BSM Searches: BSM Searches: From Tevatron to LHC From Tevatron to - - PowerPoint PPT Presentation

BSM Searches: BSM Searches: From Tevatron to LHC From Tevatron to LHC

– LHC start-up – Tevatron → LHC: examples & lessons? – Plans for “Early Physics” (mostly material collected from various recent talks)

Arnd Meyer RWTH Aachen

• 22. February 2007

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC: 22+ Years

1984: cms energy 10-18 TeV Luminosity 1031-1033cm-2s-1 1987: cms energy 16 TeV Luminosity 1033-1034cm-2s-1 Final: cms energy 14 TeV Luminosity 1033-1034cm-2s-1

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC Endgame

Crucial part: 1232 superconducting dipoles Can follow progress on the LHC dashboard

http://lhc-new-homepage.web.cern.ch/lhc-new-homepage/

The LHC Schedule

• LHC will be closed and set up for

beam on 1 September 2007 LHC commissioning will take time!

• First collisions expected in

November/December 2007 A short pilot run Collisions will be at injection energy i.e. cms of 0.9 TeV

• First physics run in 2008

~ 0.1-1 fb-1? 14TeV!

• Physics run in 2009 +…

10-20 fb-1/year ⇒ 100 fb-1/year

(Unofficial luminosity estimates)

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC Endgame

Magnet Installation Progress

• L. Evans: Presentation made to the Open Session of the

LHC Machine Advisory Committee, 7 December 2006

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC Endgame

November 2007 First beam 450 GeV Summer 2008 First physics run 7 x 7 TeV August 2007 Machine closed April 2007 End installation November 2006 Last magnet delivered

• L. Evans: 20/2/07

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC Start-up Schedule 2007

• M. Lamont

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC Staged Commissioning for 2008

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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LHC Start-up

Obvious: considerable uncertainties in schedules Dare to compare Tevatron Run II?  Summer 2000 engineering run (few stores with collisions)  April 2001 Run II started  February – April 2002 experiments collect “physics quality” data Could it be done faster at the LHC? Maybe

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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General Purpose Detectors at the LHC

• Central tracker
• EM calorimeter
• HAD calorimeter
• Muon Detectors

Trigger: Reduce 40 MHz collision rate to 100 Hz event rate to store for analysis

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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ATLAS and CMS Detectors

ATLAS cavern, 2006 CMS cavern, 2006 November 2006

• ATLAS barrel toroid magnet

reaches full current

• ATLAS barrel tracker installed

(TRT connected)

• Endap muons being installed

All CMS tracker elements at CERN (integration ongoing!) CMS lowers first detector into cavern (forward calo) Lowering on weekly basis since then

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Detectors at Start-Up in 2007

Detectors progressing well and will be fairly complete at start-up

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Expected Detector Performance

O(10 µm) 20—200 µm in rφ Tracker alignment 1% <10% Jet energy scale < 1% 2—3% HCAL uniformity 0.1% 0.5—2% Lepton energy scale < 1% ~ 1% ATLAS ~ 4% CMS ECAL uniformity Goals for Physics Expected Day 0

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Start-Up Physics: 2007

• F. Gianotti/ICHEP06

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Start-Up Physics: 2008

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Trigger Menu (Later)

Typical LVL1 menu for L= 2 ⋅ 1033cm-2s-1 – all thresholds are adjustable – multiple objects allow lower thresholds total rate ~20kHz (allowing safety margin and new ideas)

21 and 45 Electron and Jet 60 and 60 Jet and ET

miss

+calibration, monitoring, etc…

• 15*10

Electron-Muon 177,86,70 200,90,65 1-jet, 3-jets, 4-jets

• 25 and 30

τ-jet and ET

miss

59

• Two τ-jet

86

• Inclusive τ-jet

3 6 Two muons 14 20 Inclusive isolated muon 17 15 Two electrons/Two photons 29 25 Inclusive isolated e/γ CMS (GeV) Threshold

ATLAS (GeV) Threshold

Trigger type D.Rousseau

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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New Phenomena is Approximately:

Supersymmetry Supersymmetry

Bread and butter RPC MSSM  Jets + MET, 3rd Gen., lepton(s) from cascade decays, ... R-Parity Violation Long-Lived Particles (AMSB, split SUSY, RPV, ...) Gauge Mediated SUSY Breaking

Extra Dimensions Extra Dimensions

Monojets, di-leptons and di-photons Extra Gauge Bosons

Extra Gauge Bosons

W´, Z´ Leptoquarks

Leptoquarks

1st, 2nd, 3rd Generation Compositeness

Compositeness

Lepton and Quark Substructure

Alternatives Alternatives

Technicolor, Little Higgs, ...

