Highlights from the Large Hadron Collider

1. Highlights from the Large Hadron Collider • Physics at the Terascale • The LHC: brief overview and status • The LHC experiments: brief overview and status JosEngelen CERN

2. gauge x8 Standard Model and Beyond(?) H The Higgs sector – ‘the unknown’ The Supersymmetric world? Onesupersymmetric partner for each ‘standard’ particle – the Higgs sector becomes slightly more complicated: 5 supersymmetric Higgs bosons

3. The ‘Standard Model’ • is a wonderful model for describing the fundamental • particles and fields and their interactions, it provides a • quantitative description of all experimental results so far, but: • the model invokes a mechanism for dealing with mass: it is an • empirical fact that certain field particles (W, Z bosons) carry mass, • incorporating this in the theory is highly non-trivial – it requires • the introduction of a new field (Higgs field) and corresponding • particle (‘the Higgs’): this particle has never been found • by an experiment  it will be at the LHC • the model would ‘go wrong’ at high energy without the Higgs • particle (or other ‘new physics’) • ‘unification of forces’ at very high energy could be revealed by • a new trend setting in at LHC energy: ‘supersymmetry’

4. ‘The Terascale’ Based on ‘extrapolations’ from our present understanding and on quite general theoretical insights we expect the ‘new physics’ to manifest itself at an energy around or below 1 Tera-electronVolt = 1012 electronVolt, i.e. at the Terascale accessible at the LHC for the first time (and only at the LHC for years to come!)

5. Quark Gluon Plasma The LHC will also provide PbPb collisions at 574 + 574 TeV allowing unique contributions to the study of a quark gluon plasma

6. Accelerator and Experiments Underground circular tunnel 27 km circum- ference; 100 m underground 4 caverns for experiments () x  CMS BD x x RF * x  LHCb   ALICE ATLAS

7. Accelerator Collisions of 7,000 GeV on 7,000 GeV protons (for reference: proton mass = 1 GeV) Luminosity 1034 cm-2s-1 (collision rate normalized to cross section) Innovations: ‘2 in 1’ superconducting 8.3 T dipoles (operating temperature 1.9K) focusing s.c. quadrupoles Challenges: collimation (350 MJ stored energy per beam, can melt 800 kg of copper) and furthermore the mere size of the system, e.g. more than 33,000 tonnes of ‘cold mass’, 27 km of cryogenic distribution line, etc.

8. Accelerator complex Biggest ring = 27 km circumference (1959)

9. R&D pre- production industrial production 1232 plus spares

10. Van streng tot kabel NiTifilamenten, 7 (geproduceerd via extrusie)

11. In the tunnel Magnet inter- connect Quality control and Quality assurance

12. 13 kA Protection diode Magnet Interconnect 6 superconducting bus bars 13 kA for B, QD, QF quadrupole 20 superconducting bus bars 600 A for corrector magnets (minimise dipole field harmonics) • To be connected: • Beam tubes • Pipes for helium • Cryostat • Thermal shields • Vacuum vessel • Superconducting • cables 42 sc bus bars 600 A for corrector magnets (chromaticity, tune, etc….) + 12 sc bus bars for 6 kA (special quadrupoles)

13. In the tunnel Jumper connecting cryogenic distribution line and magnets (once every ~100 m) (early photo, tunnel practically empty)

14. In the tunnel Beam delivery towards interaction point Current distribution using High Temperature Supercondutor current leads

15. LHC Status • Installation complete • cryogenic distribution line • injection lines • sc dipoles and quadrupoles; interconnect • inner triplets preparing beams for collision • RF stations (sc) for acceleration 450 GeV 7000 GeV • beam dumps • collimation • beam instrumentation • Hardware commissioning • cool-down complete • pressure tests • powering tests • Commissioning with beam • circulating beams • Colliding beams • Restart Spring 2009

16. Start of Operations • The Large Hadron Collider project saw a wonderful • start of operations on September 10, 2008: • LINAC, Booster, PS, SPS were accelerating beam to • 450 GeV for injection into the LHC • The injection lines (TI8, TI2) transported the beam • to the LHC • The injection kickers sent the beam(s) into the LHC • Circulating beams, in both apertures, were established • for the first time, with the whole world looking over • our shoulders, in a matter of hours • The LHC experiments were ready and operational as • planned and recorded beam related (timing!) data • immediately • The Worldwide LHC Computing Grid was up and running

17. Start of Operations During the days following September 10 some unreliable (‘old’) elements of the electrical infrastructure (transformers) had to be repaired/replaced, but the preparations for collisions continued, one other very important milestone was passed easily, not because it was easy but because of excellent preparations: the RF system captured the beam the road to first beam-beam collisions was now fully open

