Status and Plans of the CMS Experiment

Status and Plans of the CMS Experiment

Darin AcostaUniversity of FloridaOn behalf of the CMS Collaboration

Dijet recorded 12/6/09, ET~25 GeV

17 December 2009

D.Acosta - Miami 2009 2

Outline Start-up of the LHC State of the CMS experiment Recent results from the LHC start-up Prospects for early physics measurements

17 December 2009


2009/10 LHC Beam commissioning strategy

Global machine checkout

Essential 450 GeV commissioning

System/beam commissioning

Machine protection commissioning 2

3.5 TeV beam & first collisions

450 GeV collisions

Ramp commissioning to 1.2 TeV

Full machine protection qualification

Pilot physics

System/beam commissioning

Machine protection commissioning 1

Energy Safe Very Safe

450 1 e12 1 e11

1 TeV 2.5 e11 2.5 e10

3.5 TeV 3.0 e10 probe

Experiments’ magnets at 450 GeV

Trial ramps

Xmas

2010

17 December 2009


The LHC Start-Up in 2009 Injection Tests Oct.23-25 & Nov.7-9 Nov.20, 18:00, Start of 2009 beam circulation

First beam 1 circulation by 20:40 RF captured beam 1 for several

minutes by 21:50, 4 hours after start! Beam 2 captured by 0:10

Nov.23, First collisions at 900 GeV 13:30, both beams in, evidence for collisions

at ATLAS (P1), LHCb, and ALICE 19:00, Second attempt for CMS (P5), tuning,

collisions seen! About 30min. Dec.6, First physics fills

5:00, collisions, 4 proton bunches/beam, ~4 hours Dec.8, Acceleration

21:44: both beams ramped to 1.18 TeV each Dec.11, Higher proton intensities (7E10)

Starting to accumulate luminosity at 900 GeV Dec.14, Collisions at 2.36 TeV !

4:00: about 2 hours of highest energy pp collisions 21:00: still higher intensity 900 GeV collisions (16 bunches, 1.8E11)

17 December 2009


Start of the LHC Physics Program !

23-Nov-09

Spring-2010

First collisions on Nov.23 at 900 GeV

~0.1 Hz collisions L ~ few 1024 cm-2s-1

In the last week, collisions at 900 and 2236 GeV

~10Hz collisions L ~ few 1026 cm-2s-1

Ultimately, the LHC program should take us to:

14 TeV 109 Hz collisions L ~ 1034 cm-2s-1

14-Dec-09

= 1

/L

2011

17 December 2009


The Compact Muon Solenoid (CMS)

(4T) 210 m2 of silicon sensors: 9.6M (Str) & 66M (Pix) channels

PbWO4 crystals (76K)

Scintillator/brass

Iron / Quartz fiber fwd calorimeter, 3<||<5;

+ Castor, 5<||<6.55

+ Zero Degree Calorimeter

Cathode Strip Chambers, Drift Tubes, Resistive Plates

+ Trigger and data acquisition systems: 50 kHz into High Level Trigger (100 kHz max), record O(100) Hz

2 planes of silicon modules for ECAL

17 December 2009


CMS Detector SubsystemsBarrel pixelsBarrel pixels

Silicon Silicon strip modulesstrip modules

Crystal calorimeter, Crystal calorimeter, 1/2 of one endcap1/2 of one endcap

Hadron Hadron calorimeter calorimeter (1/2 barrel)(1/2 barrel)

Magnet Magnet

Endcap muon Endcap muon system (1/8 disks)system (1/8 disks)

Barrel muon Barrel muon system (1/5 wheels)system (1/5 wheels)

17 December 2009


CMS in Closed Configuration

17 December 2009


CMS Global Commissioning Program

During 2007 and 2008, commissioned progressively larger fractions of the systems for global data-taking

Integration of detector components and data acquisition system Synchronization of detector signals with cosmic rays Calibration and alignment with cosmic rays

Restarted in 2009 during last shutdown

17 December 2009


First LHC Beams, 2008HCAL energy ECAL energy

particle debris

Beam onto collimators (splash events)

Halo muons from circulating beams

But program cut shortdue to the major fault in one LHC sector

17 December 2009


The Cosmic Runs At Four Tesla CRAFT08:

23 days from Oct.13 – Nov.11, 2008 270M cosmic triggers with B=3.8T

Followed by shutdown, then: CRAFT09:

40 days from July 23 – Sept.1, 2009 320M cosmic triggers with B=3.8T

Commission the experimentwith magnet at operating field

Operate the experiment for an extended period (month)

Collect ~300M cosmics for detector studies

17 December 2009


Detector Performance Publications 23 CMS detector performance papers (500 pages!)

submitted to the Journal of Instrumentation based on data from CRAFT08 and 2008 beams

Available on ArXiv: http://arxiv.org/find/all/1/au:+CMS/0/1/0/all/0/1?skip=0&query_id=9f85c0e5eae277b4

