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CERN/LHCC-2019-016

LHCC-140

November 2019

LARGE HADRON COLLIDER COMMITTEE

Minutes of the one-hundred-and-fortieth meeting held on

Wednesday and Thursday, 20-21 November 2019

OPEN SESSION – STATUS REPORTS

1. LHC Machine Status Report: Jose Miguel Jimenez

2. ALICE Status Report: Maximiliano Puccio

3. ATLAS Status Report: Dominik Derendarz

4. CMS Status Report: Laurent Thomas

5. LHCb Status Report: Nicole Skidmore

6. TOTEM Status Report: Diego Figueiredo

7. FASER Status Report: Brian Petersen

CLOSED SESSION:

Present: H. Burkhardt, V. Beckmann, R. Calabrese, G. Casini, F. Di Lodovico, J. Dunlop,

E. Elsen, E. Kajfasz, M. Krammer, P. Krizan, K. Krüger, M. Kuze, A. Kuzmin,

F. Moortgat, M. Morandin, P. Pakhlov, P. Salabura, C. Sfienti, F. Simon

(Chairperson), S. Smith, B. Panzer-Steindel, B. Petersen, D. Waters, T. Wengler

(Scientific Secretary), H. Wilkens, W. Wisniewski, E. Worcester

Excused: D. Glenzinski, M. Mangano

1. Procedure

The chairperson welcomed the committee members, in particular Elizabeth Worcester

(BNL) and Pavel Pakhlov (Lebedev), who are joining the committee. He also thanked

Peter Krizan and Alexander Kuzmin, who will finish their respective terms on the

committee after the present session of the LHCC, for their dedication and many

contributions to the work of the committee. The minutes of the previous session were

already approved by email. The chairperson reminded the committee that there will be a

meeting between the experiments and the CERN management on November 27th to

clarify the schedule for both LS2 and LS3. The LHCC supports both a delay of LS3 to

enable the success of the Phase-II upgrades and a slight extension of LS2, in order to

mitigate risks within the ongoing upgrade and maintenance projects. The chair

emphasized that the physics potential of Run 3 needs to be preserved, by increasing the

energy, to 14 TeV if possible, and aim for an integrated luminosity about twice that of

Run 2. The chair also introduced the provisional main agenda points for the next session

of the LHCC and reminded the committee that next year the submission of two further

Phase-II TDRs is expected.

– 2 –

2. Report from the Director of Research and Computing

The Director of Research and Computing (DRC) reported on issues related to the

European Strategy process, the LHC and CERN in general. Good progress has been made

on the MoUs for the Phase-II upgrades. An important milestone was the agreement of

the funding agencies to use Hamamatsu as the sole provider of silicon sensors, based on

the excellent reputation this vendor has in the field. The DRC reported, that ATLAS,

after extensive consultations within the collaboration and with the CERN management,

has decided to stop the FTK Phase-I upgrade project. Details are given in the ATLAS

section below. The DRC points out that many issues with this project have been pointed

out and tracked by the LHCC over the duration of the project and emphasized the

importance of the LHCC and P2UG in ensuring the ongoing upgrade projects will be

successfully completed. Plans for the future of computing in high energy physics are

developing, but there are still many unanswered questions and uncertainties. It seems

clear that the community needs to be prepared to operate on a number of different

computing architectures, that will also develop over time, in order to obtain sufficient

computing resources. The DRC reported that there has been progress on detailing the

Hostlab responsibilities over the coming years, with the corresponding document

expected to be available shortly. On the European Strategy discussions are continuing,

using the Briefing Book produced by the strategy group as a basis. There is a clear desire

to build an e+e- Higgs factory, however it still remains to be decided how to achieve it.

On the long term there is also a clear mandate for CERN to pursue the energy frontier.

The DRC stressed that apart from gathering knowledge, science also has an important

role as a global communicator and is widely seen as a way to collaborate across national

and cultural boundaries. The DRC reported on renewed discussions with Russia,

investigating the possibility of an eventual full membership, and on the increasing

collaboration with not only the IHEP, but also other institutes in China.

3. Report from the LHC Programme Co-ordinator

The possibility of injecting Oxygen into the LHC continues to be studied and North Area

fixed target experiments have now also expressed their interest in such beams. A formal

working group to study Oxygen injections has been set up by the IEFC and is ramping

up its activities. It will assess the changes required in the injector chain in order to

produce safely and efficiently oxygen ions out of the SPS. The final report is expected

in February 2020.

