lhc status, highlights and future plans

LHC Status, Highlights and Future plans

ERICE June 25th 2012Philippe BLoch

Cern

Luminosity of LHC

N = number of protons per bunch. Given by injector chain

currently up to 1.6 1011 protonsen = normalized emittance. Given also by injector chain

currently about 2 mmkb = number of bunches. Depends on bunch spacing

currently 50ns -> kb = 1331b* = beta function at collision point ; limited by triplet aperture

currently b* = 0.6 mf = revolution frequency = 11245 Hz. Can not be changed g = E/m given by beam energy F = correction factor <1, depends on crossing angle and beam separation (if different from 0)

correlated

pp: situation in 2011

14/03/11 04/04/11 25/04/11 16/05/11 06/06/11 27/06/11 18/07/11 08/08/11 29/08/11 19/09/11 10/10/110

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Operational performance

June 4th 2012 Paul Collier – LHC: Status, Prospects and Plans{lans 4

• Operational robustness– Precycle, injection, 450 GeV, ramp & squeeze & collisions

routine• Machine protection

– superb performance of machine protection and associated systems

– Rigorous machine protection follow-up, qualification and monitoring

– Routine collimation of 110 MJ LHC beams without a single quench from stored beams.

100 MJ enough to melt 150 Kg of CopperMust be dumped in a single turn 88 ms

What we learnt in 2011 The LHC injectors can provide a significantly higher

brightness beam than foreseen ( for 50ns bunch spacing)

The LHC can handle very high bunch intensities ➥ head-on beam beam not a significant problem (yet)

The control of the machine parameters and the quality of the alignment means that the available aperture in the triplets is higher than expected ➥ can be used for larger crossing angle, or lower b*➥ Partially exploited already during 2011 to go from

1.5m down to 1m

Electron cloud

Threshold effect leads to build up of electrons inside the vacuum chamber: Heat load (in cold sections), Vacuum pressure rise and beam becomes instable

The main solution is to condition the surface by electron bombardment – “scrubbing”. Very effective – but takes significant amounts of dedicated beam time

50ns bunch spacing did not require too much fight against electron cloud

➥ Electron cloud more of a problem for 25ns beams in LHC (and SPS)

➥ “Memory” is kept after scrubbing

Tests showed that the situation with 25 ns is much more difficult.

2012 Bunch Spacing – 50ns vs 25ns

50ns Operationally in good shape

25ns Not yet used operationally

Can fit 1380 bunches into the LHC

Injectors can provide very high intensity per bunch at low emittance: 1.6x10+11, e =2.0mm

Problems with electron cloud instabilities are much less apparent No need for a significant

period of dedicated “scrubbing” Smaller Emittance means larger

aperture – can run with b* = 0.6m

Can fit 2748 bunches into the LHC

Injectors cannot provide as high brightness bunches:

1.2x10+11, e = 3.0mm

Emittance growth and lifetime problems due to e-cloud effects are very strong A week of dedicated

“scrubbing” needed. Larger emittance means that the

b* is limited to 0.9mspacing 50 ns 25 ns

Peak Luminosity 6.8 1033 cm-2 s-1 4.2 1033 cm-2 s-1

Integrated lumi > 15 fb-1 ~ 10 fb-1

<Pile-up> 34 10

Chosen 50 nsfor 2012

Peak Luminosity Evolution (so far)

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Impressive Ramp-up!

The injectors are important!

Back in business – but

it is not all plain sailing!

Should never have Stopped!

1-Apr 11-Apr 21-Apr 1-May 11-May 21-May 31-May 10-Jun0

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Peak luminosity6.76 1033 cm-2 s-1

Production Running : up to 19th June

Last week before MD: 1.3 fb-1/week

Assumes 0.84 fb-1/week

Living with high pileup

ATLAS

CMS

11

Performance for physics objects largely recoveredusing tracks techniques such as assignment to vertices and subtraction techniques

The present Physics Landscape

A personal and very biased choice of some recent physics highlights(Very often the same or complementary information has been obtained in several experiments)

Much more in dedicated lectures• P.Jenni : ATLAS• J.Virdee : CMS• P. Giubellino ALICE

1: Understanding the proton as a wholeTOTEM & ALPHA Experiments

Specific runs with high b (90m, 500m in the future) to measure elastic cross section

Low uncertainty : important for extrapolations

2: Testing every corner of the Standard Model

Precision tests of the SM may allow finding deviations linked to higher order processes involving New Physics

Examples: Cross SectionsPrecise (re)measurement of EW

parametersHelicity propertiesCP violation in BsRare decays….

