people

NSF Site visit, Jan. 14-15, 2005 Young-Kee Kim, University of Chicago

NSF Site Visit:Current Research Activities

January 14-15, 2005

Young-Kee KimThe University of Chicago


People• Faculty: Young-Kee Kim• Post-docs:

– Un-Ki Yang - looking for a faculty position– Vadim Rusu - Fermi Fellow, started Oct. 2003– Ivan Furic - Fermi Fellow, started Apr. 2004

• Chicago Graduate Students:– Wojtek Fedorko (2nd year)– Clarisse Kim (1st year) - will start June 2005

• Remaining Berkeley Graduate Student:– Adam Gibson (5th year)

• Undergraduate Students:– Annie Malkus – Jen Hsin– Jon Walsh– Edmund Berry


CDF Co-Spokespersons• YKK(term duration from June 2004 to June 2006), Luciano Ristori (Pisa)

• Responsible for scientific program of CDF– CDF is now over 800 collaborators, 12 countries, 62 institutions.– Organized into detector operations, offline operations, and upgrade

project, and physics groups– appointing physics and operations leaders.– organizing CDF weekly meetings, collaboration meetings, executive

board meetings– appointing godparent committees for all analyses (~40 committees)– special committees: e.g. physics prioritization, internal reviews, …– MOU negociation– primary contact with laboratory (particle physics, accelerator physics,

computing, directorate), high energy community, funding agencies, media, …

– ……• Being co-spokesperson means I am effectively at Fermilab full time.


Physics Groups, Publications

• Internal review processes by godparent committeesafter results are approved by physics groups.

• Status:– 2001: Run II began– 2003: 4 papers published– 2004: 18 papers published or submitted– 2005 goal: 40 papers

QCD B Electroweak(W,Z + …)

Top Exotic(New Phenomena)

dilepton l+jets all hadronic mass

physics groups:

analysis groups:

common tools, issues: Joint Physics Meeting:Tracking, e, b-tagging, jet calibration, …

Physics Groups Organization:

Publications:


CDF Status• Detectors/Triggers/Offline working extremely well

– effort to keep them running smoothly - high L, beam accidents, aging,..• Accelerators delivering record luminosities: > 1 x 1032

• Collaboration focused on analysis:– so far ~10% of Run II luminosity. Exciting time has yet to come!

• Upgrades necessary to keep up with growing luminosity– Detectors: Preshower, EM timing (H. Frisch)– Triggers and DAQ

• COT(Drift Chamber) TDC - H. Frisch• Level-1 COT Track Trigger• Level-2 Silicon Vertex Trigger - M. Shochet + YKK• Level-2 Decision - M. Shochet + YKK• Level-3 Trigger• Event Builder

Strength of Chicago group is that we are all focused on success of CDF.


Level-2 Decision Upgrade

• Trigger Rates:

– Level 1 output ~ 25kHz– Level 2 output ~ 300 Hz– Level 3 output ~ 60 Hz

– Level 2 critical to CDF trigger performance• rejection factor ~ 100

• Major upgrade to Level-2 Decision is being commissioned.• will be used as CDF “real” triggers starting March 2005.


Level-2 Decision Upgrade• Primary purpose - faster, modular, more flexible, more robust

– Present: • One PC Board for every interface (6 kinds) - maintenance issues• Custom processor (alpha) + backplane (1990 technology) - slow

• Chicago has played major role since conception.– Henry Frisch was instrumental in proposing the upgrade.– T. Liu (Fermilab) led the whole effort: Chicago, Fermilab, Penn,Helsinki– Chicago engineers (with T. Liu) designed and built boards (Pulsar:

Pulser And Recorder)• Harold Sanders, Mircea Bogdan

• Chicago Personnel (firmware design, simulation, commissioning, …)– Vadim Rusu (Fermi Fellow)

• a leading postdoc for the full system and essentially 100%.– Wojtek Fedorko (grad. student)– Shawn Kwang (Shochet’s grad. student)


Level-2 Decision Upgrade OverviewPulsar pre-processors

L1 MuonL1 TracksL1 Trigger decsion

CentralTrigger

Distribution

L2 CALO(Cluster/IsoCluster)E Sums

Shower Max

SVT

Muon

Cluster

Electron

Merger

SVT

L2toTS

Merger

PC

SLINK

All boards identicalFPGAs reprogrammed for each system

e, , , , jet, missing Et, displaced track,….