The beam energy for an Oxygen-Oxygen run is under discussion with ATLAS, CMS and

ALICE. The preferred scenario is running at the same energy per nucleon as in PbPb in

order to be able to use the same proton-proton reference run and compare directly to

PbPb without any extrapolation. However, this would require an additional 2-3 days of

optics setup and validation, extending the length of such a run to about 10 days. It would

also lower the beam energy for a proton-Oxygen run which is in conflict with the LHCf

request for maximum energy to reach the highest possible cosmic ray equivalent

energies. An alternate solution exists but would result in reduced proton-Oxygen

luminosity for ALICE. In either solution the beam energy would not match any existing

proton-proton reference data.

Preparation of the proton-proton beam configuration for Run 3 continues and the first set

of optics files has been made available to the experiments. These will need to be checked,

particularly by the experts of the forward physics detectors which are sensitive to optics

– 3 –

changes. A first rough plan for the 2021 beam recommissioning has been prepared. It

estimates about 10−1+2 weeks for beam commissioning independent of the collision

energy. The first stable beam at 450 GeV could be available after about five weeks of

beam recommissioning and be used for early detector commissioning, while the first

stable beams at top energy are expected two weeks later.

4. Test Beams

The upgrades and consolidation of the injectors as well as the renovation of the East and

North experimental areas are progressing according to schedule, aiming at a restart of the

test beams early Q2 2021. A follow-up proposal to the AIDA-2020 project is being

prepared for submission to an upcoming call within the current EU framework program.

It will contain a significant work package for the upgrades of the existing EUDET/AIDA

telescopes with high rate planes, and fine time resolution planes, as well as common

infrastructure for testing irradiated sample in cold environments.

5. Discussion with ALICE

Scientific output and current activities:

ALICE continues to make excellent progress on its physics programme, with 19

papers submitted since the last session of the LHCC, bringing the total number of

publications to 283. A total of 27 talks and 68 posters were presented at the recent

Quark Matter 2019 conference, including several preliminary results. Recent

results include new measurements of the centrality and transverse momentum

dependence of inclusive J/ production in PbPb collisions at √sNN = 5.02 TeV,

measurements of the Production of (anti-)3He and (anti-)3H in pPb collisions at

√sNN = 5.02 TeV and a study of underlying event properties in pp collisions at

√s = 13 TeV.

The LS2 activities are progressing well. The TRD rework as well as reinstallation

of CPV, PHOS and DCAL have been completed. Service installation is also

progressing well. As of today, 4 weeks of delay were accumulated with respect to

the original LS2 plan.

Phase-I upgrades:

Good progress has been reported for the Muon tracking system. The first batch of

FLEX (about 2/3 of the full production) has been delivered at CERN on November

13th, amounting to an additional four weeks delay with respect to the original

schedule. The assembly and pre-commissioning of the full Station 3 is

nevertheless expected by the end of the year by carrying out mounting of

components and commissioning in parallel. The schedule for installation and

commissioning of Station 4 and 5 thus remains unchanged with respect to the last

LHCC.

All TPC ROCs have been installed with two weeks delay due to a sector

replacement. FEC installation has been completed. Field cage and GEM-HV

power tests have been successfully completed. Filling with the final gas

composition is ongoing and first results on the pre-commissioning will be

available by the end of November.

Production and test of the European batch of CRUs (232 in total) has been

completed. The production of the remaining 290 CRUs has now been moved to

– 4 –

Europe: delivery and test of 40 CRU/week is expected from April 2020 such that

no delay of the overall ALICE upgrade schedule is expected.

All 4 IT-modules of CR0 have been installed. A full-load test has demonstrated

that the cooling power is sufficient to cool the maximum load for ALICE. Work

on the control system to cope with large load variations expected for GPUs is still

to be completed. A vertical slice of the Event Processing Node (EPN) farm is being

installed in preparation for a slice test. Benchmark tests on AMD GPUs are still

ongoing (compiler issues) and the PRR for the EPN has been postponed by at least

one month. As reported during LHCC 139, the TPC cluster finding will be

performed on EPN GPUs rather than in the CRU FPGAs, which are needed for

zero suppression. This is expected to require up to 550 additional GPUs. Small

deviations between CPU and GPU results on TPC cluster finding when GPU

optimisation is switched on are under investigation.

