Burkhard Schmidt for the LHCb Collaboration
Helpful discussions with L. Rossi and several other colleagues from the machine acknowledged
Will LHCb be running during the HL-LHC era?
Outline: • Introduction and Physics Motivation
• LHCb Detector and Trigger Upgrade
• Machine related issues to the LHCb upgrade
• Conclusions
YES
Will LHCb be running during the HL-LHC era?
LHCb believes there is a strong case for continuing to run beyond LS2 in 2018.
We appreciate that at fixed luminosity the data-doubling time will become long, so we consider it essential to upgrade the experiment to increase the signal rate to storage by an order of magnitude.
The physics case for 50 fb-1 in LHCb has been presented in detail to the LHCC in a Letter of Intent and endorsed by them.
The evidence for CP violation in the charm sector is one of the most important and unexpected results to have come from the LHC so far, and illustrates the potential of probing for new physics in the flavour sector.
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Physics Motivation LHCb performs precision measurements of CP
asymmetries and investigates potential effects of physics beyond the Standard Model.
The LHCb physics program is complementary to the direct searches of ATLAS and CMS. complementary to the physics program of Super-B factories.
LHCb contributes to the diversity of the CERN Physics program.
3
Discover New Physics through indirect effects of new states via virtual production in loop diagrams.
Sensitive far beyond direct particle production reach
B. Schmidt LHC performance workshop Chamonix 2012
Physics motivationExample: Φs: the Bs mixing phase
Mixing induced CP-Violation in Bs Obtained compelling results
from initial measurements Tevatron SM discrepancy
resolved
Precision measurements challenging in the forward region at a hadron collider▪ Need luminosity ▪ Need a detailed understanding of detector & systematics
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Wor
ld B
est
Until 2017 (Phase I) : Observe NP in ϕs if larger than 3 x SMUpgrade (from 2019): Beyond SM precision measurement:
σ≈0.006
LHCb Trigger – key to better performance
5
40 MHz
Max 1 MHz
3-4 kHz
Storage: event size ~50kB
Final states with muons Linear gainHadronic final states Yield flattens out Must raise pT cut to stay within 1 MHz readout limit
To profit of a luminosity of 2 x1033cm-2s-1, information has to be introduced that is more discriminating than ET.
hard
war
e
Upgrade strategy: 40MHz readout rate
Fully software trigger 20kHz output rate
software
B. Schmidt LHC performance workshop Chamonix 2012
Level-0μ, had, e, γ
HLT2global recon.
HLT1part. recon.
Present Trigger
LHCb Detector Upgrade
• Physics program: Wide range with quark flavour physics as main component,
but includes also lepton flavour physics, electroweak physics and exotic searches
General purpose detector in the forward region with 40 MHz readout and a full software trigger. 6
TORCH RICH: change HPD’s to MAPMT’s
New VertexDetector
New Silicon Tracker
LHCb Upgrade L = 2 x1033/cm2/s
collect > 50 fb-1
~5 fb-1/year√s =14TeV
Calorimeters: replace R/O Muon System; allmost compatible
Outer Tracker: replace R/0
B. Schmidt LHC performance workshop Chamonix 2012
LHCb Upgrade The Physics program of LHCb is limited by the detector, not
by the LHC. The detector upgrade allows LHCb to better utilise the LHC
capabilities.
The LOI for the upgrade has been submitted in March 2011 and endorsed by the LHCC in June 2011.
LHCb has been encouraged to proceed preparing TDRs.
LHCb intends to upgrade the detector in LS2, scheduled for 2018, and to take data for about 10 years afterwards.
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Luminosity and Pile-Up LHCb design: L ~ 2x1032 cm-2 s-1 at √s of 14TeV
with 25 ns BX interactions / bunch crossing µ = 0.4
LHCb operation in 2011: L up to 4 x 1032 cm-2 s-1
at √s of 7 TeV with 50 ns BX µ = 1.6 LHCb upgrade: L > 2 x 1033 cm-2 s-1 at √s of 14TeV
with 25 ns BX µ = 4
With 50ns BX the average pile-up would be up to 8, which leads to a too largedetector occupancy
B. Schmidt LHC performance workshop Chamonix 2012
25 ns LHC operation is fundamental
for the LHCb upgrade
Machine related IssuesTarget Absorber for Secondaries (TAS): The high luminosity insertions at IP1 and IP5 are equipped with a TAS
and a TAN to protect the triplet quadrupole magnets and other machine elements from particles leaving the IP.
