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BaBar RAL Staff Talks. Outline. The Group Fergus Wilson – Group Leader since Oct 2004 Tim Adye Emmanuel Olaiya (at SLAC) Chris Brew (50% Computing Group) Boda Franek (50% LHCb) Adil Hasan (briefly!) The Speakers: Fergus – RAL, BaBar Physics and the Future.

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  • The Group

    • Fergus Wilson – Group Leader since Oct 2004

    • Tim Adye

    • Emmanuel Olaiya (at SLAC)

    • Chris Brew (50% Computing Group)

    • Boda Franek (50% LHCb)

    • Adil Hasan (briefly!)

  • The Speakers:

    • Fergus – RAL, BaBar Physics and the Future.

    • Tim – BaBar Computing as a testbed for the LHC.

    • Chris – BaBar and the GRID.

    • Adil – New Computing Technologies (SRB).

  • Non-Speakers

    • Boda - Run Control.

    • Gian - Retired but still working on physics.

    • Manny - Our contact person at SLAC.

RAL BaBar Staff Talk

In the beginning
In the beginning…

Why does the Universe look like this…

…and not like this?

Perhaps matter and anti-matter behave differently…

RAL BaBar Staff Talk

Stanford linear accelerator center

Sea (Pacific)



San Andreas Fault


San Francisco

San Jose

and some physics…


Stanford Linear Accelerator Center

10 Countries 77 Institutions 593 Physicists

RAL BaBar Staff Talk

The babar detector at slac
The BaBar Detector at SLAC

Linear Accelerator

26th May 1999: first events recorded by BaBar

2.2km ring


The accelerator
The Accelerator

250 million collisions per second from which we store on disk about 5 per second.

Currently have 230 million B pairs (about 18 times previous experiments)

World’s largest computer database (ignoring the NSA…)

RAL BaBar Staff Talk

What ral is involved in
What RAL is involved in

  • Supporting the Experiment

    • See Tim’s talk

  • Developing the GRID

    • See Adil’s Talk

  • Developing GRID production for BaBar

    • See Chris’s Talk

  • Leading the First Level Trigger hardware upgrade project

    • Completed in 2004 and now running (Nicolo de Groot)

  • Exploiting the physics

    • Next page…

RAL BaBar Staff Talk

2005 ral physics
2005 RAL Physics

  • We have concentrated on charmless decays, direct CP, Branching Fraction measurements, interference, extraction of weak and strong phases.

  • Analyses inherited from Bristol:

    • Dalitz Analysis (RAL/Bristol/Birmingham/Warwick)

      • B+→ π+π+π-

      • B+→ K+π+π-

      • B+→ K+K+K-

    • B+ → a1+π0, B+ → a10π+ (Dan Walker, student)

    • B+→ K*0K- , B+→ K+K-π- Dalitz (Jim Burke, student)

    • Lepton Flavour Violation: e+e- → μ+τ- (Marc Kelly)

  • New and upcoming analyses:

    • B+(0)→ K*+(0) h- h+ (inclusive/exclusive decays) (Manny + Fergus)

    • Lepton Flavour Violation: e+e- → μ+τ- (Gian Gopal + Fergus)

    • B+→ K*+π0 , B+→ K0S ρ+ (Fergus)

    • Factorization fits (Noel Cottingham + Fergus)

  • If we can pull this off, we will have ~9 papers with major RAL input.

I should have written the first paper last week…

RAL BaBar Staff Talk

The future
The Future

  • BaBar should run until 2008.

  • Quadruple our dataset.

  • 1/3rd of the collaboration (200 people?) will do their analysis at RAL.

  • RAL will continue to be central to BaBar’s exploitation for many years to come.

RAL BaBar Staff Talk

Babar tier a at ral

BaBar Tier A at RAL

Tim Adye

PPD Staff Talks

4th April 2005

Ral tier a
RAL Tier A

  • RAL is a BaBar “Tier-A” site

    • “Tier-1” in Grid-speak

    • This means that we provide a good fraction of the Collaboration’s computing resources

      • in exchange for a rebate from the UK’s contribution

  • Until last year, it was just SLAC, Lyon, and us.