A delay of about three months has been reported for the PRR of the FIT

electronics. The installation schedule still foresees sufficient contingency.

The LHCC congratulates ALICE on its continuing rich physics output and for

the progress made on its upgrade programme and in preparing for Run 3.

The LHCC congratulates ALICE for the progress made on the Muon system and

TPC and expects an update on the pre-commissioning of the TPC and Muon

Station 3 by the next LHCC.

The LHCC acknowledges the progress on the O2 system and is looking forward

to an update on the EPN farm progress at the next session.

Following the delay reported on the PRR for the FIT electronics, the LHCC

requests a complete status report at the next LHCC.

In case LS2 is prolonged, the LHCC encourages ALICE to keep the present

schedule and use the additional time for extended global commissioning.

The LHCC acknowledges the plan of ALICE to build a forward calorimeter

(FOCAL) to be implemented during LS3. ALICE internal technical and resource

reviews are ongoing. If the plan is endorsed by the ALICE collaboration an LoI

will be delivered at least three weeks ahead of the next session of the LHCC.

6. Discussion with ATLAS

Scientific output and current activities:

ATLAS continues to deliver high quality physics results, with 895 papers

submitted to date, including 15 since the last LHCC. Recent new results include a

test of CP invariance in VBF production of the Higgs boson, new measurements

of the J/ and (2s) production cross sections and a determination of the top mass

with an uncertainty of only 0.45%.

Work on refurbishment of detectors (electronics, gas leaks) is progressing well on

Liquid Argon, Tile Calorimeter and Muon system (RPC). The inner detector has

undertaken a successful two-week technical run, using the thermosiphon cooling

for pixel and SCT. An increase of the leak rate in the TRT following a power cut

is under investigation.

– 5 –

Phase-I upgrades:

The Phase-I upgrades for LAr and TDAQ are making good progress. Most of the

delays accrued thus far do not appear to threaten the timely completion of these

upgrades. The status of L1Calo eFEX is of some concern and requires continued

vigilance.

After extensive consultations within the collaboration and with the CERN

management, ATLAS has decided to stop the FTK Phase-I upgrade project. Many

complex technical challenges have been accomplished in this project, such as the

design, production and testing of the main associative memory chip AM06. As

observed in previous LHCC meetings, the project was very delayed, and many

issues mainly related to firmware remained unsolved. At the same time the

planning for the Run 3 running conditions and the increased power of the ATLAS

high-level trigger farm have diminished the need for the FTK system. The

resulting lower priority has made it impossible to find the needed additional

resources to pursue the project.

The NSW has continued to make progress. However, the project remains on the

critical path for installation in LS2. An ATLAS internal readiness review was held,

leading to a best estimate for NSW-A completion on 15 October, a two-month

delay with respect to the last report. The slice test that was to be performed before

the readiness review has only been done partially. A contingency of four months

is required to buffer any further delays. The goal is to install NSW-A during LS2.

NSW-C installation is targeted at an EYETS in 2021/22. The schedule uncertainty

should be reduced significantly by the end of February 2020, for the next LHCC

meeting, when several of the main critical items will have been addressed. The

review panel recently convened has provided valuable advice to the NSW team

and will continue to review NSW progress over the next year. These reviews

should be scheduled so that recommendations (and latest report, if possible) will

be available at the subsequent LHCC meeting, including reports from the NSW

management on follow-up of the review panel recommendations.

Phase-II upgrades:

Five of the six MoUs have been finalized and sent out for signature to the funding

agencies. The ITk pixel MoU has been finalized by the October RRB.

The HGTD team continues to make steady progress on understanding the sensors,

including thermal runaway and irradiation, front end ASICs and bare module

assembly. Optimization of the layout of the detector continues. The Committee

looks forward to the TDR which will be submitted in April.

The evaluation of the effects of the material due to the ITk pixel post-TDR lay-out

is still in progress with many results already available. The achieved level of

accuracy is believed to be equal or even surpassing that of the current Run 2

geometry model. The preliminary results appear to indicate that material-induced

performance changes due to the increased cable mass in the direct transmission

model, as well as due to layout changes and services routing may not be large.

