Transcript LHC Status, Highlights and Future plans ERICE June 25th 2012 Philippe BLoch Cern Luminosity of LHC N = number of protons per bunch.

LHC
Status, Highlights and Future plans
ERICE June 25th 2012
Philippe BLoch
Cern
Luminosity of LHC
N = number of protons per bunch. Given by injector chain
currently up to 1.6 1011 protons
en = normalized emittance. Given also by injector chain
currently about 2 mm
kb = number of bunches. Depends on bunch spacing
currently 50ns -> kb = 1331
b* = beta function at collision point ; limited by triplet aperture
currently b* = 0.6 m
f = revolution frequency = 11245 Hz. Can not be changed
 = E/m given by beam energy
F = correction factor <1, depends on crossing angle and beam
separation (if different from 0)
pp: situation in 2011
4000
3500
1400
Peak luminosity
kb
1200
2500
50 ns
1000
500
Increase
Number of
Bunches
Emittance
Reduction
(Injectors)
MD, technical stop
1500
MD, technical stop
2000
MD, technical stop
Mini-Chamonix
800
75 ns
600
400
b* = 1m
200
0
0
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 10/10/11
Number of Bunches
1000
Intermediate energy run,
technical stop, scrubbing
Peak Luminosity / 10+30 cm-2 s-1
3000
Operational performance
• 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 Copper
Must be dumped in a single turn 88 ms
June 4th 2012
Paul Collier – LHC: Status, Prospects and Plans{lans
4
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
25ns
 Operationally in good shape
 Not yet used operationally
 Can fit 1380 bunches into the LHC
 Can fit 2748 bunches into the LHC
 Injectors can provide very high
intensity per bunch at low
emittance: 1.6x10+11, e =2.0mm
 Injectors cannot provide as high
brightness bunches:
1.2x10+11, e = 3.0mm
 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
 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 0.9m
spacing
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 ns
for 2012
Peak Luminosity Evolution (so far)
7000
1200
Should
never have
Stopped!
Impressive
Ramp-up!
1000
in
Peak Back
luminosity
business
6.76
1033 cm–-2but
s-1
4000
3000
2000
1000
0
1-Apr
it is not all
plain sailing!
MD, Technical Stop
Luminosity / 10+30 cm-2 s-1
5000
11-Apr
21-Apr
800
600
The
injectors are
important!
400
200
1-May
11-May
21-May
31-May
0
10-Jun
Number of Bunches
6000
1400
Production Running : up to 19th June
Assumes 0.84 fb-1/week
Last week before MD:
1.3 fb-1/week
Living with high pileup
CMS
ATLAS
Performance for physics objects
largely recovered
using tracks techniques such as
assignment to vertices and
subtraction techniques
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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 whole
TOTEM & 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 Sections
Precise (re)measurement of EW parameters
Helicity properties
CP violation in Bs
Rare decays
….
PDG : 0.23108 ± 0.00005
t polarisation in W decay
(through r polarisation)
Constraints on proton PDFs
Example:
Rare decays : Bs->mm
Bs  m+m- candidate
Bs  m+m- strongly suppressed in SM
Predicted BR = (3.2 ± 0.2)  10-9 *
very sensitive to new physics
[JHEP 1010 009]
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)
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CP violation in Bs mixing
Analogous to sin2b
mesured in Bd->J/y Ks
Here Bs->J/y f
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
Impact of Bs results
LHCb results provide strong constraints on possible models for new physics
limit on Bs  m+m- constraining SUSY at high tan b
and combination of Bs  m+m- and fs restricting various models:
[N. Mahmoudi, Moriond QCD]
[D. Straub, arXiv:1107.0266]
Direct exclusion
(CMS 4.4 fb-1)
(fs)
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+pRobust: 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 Higgs
Status 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…)
4: direct searches for BSM Physics
We know that even with the Higgs, the SM is incomplete
Neutrino Masses (ESM)
Dark Matter
Inclusion of Gravity in the picture
Hierarchy
But it resists very strongly !
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The
g+ (
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
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
2013/14
LHC shut-down to prepare machine for design
energy and nominal luminosity
Run 2: Ramp up luminosity to nominal (1034 cm-2 s-1), ~50 to 60 fb-1
2018
Injector and LHC Phase-I upgrades to go to ultimate luminosity
Run 3: Ramp up luminosity to 2.2 x nominal, reaching ~100 fb-1 /
year accumulate few hundred fb-1
~2022
Phase-II: High-luminosity LHC. New focussing magnets and
CRAB cavities for very high luminosity with levelling
Run 4: Collect data until > 3000 fb-1
2030
Next machine ?
Post Shut Down performance (t.b.c)
25ns nominal
50 ns
25 ns low
emittance t.b.c
Energy TeV
6.5
6.5
6.5
Bunch intensity x
1011
1.15
1.7
1.15
Emittance
2.8mm
2.1mm
1.4 mm
b*
50
50
50
Peak Luminosity
1.2 e34
1.7 e34 leveled 0.9e34
2.2 e34
<Pileup>
28
76
46
40-50
Depends on
• Electrons cloud
• Electronics radiation hardness –SEU’s
• Emittance growth
• …..
Wait and see !
57
103535- no level
Luminosity (cm-2 s-1)
Int Lumi /year fb-1 32
leveled 40
Level at 5 10
34
1.E+35
8.E+34
6.E+34
4.E+34
Average
no level
Average level
2.E+34
0.E+00
0
5
10
15
time (hours)
20
25
Ultimate step : HL-LHC for 2022
Work on the injectors (and
LHC) to increase the beam
brightness N/en
Cannot reduce the bunch
spacing – stick with 25ns
(50ns), 2808(1404) bunches
N kb f g
L=
R
* q
4pen b
2
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
2009
2013/14
2018
~2022
2030
Start of LHC
Consolidation of Infrastructure for all
CMS 4th Muon station forward
New reduced diameter Be beam pipes CMS & ATLAS
ATLAS : new pixel internal layer (IBL)
ATLAS: Upgrade Trigger, new small Muon wheels, FTK trigger, Forward physics
CMS : Upgrade Trigger, New pixel detector, New photosensors for HCAL, Forward
Muon chambers
LHCb : 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
The longer term future
• LHeC (medium term) ?
• High Energy LHC ?
LHeC: electron-proton collider
RR LHeC:
new ring in
LHC tunnel,
with bypasses
around
experiments
LR LHeC:
recirculating
linac with
energy
recovery,
or straight
Linac 60 GeV
RR LHeC
e-/e+ injector
10 GeV,
10 min. filling time
√s ≥ 1.3 TeV
LHeC physics
• Precise measurement of structure functions in a
domain relevant for LHC
flavour 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
44
Possible magnet cross section
HE-LHC – LHC modifications
HE-LHC
2030?
SPS+,
1.3 TeV
2-GeV Booster
Linac4
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…..)
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
49
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)