Particle Physics

• Particle Physics Department– 90 staff + 65 direct staff-years in other departments– Scientific Programme

• Large Electron-Positron Collider @ CERN• HERA (Electron-Proton Collider) @ DESY

• e+e- Physics (SLD & BaBar) @ SLAC• Neutrino Physics @ MINOS & ISIS• Neutron Electric Dipole Moment @ ILL• Dark Matter Searches @ Boulby• The Large Hadron Collider @ CERN• Particle Accelerators for Particle Physics• Theory and Phenomenology

– Computing and Resource Management

Peach:1) LEP (John Thompson to co-ordinate)

a) A transparency of the W-mass measurement with a brief explanation (for me) as to its significance b) I have a WW-> qqll event, but another nice one always helps

An alternative might be something which compares the three experiments in a direct physics way from physics done in PPD, but this may not be possible.

2) HERA (John Morris/Norman McCubbin)a) Some data from 1997 on structure functions (not too many, but giving something to 'explain' to councilb) A nice typical event

3) SOUDAN/MINOS (Peter Litchfield)a) a neutrino event in SOUNDANb) the R-plotc) a picture of SOUDAN

4) SLD/FLC & etc (Chris Damerell)a) a picture of VXD3b) a picture of an SLD b eventc) a physics plot from SLD b-physicsd) something from Hywel Phillips on future linear colliderse) Something from Bill Murray on Muon Colliders and muon derived neutrino beams

ALSO, do we have a CCD to show, or a ladder, or something tangible

5) BABAR (Gian Gopal)a) a picture of the electronics design for the calorimeterb) a colour transparency of the BaBar detector layoutc) a picture of the current state of BaBard) a simulated b-J/psi Ks

ALSO, do we have anything to show (board designed at RAL, a crystal, ???)

6) ILL (Keith Green)a) A picture of the actual detector (I have the rest)

ALSO, is there anything that we can touch?

7) DM (Nigel Smith)a) The map of Boulbyb) a picture of the site (surface and underground)c) Calibration plot of gamma and neutronsd) data plote) sensitivity plot comparing with the world

ALSO, is there anything that we can touch?

8) ATLAS (Peter Norton)a) picture of ATLASb) Higgs production Feynman diagramc) Higgs production cross-section with others (inc. total cross-section)d) something PPD has done on the SCTe) something PPD has done on the trigger

ALSO, could I have a piece of (simulated?) SCT and some ASIC

9) CMS (Bob Brown)a) Picture of CMSb) Higgs to 2 photon simulated event in CMSc) Higgs plot for aboved) something PPD has done on PbWO3

ALSO, can we have a crystal and VPT or something?

10) THEORY (Dick Roberts)a) an impressive MRSW plot against lots of datab) something from Mike c) something from Herbie (on SUSY please)d) something from Hong Mo

11) CRM (Paul Jeffreys)a) a complicated computing diagram showing that we are networking

lots of computers into single system (Bert MPPC concept)b) something on networking c) a resource management plot (perhaps Dave's monthly accumulation plot or something

Peach:1) LEP (John Thompson to co-ordinate)

a) A transparency of the W-mass measurement with a brief explanation (for me) as to its significance b) I have a WW-> qqll event, but another nice one always helps

An alternative might be something which compares the three experiments in a direct physics way from physics done in PPD, but this may not be possible.

2) HERA (John Morris/Norman McCubbin)a) Some data from 1997 on structure functions (not too many, but giving something to 'explain' to councilb) A nice typical event

3) SOUDAN/MINOS (Peter Litchfield)a) a neutrino event in SOUNDANb) the R-plotc) a picture of SOUDAN

4) SLD/FLC & etc (Chris Damerell)a) a picture of VXD3b) a picture of an SLD b eventc) a physics plot from SLD b-physicsd) something from Hywel Phillips on future linear colliderse) Something from Bill Murray on Muon Colliders and muon derived neutrino beams

ALSO, do we have a CCD to show, or a ladder, or something tangible

5) BABAR (Gian Gopal)a) a picture of the electronics design for the calorimeterb) a colour transparency of the BaBar detector layoutc) a picture of the current state of BaBard) a simulated b-J/psi Ks

ALSO, do we have anything to show (board designed at RAL, a crystal, ???)

6) ILL (Keith Green)a) A picture of the actual detector (I have the rest)

ALSO, is there anything that we can touch?

7) DM (Nigel Smith)a) The map of Boulbyb) a picture of the site (surface and underground)c) Calibration plot of gamma and neutronsd) data plote) sensitivity plot comparing with the world

ALSO, is there anything that we can touch?