The alternative Event Filter (EF) track working group set up by TDAQ has

concluded its work. Software tracking in standard processors has been identified

as a fallback solution up to a pile-up of 140 in case the HTT system is not available

at the beginning of Run 4. This solution comes at no extra cost with respect to final

TDAQ cost but requires anticipating the deployment of full EF farm needed for

– 6 –

pile-up 200 to the beginning of Run 4. The results indicate that there is an

opportunity to evaluate this solution beyond a simple fallback, extending it to the

full pile-up level of 200 with additional resources in EF or further optimised

software. A new study group has been launched to study a corresponding TDAQ

architecture variant based on these results.

The LHCC congratulates ATLAS on the large amount of new physics results

produced, as well as the good progress reported on the upgrades and in preparing

for Run 3.

The LHCC urges the TDAQ project and ATLAS managements to ensure that no

other components run into similar difficulties as encountered by the eFEX.

Lessons learned should be applied to the Phase-I and Phase-II Upgrade projects.

The LHCC endorses the process that ATLAS management has followed in

terminating the FTK Project due to unavailability of adequate resources. The

LHCC notes in particular the efforts under way to ensure results obtained while

executing the project will not be lost.

The LHCC commends ATLAS for its investigations of alternative tracking

solutions in the Event Filter for Phase-II. The LHCC is intrigued by the results

obtained so far and encourages the experiment to continue to pursue this way

forward.

The LHCC endorses the NSW review panel conclusion that a contingency of 4

months is a reasonable estimate of the uncertainty on the NSW-A project

completion date and concurs that the 3.5 additional months requested by ATLAS

to be added to the duration of LS2 would provide significant buffer against risk of

failure. However, the LHCC does not feel that this buffer will provide a guarantee

of success.

7. P2UG report ATLAS

A P2UG review for ATLAS took place on November 5-6, consisting of an in-depth

review of TDAQ, ITk-pixels, ITk-common and Tile projects, and regular reviews of ITk-

strip, LAr, and Muon projects. The review committee would like to commend the

collaboration for the timely submission of detailed material to the review committee and

for the very collaborative attitude during the review. The P2UG came to the following

main observations and recommendation:

The milestone table shows that there has been good progress in general, but also

signals a low completion rate for some projects. In some cases, the information

related to the critical path of projects is not yet fully dependable. This should be

addressed as soon as possible.

The LS3 schedule looks very tight, with a preliminary plan exceeding the currently

expected length of the shutdown with no explicit contingency embedded in the

model. However, since this is a preliminary schedule, it is recommended to

maintain the current target of 2.5 years until further refinements and optimisations

are available. Given the currently projected ITk readiness for installation date, a

shift of the start of LS3 seems unavoidable at this point. Even with such a shift,

the float in the ITk pixel schedule is much less than would be appropriate for a

project of that duration and complexity, requiring additional examination and

optimisation.

– 7 –

The TDAQ project has made major steps in organization and technical progress

since the last review, and is still essentially on track, despite having delayed most

of the recent milestones. There are, however, key decisions yet to be made in the

project, mostly in the area of the HTT architecture and implementation.

Competition for firmware engineering effort across several projects starts to

appear, underlining the importance of coordination to make best possible use of

the available resources.

The ITk pixel project has undergone several substantial changes since the Spring

2019 P2UG review. Chief among them are changes in management, with new

project leader and deputy. In addition, the schedule has been fleshed out

considerably. The project has clearly pivoted from an R&D stance to a

construction project with clear plans for promptly closing the remaining open

options. There have recently been a few delays in the reviews, chiefly from the

delay of the Services and Hybridization.

The ITk-Strips project has made significant progress on many fronts since the May

P2UG meeting. The schedule has been updated to account for the sensor delivery

timeline after signing the contact with HPK, and for delays in pre-production of

the FE ASICs. These changes have resulted in about a 4-months delay in the

completion/readiness of Strips for integration in ITk, whose schedule is however

driven by ITk-Pixel - ready for integration at CERN only ~12 months later.

The overall ITk common items schedule is on track. It inherits some delays from

other subprojects, with the major concerns being the “ITk readiness for

installation”. While all 5 ITk sub-project schedules were baselined, the links

between the schedules are still under evaluation. The process is expected to end in

early 2020.

