Burkhard Schmidt for the LHCb Collaboration

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.

B. Schmidt LHC performance workshop Chamonix 2012 2

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


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


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


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.

7B. Schmidt LHC performance workshop Chamonix 2012

8

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


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)


Beam losses and luminosity at IR8


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


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


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


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.

13B. Schmidt LHC performance workshop Chamonix 2012

Backup Slides

Beam losses and luminosity at IR8


L= 4x1032/cm2/sBLM~ 1.5x10-6 Gy/sBLM in cell 5 (follows the beam intensity)


Beam losses right of IR8


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


Machine related Issues TAS:

Space is very tight due to compensator magnets (on both sides).

TAN: The situation is much better space wise.


MBXW TCDD/TDI MKI MSI

Burkhard Schmidt for the LHCb Collaboration

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