    • Now also Karlsruhe and Bologna

RAL BaBar Staff Talk

Our r le
Our Rôle

  • RAL has concentrated on physics analysis computing

    • Other sites took care of generic production

      • Event Reconstruction, Monte Carlo generation, etc

    • Has meant lots of physicist users (277 in total)

RAL BaBar Staff Talk

RAL BaBar Staff Talk

What we have to do
What we have to do

  • Keep software up to date

    • New BaBar releases every few weeks (1-2 GB each)

    • Maintain BaBar-specific services

      • Objectivity, xrootd, etc

  • Customise the user environment

    • Make it as SLAC-like as possible

  • Import and manage BaBar data

    • events and detector conditions

    • Currently have 70 TBytes, but we’ll run out soon!

  • Register new BaBar users

  • Help our user community with problems

    • most are specific to BaBar, so need expertese beyond just system support

RAL BaBar Staff Talk

Babar batch cpu use at ral
BaBar Batch CPU Use at RAL

RAL BaBar Staff Talk

Babar batch users at ral running at least one non trivial job each week
BaBar Batch Users at RAL(running at least one non-trivial job each week)

RAL BaBar Staff Talk

The babar computing model
The BaBar Computing Model

  • Until last year, BaBar had two event data formats

    • Objectivity

      • Object-oriented database. Commercial software.

      • Original design. Used for simulation and reconstruction.

      • Cumbersome for physics analysis and data distribution

    • KanGA

      • “Kinder and Gentler Analysis”. Simple ROOT files.

      • Easier for users, more compact, and simpler to install and import.

  • RAL was the only place that held all the KanGA dataset

    • This made us very popular!

    • I developed the import and management tools used here and at all other (Tier C) sites.

RAL BaBar Staff Talk

New computing model
New Computing Model

  • This hybrid couldn’t last

    • Using both Objectivity + KanGA was a waste of resources, expertese, and time

      • and Objectivity was a nightmare (if not for us at RAL  )

  • Last year BaBar developed a new computing model

    • Dropped Objectivity and improved KanGA

    • I did the data distribution and user bookkeeping tools

      • completely redesigned bookkeeping (“meta-data”) system

      • this took over the “event navigation” functionality previously done (very badly) by Objectivity

  • Physics analyses now assigned to different Tier As

    • according to the type of data (“skims”) they need

    • We are responsible for “Charmless” and “Tau/QED”

      • These are predominently UK topics

RAL BaBar Staff Talk

My other interests a
My other interests (a)

  • “SqlAbstractor”

    • Came out of my work on the BaBar bookkeeping

    • Provides an object-oriented interface to a group of database tables

      • Perl and command-line interfaces

      • user does not need to know about table structure/schema

      • developer can provide “synthetic” data items or override database selections/return values

      • A public release is nearly ready (CPAN)

RAL BaBar Staff Talk

My other interests b
My other interests (b)

  • Created new Masterclass exercise

    • replaces 8 year-old OPAL exercise

    • students view BaBar events to measure B-lifetime

    • 500 students used it for the first time this year

      • Measured τB = 2.6 ps. PDG has 1.6 ps.

        • Not bad for an hour’s analysis!

  • Starting to look at making a generic “unfolding”(AKA “deconvolution” or “unsmearing”) package for ROOT

    • Currently there are several techniques

      • each implemented in it’s own stand-alone program

    • I want to allow people to access them from a single interface

      • Can compare different methods without starting from scratch

      • Analagous concept to using MINUIT or RooFit for fitting

RAL BaBar Staff Talk

My other interests c
My other interests (c)

  • PPD web

    • with Gareth Smith and Janet Haswell

  • RAL HEP Summer School tutor

    • though I feel more like a student than a tutor!

  • Science fiction

    • books, films, criticism

      • I even collaborated on a book about it

        • (pity about the naff cover the publisher gave us)

    • … but I guess this is supposed to be aboutmy professional interests.

RAL BaBar Staff Talk

Boda franek
Boda Franek

RAL BaBar Staff Talk


Object Oriented Framework for designing and implementing

Distributed Control Systems

  • Upgraded from SMI to SMI++ in 1996-99 for use in BaBar to design BaBar Run Control ( B.Franek and C.Gaspar)

  • Currently also being used by

    • ATLAS and CMS for the design of their Detector Control System

    • ALICE and LHCb for the design of the complete Experiment Control System

  • Maintained and further developed by B.Franek

RAL BaBar Staff Talk

Run control orc
Run Control ORC

Online Run Control

Designed and implemented using SMI++ toolkit 1996-1999 by B. Franek

Since 1999 maintained and further developed

RAL BaBar Staff Talk

Chris brew
Chris Brew

RAL BaBar Staff Talk

Babar spgrid
BaBar SPGrid

  • Last round of BaBar MC Production generated 2.7B Events at about 69M Ev/Week

  • Distributed production over 19 sites with person at each site responsible for maintaining software and running jobs