Unknown Unknown

Signature Based Searches

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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New Physics Reach at the LHC

100 GeV – 1 TeV (30 fb-1) covers full (mA, tanβ) ~ 3 TeV (300 fb-1) ~ 5 TeV (100 fb-1) ~ 25 / 40 TeV (30 / 300 fb-1) ~ 6.5 / 3 TeV (100 fb-1) ~ 9 / 6 TeV (100 fb-1) ~ 6 TeV (100 fb-1) < 6 – 10 TeV SM Higgs MSSM Higgs SUSY (squark, gluino) New gauge bosons (Z’) Quark substructure (ΛC) q*, l* Large ED (MD for n=2,4) Small ED (MC) Black holes

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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CMS Physics TDR

650 pages 308 figures 207 tables 1.50 Kg http://cmsdoc.cern.ch/cms/cpt/tdr/ CERN/LHCC 2006-001 CERN/LHCC 2006-021 February 2006 June 2006

ATLAS Performance and Physics TDR published in 1999 – consistent set of new notes in Spring 2007

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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The SUSY Landscape at 1 fb-1

SUSY cross sections can be large. O(100 pb) for squarks / gluinos (105 sparticles in 1 fb-1). First priority: discovery tools for 1 fb-1 SUSY manifests itself as: Conventional jets+MET? Leptons + jets + MET? GMSB with photons? Long lived R-hadrons? SUSY signatures, however, are very diverse! Many different signatures could be “the one” we need to be ready for.

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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The Physics Landscape

Beyond SUSY, there are many other possible models of new physics that could easily produce results in 1 fb-1. While SUSY may be popular, all that is certain is a high probability for some sort

• f new physics in the LHC range.

Need to be ready: Nature could be kind and give us new physics quickly.

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Do we have the tools to properly model MET resolution (real zero bias overlay, etc.) Do we have tools to “clean” MET, and remove contributions from hot channels, cosmics, beam-halo, etc.? Do we know how to get the jet energy scale for the highest energy jets? Can we trigger on massive, slow-moving particles? Can we trigger on signatures that contain a very large number of low PT particles? Can we trigger on... what we do not know yet? – We have to confront these challenges before startup and in parallel: work within

• ne physics group must not distract from work in the detector

performance / trigger / simulation / ... groups.

BSM challenges the detector hardware, reconstruction algorithms, and trigger

Connect to Detector, Reconstruction, Trigger, ...

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Benchmark analyses can be the guide towards extracting the physics from the first data. The documentation can be the “template” for the first papers, and the tools developed will be used with the first data. To be useful, need to deliver them in time (by late 2007).

The Path to Benchmark Analyses (CMS)

Trigger path defined and studied, and trigger efficiencies measured and understood, with appropriate dataset definitions Develop and apply methods for extracting backgrounds and efficiencies, from data wherever possible. Definition of trigger paths and data sets needed for data-based efficiency and background measurements Full systematics for startup luminosities Justified selection criteria Methods of demonstrating robustness of signal and correctness of background prediction

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Based on physics prejudice and feasibility with 1 fb-1:

• A. mu+jets+MET (mu based trigger paths)

e+jets+MET (e based trigger paths)

• B. Jet + MET (jetMET based trigger paths)
• C. Di-object resonances (dielectron, dimuon, ditau, dijet, diphoton)
• D. Photons / jets / MET
• E. SUSY reconstruction methods – model parameter extraction

and model discrimination (is it SUSY? UED? Little Higgs? etc.?)

