Task C Activities in the CMS Experiment

Task C Activities in the CMS Experiment

Greg Landsberg

DOE Site Visit

September 28, 2006

DOE Site Visit 2006 Greg Landsberg, Task C Activities in CMS 2

Brown and CMS• Next energy frontier and a natural way for our group to evolve is LHC• While have realized this a while ago, it would have been a hard decision

to move part of our DOE-supported group away from DØ w/o stretching thin our major responsibilities there

• The NSF CAREER Award won by GL in June 2003 allowed us to expand in the new direction w/o compromising our DØ strength

• Why CMS?– Better detector– Strong Fermilab presence allowing for an adiabatic transition

• December 2003: formal application to join CMS• March 2004: presentation of our application at the CMS Week• June 2004: Brown was voted in and became a full member of CMS• At the same time, Ryan Hooper, a new RA to work on DØ and CMS has

been hired using the NSF Grant• Based on our strong ties with Fermilab’s SiDet, we have joined Tracker

Outer Barrel construction project• Where do we stand now, two years since we’ve joined?


CMS – Soon to be Lowered!

September 2006 CMS Week


CMS Explained

[Jos Engelen, SLAC 2006

Summer School]


CMS All-Silicon Tracker

5.4 m

End Caps (TEC 1&2)

2,4

m

Inner Barrel & Disks

(TIB & TID)

PixelsOuter Barrel (TOB)

volume 24.4 m3

running temperature – 20 0C

Brown group involvement


TOB Construction•Major hardware project accomplished via joint effort of Brown, Fermilab, KU, Rochester, UCSB, UIC, and UCR •Two mirror production facilities: Fermilab and UCSB•Some TOB statistics:

–Total number of modules: 5208 + 5% spares–Total number of rods: 688 + 5% spares–Total silicon area: ~1000 ft2

–Total silicon weight: ~100 lbs

•Brown involvement: Q&A, rod assembly, single-rod test stand•People: GL, Ryan Hooper, Hai Duong Nguyen, Patrick Tsang, Scott Wolin, several more SS•Rod production took place in FY2006 (November-July)

•Uncovered and fixed many problems since mid 2005:

–Common mode noise in ST sensors – replaced w/ Hamamatsu–Wire bond breakage due to vibration – module encapsulation–I2C communication problems – redesigned cards–Degradation of the Ag-based epoxy bias connection – switched to wire-bonding;–Sensor damage due to discharges between the ground and the silicon surface – encapsulated wire bonds and modified HV power supplies

•Despite the unexpected delays, the project has been successfully finished

–All the rods have been assembled, tested, and delivered to CERN on time!


Rods & Single-Rod Test Stand

An assembled rod and its readout end Single-Rod Test Stand (SRT),and the “Brown Box” for reading rod temperature.Over 700 rods went through SRT


Typical SRT Rod FailureSRT Opto Scan and Noise

Saturated AOH laser channel


TOB at CERN – Rods Being Installed


Actual Rod Installation

100 m axial precisionover the length of the

rod (~3ft)![0.5 mil/sensor!]


LPC Activities•LHC Physics Center (LPC) at Fermilab has been founded in 2004 as a “Mortar and Brick” foundation to accommodate critical mass of experts and support LHC physics efforts by the US community•Brown group was one of the first groups to join (GL served on the Advisory Board in 2004-2005; Yuri Gershtein, than a Brown RA, became a convener of the e/ group)•Many successes, from thorough work on development and optimization of ID algorithms within the new CMS software framework, to support of MC physics studies by students and software tutorials•Helped our group to move to CMS adiabatically, without compromising the DØ connection

•LPC grew significantly over the last two years; still remains to be seen if the critical mass of experts can be achieved during CMS running •Could serve as a good alternative to maintaining the core of the group at CERN (COLA, remoteness, need to relocate several people at once)•2007 LHC pilot run will serve as a proof of principle•In 2005-2006 GL took a year-long sabbatical supported by LPC and has been appointed as the LPC Trigger Group convener•Meenakshi Narain just started as an LPC b-tagging Group convener•Maintain LPC office space to provide students, postdocs, and commuting faculty with excellent working conditions


Triggering at Hadron Colliders• e+e- colliders: low total cross section,

low rates– Trigger pretty much on everything,

perhaps with the exception of very forward processes (low-angle Bhabha)

• Hadron colliders: enormous cross section, unattainable rates– Trigger is very selective– Only small fraction of collisions is

written to tape– Additional complications due to pile-

up

• LHC: – tot = 110 mb, in ~ 70 mb– L = 1034 cm-2s-1 = 10 nb-1s-1

– 25 ns bunch crossing– Total rate: ~109 s-1 or ~20/crossing– An order of magnitude more complex

triggering than that at the Tevatron

[Block, Halzen, hep-ph/0510238 ]