To appear in a single volume of JINST Coverage:

Performance of all major detector systems, including trigger

Precision mapping of magnetic field in the steel return yoke Performance of track and muon reconstruction algorithms Alignment and calibration

http://arxiv.org/find/all/1/au:+CMS/0/1/0/all/0/1?skip=0&query_id=9f85c0e5eae277b4

17 December 2009


CRAFT Results in Thumbnails

17 December 2009


Alignment of the Silicon Strip and Pixel Trackers

Distributions of the means ofthe residuals, barrel components

Much improved from the survey accuracy of O(100m)

Close to ideal alignment even before collisions

Barrel Pixel: 2.6 m

Tracker outer barrel: 2.6 m

Tracker inner barrel: 2.5 m

17 December 2009


Tracking Performance Efficiency and resolution measurements

Tag a muon in the muon detectors and study the inner tracker (or vice versa)

Split a cosmic track into 2 “legs” and compare them Silicon tracking efficiency

99.5% for muons passing completely through the detector and close to the beamline

Muon momentum resolution 1% for pT=10 GeV, increasing to 8% for pT~500 GeV

(should improve to 5% when detectors are perfectly aligned)

17 December 2009


’08-’09 Shutdown – CMS Activities After the cosmics run (Nov ‘08), detector was opened for

maintenance & repair activities, installation of preshower subdetector & CASTOR forward calorimeter.

Work progressed according to the schedule laid down in Nov. 2008.

Major Accomplishments: Removal, repair, and re-insertion of the forward pixel system Installation and commissioning of the preshower detector Completion of maintenance & (some) repairs of all sub-systems Completion of the revision of the tracker cooling plant Understanding of magnetic field in the return iron-yoke Overpressure protection (new item) Re-commissioning of CMS New TOSCA B Field Map – agreement of data & MC now better

than 2% Large Monte Carlo production & analysis exercise at 10 & 7 TeV

17 December 2009


Sub

dete

ctor

Operational Fractions

Detector and Data-Taking Status for CRAFT09

TID TEC

1 control ring

1 cooling loop

Strips: 98.1%Pixels: 98.5%Strip Tracker Status Map:

Average CRAFT09 data-taking efficiency: 71%Without service disruptions: > 80%

2009 LHC Operations

17 December 2009


Beam “Splash” (~109 protons onto upstream collimator)

Beam 2

Nov.7-9, 2009 injectiontests

ECAL energy deposits in red, HCAL energy deposits in blue (light blue for HF and HO)

RPC muon hits are in yellow, and CSC muon hits are in magenta.

Silicon strips and pixels off for safety

17 December 2009


ECAL vs. HCAL Observed Energy O(1000) splash events in a wide

range of beam intensity Good linear correlation between

ECAL and HCAL measured energies Response in EndCap+ is lower than EndCap-

due to particle losses from material in CMS

Barrel

EndCap+

EndCap-

O(1M) muons per event 1000’s of TeV/event!

17 December 2009


Synchronization with Splash Events, HCAL

HCAL Barrel: RMS= 1.9 ns

HCAL Endcap: RMS= 2.3 ns

Splash09 - Before Splash09: After

HCAL Barrel: RMS= 1.2 ns

HCAL Endcap: RMS= 1.4 ns

Similar timing improvements were achieved in ECAL Endcap and Preshower

Corrections checked with new splash events

17 December 2009


ECAL Occupancy CMS 2009 Preliminary

ECAL Endcap - ECAL Endcap +

ECAL BarrelECAL Barrel

Average energy per crystal in ECAL

White regions are masked channels

0.9% of total one quarter may

be recovered. Use coarse trigger

data to recover allbut 0.15%

Energy modulations are combination of energy flow traversing CMS & geometry effects.

For the hadron calorimeter, no dead channels

=0

=1.5

= -1.5

=1.5

= 3

beam

bott

om

17 December 2009


Collisions ! Dec.6, Early Sunday morning

First “physics” fill of the LHC with 450 GeV beams colliding for several hours

(Very first collisions were provided Nov.23 with partial tracking) All CMS detectors powered, including pixel and strip

trackers, magnet on

17 December 2009


Muons Much lower rate than cosmic rays at this luminosity

17 December 2009


Dimuon Candidate at 2.36 TeV

17 December 2009


Rediscover mesons: 0

Mass uncorrected for effects of the readout threshold of ECAL that had to be lowered, and material effects

Data will be used to intercalibrate the ECAL crystals, precision expected is O(1%)

Data Simulation

17 December 2009


Rediscover mesons:

Data Simulation

Mass and width compatible with MC yield scale as expected:

N() / N(0) = 0.020 ± 0.003 DATA N() / N(0) = 0.021 ± 0.003 MC

17 December 2009


Rediscover mesons and baryons: K0, K0s

Ks

0.4975 GeV 1.115 GeV

Tracking reconstruction software working These events tagged by separated vertex (V0)