Would a TAS/TAN be needed in IP8 for the envisaged luminosity increase to 2 x 1033/cm2/s? Good knowledge of BLM thresholds around IP8 is important. Detailed FLUKA simulations are needed.
A first glance at the issue of the TAS: Look at beam losses up- and down-stream of IP8 for a fill in 2011
where the luminosity has been 4x1032/cm2/s in LHCb (at √s of 7 TeV). Factor 5 below maximum luminosity for the upgrade, and factor 2 less in energy Factor 4 is needed to take into account the difference between L peak and L Level
How far are we from the threshold causing a beam dump? (which is at ~30% of the quench limit)
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Beam losses and luminosity at IR8
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L = 4x1032/cm2/sBLM RS12=1.5x10-6 Gy/s
Courtesy Mariusz Sapinski
Fill 2242 on October 23/24, 2011
Beam losses left of IR8
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LHCbQ4 D2 D1 Q3 Q2 Q1
• beam 1 • beam 2 • Dump limit
Running Sum 12 (84s) for beam loss signal averaged over 5 hours luminosity of 4 x 1032/cm2/s
The losses are a factor 10-1000 or more below the dump threshold Better knowledge of BLM thresholds is important.
BLM close to beamline
Courtesy Mariusz Sapinski
Machine related Issues R2E issues (M.Brugger):
Relocation of some equipment is foreseen in LS1. More simulations are needed to determine whether other
equipment needs to be mitigated. Cable length to be checked.
Safe room needs to be reviewed.
Aperture and Beam-Screen (LBOC 24.o1.12, R. Bruce et al.): Beam screen orientation is optimized for external horizontal crossing angle. Move to vertical crossing angle this year
Aperture should give no problems at top energy Aperture at injection more problematic
450 GeV, beta*=11m, 170urad H 3.5 TeV, beta*=3m, 100urad V
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0.03 0.02 0.01 0.01 0.02 0 .03x m
0.02
0.01
0.01
0.02
y m
450 G eV, 11m, sep 2mm, 170rad
3.5 T eV , 3.5m, sep 2mm, 100rad
Rotation of the beam-screen in the triplet by 90o in LS1 would be desirable
Conclusions LHCb submitted an LOI to the LHCC in March 2011 and
has a firm plan to upgrade the detector by 2018 LHCC considers “the physics case compelling” and the 40 MHz readout as the
right upgrade strategy. LHCC encouraged LHCb to prepare a TDR as soon as possible.
Given its forward geometry, its excellent tracking and PID capabilities and the foreseen flexible software trigger, the upgraded LHCb detector is an ideal detector for the next generation of flavour physics experiments provides unique and complementary possibilities for New Physics studies.
LHCb intends to run for about 10 years after the upgrade and relies on 25 ns LHC operation, luminosity levelling, equal amounts of data for the two spectrometer magnet polarities.
First discussions with the machine in relation to the upgrade took place and we intend to continue them in view of the TDRs under preparation.
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Backup Slides
Beam losses and luminosity at IR8
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L= 4x1032/cm2/sBLM~ 1.5x10-6 Gy/sBLM in cell 5 (follows the beam intensity)
Courtesy Mariusz Sapinski
Beam losses right of IR8
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LHCb Q1 Q2 Q3 D1 D2 Q4
• beam 1 • beam 2 • Dump limit
Running sum 12 (84s) for beam loss signal averaged over 5 hours in fill 2242 on October 23/24 with stable luminosity of 4 x 1032/cm2/s
The losses are a factor 10-1000 or more below the dump threshold
Courtesy Mariusz Sapinski
Machine related Issues TAS:
Space is very tight due to compensator magnets (on both sides).
TAN: The situation is much better space wise.
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MBXW TCDD/TDI MKI MSI