LHC:tot = 107.3 ± 1.2 mb

[PDG]


Trigger Architecture• Must reduce 2.5-40 MHz of input interactions to 50-100 Hz

– Do it in steps/successive approximations: “Trigger Levels”

Front end pipelines

Readout buffers

Processor farms

Switching network

Detectors

Lvl-1

HLT

Lvl-1

Lvl-2

Lvl-3

Front end pipelines

Readout buffers

Processor farms

Switching network

Detectors

“Traditional”: 3 physical levels CMS: 2 physical levels

x400 rejection

x1000 rejection


CMS Level-1 Trigger SchemeElectrons, Photons, Jets, MET

Muons

3<||<5 ||<3 ||<3 ||<2.1 0.9<||<2.4 ||<1.2


LPC Trigger Group• Charge – in concert with the international CMS

Online Selection PRS group– Simulate, develop, and maintain L1 and High-Level

Trigger algorithms– Work on creating realistic trigger table for the startup pilot

run, as well as for low and high luminosity physics running– Maintain and operate Remote Operations Center (ROC) at

Fermilab – a mirror control room for the experiment– Participate in the MTCC (Magnet Test & Cosmic

Challenge) shifts and data monitoring and analysis

• LPC Trigger Group Statistics:– About 25 active members– Regular biweekly meetings (one later this afternoon!)– Two successful workshops (L1 & HLT) in the past year– Deep connection with Online Selection PRS group


LPC Trigger Group Activities• Contribution to vol.2 of the CMS Physics TDR (Brown,

Fermilab, Wisconsin)• Trigger tables and rates (Brown, Fermilab, Wisconsin)• Optimization of the L1 Calorimeter trigger (Brown)• L1 calorimeter calibration and jet energy corrections (Brown,

Wisconsin)• Implementation of the L1 calorimeter emulator in the CMSSW

framework (TAMU, Wisconsin)• HLT Jet/MET trigger suite implementation and timing studies

(Brown, UIC)• Remote Operations and Control (Fermilab, Maryland; Brown

is getting involved)• Test beam and cosmics data analysis (Fermilab, UIC)• Calorimeter noise studies (Brown, Rochester, UIC)• Minbias trigger design (UIC)


L1 Calorimeter Trigger Optimization• Pursued by GL and Sara Vanini• Focus on the basics:

– Systematic studies of noise– Adjusting trigger thresholds to match

noise– Optimizing trigger algorithms– Improving turn-on and resolution– Improving MET resolution

• In the process uncovered and fixed many trigger simulation bugs and cleaned up ORCA code and propagate fixes into CMSSW

• Example: – greatly improved single jet trigger turn-

on – an important tool for multiobject triggers (e+jets, +jets, etc.)

Optimized thresholds

Original defaultthresholds

ETgen, GeV

ETgen, GeV


Hardware Implementation•Proposed optimized thresholds have been endorsed and approved by the CMS HCAL Electronics and Trigger groups•They are currently being implemented in firmware and the new L1 emulator code

–Brown group spearheads this effort and will redo simulations with the new software

•Also work on implementing and simulating dynamic baseline subtraction scheme•Energy is determined as a weighted sum: E = fiEi over several time-slices

TB04

5% 70% 23% 2%

•Automatic baseline subtraction: fi = 0•Being implemented for HCAL: fi = -1.0, -1.0, 1.0, 1.0•Will require slight timing realignment (~1 ns)•Robust against coherent noise and hot cells


L1 Calorimeter Trigger Calibration•Problem: CMS calorimeter is

–Non-linear–Non-compensated–Has -dependent response

•Goal: correct for these deficiency via proper calibration either at the jet or the trigger tower level•New L1 JES corrections:

–Fit (or take the mean) of ETgen – ET

L1 distributions in bins of ET,

•Effect on MET in W+jets:–Left: ME|| resolution–Right: ME|| pull

•Corrections remove pull , but worsen the resolution by similar amount •Next step: introduce “new dimension” in tower calibration: e/h

No JES corr.After JES corr.

[GL, Scott Wolin]

[GL, Sara Vanini]


Future Plans•CMS Hardware & Commissioning

–Our current CMS hardware project has been a success, but it came to an end

–Important to maintain hardware experience in the group, especially given new students and postdocs joining the group

–Want to maintain close ties with the US “Silicon Consortium” – work well together, common goal in bringing tracker online

–Will participate in TOB commissioning via ROC in MTCC-II (later this year) and underground SX5 cosmic running (2007)

–Consider manning test beam and commissioning shifts at CERN via short-term visits

•SLHC Upgrade–A lot of opportunities for new major hardware efforts

–Participate in the SLHC Steering Group meetings and SLHC workshops

–CMS SLHC LoI will go to the funding agencies later this year

–[Hope for enthusiastic support from you guys!]