Magnetic field calibrated (mapped to precision <0.1%)

17 December 2009


K0s Candidate at 2.36 TeV

17 December 2009


Rediscover the Standard Model: Jets

CMS Experiment at the LHC, CERNDate Recorded: 2009-12-06 07:18 GMTRun/Event: 123596 / 6732761 Candidate Dijet Collision Event

Anti-KT algorithm with cone size R=0.7

Jet 1 Jet 2

Corrected pT (GeV) 24 26

0.3 2.0

2.5 -0.7

CMS Preliminary

17 December 2009


Multi-jet Candidate at 2.36 TeV

17 December 2009


(To come) Rediscover the Standard Model: QCD

Soft: Charged hadron measurements at 900 GeV up to 10 TeV

Pseudo-rapidity distribution expectedwith only 5K events

Also underlying event properties 10 TeV

Hard: Inclusive jet cross section measurements Example for 10pb-1 at 10 TeV

with kT algoirthm

17 December 2009


(To come) Rediscover the Standard Model: EWK

To be followed by measurements of, for example, the rapidity distribution and PT(Z) -- understanding of PDFs and pQCD at LHC

Isolated muon with PT>25 and ||<2 Two isolated electrons with ET>20 and ||<2.5

Systematic uncertainty: 2.4% 10% (lumi)

10 TeV 10pb-1

17 December 2009


Discover! New Z’ gauge boson Feasibility study

Luminosity required for 5 discovery as a function of Z’ mass in dimuon decay channel (very similar for dielectron) for two models and for several machine collision energies

Need 100 pb-1 at 10 TeV for discovery of mass > 1 TeV

17 December 2009


Discover! SUSY Opposite sign dileptons

Dilepton edges in MSSM:

PTl >16; 3 jets ET>100, 50, 50; MET>100

Feasibility study of LM0: m0=200, m1/2=160, A0=-400, µ>0,

tan=10 = 150 pb 52.7 GeV endpoint

200pb-1 of 10 TeV data, fit shape: Mll,max = 51.31.5(stat) 0.9(syst)

Opposite sign, ee, Opposite sign, e +

0 02 1 0 0

2 1

p

p

g~

b~

b

b

01~

02~

~

q~

17 December 2009


Future Plans LHC stopped 2009 operations yesterday, Dec-16 A short shutdown follows for XMAS and to complete

commissioning of the LHC quench protection system in January

CMS will use the short shutdown for maintenance Replacement of cooling circuit connections on endcaps

We resume operations in Feb-2010 with operations at a 3.5 TeV beam energy

Deemed safe with remaining anomalous resistance in some splices between magnets

Possible step-up to 4 to 5 TeV beam energy after ~3 months, requiring one month to reestablish physics, and running another 4-5 months

Heavy ion collider run for 1 month at end

17 December 2009


Conclusions After a long road of design, construction, and commissioning the

CMS experiment and the LHC are here! All detector systems are operational Excellent synchronization, alignment and calibration precision

achieved using cosmic rays and initial beam data Achieved high operational data-taking efficiency Recorded data from cosmic muons, “beam splashes”,

and collisions at 900 and 2360 GeV (& many known resonances seen!)

CMS is ready for physics !

Backup

17 December 2009


The Large Hadron Collider (LHC) 27 km ring 7 TeV maximum

beam energy 3.5 TeV for start

of 2010 0.45 TeV @ injection

1232 superconducting 8.4T dipole magnets @ T=1.9ºK

4 experiments ATLAS, CMS ALICE, LHCb

First launched Sept.10, 2008

17 December 2009


CRAFT09 Data Acquisition

Efficient running with 80 kHz input rate

All systems in, including Preshower detector

> 4700 applications running on 672 PCs

for High Level Trigger

Huge muon trigger rate, DAQ still ok

17 December 2009


Muon dE/dX Measured in Calorimeters ECAL: Measurement of the

absolute energy loss in PbWO4 as a function of measured muon momentum, compared to calculation

collision

radi

ativ

e

HCAL: Measurement of the energy loss in the barrel hadron calorimeter as a function of measured muon momentum, compared to Monte Carlo

17 December 2009


Silicon Strip Tracker: Signal / Noise

Deconvolution mode is the APV readout mode planned for LHC operation (narrow pulse shaping to minimize pile-up from out-of-time collisions)

Implemented for second half of CRAFT09

The ratio S/N (Peak/Deconvolution) is ~ 1.7 as expected (x1.5 noise and x0.9 signal) and sufficiently high for efficient hit identification

QuickTime™ et undécompresseur

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APV Pulse shape

Peak mode

Deconvolution mode

Change of cosmic trigger typeS

igna

l to

nois

e ra

tio

CMS preliminary

Signal/Noise

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Status and Plans of the CMS Experiment

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