Examples for Benchmark Analyses (CMS)

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Map Trigger / object path → benchmark physics → key experimental issues:

GeV muon-based samples → MSSM SUSY search Understand tails on MET TeV muons → Zprime search Stress high pT lepton ID GeV electron-based samples → MSSM SUSY search Understand difficult physics bgrds. TeV electrons → Zprime search Stress high pT lepton ID Tau-based samples → MSSM SUSY Instrumental backgrounds GeV jet-based samples → MSSM SUSY search Trigger / “cleanup” problems Tev jets → Zprime search High ET jet calibration Photon-based samples → GMSB QCD fakes Heavy stable particles → stable stau Relation to ID groups SUSY-reconstruction → MSSM SUSY Prepare for success

Examples for Benchmark Analyses (CMS)

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Example: DØ Run II NP Publications

17 publications on a wide variety of topics (CDF numbers similar)  8 x supersymmetry 8 x supersymmetry  4 x leptoquarks 4 x leptoquarks  2 x excited fermions 2 x excited fermions  2 x extra dimensions 2 x extra dimensions  1 x signature based 1 x signature based Time lag between “data taken” and publication: few months (“discoveries”) to ~3 years Physics data taking since 2002 – first publication 2004 (“beat” Run I)

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Constraints for “Early Physics”

Early physics results will be those that do not (strongly) depend

• n Monte Carlo

For searches, this implies

 Something that “sticks out” (resonance, “bump-search”), or  Backgrounds can be modeled from data, or  Signal is so big that backgrounds become less important (unlikely, luminosity accumulates slowly!)

Keep it simple!

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Constraints for “Early Physics”

Early physics results will be those that do not (strongly) depend

• n Monte Carlo

Computing Computing (working, not perfect) Detector Detector (working, partially) Monte Carlo Monte Carlo (Physics, SM and beyond)

Analysis

(analysis tools) Reconstruction Reconstruction (also development  detailed knowledge) Need all 5  shortcuts

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Discoveries

Not always on day one Top discovery: 7 years after turning on Tevatron In 2006, 18 years after “day one”:

 Bs mixing  WZ production  Single top

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Example: Squarks and Gluinos

New “dijet” candidate with highest MET

Jet 2: (174.3 ,-0.37,0.12) Jet 1: (282.4 ,-0.18,1.52) MET = 369 GeV

LSP assumed stable (Rp conserved)   2 jets + MET

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Example: Squarks and Gluinos / MET

Most of the time, a problem in online data taking will generate “fake” MET Excellent detector operations are needed to trigger on MET A perfect understanding of the calorimeter is required to control the MET tail A huge amount of work, online and offline, prior (parallel?) to physics analysis Patrice Verdier

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Example: Squarks and Gluinos / MET

Choosing the wrong vertex is often the main source

• f QCD background in

analyses where MET is important

Patrice Verdier

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Example: Squarks and Gluinos / MET

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Example: Squarks and Gluinos / MET

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Squarks and Gluinos: Lessons?

Run II started in 2002, first publication in 2006... Should have had experience from Run I

 But: different people, different software, different detector, different ...

Had 6 years between end of Run I and beginning of Run II Lack of competition cannot be an excuse

 DØ vs. CDF. Still no CDF publication on the subject in Run II

Collaborations with > 600 people (still lack of people?!?) Maybe SUSY did not have the priority

Arnd Meyer (RWTH Aachen)

• 22. February 2007

Page 35

Squarks and Gluinos: Lessons?

Having triggers ready and understand them Understanding jets and MET – same people who may commission the detector, work on trigger Understanding SM background processes, in particular where predictions are uncertain (V + jets) CMS / ATLAS (?): ask for people interested in measuring the water pressure in the restrooms, and you'll get 100 answers

 But does the “important” work get done? Organization?

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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SUSY Expectations for early LHC

Inclusive channel leading Others not far behind Leptonic channels may be there sooner Need redundancy & confirmation Low mass SUSY could be in the data early on – time to discovery is then determined by understanding of SM processes: W+jets, Z+jets, top, ...