PDG : 0.23108 ± 0.00005

t polarisation in W decay(through r polarisation)

Constraints on proton PDFsExample:

20

Rare decays : Bs->mm

Bs m+m- strongly suppressed in SMPredicted BR = (3.2 ± 0.2) 10-9 *

very sensitive to new physics

World-best limit set:BR < 4.5 × 10-9 LHCb (at 95% CL) < 7.7 × 10-9 (CMS arXiv:1203.3976) < 22 × 10-9 (ATLAS CONF-2012-010)

Combination BR < 4.2 × 10-9 (at 95% CL)

[JHEP 1010 009]

Bs m+m- candidate

CP violation in Bs mixing

Results correlated with DGs = width difference of the Bs mass-eigenstates plotted as contours in (fs vs DGs) plane• LHCb result consistent with Standard Model fs = -0.036 ± 0.002

rad First significant direct measurement of DGs = 0.116 ± 0.018 ± 0.006 ps-1

• fs also measured in a second mode: Bs J/y f0 Combined result: fs = -0.002 ± 0.083 ± 0.027 rad

Analogous to sin2b mesured in Bd->J/y Ks

Here Bs->J/y f

LHCb results provide strong constraints on possible models for new physicslimit on Bs m+m- constraining SUSY at high tan band combination of Bs m+m- and fs restricting various models:

[D. Straub, arXiv:1107.0266][N. Mahmoudi, Moriond QCD]

Impact of Bs results

(fs)

Direct exclusion(CMS 4.4 fb-1)B s

m+m-

(LHCb 1 fb-1 )

A surprise ? CPV in Charm decay• Expected to be small in the SM (< 10-3)• Enormous statistics available:

> 106 D0 K+K- from D*+ D0 p+

Charge of p from D* determines D flavour• DACP = difference in CP asymmetry

for D0 K+K- and D0 p+p-

Robust: detection and production asymmetries cancel (at first order)DACP = (-0.82 ± 0.21 ± 0.11)% Zero CPV is excluded at 3.5 s

• Before the LHCb result: “CP violation…at the percent level signals new physics” [Y. Grossman, arXiv:hep-ph/0609178] (and many others)

After: “We have shown that it is plausible that the SM accounts for the measured value… Nevertheless, new physics could be at play” [J.Brod et al, arXiv:1111.5000]

3: Searching for the HiggsStatus with full 2011 dataset

• SM Higgs boson excluded with 95% cl up to a mass of 600 GeV except for the window 122.5 to 127.5 GeV

• Interesting fluctuations around masses of 124-126 GeV

2012 run 8 TeV, expect ~15fb-1

First 6fb-1 will most probably be disclosed next week at ICHEP12

SM-Higgs Boson up to a mass of some 600 GeV will either be discovered or ruled out until end 2012

• Finding the Higgs Boson would be a fantastic discovery, awaited since ~45 years

• Not finding the Higgs would be an even greater surprise (probably more difficult to explain to the public and our financing agencies…)

x2 more luminosity recordedEfficiencies increased

More news in a couple of days(4th July 9.00)

Stay tuned

4: direct searches for BSM Physics

We know that even with the Higgs, the SM is incompleteNeutrino Masses (ESM)Dark MatterInclusion of Gravity in the pictureHierarchy

But it resists very strongly !

5: Exploring the Quark Gluon Plasma

Great complementarity + collaboration among experiments

+ LHCf p0 data h from 8.9 to 11

All these results are obtained due to the 3 components exceeding their expected performance

– The LHC accelerator with brighter beams than expected and efficiency (37% stable beam in 2012 ) x ~2 more than assumed

– The experiments with unprecedented efficiency (> 95%) and coping with a pileup in excess of what was foreseen for design luminosity (~20)

– The computing GRID which exceeds also the transfer and processing rates

A look at the LHC future

Predictable future (2012-2030)Long term (> 2030)

The predictable future: LHC Time-line

~2022

2018

2013/14

2009 Start of LHC

Run 1: 7 TeV centre of mass energy, luminosity ramping up to few 1033 cm-2 s-1, few fb-1 delivered

