-tagEvents for 10/pb

* exact numbers to be confirmed, but quoted as an illustrationGregory Hammad, Jan Heyninck

QCD

ttbar

Top quark: QCD multi-jet background



SUSY group: Basic Tasks and Data Driven Methods

Current Work Priority: Focus on “Basic Tasks” as they are prerequisite for the analyses. This work must be carried out in close collaboration with the POG’s and other PAG’s.

Examples are:Cleaning of leptons, jets, MET and the event

Data driven estimates of efficiencies and fake rates

Background estimations from the data

Trigger definition and efficiencies (see next slides)



SUSY: Task and Commitment List

Basic SUSY Tasks

Background Tasks

SUSY Analyses

Assemble new task and commitment list:https://twiki.cern.ch/twiki/bin/view/CMS/SusyTopics

This is a great opportunity for established groups to refine their commitments and for new interested groups to join!



Leptonic & Hadronic SUSY TriggersA thorough suite of leptonic and hadronic triggers applicable for SUSY searches has been developed in the course of the “HLT Exercise”Leptonic SUSY triggers:

Single leptons and dileptonsLepton + (b-tagged) jets

Hadronic SUSY triggersMutlijetsAcoplanar jetsGlobal quantities (MET, HT, MET + HT)

Good start, but many of these triggers have not been thoroughly optimized for SUSY caseRemains to be done:

Evaluate the performance of the current 1_6_0 HLT suite for a set of benchmark SUSY points and find weak spotsWork with the TSG on optimization of present triggers and help introducing new ones, which can improve efficiency or increase robustness for early operationEnsure that corresponding prescaled triggers with lower thresholds are available for efficiency/turn-on determinationUnderstand what triggers with what thresholds are required for unbiased determination of backgrounds



Forward physics (ex diffraction) groupAnalyses:

1. Exclusive dilepton production: γγ → ll and γPomeron →Υ (AN-2007/032) Jonathan Hollar, Xavier Rouby, Severine Ovyn

In good shape, missing are systematic studies of impact of Caloeffects (noise, dead channels, etc, using MET group procedure)

Aim at pre-approval around CMS week; approval in Jan?2. Ratio of single diffractive to inclusive production of W (AN-2007/033) Antonio Vilela Pereira, Michele Arneodo

Study of best separation criterion for diff and non-diff sample on-goingBiggest obstacle, non-availability of CSA07 EWK samples, now overcome;

Decide this week if work advanced enough for Jan pre-appMeanwhile contributions to EWK W →µν Xsection note study of MET calibration method from Z → µµ events

3. Forward di-jet production (no AN yet) Salim Cerci, David D’EnterriaWill decide this week about time scale for (pre-) approval

Overall goal: Have results approved in time for the spring conferences


Heavy Ion GroupPaper 2007 analyses

Joint QCD/HI analyses for 2007 paper exercise are scheduled for approval this CMS week

Major HI conference 4-10 February 2008Group is focused on getting new studies ready for that conference

One plenary talk

Three parallel talks

γ+jet as a probe of quenching in HI events

Z0→µµ in HI events

Soft physics capabilities in pp collisions at 14 TeV

Analyses and approval process prioritized according to this conference needs during December and January

Soft physics talk will be based on 2007 paper

Pre-approvals planned for CMS week for γ+jet and Z0 analyses

Very tight schedule



Cal

oJe

tR

esp

on

se

CaloJet η

K. Kousouris

Jet Correction StatusL2 (η) & L3 (PT) Correction in CMSSW L4(EMF) Correction in CMSSW

L5(Flavour) Correction in CMSSW L6-L7(Parton) Correction Developing

MC

Jet

Res

po

nse

S. Esen

Jet

Fla

vou

rC

orr

ecti

on

J. Cammin Par

ton

Res

po

nse

GenJet ET (GeV)

A. Santocchia