Triggers formed by combinations in 10-30 s

Kwang

RusuFedorko


Level-2 Decision Upgrade: Current Status• Full system installed• Muon board fully integrated into Level-2 decision.• Parasitic running until February for other boards.• Original schedule for installation was Summer 05

- well ahead of schedule


Responsibilities for Level-2 Trigger

• Chicago group will have continuing responsibilities for CDF Level-2 trigger, especially as luminosity grows.

• Responsible for– Firmware and trigger simulation– Operations– Monitoring the performances

• Monitoring program:– Initiated and designed by V. Rusu– Collaborative effort: Rusu, Fedorko, Kwang with Penn,

Fermilab.– Monitoring at board level and system level– Invaluable tool for commissioning and testing in beam


YKK Group’s Physics Program

Top Mass

SUSY Searches

Bs Mixing


Initial Analyses (warm-up) on Run II Data (72 pb-1)

• W, Z cross sections– PRL accepted, PRD under Collaboration’s review– Primary authors include G. Veramendi, YKK

• Forward-Backward Asymmetry using e+e- events– PRD submitted– G. Veramendi (UCB Ph.D. 2003), A. Gibson, YKK, G. Lentdecker


Top Mass and Electroweak Symmetry Breaking• Worked on Precision Meas.s

of MW and Mtop

– Run Ia, Ib: W Mass– Run II: Top Mass

• Top Mass:– Prior to co-spokesperson’s term,

YKK was Top mass group co-leader– Pursuing two methods in lepton+jets channel

• Template method– Use mass shapes generated by MC– Fit shapes to 0B, 1B, 2B-tagged events

• Matrix Element method (A. Gibson’s Thesis)– Evaluate likelihood that event kinematics are top like


Top Mass (l+jets) - Template Method• First Results: Summer 03 (B tags)

– 108 pb-1 – UCB: E. Brubaker, A. Gibson– Chicago: U.K. Yang, YKK– Toronto: J.-F. Arguin, P. Sinervo

• May 2004 (B tags)– 162 pb-1

– E. Brubaker’s thesis (UCB Ph.D. 2004)– Chicago: J. Adelman, U.K. Yang,

M. Shochet, YKK– Toronto: J.-F. Arguin, P. Sinervo

• August 2004 (0 + 1 + 2-B tags)– 162 pb-1

– Chicago: J. Adelman, E. Brubaker, U.K. Yang, M. Shochet, YKK

with Toronto, Dubna, Fermilab

174.9 +7.1-7.7 (stat) ± 6.5 (syst) GeV


Top Mass - Template Method (Aug. 2004)

Mtop = 177.2 +6.0-5.5 (stat) ± 7.1 (syst) GeV


Top Mass - Template Method (Publication)• Higher statistics (305 pb-1)• Much smaller uncertainty in jet energy

scale (x2) - better understanding– calorimeter simulation

(Undergrad: D. Hoffman - pion responses)

– Detector(Undergrad: A. Malkus, UCB grad: A. Gibson - -jet balance studies)

– method in estimating uncertainties

Time Run I Summer 2004

Spring 2005

Lum 110 pb-1 162 pb-1 305 pb-1

mtopstat 5.1 GeV 5.7 GeV 4.2 GeV

mtopjet E 4.4 GeV 6.8 GeV 3.4 GeV

mtopothers 2.9 GeV 2.2 GeV 1.8 GeV

mtoptotal 7.3 GeV 8.5 GeV 5.6 GeV

PRD draft written - being reviewed by godparent committee.The numbers and figures will be finalized in a few months.

Un-Ki Yang is leading this effort.