  • Next round needs to produce 1.5 – 2 times as much data in a shorter time

  • Trying to use grid tools to use more resources with less effort

RAL BaBar Staff Talk


  • Idea is to make LCG look just like another farm to the BaBar Production system so one manager on one machine can submit jobs to many sites

  • But BaBar MC Jobs have needs:

    • Software

    • Conditions DB

    • Background Input

      We need to be able to make sure these are available to the Job

RAL BaBar Staff Talk


  • BaBar MC software is now packaged for pre-installation using LCG tools

  • Interface of LCG job submission and data recovery into MC production tools is working

  • Simple monitoring of jobs is working

  • Initial shake down production of ~4 Million events on the RAL Tier 1 and RALPP Tier 2 is running. Peak rate about 500,000 Ev/day

RAL BaBar Staff Talk

Deploying xrootd at ral
Deploying Xrootd at RAL

  • BaBar will have 75TB of data at RAL comprising 150k files on 64 disks

  • Real headache keeping track of them

  • Xrootd system developed at SLAC as part of project to replace Objectivity

  • Two type of servers

    • Load Balancers

    • Data Servers

  • Client contacts the Load Balancer which takes care of finding the file they want and redirects them to a data server that has it

RAL BaBar Staff Talk

Data Server

xroot daemon

olb daemon

Load Balancer

olb daemon

xrootd daemon


RAL BaBar Staff Talk

Xrootd at ral 2
Xrootd at RAL 2

  • Now deployed at RAL with 46 TB of data on 21 servers

  • Adding resiliency by interfacing to the Atlas DataStore.

    • All data is being copied to tape

    • If a server goes down and a client requests a file that was on that server the client will automatically be redirected to another server that will copy the file from that DataStore

    • Even works if a server goes down while a client is reading a file

RAL BaBar Staff Talk

RAL BaBar Staff Talk

Adil hasan
Adil Hasan

RAL BaBar Staff Talk

Babar and srb

BaBar and SRB

Adil Hasan (RAL) - project coordinator

Wilko Kroeger (SLAC) and Jean-Yves Nief (ccin2p3)

What is srb
What is SRB?

  • The Storage Resource Broker developed by San Diego Super Computing Center is a Client/Server architecture.

  • Provides uniform interface to different network-connected resources.

    • So can access tape resource and disk resource in same way.

  • Provides a metadata catalogue.

    • Allows logical names to be associated to physical files (concept of collections, datasets, etc).

    • Allows fine-grained access control.

  • Has the concept of Federation to allow multiple SRBs to act as part of the same Virtual Organization.

RAL BaBar Staff Talk

What is srb1
What is SRB?

RAL BaBar Staff Talk

Srb in babar
SRB in BaBar

  • Part of the BaBarGrid effort.

  • Used for Tier 1 (or A) data distribution from SLAC to ccin2p3, currently more than 95TB data copied (over 170K files).

  • For new run (starting now) have setup and federate SRB MCAT at SLAC, ccin2p3 and will setup one at RAL.

    • Will allow SLAC, ccin2p3, RAL to copy data from each other easily (don’t need to know site storage intricacies).

  • Currently working on incorporating client-side applications into user data-distribution tools (Tim).

RAL BaBar Staff Talk

Example of network utilization on esnet us 1 server
Example of network utilization on ESNET (US): 1 server.

SLAC (US)  IN2P3 (FR)

1 Terabyte/day

Fermilab (US) CERN

SLAC (US) INFN Padva (IT)

Fermilab (US)  U. Chicago (US)

U. Toronto (CA)  Fermilab (US)

Helmholtz-Karlsruhe (DE) SLAC (US)


INFN Padva (IT)  SLAC (US)

Fermilab (US)  JANET (UK)


DOE Lab  DOE Lab

Argonne (US)  Level3 (US)

DOE Lab  DOE Lab

Fermilab (US)  INFN Padva (IT)

Argonne  SURFnet (NL)

IN2P3 (FR)  SLAC (US)

RAL BaBar Staff Talk