The Tile project overall is in good shape. Schedule delays were found to be

relatively minor and far from the critical path. The Tile group has demonstrated a

good understanding of the main issues and challenges ahead.

The LAr project is in good shape and on schedule for many PDRs in early 2020.

Much progress has been made on the Muon project in the last quarter with many

milestones completed either on time or with modest delays. Seven milestones were

delayed, with a maximum delay of approximately four months. In all sub-projects,

there is still substantial schedule contingency.

8. Discussion with CMS

Scientific output and current activities:

CMS continues to have a rich scientific output, with 932 papers submitted to date,

including 22 since the last LHCC. Recent results include a measurement of the

𝐻 → 𝑊𝑊 differential cross section with the full Run 2 data set, a measurement of

the 𝑡𝑡 forward-backward asymmetry and anomalous dipole moments, and strong

evidence for 𝑡𝑡 production in PbPb collisions.

The LS2 activities are progressing steadily. Remaining critical parts (beampipe,

pixel, magnet systems) are on track. The installation of the GE1 GEM chambers,

a Phase-II upgrade, is on track. CMS has been successful in fixing a large fraction

(60%) of the leaking RPC muon chambers (75). Muon system DT high voltage

power supplies have shown a significantly increased failure rate, with the reason

still under investigations. The power supplies are accessible and enough spares are

available. Recently observed sparking in new BPIX layer HDIs between the HV

– 8 –

line and grounding grid prompted the submission of two new HDI versions to

mitigate the problem. The new HDIs still remain to be fully tested.

Underground infrastructure modifications for Phase-II are under way. Because of

accumulated delays, and the unexpected failure of a vacuum pump for the magnet

cryostat and corresponding longer magnet commissioning (last task), an additional

6-8 weeks to LS2 could be advantageously put to use.

Phase-I upgrades:

With the successful installation and commissioning of the hadron barrel

calorimeter on schedule the last Phase-I upgrade project has been completed.

Phase-II upgrades:

Most Phase-II projects are now in the P2UG realm, with several more still at the

LoI level (PPS) or steadily approaching TDR level with different submission

timescales (L1 Trigger in Q1 2020; BRIL and DAQ/HLT Q2 2021).

Phase-II site infrastructure is progressing well, but much more design work is still

needed. It is essential to complete the services and infrastructure early in order to

commission the Phase-II detectors. Key infrastructure work needs to be done in

YETS or EYETS before LS3.

Finalization is needed for the design and funding of some critical/important

infrastructure buildings at P5 which could induce schedule delays for Phase-II

preparation and running. Help is needed from CERN, in particular design effort

for the infrastructure and for the funding of the construction of the building shells.

CMS and CERN are encouraged to rapidly agree on the level of detail required for

the documentation of the CMS infrastructure requests which CERN needs to move

forward in the corresponding discussions.

The LHCC congratulates CMS on its very productive physics programme as well

as the substantial progress made on the upgrade projects and in preparing for

Run 3.

The LHCC is concerned about the failure of some DT HV power supplies. The

cause of the failure should be better understood, and a backup solution should be

explored in case the failure rate becomes unsustainable.

The LHCC urges the collaboration to optimise the use of a possible extension of

LS2 to fully test the new BPIX Layer 1 HDIs, including on-module tests.

The LHCC would like to see full assessment of the status of the RPC gas system,

once the gas flow has been restored.

9. P2UG report CMS

A P2UG review for CMS took place November 11-12, including an in-depth review of

the Muon system and Barrel calorimeter. The P2UG appreciates the effort by the CMS

collaboration to prepare for this review, the high-quality presentations and the open

discussions. The committee felt that the presentations were frank and honest. The MTD

was added to the P2UG review recently but was not yet reviewed in detail. Three

projects, Tracker, HGCAL and Barrel Calorimeter, saw significant changes in their

schedule, some of which were unexpected, which have resulted in a very small remaining

schedule contingency. The P2UG came to the following observations and

recommendation:

– 9 –

The collaboration is to be commended on the progress since the last P2UG. Good

progress has been made in many technical areas, designs have been advanced,

and the systems are more mature and well-understood. The forward planning,

trying to get a head start on various project during YETS and Long Shutdowns,

is a very good approach. Still, the schedule contingency is very low for major

subsystems. To increase this to an appropriate level, corresponding to 25% - 35%

of the nominal time remaining to completion, a shift of LS3 by at least one year

is inevitable.

