1#

BaBar Overview & Plans

Hassan Jawahery, spokesperson University of Maryland

PEPII MAC MeetingNovember 15-17, 2007

2#

BaBar Upgrade: Completed the upgrade of the Instrumented

Flux Return (IFR)- replaced RPC’s with 12 layers of LST’s & 6 layers of brass in each of the remaining 4 sextants (2 sextants were done in 2004). Have fully recovered muon and KL identification capabilities of the detector.

Run 6: January 19– Sept. 4, 200790/fb delivered & 86/fb recordedwith the total of BaBar data at ~477.45/fb

Analysis of Runs 1-5 data set (390/fb)

Major Activities of the Collaboration

3#

A typical (good) day of BaBar running with PEPII

BaBar continues to collect most of PEPII delivery (dead-time typically at <2%)-crucial to keep this- Improvement in data-flow for SVT, DIRC, EMC have been implemented.

Data taking in 2007

4#

Are we ready for higher luminosity• Machine-Detector issues covered by M. Weaver

yesterday:The detector can withstand the “expected” radiation level &

the rise in the occupancy at some (but small) cost to the performance.

• Data Flow & Trigger:– Worked on reducing L1 trigger rate, transmitted data rate and

readout out time. (Run 6 averages: L1:2.65 KHz, & dead time 1.8%).

DCH: In Run 5, upgraded the front end electronics to reduce the transmitted info. Working well and no longer an issue.

SVT: Readout time window narrowed by ~27%, chip threshold adjustment & left- right readout.

DIRC: readout time reduced with newly cleaned up readout code. EMC: data flow rate reduced

Added a new trigger line (1E)- single energy cluster >800 MeV; Covers Y(nS)(invisible)- light Higgs & dark matter candidates; Level 3- Energy Threshold of 2 GeV. Adds around 12% to Level-1 trigger.

Emergency L1 trigger developed- to be deployed if needed.– We are OK up to ~7 KHz of level-1 trigger rate.

5#

6#

7#

Run Strategy The primary focus of the program continues to be on running at

the (4S) for this final run.

We are considering other opportunities for a part of the run:

New Trigger: single photon trigger (1E) added at the end of run 6. Covers Y(ns) invisible) – low mass higgs & dark matter

candidates,..

Running on narrow resonances; (3S) is emerging as the favorite place.

Search for b & other resonance physics. Measuring invisible decays of (1S), thru (3S) (1S)

cascade. Search for light higgs or dark matter candidates.

With about 2 weeks of running we will have six times the current data on (3S).

Running on (5S) for Bs physics(??) Needs lots of data to be useful.

We are working on optimizing the amount of off-resonance running - - may reduce it from the current 10%.

8#

Computing the BaBar data• Online data collection and processing in good

shape.

• Some challenges in the offline computing infrastructure at SLAC- progress being made to secure resources for processing run 7, and reprocessing runs 1-6.

– Have developed the final event reconstruction code- aimed for the “the best code possible” for our final processing of the data. The outcome is Very close to the goal.

– Now in the validations phase.

– Will be ready for run 7; Normally reprocess the 1st month, expect to happen February 1st; Also aiming for final reprocessing of runs 1-6 –starting around April 1.

9#

BaBar Performance

10#

Muon ID capability fully restored with the upgraded IFR (better in fact)

LSTLST

11#

-

4S)

B0

B0

D-

+

+

K-

e+

+z

e-

Overall performance measured with Oscillation in Dileptons

00 BB

12#

e+

+

0SK

e—

—

z

(4S)

0CPB

J/

00 BB

tags,, Ke

00 BB Overall performance measured with Oscillation with

fully reconstructed B’s

00 BB

13#

BaBar Physics

14#

BaBar Data: Runs 1-5

BB x100.4~ 9

cc x100.5~ 9

x100.4~ 9

ISR

qq e e

& -

Partial composition of the dataBaBar collects

~97% of PEP II delivery

15#

The physics reach of the BaBar Data

Just about any physics that is

accessible at

Charm Physics

Tau physics

Continuum e+e- hadrons

ISR: e+e- hadrons from threshold to ~5 GeV

GeVs 10

CP Studies with B’s

& B Physics

• Origin of CP breaking

•Test CKM paradigm

•Constraints on New Physics possibilities

D0 Mixing; New States,FDs

New States: DsJ, Y(4260), etc

Lepton Flavor Violation

Measuring the hadronic part of photon vacuum polarization

16#

A look at the timeline of our data collection vs our physics output

•There are more than 200 ongoing analyses of BaBar data.

•More than 317 papers published & submitted for publication.