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Charginos / Neutralinos

“Golden channel” at Tevatron: Cascade decays involving leptons  three charged leptons + MET But: small event rate ( x BF < 0.5pb), soft leptons Selection (6 channels in DØ):

 Three leptons (ll + track), pT > 3 GeV (or higher depending on channel)  Missing transverse energy  Veto events with Z  ll decays

Backgrounds



Multijet events with misidentified leptons



Drell-Yan, Z-production with Z  ll



Di-boson

Still challenging – but first publication earlier than inclusive channels

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Gauge Mediated SUSY Breaking

Gauge Mediated SUSY Breaking: Gravitino G is LSP Possible scenario: neutralino NLSP,   γG  Chargino / neutralino production leads to final state γγ + ET  Inclusive search for 2 photons plus ET (∫L dt = 760 pb-1)

~

1

~ ~

Limits for chargino and neutralino (N5=1, Mm=2, tan=15, >0): m( m(  ) > 120 GeV ) > 120 GeV m( m( ±

±) > 220 GeV

) > 220 GeV

1

~ ~

Lifetime unknown Assume here: prompt decay

Selection: Two central photons with ET > 25 GeV Optimized cut ET > 45 GeV Data: 4 events, expect 2.1 ± 0.7 events background

Backgrounds estimated from data → little MC dependence

Predecessor of this analysis was the first Run II DØ NP publication

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Backgrounds in GMSB Search

Background without true MET: QCD multijet, direct photon, Z → ee

 “Invert” suitable photon ID criterion (shower shape) → “QCD sample”  Verify that the resulting sample has characteristics similar to di-photon sample  Normalize the QCD sample at low MET, using the shape to extrapolate to high MET

Background with true MET (small): Wγ, ttbar, etc.

 Start from eγ sample  Subtract QCD background, using low MET normalization  Apply e→gamma fake rate measured from Z → ee events

(GMSB can of course also lead to “delayed” photons, maybe not for day one)

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Unusual signatures: Stopping Gluinos

Gluinos hadronize into R-hadrons. Charged R-hadrons can lose all their kinetic energy through ionization and come to rest. See hep-ph/0506242 (“split SUSY”  heavy squarks, light gauginos)

 Lifetime between 10 ns and 100 sec, decay into jets + ET (LSP)  Tevatron: ~500 “stopped gluinos” in 2 fb-1 for m(gluino) = 300 GeV

DØ analysis:

 Exactly one central, “broad” jet with ET > 90 GeV  “Rapidity gap” trigger, as veto against pp interaction  No primary vertex, veto against muons Signal MC m(gluino)=400GeV m(LSP)=90GeV

– Backgrounds (beam halo, cosmics, detector, ...), trigger, readout challenging

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Stopping Gluinos, R-Hadrons

A.Arvanitaki, S.Dimopoulos, A.Pierce, S.Rajendran, J.Wacker

O(106) stopped gluinos / 100 fb-1

LHC 100 fb-1 Tevatron 2 fb-1

GEANT simulation: energy loss of a 300 GeV R-hadron in the ATLAS calorimeter For  > 0.5, discovery potential for R-hadrons up to ~ 1.5 TeV If the stopping gluinos are missed, maybe those that sail through will be found...

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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More Unusual Signatures

Neutral long-lived particles, e.g. RPV SUSY → ability to reconstruct displaced vertices >> cm, and trigger on such topologies Charged massive stable particles: staus, or charginos in AMSB → dE/dx or timing to identify slow-moving particles “Late” photons (GMSB with long-lived Neutralino) → ability to recognize non-pointing photons ......

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Special Signatures

In some models/phase space the gravitino is the LSP Then the NLSP (neutralino, Stau lepton) can live ‘long’

• Eg. χ→γ+ gravitino or heavy (slow) stau slepton

Signatures

• Displaced vertices
• Non-pointing showers
• Long lived ‘heavy

muons’ (time of flight)

Challenge to the experiments!

E.g. GMSB

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Special Signatures

... and in fact some signatures may be more accessible (or only) at “low” luminosities

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Signature Based Searches

The simplest example: di-lepton anomalies Border between “model-dependent” and “model-independent” is fuzzy

First months of operation

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Summary

Little time left before LHC starts up Transition Tevatron → LHC without long lasting gap → synergies For sure we don't want to miss anything exciting, and there are plenty of opportunities (apologies for only mentioning a small fraction today)

Arnd Meyer (RWTH Aachen)

• 22. February 2007

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Large Extra Dimensions

Main search streams: Real graviton emission

Apparent energy-momentum non-conservation in 3D-space ⇒ “Monojets” Direct sensitivity to the fundamental Planck scale MD

GKK g q q GKK g g g V V GKK GKK f f f f

Virtual graviton exchange Modifies SM cross sections

Sensitivity to the theory cutoff MS (MS expected to be ∼ MD)