Diameter 8.5 km Beam energy: 7 TeV Luminosity: Protons/bunch: 1.15x10 11 Bunches: 2808 Bunch spacing: 25 ns

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1 Compact Muon Solenoid o Results and Plans Stephan Linn - Florida International Univ. on behalf of the CMS Collaboration 1

2 Large Hadron Collider Diameter 8.5 km Beam energy: 7 TeV Luminosity: Protons/bunch: 1.15x10 11 Bunches: 2808 Bunch spacing: 25 ns Machine current: 0.5 A Beam Stored energy: 362 MJ Operating temperature: 1.9 K Number of magnets: ~9300 Magnet Stored Energy 8800 MJ Power consumption: ~120 MW Cost: 9.0x10 9 $ 2

3 Magnet Basics o K 8.4T Amps It Interconnected tdin series 3

4 19 Sept 2008 The offending connector in this incident had an estimated resistance of 220 n.the maximum resistance of the remaining 10,000 connections is 3 n 4

5 Phase 1 +2 LHC repairs + cryogenics! S. Meyers - Chamonix

6 Accelerator Progress 10 Sep GeV beams 19 Sep 08 The incident 8D Dec 09118TVb 1.18 TeV beams 15 Oct 10 L=10^32 cm^2 sec^-1 1 Nov 10 45/pb recorded Goal: > 1/fb by Dec 2011 at TeV/beam Then shut down for 1 year to fix all splices. 6

7 Increasing the Luminosity Proton beams are made of bunches with N=10^11p 1/f=k* 25ns R=20 m L ~ 10^34/sec/cm^s r 2 Rate L r 2 R 20 P 1 N R P N r N R 2 2 L N f 4 R 2 7

8 CMS CMS dwg 8

9 CMS Slice 9

10 Silicon Tracker 10 layers of position measurement. Detectors t are biased silicon diodes. A charged particle elevates a valence band electron to conduction and a current flows. 10,000,000 strips Pitch ~ 50 m On-chip p amplifiers, discriminators, digitizers, and serializers Readout ~ usec 10

11 EM Calorimeters Measure e/ energy JINST 2 P04004 (2007) 11

12 Hadron Calorimeter Hadronic - proton,neutron,pion.. Sampling=100% -> 1 photon/gev Noise=124 MeV -> pedestals Constant=5% -> calibration+e/pi Brass/Scintillator sampling WLS fiber readout Digitize/serialize 25 ns 12

13 Muon Tracker 13

14 Particle Flow Particle flow combines tracking and calorimetry 14

15 Performance 0 K S p 15

16 Standard Model at 7 TeV 16

17 Standard Candle : Jets PRL 101, (2008) 45/pb of 7 TeV data, will probe beyond Tevatron and test QCD at a new energy scale. 17

18 Standard Candle : photons CMS preliminary 2010 PLB 639 (2006) 51 PRD80 (2009)

19 Standard Candle: W 19

20 Standard Candle: Z W/Z Cross sections measurements are now systematic limited. CERN-PH-EP

21 Standard Candles: Top 21

22 Particle Correlations The Ridge 22

23 Resonances Exclude strings M < 2000 GeV Others M < 1000 W,Z, G not sensitive yet 23

24 If quarks are made of smaller things we expect a harder pt spectrum and thus more central events Use the central/forward rapidity bins ratio cancels systematic Compositeness 24

25 Higgs Production gluon fusion section in pb boson fusion Cross radiation 25

26 Higgs Decay G F m 2 f M (h ff ) h 4 2 (h WW ) G F M h

27 Higgs Reach 27

28 The first ZZ -> 4u event QuickTime and a decompressor are needed to see this picture. 28

29 LHC vs TeVatron The 2 TeVatron with 10 fb -1 has the same or greater reach than the LHC at 10 TeV and 1 fb -1 for particles with a qqbar intial state. For some processes it is competitive until 2013 when LHC resumes 29

30 Heavy Ions Pb+Pb 2.75 TeV CMS /Nucleon First Z->ee events observed Evidence of Quark-Gluon Plasma Jet quenching in high centrality events Centrality measures nuclear overlap ~ mult 30

31 Finally LHC is working well. Expect large increase in luminosity. > 1/fb in shutdown and configure for 7 TeV/beam CMS is working well Calibration with Standard model underway 13 publications on data thus far Challenges Understand the effects of high Luminosity ( pileup ) Most analysis systematic limited Much room for analysis optimization Understand backgrounds for Higgs and SUSY 31

32 Reach LHC now What can we discover with 1/fb? Need at least 5 events if it has no background 10 fb cross sections(50% acceptance) Examples of things with no backgrounds: Z -> ee, uu (bump hunting) heavy stable charged particles Things with large cross sections: SUSY (events with excess jets+ large MET) excited quarks to dijets, contact interactions (bump hunting, excess at very high mass) 32

33 Limitation 1: MSSM has 124 parameters. Convenient to use 4-5 msugra parameters: m1/2 -The gaugino g mass m0 -The scalar masses A0 -Soft breaking trilinear coupling constant (higgs- sfermion sfermion) tan = v2/v1 - the ratio of the VEVs of the two Higgs sign( ) - The sign of the Higgsino mass parameter (bilinear higgsino coupling constant) The magnitude of is determined. SUSY Searches: like- sign dilepton 33

34 Limitation 2: Backgrounds unknown Signal Jets +MET High efficiency Large SM backgrounds Plan to use datadriven techniques to determine backgrounds. SUSY Searches - all Hadronic 1/fb can exclude 750 GeV squark and 500 GeV gluino 34