The projects critically depend on several external ASICs, requiring close tracking

and the availability and maintenance of resources at CERN, Fermilab and

elsewhere. The irradiation facility at Fermilab is a crucial element for full

validation of many components, and thus should be expeditiously completed and

brought into operation.

The Muon GE1/1 project is well on track. The threshold trimming procedure to

increase MIP efficiency is under development. The GEM discharge propagation

mechanism is now well understood, but the mitigation measures still need to be

carefully checked in realistic environments. GE2/1 is on track. Attention should

be given to the production sites’ validation and production uniformity. The ME0

project is progressing well, with some concerns on the now higher expected dose

with respect to the TDR design due to the HGCAL evolving design. This effect

should be carefully evaluated. The CSC project is on track with no problems

encountered during cooling circuit installation. The addition of new manpower

highly profits the RPC project. This additional manpower should be available to

the project long-term if at all possible.

The Barrel calorimeter project is overall in good shape, but problems with LiTE-

DTU chip are causing delays at the level of several months to many system

component qualifications. Despite this, the float of the project remains positive.

An assessment and plan for resubmission of the LiTE-DTU chip should be

developed as soon as possible.

The outer tracker is progressing well, with concerns over the number of vendors

for the hybrids. This is well recognized by the project, with active work under

way to establish and qualify at least one additional vendor. For the inner tracker,

the CROC has adequate resources and is making good progress, with a spark

protection task force established to tackle this long-standing problem. Sharing of

experience with ATLAS is recommended on this issue. The pixel size of the barrel

sensors remains open, with 50 x 50 µm2 validated as a baseline technology, and

ongoing studies for 100 x 25 µm2, which promises additional physics benefits.

For the HGCAL, a rich harvest from test beam data is in progress. Significant

efforts have been undertaken to bring the development of the ECON chip back

on track. Issues with backplane fragility of 8in sensors have been observed and

measures to resolve this issue are under discussion between HPK and CMS. The

project has seen a delay of about 3 months since the last P2UG meeting.

10. Discussion with LHCb

Scientific output and current activities:

LHCb continues to make excellent progress on its physics programme, with a total

– 10 –

of 500 publications to date, including 10 new papers since the last session of the

LHCC. New results include a search for 𝐴′ → 𝜇+𝜇− decays, the determination of

quantum numbers for excited charmed mesons and a measurement of Ξ𝑐𝑐++

production in pp collisions at √s = 13 TeV.

LHCb is undertaking a full pp data reprocessing, which should be finished by the

end of the year. Otherwise MC production is taking 90% of the CPU, with 40% of

the sample produced on the online computing farm.

Real Time Analysis (RTA) can now be operated at the required HLT1 rate, with

further optimisations under way. Two architectures are being considered for the

system, CPU (baseline) and GPU, with evaluations still ongoing.

Phase-I upgrades:

Good progress has been reported on the Phase-I upgrades. The VELO is still on a

tight schedule. Issues with the tile glue stopped module production which should

resume before the end of the year once the gluing study has been finalised. Overall

there is a delay in production of three months.

Good progress has been reported on the UT, however the installation schedule is

still critical. SALT v3.8, needed for the 8-chip hybrids, is being validated on 4-

chip hybrids at the moment, but has not been tested yet on the final hybrid. These

tests should start in December. The installation of UT in a regular YETS is

feasible, if installation in LS2 cannot be achieved.

Delays in the SciFi infrastructure and problems with dipole clamps will cause a

delay of about 4.5 months in the beam pipe installation.

All other systems are making good progress; however, the achieved milestone

schedule still lags behind. The additional delays have eaten up the contingency

and time for commissioning is now very compressed. An extension of LS2 by

three months would be beneficial.

The LHCC congratulates LHCb on its rich scientific output and commends the

collaboration for the progress made on its Phase-I upgrade programme and in

particular on the successful MC production and data stripping campaigns.

The LHCC is concerned about the delays in the VELO and UT projects.