17#

New Major Physics results Since last MAC (06)

• Oscillation observed

• Completed the picture of semileptonic B decays with the observation: &

• New States

00 DD

*DB DB

18#

mixingParticleAntiParticle Evidence for the missing pieces of the

puzzle

Already seen for :

)()( 00 dbBdbB

)()( 00 dsKdsK )()( 00 ucDucD

)()( 00 sbBsbB

The responsible processes :In the Standard Model

An opportunity for New Physics

Particles to contribute

WWZW

W c0D

cu

u0D0D 0D

O(10-3 - 10-2) O(10-5)

19#

Charm physics with Search for D0 mixing – highly suppressed in SM- a powerful window

for NP searches

A little bit of History from Fall 2006

cc x100.4~ 9

Observables:

CP even state: width , massm1 ;

CP odd state: width , massm2

y = -

x = (m1 – m2) / = m /

Last summer

from BaBar

In 2006 it looked like the Limits were approaching the SM expectation

20#

The BaBar observation of D0 mixing

(t) exp(-t) R + R y’ t + ¼ ( x’2 + y’2 ) t2 (t in units of D )

Identified about 1 million D0 K-RS) decays & 4000 D0 K+WS)

Found evidence for ~500 that had switched to anti-D0 before decaying

%31.044.097.0

%021.0030.0022.02

y

x

21#

D0 KK

D 0 KK 0 + c.c.D K

= 409.3 ± 0.7 fs

t (ps)

t (ps)

t (ps)

t (ps)

= 401.3 ± 2.5 fs = 404.5 ± 2.5 fs

(stat. errors only, syst. errors cancel largely in the lifetime ratios)

99.9% signal

70,000 KK events99.6% purity

31,000 events98.0% purity

K and KK lifetimes differ!

0 0,D D K0D KK0D KK

0D

0D

D0 lifetimes

Now also measured in decay time measurements

22#

23#

B Physics [with the ] 109 BB

Investigation of CP violation in B meson Decays & tests of the CKM paradigmIs the CP symmetry broken in B decays?Can we fit the CPV effects in the CKM picture?

Is there room for New Physics?

Search for New Physics in rare (SM suppressed-FCNC) decays ?

B Decays dynamics: Tests of QCD predictions

The “B physics” reach of the BaBar Data

BB x100.4~ 9

24#

109--

1982-B meson observed

1987-B0 mixing & Vub measured; Lower bound on m(top)>42 GeV; with non-zero Vub, CKM in the game as a source of CPV

1993-Radiative penguin bs observed; Major constraint on models of New Physics;Rare decays BK and obserevd; Role of gluonic penguins established;

B factory projects launched.

1999- B Factories start operation.

2001- CPV in B decays observed. Sin2 consistent with SM

The 1/ab phase: Precision tests of the CKM paradigm- Search for N.P. using loop dominated B decays, LFV tau decays, DD(bar) mixing …

Precision sin2; & measured; CKM over-constrained and established as the primary source of observed CPV in nature. Data consistent with no NP effects in b-d and sd.

108--

107--

104--

105--

106--

#B’s

A brief history of major milestones in B physics

25#

Tests of the CKM Paradigm

Picture from A. Hoecker

Theorist view of CKM Observables The view from the experiments

02.0)2sin

8)

105)

%5|)

o

o

ubV

Now

~7%

~20o

~10-15o

~0.04 (~1o)

Aiming for:

26#

A major focus of the experiment is now on searches for New Physics via FCNC decays of B- Deviation from SM searched for:

d

bR

tL

bL

WsL

L

Possible New Physics presence can alter the observables from SM expecations

b ss

sd

g

, ,u c t

W

There is more than just rate in these channels now:

•Photon polarization in bsL ( left-handed in SM)

•Direct CP violation – nearly zero in SM

•In BKll- q2 dependence of the rate; FB asymmetry, polariztion

Search for NP modification of Wilson coefficients C7, C9, C10

Sin2test in Penguin

dominated modes

27#

Simple average: Spenguins=0.56 +/- 0.05 vs reference point: sin68+/-0.03

~ 2.5 deviation at this point.

Latest on Sin2test in Penguin dominated modes-

Our other 2-sigma effect

28#

Observation of B → D(*)

Confirmation of Belle observation in D*+, first

observation of D*0 and first evidence for the D modes

(B → D)/(B → Dl)

arXiv:0707.2758

29#

New States found at the B factories (Summary from E. Eichten)

Candidates for new QCD states: Hybrid (cgc), Molecules(DD)....

