Recent cdf results on b s flavor oscillations
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Recent CDF Results on B s Flavor Oscillations. The CDF B s Mixing Group CDF Executive Board Meeting 13 April 2006. J. Kroll (Penn), F. Bedeschi(INFN – Pisa), M. Herndon (Wisconsin), Ch. Paus (MIT), K. Pitts (Illinois). The CDF B s Mixing Group. 80 people, 27 Institutions

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Recent CDF Results on B s Flavor Oscillations

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Recent cdf results on b s flavor oscillations

Recent CDF Results on Bs Flavor Oscillations

The CDF Bs Mixing Group

CDF Executive Board Meeting

13 April 2006

J. Kroll (Penn), F. Bedeschi(INFN – Pisa), M. Herndon (Wisconsin), Ch. Paus (MIT), K. Pitts (Illinois)


The cdf b s mixing group

The CDF Bs Mixing Group

80 people, 27 Institutions

Big effort with many separate

important contributions


Made possible by the cdf detector

Made Possible By the CDF Detector

  • Trigger

    • high bandwidth & tremendous flexibility

    • XFT and SVT

  • Exquisite charged particle tracking

    • excellent pattern recognition & mass resolution (COT, solenoid)

    • precise production & decay point reconstruction (L00, SVX)

  • Particle identification

    • Time of Flight (TOF) and dE/dx in COT

  • Extremely dedicated collaborators for operations

    • a lot of sleepless nights for analysis but many more for operations

    • many of the analyzers spent sleepless nights working on critical detector components too


Sequence of cdf run ii results on b s mixing

Sequence of CDF Run II Results on Bs Mixing

  • Fall 2001: 1st heavy flavor signal from TTT data

  • Summer 2002: 1st lifetime measurements

  • Winter 2003: 1st fully reconstructed Bs! Ds

  • Summer 2003: 1st blessed opposite side flavor tag (muon)

  • Summer 2004: 1st B0md result

A lot of ideas and development in Run I


Sequence of cdf run ii results on b s mixing1

Sequence of CDF Run II Results on Bs Mixing

  • 1st result March 2005 – presented at Moriond QCD

    • hadronic modes from two-track trigger

    • semileptonic modes from lepton + SVT trigger

    • opposite-side flavor tags: muons, electrons, jet-charge

    • combined sensitivity ms > 8.4 ps-1

  • 1st update: October 2005 – presented at PANIC 2005

    • substantial increase in semileptonic signal from TTT

    • several analysis improvements, e.g.,

      • neural net based jet-charge opposite side flavor tag

      • improved opposite side flavor tag calibration

      • improved boost resolution on semileptonic decays

    • combined sensitivity  ms > 13.0 ps-1

These results based on 360 pb-1 (0d data)


Current cdf b s oscillations analysis

Current CDF Bs Oscillations Analysis

  • This winter our focus shifted to three main areas

    • adding same-side kaon tagging (SSKT)

      • blessed on 23 February 2006

    • adding 0h and 0i data (an additional 640pb-1) (done – see later)

    • using partially reconstructed hadronic decays (still in progress)

  • 1st step – add SSKT to 360pb-1 hadronic analysis

    • Schedule had us unblinding on 13 March 2006

    • DØ announcement at Moriond EWK on 12 March 2006

    • CDF unblinded hadronic scan on 13 March 2006 as foreseen

    • found ~3 excess @  ms = 17.3 ps-1

    • 0d hadronic-only result already much more significant than DØ

    • preblessed at B meeting on 16 March 2006

    • decided to add 0h & 0i data asap for both hadronics & semileptonics


D result

reminder: oscillation probability

DØ Result

Presented at Moriond EWK on 3/12/06

Amplitude peaks @  ms = 19ps-1

2.5 discrepant with A=0 (1%)

10% compatible with A=1

17 <  ms < 21 ps-1 @ 90% CL

Probability that random

fluctuation produces this signal

p-value = (5.0 § 0.3)%


Cdf hadronic data 355pb 1

CDF Hadronic Data (355pb-1)

We were on schedule to unblind 1st part of hadronic data on 3/13/06

caution: arbitrary offset

90%

This result was comparable in sensitivity to DØ result

We had a lot more data, so we decided to add it, and fast


Rapid progress from 3 13 to 3 31

Rapid Progress from 3/13 to 3/31

  • This was a well-tuned analysis & extensively reviewed

    • Winter 2005 had two independent semileptonic analyses

      • included independent fits and data sets, which were fed to each other

      • direct comparison of amplitude scans

    • also independent lifetime measurement in Bs! Ds

  • Emphasis on adding new data was validation

    • signal invariant mass distributions

    • signal lifetime distributions

    • particle identification (TOF and dE/dx)

    • proper time resolution

  • Had to understand how to move from limit to measurement

    • required evaluation of probability of background fluctuation

    • determination of ms including systematic uncertainties

  • Unblinded amplitude scans after B meeting on 3/30/06

    • presented at Joint Physics Meeting on 3/31/2006


Result amplitude scans in 1 fb 1

Result: Amplitude Scans in 1 fb-1

Hadronic Decays

Semileptonic Decays

Single experiment sensitivity > combination of previous results


Result ln likelihood m s v td v ts

Result: -ln(likelihood) & ms, |Vtd/Vts|

A = 1.01 § 0.29 (3.5)

p value: 0.5%

Limited by theoretical

(lattice) uncertainties


Impact on ckm unitarity triangle

Impact on CKM Unitarity Triangle

EPS05

EPS05 + CDF

Figures courtesy of Z. Ligeti (LBNL)


Since blessing on 6 april 2006

Since Blessing on 6 April 2006

  • Special Wine & Cheese on Monday 10 April 2006

    • 3 rehersals: Friday & Sunday afternoon, Monday morning

    • 1 West was standing room only

    • spectacular performance by speaker Ivan Furic

  • FNAL press release on Tuesday 11 April 2006

  • 1st Conference presentation at FPCP 2006, Vancouver, BC

    • CDF contingent flew Monday night

    • Rehersal in hotel room Tuesday morning

    • Excellent presentation by Guillelmo Gomez Ceballos

      • Received with great enthusiasm by Flavor community

  • Several requests for seminars from National Labs

    • ANL, BNL, DESY, LBNL, SLAC …


Public documentation

Public Documentation

  • PRL in preparation

    • 1st draft: Ch. Paus, JK

    • Godparents: Ristori (Chair), Glenzinski, Wuerthwein

    • Heinrich, Punzi are statistics committee consultants

    • plan for accelerated review process

  • Public Document (CDFNOTE 8204)

    • K. Pitts editor, many contributors

    • circulating in collaboration now – please read and send comments

    • would hope to make public by next week

    • could serve as PRD draft

  • Web page

    • link on main CDF public page to main plots & talks

    • http://www-cdf.fnal.gov/physics/new/bottom/060406.blessed-Bsmix/


What s next

What’s Next?

  • Analysis improvements (all already well underway)

    • add satellite peaks (Ds*, Ds) in hadronic modes

    • neural networks for hadronic signal selection

    • use all semileptonic trigger paths (lepton + SVT, SUSY dilepton)

    • neural networks for opposite side tags

    • improve SSKT by combining kinematics and particle id

    • use particle id in signal selection (Ds! K*K)

  • Technical improvements

    • reprocess all data offline version 6

      at least 1st 360 pb-1

    • improvements to fitter implementation

      • e.g., replace ascii input file with ntuple

  • Related physics results (e.g., lifetimes)

Goal: 5 observation for ICHEP 2006


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