The LHCC requests by the next session of the LHCC a presentation of the fully

specified procedure for selecting either CPU or GPU for the RTA.

11. Discussion with TOTEM

Design for a new T2 telescope is going well. Different light collection configurations are

under test using cosmic rays. TOTEM plans to finish the studies on scintillators by

November and to define the final production tile and start the mass production of

scintillators and mechanics early next year.

The TOTEM-PS2 LS2 activities in the LHC tunnel are on schedule. In September the

relocation of the horizontal Roman Pots (RP) and the vertical levelling of all RP units

has been performed. The RP movement hardware test in sector 5-6 has been completed,

and for sector 4-5 it is planned for the end of November.

TOTEM physics analysis is in a good shape. The last three submitted papers have now

been published, and a fourth paper is under review. Several physics analyses are

ongoing.

– 11 –

The LHCC congratulates TOTEM on the progress made on physics analysis and

on the design of the new T2 detector.

The LHCC notes that the TOTEM-PS2 LS2 activities LS2 in the LHC tunnel are

on schedule.

12. Discussion with WLCG

WLCG and the experiment computing systems are working well. Even though operations

are calmer during the shutdown period, the services and resources are fully used. Work

continues on developing solutions for Run 3 and HL-LHC computing. A review of the

HL-LHC computing strategy will be carried out starting May 2020 led by Amber

Boehnlein (JLab). The target period for submission of the HL-LHC computing TDR is

Q3/2023 for a recommendation to the LHCC in early 2024. Continuous effort in software

R&D is needed to arrive at manageable resource requests. One of the biggest components

is detector simulation, largely based on Geant4. However, Geant4 currently does not run

on HPCs or GPUs, excluding such resources for simulation processing, unless significant

effort is invested into porting Geant4 to these architectures. Identifying tasks in Geant4

development that allow partners to have good visibility can help funding agencies to

commit to Geant4 related tasks. The Geant4 team and the experiments need to continue

their close collaboration, for example on frameworks for fast simulations. In addition to

fast simulation, the focus should be on reducing the event size and on the use of

heterogeneous infrastructures in order to bring computing needs to a level that matches

the resources that can be expected to be available for HL-LHC.

The LHCC congratulates the WLCG and the experiments on the successful and

efficient use of the computing resources.

While there are important developments in the use of HPC centres, the LHCC

notes that it is at this point not evident that this can be a general solution to the

HL-LHC computing challenge. Better coordination should be put in place for the

ongoing activities on HPC and GPU usage.

The LHCC takes note of the schedule to produce the computing TDR and urges

the authors to consider experiment specific issues along with discussing common

tools and community software in preparing for the TDR.

13. Discussion with FASER

FASER is a small-scale experiment designed to search for light, weakly-interacting

particles produced at the LHC. The experiment will be installed 480 m downstream of

the ATLAS IP in the TI12 service tunnel during LS2 and perform its search during Run 3.

FASERnu is a proposed extension designed to measure neutrinos from decays of

particles produced in pp collisions at the ATLAS IP. It consists of a stack of emulsions

and tungsten slabs, with a total mass of 1.2 t, located in front of the FASER detectors. At

its September meeting, the LHCC discussed the FASERnu proposal and encouraged the

proponents to submit a Technical Proposal (TP). This was provided to the referees on

October 28th. A meeting concerning the proposal was held on November 13th, during

which the referees received answers to their questions on the TP and received an update

on the status of the main FASER detector.

The construction of the main FASER detector is progressing well, and space for the

commissioning of the detector above ground has been identified in ENH1. The next steps

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are the civil engineering works planned for January to March 2020, and the installation

in May 2020. An alternative installation path is being explored in case the third magnet

is late. This profits from a protection cover of the LHC machine, which is needed for

FASERnu and allows installation across the cold machine. The cover has already been

produced.

The civil engineering work required to accommodate FASERnu has already been

included to a large extent in the FASER plan, only a small addition to the crane

equipment is needed. The cost of the FASERnu detector is dominated by the emulsion

and the tungsten plates, for which reliable estimates are available. Funding is available

for about half of the detector cost, and additional funding is actively pursued, with good

prospects of covering the remaining hardware cost and additional support for person

power. Nagoya University is committed to produce the necessary amount of emulsion

films. Expected host lab contributions are moderate and consist of transport services and

infrastructure, the use of a dark room, chemical disposal and computing.