30#

The BaBar Collaboration

October 17, 2006

31#

Russia [1/10]Budker Institute, Novosibirsk

Spain [2/7]IFAE-BarcelonaIFIC-Valencia

United Kingdom [11/58]U of BirminghamU of BristolBrunel UU of EdinburghU of LiverpoolImperial CollegeQueen Mary , U of LondonU of London, Royal Holloway U of ManchesterRutherford Appleton LaboratoryU of Warwick

USA[34/256]

California Institute of Technology

UC, IrvineUC, Los AngelesUC, RiversideUC, San DiegoUC, Santa BarbaraUC, Santa CruzU of CincinnatiU of ColoradoColorado StateHarvard UU of IowaIowa State UJohns Hopkins ULBNLLLNLU of LouisvilleU of MarylandU of Massachusetts, AmherstMITU of MississippiSUNY, AlbanyU of Notre DameOhio State UU of OregonPrinceton USLACU of South CarolinaStanford U

Canada [4/23]University of British ColumbiaMcGill UniversityUniversity de MontréalUniversity of Victoria

France [5/40]LAPP, AnnecyLAL OrsayLPNHE des Universités Paris VI et VIIEcole Polytechnique, Laboratoire

Leprince-RinguetCEA, DAPNIA, CE-Saclay

Germany [6/31]Ruhr Universitaet BochumUniversitaet DortmundTechnische Univeritaet DresdenUniversitaet HeidelbergUniversitaet RostockUniversitaet Karlsruhe

The BABAR Collaboration

10 Countries 77 Institutions522 Physicists

+21 non-Physicists

Italy[12/90]

INFN, BariINFN, FerraraLab. Nazionali di Frascati dell'

INFNINFN, Genova & UnivINFN, Milano & UnivINFN, Napoli & UnivINFN, Padova & UnivINFN, Pisa & Univ & Scuola

Normale SuperioreINFN, Perugia & UnivINFN, Roma & Univ "La

Sapienza"INFN, Torino & UnivINFN, Trieste & Univ

The Netherlands [1/3]

NIKHEF, Amsterdam

Norway [1/4]U of Bergen

U of TennesseeU of Texas at AustinU of Texas at DallasU of WisconsinYale

32#

Status of the Collaboration

77 Institutions in 10 countries

The collaborations is on a very strong foundation

With 154 students and 89 postdocs, BaBar continues to be a major educational institution as

well

Faculty PhD Staff Postdoc Grad Non-PhD Totals

Canada 10 1 4 8 23

France 13 14 3 10 4 44

Germany 7 5 3 16 1 32

Italy 29 30 11 20 90

Netherlands 1 2 3

Norway 2 2 4

Russia 2 7 1 1 11

Spain 2 2 3 7

United Kingdom 21 2 16 19 2 60

United States 79 54 50 73 13 269

Totals 164 115 89 154 21 543

One of the few remaining

institutions for training future HEP physicists for the

LHC & ILC era

33#

The Manpower needed to operate the experiment

BaBar’s technical coordinator (Bill Wisniewski) has determined that it takes ~ 110 of collaboration-FTE to operate (Detector maintenance and calibration, and computing tasks- excluding the technical and computing professionals) to operate BaBar. This also does not include the data taking shifts.

System managers have done detailed planning for coverage of the tasks till end of the data taking-e.g. for SVT:

34#

Planning for BaBar in 2008 & BeyondAnalysis of the final data set

35#

Guided by the need for timely performance of the key measurements that define the scientific mission of the program:

Precision knowledge of the Standard Model is an extremely important element of the search for “New Physics” in the (LHC) era, with the B factory data largely in charge of the flavor sector– “Textbook” measurements of the CKM sector are expected to emerge.

Processes involving loop effects are expected to help in understanding the nature of the results that may emerge from LHC. To be relevant these measurements must be available on the same time scale.

The key players in the analyses effort are the postdocs and graduate students, whose life span in the experiment is a major factor in defining the time window required for performing these measurements.

A period ~2-3 years of intense analysis activity, following the end of the data taking, in order to perform and publish the core physics channels.

2009-2011

Given the very broad physics reach of the “1/ab” data, the full exploitation of the physics will take much longer- LEP/SLC/CLEO experiences points to an overall 5-8 year program

The planning of BaBar in 2008 & Beyond(cont’)

36#

A list of topics on BaBar’s “core”

physics program

The ultimate job on CKM – until the SuperB era

The

no-stone-unturned search for New

Physics

37#

Summary remarks The near-“1/ab” phase of BaBar is here:

The LST installation, the last major detector upgrade, has successfully been completed & the muon Id capability of BaBar fully restored for the run 6 and run 7 data.

The collaboration is healthy with a strong base of students and postdocs.

An intense-analysis period of 2-3 yrs is expected to follow the end of the data taking period, requiring continued major support for the experiment.

An enormous amount of physics still to come from Flavor physics with BaBar in this phase. Two of the expected major outcomes are: Precision knowledge of the charge weak sector of the SM & the CKM

parameters; The CKM part of SM is still under construction (expt’s wise)With the possibility of revealing deviation from the SM

Measurements of CP violation and decay properties in rare decay modes, with the possibility of revealing New Physics effects. Hints are already present in the current data.

BaBar is continuing to serve as a major institution for educating future High Energy Physicists who will work on LHC and ILC.

38#

The BaBar community is truly grateful to our PEPII colleagues for their outstanding and dedicated effort in creating the principal

element of this enterprise.