SUSY Searches• Signature based search using like-sign dilepton

– Include trilepton events (Chargino-Neutralino) - flagship analysis for discovering SUSY at Tevatron

– V. Rusu with Penn and Fermilab– Results by Spring conferences

• Stop searches– 2 photons + 2 jets + missing Et– A. Malkus (undergrad), YKK,

with Liverpool– APS/DPF abstract submitted M = 60 GeV

100 GeV150 GeV

Expected # of events w/ 400 pb-1

by A. Malkus


Bs Mixing

World limit: ms > 14.4 ps-1

SM pred. (99% prob.): 15 < ms < 27 ps-1

Fully reconstructed Bs (all hadrons) • provide the greatest reach in ms (Boost is known)• triggered by SVT• unique to CDF due to SVT and high bandwidth triggers


Bs and SVT Upgrade• Ivan Furic

(Fermi Fellow - started April 2004)– Co-convener of B physics working

group (BPAK).– BPAK responsibilities

• tool development group for Bs mixing ++

• Particle ID tools: TOF, dE/dx• Tracking evaluation: L00,

event primary vertex• Review and bless common

tools in analyses• Foster development and

evaluation of new & improved triggers (large effort)

• Clarisse Kim(Grad. Student - starting June 2005)

• Edmund Barry(Undergrad. - started Dec. 2004)

• Ultimate goal: Bs mixing• SVT upgrade work by I. Furic (~50%)

and E. Barry - see M. Shochet’s talk• Data Analysis Goals by this Spring

– Done:• Reconstructed Bs, B0, B±

D signals• Measured relative decay rates• PRL under collaboration’s

review– Ongoing work:

• Measuring B0, B± lifetimes• Measuring Bd mixing

• First Bs mixing limit for spring conferences


Hadronic B0, B±, Bs Decays to D(with MIT, INFN Padova)

• First observation with large statistics• Understanding of spectrum composition,

trigger modeling necessary for Bs lifetimes, mixing

• Measure ratios of branching fractionsFirst measurements (PRL draft under collab.’s review)

Br(Bs Ds) / Br(B0 D-)= 1.38 ± 0.19 (stat.) ± 0.10 (syst.)

± 0.36 (Br) ± 0.10 (PR)

Br(B+ D0) / Br(B0 D-)= 1.95 ± 0.10 (stat.) ± 0.14 (syst.)

± 0.14 (Br)

Bs Ds

B0 D+


Towards Bs Mixing: B0, B± Lifetimes

(with MIT, Cantabria)• Simultaneous unbinned likelihood fit for mass and lifetime• Difficulty: trigger and analysis selection sculpt c distribution• Lifetime fits for B±, B0 lifetime in good agreement with world average

c (B0) = 454.4 ± 10.3(stat.) m (PDG: 460.5 ± 4.2 m)c (B+) = 519.5 ± 12.7(stat.) m (PDG: 501 ± 5 m)

B0 K+


Towards Bs Mixing: Bd Mixing Measurement(with MIT, Cantabria)

• Add tagging information to lifetime distribution (SST tagger)• Fit for Bd mixing

• Next step for Bs mixing: test fitter, calibrate taggers

• Expected Bs mixing sensitivity by this spring (hadronic modes only):

– 95% CL at ms > 10 ps-1 (pessimistic), ms > 20 ps-1 (optimistic)

md agrees with world average.

Bd

md = 0.59 ± 0.07(stat) ps-1

(PDG: 0.59 ± 0.07 ps-1)


Conclusion• Collider program has high potential for major discovery..• Important to harvest results from previous large investment in CDF.

– ~10% of luminosity so far - strong support over next 4 years critical.

• Chicago group continues leadership role in CDF– hardware, physics, management– Quality and impact of group (post-docs and students) is very high.– Faculty actively engaged - important for CDF’s success.– Leads several high-profile analyses.

• YKK group active in fundamental physics measurements– Top mass– Bs mixing– SUSY Chargino-Neutralino

• YKK co-spokesperson through June 2006.• Planning to move to ATLAS after CDF spokesperson’s term ends.

people

Documents

physics groups organization

physics prioritization

accelerator physics

laboratory particle

joint physics meeting

analysis groups

success of cdf

cdf weekly meetings