2030 Next machine ?

Phase-II: High-luminosity LHC. New focussing magnets and CRAB cavities for very high luminosity with levelling

Injector and LHC Phase-I upgrades to go to ultimate luminosity

LHC shut-down to prepare machine for design energy and nominal luminosity

Run 4: Collect data until > 3000 fb-1

Run 3: Ramp up luminosity to 2.2 x nominal, reaching ~100 fb -1 / year accumulate few hundred fb-1

Run 2: Ramp up luminosity to nominal (1034 cm-2 s-1), ~50 to 60 fb-1

Post Shut Down performance (t.b.c)

25ns nominal 50 ns 25 ns low emittance t.b.c

Energy TeV 6.5 6.5 6.5Bunch intensity x 1011

1.15 1.7 1.15

Emittance 2.8mm 2.1mm 1.4 mmb* 50 50 50Peak Luminosity 1.2 e34 1.7 e34 leveled

0.9e342.2 e34

<Pileup> 28 76 leveled 40 46Int Lumi /year fb-1 32 40-50 57

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Average no levelAverage level

Depends on • Electrons cloud • Electronics radiation hardness –SEU’s• Emittance growth• …..Wait and see !

Ultimate step : HL-LHC for 2022

Cannot reduce the bunch spacing – stick with 25ns

(50ns), 2808(1404) bunches

Work on the injectors (and LHC) to increase the beam brightness

N/en

Decrease the b* to 10-20 cm

Implies new large aperture final focus quads but also implies lower value of Rθ

Use Crab cavities to recover the geometric

reduction factor – and as a mechanism for

Leveling

Goal is to reach >250 fb-1 per year and run until 2030

The predictable future: LHC detectors Time-line

~2022

2018

2013/14

2009 Start of LHC

2030

Consolidation of Infrastructure for allCMS 4th Muon station forward New reduced diameter Be beam pipes CMS & ATLASATLAS : new pixel internal layer (IBL)

ATLAS: Upgrade Trigger, new small Muon wheels, FTK trigger, Forward physicsCMS : Upgrade Trigger, New pixel detector, New photosensors for HCAL, Forward

Muon chambersLHCb : Upgrade FE electronics: New 40 MHz readout, x10 luminosity ! ALICE : New vertex detector (ITS), faster TPC, DAQ,….

ATLAS: New central Tracker + …?CMS : New central Tracker + ….LHCb : continue until 50 fb-1

ALICE : continue until 10 nb-1

• LHeC (medium term) ?• High Energy LHC ?

The longer term future

LHeC: electron-proton colliderRR LHeC:new ring in LHC tunnel,with bypassesaround experiments

RR LHeCe-/e+ injector10 GeV,10 min. filling time

LR LHeC:recirculatinglinac withenergy recovery,or straightLinac 60 GeV

√s ≥ 1.3 TeV

LHeC physics• Precise measurement of structure functions in a

domain relevant for LHCflavour content of proton for all flavours

(u,d,c,s,b,t) and for the antiquarks• Precise measurement of EW (ex: sin2 qW) or QCD

(ex: aS) parameters• Very low x (saturation) domain• BSM search in specific domains (right handed

currents, excited leptons, 1st gen, leptoquarks,..) • eA physics

CDR (physics + machine) submitted last week : arXiv:1206.2913

HE-LHC

Double (or even x 2.5) LHC energy

16 to 20 Teslas magnet compatible in size with LHC tunnel

HE-LHC parameters

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Possible magnet cross section

HE-LHC – LHC modifications

2-GeV Booster

Linac4

SPS+,1.3 TeV

HE-LHC 2030?

S. Myers ECFA-EPS, Grenoble 47

2012-2013: deciding years….

Experimental data will take the floor to drive the field to the next steps:•LHC results•q13 (T2K, DChooz, RENO, DayaBay,..) ✔•n masses/nature (Cuore, Gerda, Nemo…)•Dark Matter searches•Sky surveys (Fermi, Planck…..)

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European Strategy Update

• Update of Strategy defined in 2007• Process to be launched in the next weeks• Time scale defined by LHC results

– meeting 10-12 September 2012 in Krakow– Finalisation spring 2013

In conclusion

Hard work and a lot of good results Integrated luminosity records Great Performance of accelerator & experiments Grid computing outperforming its specs So, what’s next ?

(Courtesy of S. Bertolucci)