An additional Interface Tracker is considered for installation in the YETS 2021/2022 that

would allow tracking of events through FASERnu and the main FASER detector.

The LHCC congratulates FASER on the progress on the main detector and the

timely submission of the FASERnu TP.

The LHCC finds that FASERnu offers an attractive extension of the FASER

physics program with limited cost. The detector is well defined. Production,

assembly, installation, emulsion development and analysis are well understood.

The LHCC endorses active pursuit of the interface detector.

The LHCC notes that in order to fully profit from the synergies with civil

engineering work for the main FASER detector, the decision to install additional

crane equipment needed for FASERnu should be made soon.

The LHCC recommends approving the FASERnu proposal. Regular updates on

the status of FASER including FASERnu should be provided to the LHCC.

14. Follow up with XSEN

A discussion with the proponents of XSEN, who had submitted an LoI to LHCC 139,

was held prior to the main LHCC session. The LHCC observes that at present the

collaboration is not yet defined, resources and access to infrastructure have not yet been

secured, and the relationship with the SHiP collaboration is in need of clarification. These

issues would need to be addressed before a Technical Proposal can be considered.

15. General Comments

The following comments are applicable to more than one project.

The LHCC fully supports CERN and the experiments in their efforts to converge

on a plan the optimises the duration and / or scheduling of LS2, Run 3, YETS/

EYETS and LS3, taking into account progress of LS2 activities, Phase-II upgrades

and physics considerations. The committee recognizes the need to defer LS3 by at

least one year to enable a successful implementation of the ambitious Phase-II

upgrades of ATLAS and CMS. LHCC advocates running at the highest possible

energy in Run 3, ideally the full design energy of 14 TeV. The committee

recognizes the need for pragmatism on this question, depending on evolution of

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magnet training, considering achievable energy and reliability in the choice of

Run 3 conditions. Stable energy should be available for the bulk of Run 3, with

the raising of the energy done in 2021. In terms of the run plan, shutdown and

upgrade needs of the experiments have to be considered, but we also stress the

importance of collecting a significant data set, with a luminosity profile that

ensures good physics potential throughout Run 3.

The development of the common lpGBT at CERN has been delayed by close to

one year and now is very close to driving the critical path of many systems in both

ATLAS and CMS. The LHCC welcomes the move by CERN to strengthen the

lpGBT team and urges the lpGBT project leaders to ensure no further significant

delays are generated, to avoid impacting the Phase-II schedules of the

experiments.

The LHCC commends CERN on establishing dedicated effort to support ASIC

development activities through consultancy and encourages the experiments to

take advantage of the possibilities provided by these additional resources.

16. REFEREES

The LHCC referee teams for this session are as follows:

ALICE: G. Casini, J. Dunlop, P. Salabura, C. Sfienti (Co-ordinator)

ATLAS: V. Beckmann, R. Calabrese, F. Di Lodovico, W. Wisniewski (Co-ordinator)

CMS: D. Glenzinzki, E. Kajfasz (Co-ordinator), A. Kuzmin, P. Pakhlov, D. Waters

LHCb: C. Hearty, P. Krizan (Co-ordinator), K. Krüger, M. Kuze, E. Worcester

LHCf, MoEDAL, TOTEM: A. Kuzmin, F. Di Lodovico, M. Mangano (Co-ordinator)

LCG: V. Beckmann (Co-ordinator), J. Dunlop, M. Kuze, D. Waters

FASER: K. Kruger, M. Mangano (Co-ordinator), W. Wisniewski

XSEN: K. Kruger, F. Di Lodovico (Co-ordinator), M. Mangano, D. Waters

17. The LHCC received the following documents:

CERN-LHCC-2019-010 Minutes of the one hundred and thirty-ninth

meeting of LHCC held on 11-12 September 2019

CERN-LHCC-2019-017 FASERnu Technical Proposal

DATES FOR LHCC MEETINGS

Dates for 2020

19-20 February

4-5 June Thorsten Wengler

2-3 September E–mail: Thorsten.Wengler@cern.ch

18-19 November Tel. 71298

LHCC Secretariat: Patricia Mage (Bldg. 3/R-018) Tel. 78135

patricia.mage@cern.ch