Transcript Will LHCb be running during the HL-LHC era? Burkhard Schmidt for the LHCb Collaboration Helpful discussions with L.

Will LHCb be running
during the HL-LHC era?
Burkhard Schmidt for the LHCb Collaboration
Helpful discussions with L. Rossi and several other
colleagues from the machine acknowledged
Outline:
• Introduction and Physics Motivation
YES
• LHCb Detector and Trigger Upgrade
• Machine related issues to the LHCb upgrade
• Conclusions

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

LHCb performs precision measurements of CP
asymmetries and investigates potential effects of
physics beyond the Standard Model.
Discover New Physics through
indirect effects of new states via
virtual production in loop diagrams.
Sensitive far beyond
direct particle production reach

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.
B. Schmidt
LHC performance workshop Chamonix 2012
3
Example:
 Φs: the Bs mixing phase
from initial measurements
 Tevatron SM discrepancy
resolved
World Best
 Mixing induced CP-Violation in Bs
 Obtained compelling results
 Precision measurements
challenging in the forward region at a hadron collider
▪ Need luminosity
▪ Need a detailed understanding of detector & systematics
Until 2017 (Phase I) :
Observe NP in ϕs if larger than 3 x SM
Upgrade (from 2019):
Beyond SM precision measurement:
σ≈0.006
B. Schmidt
LHC performance workshop Chamonix 2012
4
Present Trigger
hardware
40 MHz
Level-0
μ, had, e, γ




 Must raise pT cut to
stay within 1 MHz
readout limit
Max 1 MHz
HLT1
Final states with muons
Linear gain
Hadronic final states
Yield flattens out

3-4 kHz
Upgrade strategy:
Storage: event size ~50kB
40MHz readout rate
Fully software trigger
20kHz output rate
software
global recon.
To profit of a luminosity of 2 x1033cm-2s-1,
information has to be introduced that is more
discriminating than ET.
B. Schmidt
part. recon.
HLT2
LHC performance workshop Chamonix 2012
5
Calorimeters: replace R/O
Muon System; allmost compatible
New Silicon Tracker
New Vertex
Detector
LHCb Upgrade
L = 2 x1033/cm2/s
collect > 50 fb-1
~5 fb-1/year
√s =14TeV
Outer Tracker: replace R/0
TORCH
•
RICH: change HPD’s to MAPMT’s
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.
B. Schmidt
LHC performance workshop Chamonix 2012
6





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.
B. Schmidt
LHC performance workshop Chamonix 2012
7

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 large
detector occupancy
 25 ns LHC operation is
fundamental
for the LHCb upgrade
B. Schmidt
LHC performance workshop Chamonix 2012
8
Target 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)
B. Schmidt
LHC performance workshop Chamonix 2012
9
Fill 2242 on October 23/24, 2011
L = 4x1032/cm2/s
BLM RS12=1.5x10-6 Gy/s
Courtesy Mariusz Sapinski
B. Schmidt
LHC performance workshop Chamonix 2012
10
Running Sum 12 (84s) for beam loss signal averaged over 5 hours
luminosity of 4 x 1032/cm2/s
• beam 1
limit
Q4 D2
• beam 2
• Dump
Courtesy
Mariusz
Sapinski
BLM close
to beamline
D1 Q3 Q2 Q1
LHCb
 The losses are a factor 10-1000 or more below the dump threshold
 Better knowledge of BLM thresholds is important.
B. Schmidt
LHC performance workshop Chamonix 2012
11

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
 Rotation of the beam-screen in the
triplet by 90o in LS1 would be desirable
B. Schmidt
y m
0.02
0.01
x m
0.03
0.02
0.01
0.01
0.02
0.03
0.01
0.02
LHC performance workshop Chamonix 2012
12
3.5 TeV,
3.5m, sep 2mm,
100 rad

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.
B. Schmidt
LHC performance workshop Chamonix 2012
13
L= 4x1032/cm2/s
BLM~ 1.5x10-6 Gy/s
BLM in cell 5 (follows
the beam intensity)
Courtesy Mariusz Sapinski
B. Schmidt
LHC performance workshop Chamonix 2012
15
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
• beam 1
• beam 2
• Dump limit
Courtesy
Mariusz Sapinski
Q1 Q2
Q3 D1
D2
Q4
LHCb
 The losses are a factor 10-1000 or more below the dump threshold
B. Schmidt
LHC performance workshop Chamonix 2012
16

TAS:
 Space is very tight due to compensator magnets (on both sides).

TAN:
 The situation is much better space wise.
MBXW
B. Schmidt
TCDD/TDI
MKI
LHC performance workshop Chamonix 2012
MSI
17