–Discussed participation in the following areas:

•Construction of a part of the CMS silicon tracker replacement•L1 tracking trigger design and construction (hardware + firmware)

–More in Meenakshi’s presentation


The LHC Schedule [Winter 2006]• Physics running: 140 days/year

• ATLAS/CMS running: ~100 days/year• Typical efficiency for physics: 40%• Effective ATLAS/CMS running time/year: ~1000 hours ~ 4 x 106 s ~

4 x 1038 cm-2 = 4 x 1014 b-1 = 400 pb-1 @ 1032cm-2s-1

• Note that the schedule below [R. Bailey, Aspen 2006] is “all goes well” scenario

2007 2008 2009 2010 2011

Pilot run, 75nsL~5x1030 cm-2s-1

Ldt ~ 20 pb-1

2008, 75/25nsL~3x1032 cm-2s-1

Ldt ~ 1.2 fb-1

2009, 25nsL~1x1033 cm-2s-1

Ldt ~ 4 fb-1

2010, 25nsL~1x1034 cm-2s-1

Ldt ~ 40 fb-1

Our contract renewal date: ~ 5fb-1, first physics papers!


Revised LHC Schedule (Summer 2006]

• Pilot 2007 Run– Starts ~2 months later than previously expected– Accelerator runs at injection energy (450 x 450 GeV pp)– Expected luminosity: ~1029 cm-2s-1

– Collision data sometimes in November 2007: ~50 nb-1

• Three-month shutdown following with 14 TeV data in Spring 2008– The goal to deliver a few fb-1 by the end of the run

• The rest of the schedule stays the same


CMS Physics•All what we have been doing is really driven by our desire to become major players in the CMS physics, in the same way we maintained physics leadership within DØ over the last 15 years•Currently focus on low-level task: optimization, validation, and certification of trigger, reconstruction and particle ID

–See Tulika’s talk on this

•Actively contributed to the Volume 2 of the CMS Physics TDR•Getting involved in the Pilot 2007 Run data analysis as a preparation to the 2008 physics run•Picking/negotiating physics topics to work on – from rediscovering SM with the first data to searches for black holes at the LHC•Use our two-decade experience and leading role in the Tevatron physics as a guiding star


(Wo)manpower on CMS – Doubling!FY2006

•Greg Landsberg – PI (90%)•Tulika Bose – RA (50%)•Ryan Hooper – RA, NSF (75%)•Sara Vanini – VRA (75%)•Zongru Wan – VRA (20%)•Hai Duong Nguyen – GS, M&O (100%)•Patrick Tsang – SS (25%)•Scott Wolin – SS, UTRA (20%)

•Total: ~4 FTE

FY2007•Dave Cutts – PI (50%)•Greg Landsberg – PI (80%)•Meenakshi Narain – PI (50%)•Tulika Bose – RA (75%)•Leonard Christofek – RA (50%)•Selda Esen – RA, NSF (100%)•Aram Avetisyan – GS (75%)•Paul Huwe – GS (40%)•Hai Duong Nguyen – GS (100%)•Patrick Tsang – GS (100%)•2-3 SS (50-75%)

•Total: ~8 FTE

FY2005•Greg Landsberg – PI (30%)•Ryan Hooper – RA, NSF (100%)•Hai Duong Nguyen – SS, M&O (25%)•3 Temps – SS (75%)

•Total: ~2 FTE


Our Newest Addition to the Group

• Selda Esen, who is graduating from Turkish University of Cukurova this week and will start with us on October 1– CMS thesis based on jet studies

and HCAL test-beam data analysis

– Will work 100% on CMS and replace Ryan Hooper

– Supported by the NSF grant


Conclusions• Our 2004 bid for LHC, made possible by the NSF support,

has paid up• Our group is now well-plugged and recognized within the

CMS community and has contributed to several aspects of hardware, firmware, and software

• Our adiabatic transition from DØ to CMS has been successful: we still maintain important responsibilities in DØ (Luminosity Monitoring, Level 3/DAQ, B-physics, Top, Single Top, New Physics Searches), while ramping up our CMS effort

• Our CMS involvement doubled every year since we have joined CMS – while such a growth can’t be sustained much longer, it’s up to you to ensure that it will continue

• LHC is imminent; three years from now we very well may be reporting a major discovery made possible by the Brown group efforts!

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Task C Activities in the CMS Experiment