18. Final Hardware Commissioning The magnets in Sector (‘Octant’) 34 had not been commissioned yet to full current for operation at 5 TeV (i.e. commissioning to 5.5 TeV) The 7 other octants of the LHC had been commissioned to 5 TeV (and well above) without problems On September 19 (around 11:18) an incident occurred, leading to a large Helium leak in sector 34 – cold Helium escaped into the tunnel, the insulation vacuum was broken (up to vacuum barriers), the beam vacuum was broken (up to sector valves)

19. Recovery Sector 34 It is now clear that recovery of Sector 34 will take until (‘into’) the planned (and obligatory) Winter shutdown – LHC operations will restart Spring 2009. A precise planning is being worked out. The nature of the incident has been understood – it is due to an electrical fault (resistive splice in interconnect) The loss of the insulation vacuum lead to some collateral damage – the logistics of the repair program are being worked out. Very importantly: diagnostic tools are being designed to avoid such problems in the future

20. Schedule of Experiments The experiments will now go into ‘long shutdown’ mode, to be ready again in early Spring 2009: a more precise date will be agreed with them as soon as this is possible Most experiments have identified a useful and/or necessary program of work of 4 – 5 months: repairs, refurbishments, improvements, additional installation work Everybody involved in the LHC project is as motivated as ever (or more motivated than ever) to overcome this temporary setback! Everybody has reacted professionally and with determination.

21. The successful start-up The behavior of the beams was excellent and understood

22. Cross-section of LHC cryodipole

23. CooldownStatus

24. CooldownStatus

25. RF cavities

26. The RF cavities and transverse dampers Preparation for Beam RF synchronization in place – clocks and timing now going from SR4 to all users. Recent successful dry run tests with all users and OP group, including basic software. Procedures for beam commissioning well defined. Longitudinal diagnostics in good shape to study and commission first beams…. Fibre-optics signal distribution from RF in SR4 to Experiments, BT & BI equipment and to CCC. 40 MHz bunch clocks, revolution frequencies, 40 MHz 7TeV reference. Injection & dump kicker pulses Courtesy Edmond Ciapala

27. Synchronisation Courtesy Roger Bailey

28. Injection Region

29. 08 08 08 Courtesy Roger Bailey

30. First Trajectory

31. Kick response compared with theoretical optics

32. Dispersion 2-3 The trajectory of the off-momentum (1 per mil) beam. On the far left is the end of TI2 where there are no measurements. It goes through LSS2 and Alice with practically zero dispersion. In the arc there is a slight mismatch which is of no consequence and LSS3 it perfectly maps the large dispersion bump from positive to negative that is designed to stop uncaptured particles (which will be lost as the field rises since they are not accelerated) on the collimators. The vertical dispersion (bottom) is zero as it should be.

34. Beam on turns 1 and 2 Courtesy R. Bailey

35. Few 100 turns Courtesy R. Bailey

36. Dump dilution sweep

37. No RF, debunching in ~ 25*10 turns, i.e. roughly 25 mS Courtesy E. Ciapala

38. Capture with optimum injection phasing, correct reference Courtesy E. Ciapala

39. The LHC experiments have seen first ‘man made’ beam

40. ALICE Detector ACCORDE TOF HMPID TRD TPC PMD PHOS ITS Muon arm

41. Injection tests SPD hits versus bunch intensity (beam through ALICE) FMD event display (1 bunch through ALICE, > 100 000 hits) FMD hits versus SPD hits (beam through ALICE) SPD/SSD, Sunday, 15.6 Dump on TED

42. Luminosity monitor (V0) Double turn, beam 1 back at point 2 ! Single turn

43. Beam pick-up T0 SPD V0 Auto-correlation for SPD trigger, with multi-turn correlations (3564 bunch crossings) Trigger timing (before alignment) versus bunch number single shot for SPD, V0, beam-pickup BPTX, T0 triggers

44. First interactions 12th September Circulating beam 2 stray particle causing an interaction in the ITS ITS tracks on 12.9.2008

45. TPC Particle Identification Momentum Resolution Krypton Gain Calibration

46. LHCb Spectrometer OT Muon System Magnet RICH1 VELO RICH2 Calo. System TT

47. SPD (provided trigger) TED events LHCb sees tracks from the LHC injection tests Muon chambers VELO (Run 30933, Event 14) Silicon tracker

48. Beam1 induced OT tracks originating close to the beam pipe

49. Status of ATLAS ATLAS 45 m ATLAS superimposed to the 5 floors of building 40 24 m 7000 Tons

50. Very first beam-splash event seen in ATLAS (as seen online in the ATLAS Control Room) on 10-Sep-2008 at 10:19