8) ATLAS (Peter Norton)a) picture of ATLASb) Higgs production Feynman diagramc) Higgs production cross-section with others (inc. total cross-section)d) something PPD has done on the SCTe) something PPD has done on the trigger

ALSO, could I have a piece of (simulated?) SCT and some ASIC

9) CMS (Bob Brown)a) Picture of CMSb) Higgs to 2 photon simulated event in CMSc) Higgs plot for aboved) something PPD has done on PbWO3

ALSO, can we have a crystal and VPT or something?

10) THEORY (Dick Roberts)a) an impressive MRSW plot against lots of datab) something from Mike c) something from Herbie (on SUSY please)d) something from Hong Mo

11) CRM (Paul Jeffreys)a) a complicated computing diagram showing that we are networking

lots of computers into single system (Bert MPPC concept)b) something on networking c) a resource management plot (perhaps Dave's monthly accumulation plot or something

Peach:Peach:

Departmental structure

Particle Physics Departm ent

SCTM ike Tyndell

TriggerNorm an Gee

ATLASPeter Norton

SLD/FLCChris Dam erell

BABARNeil Geddes

Dark MatterNigel Sm ith

EDMKeith Green

Soudan/M INOSPeter Litchfield

Experim ent AChris Dam erell

Deputy: Peter Norton

CM SBob Brow n

ALEPHJohn Thom son

DELPHIRobert Sekulin

OPALKen Bell

H1John M orris

ZEUSNorm an M cCubbin

LHC b

Experim ent BBob Brow n

Deputy: Norman M cCubbin

TheoryDick Roberts

Resource Managem entPaul Jeffreys

Com puting GroupPaul Jeffreys

Com puting & Resource M anagem entPaul Jeffreys

Special ProjectsGeorge Kalm us

Ken PeachDirector

Deputy: Bob Brown

BaBar - Physics

CP Violation - An asymmetry between matter and anti-matter - Part of the explanation of why we are made of matter B mesons - A good laboratory to test current theories - But you need a lot of them (>10,000,000)BaBar - Detailed study of differences between B and anti-B mesons - Stanford CA, over 500 physicists from over 75 institutions

(UK: Birmingham, Bristol, Brunel, Edinburgh, Imperial College, Liverpool, Manchester, RAL, RHBNC, QMW)

BaBar - Status

Detector completed in May 1999CLRC: Electronics design (calorimeter/trigger) Mechanical design (calorimeter) Computing + software

Early progress has exceeded expectations

events recorded (1,600,000 Bs)RAL provides UK analysis centre with4.5TB disk array + tape storage + servers.

Neutrino mass

•The Standard Model assumes that neutrinos have no mass, observation of a mass would be the first chink in the armour of the model and give clues to what lies beyond

•Neutrinos come in three types, recent results give strong evidence that they have mass

Neutrinos detected from the sun are less than required by the fusion processes that fuel the energy output. (Super-Kamiokande, SNO)

Muon neutrinos from cosmic ray interactions appear less frequently from the other side of the earth than from above (Super-Kamiokande, Soudan 2)

Neutrinos types that should not be produced may be observed from proton beam dumps (Los Alamos says yes, KARMEN at RAL says no)

•These phenomena can be explained by neutrino oscillations. If neutrinos with slightly different masses propagate through space, quantum mechanics says they may change from one type into another. How much and how fast depends on the mass difference, the distance travelled and the coupling between the different types

MINOS

•The solar and atmospheric effects depend on natural neutrinos and the source strength and composition must be calculated from theory

•We need a controlled experiment using accelerator neutrinos-----MINOS

MINOS will use neutrinos from a new, very intense, source; the New Main Injector at Fermilab , sending them 730km to the Soudan mine laboratory

The beam produced at Fermilab is mostly muon neutrinos. The composition is measured at Fermilab using a relatively small 1kton detector. It is measured again at the Soudan mine in a massive 5kton detector. If it is different, neutrino oscillations have occurred. We can study the region suggested by the atmospheric effect

RAL is providing project leadership, readout electronics, mechanical engineering and on-line and off-line programming

The Search for Dark Matter

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Observed BackgroundCompton Calibration

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Time Constant (ns)

Anomalous events

• Galactic Dark Matter• From dynamics: 90% of Galaxy is non-luminous• New type of particle?

– WIMP - weakly interacting massive particle– Predicted by new particle physics models (SUSY)

• Search using sensitive scintillation detectors (NaI,Xe)• Shield from cosmic rays by going underground

– UK: 1100m down the Boulby potash mine, N.Yorks

• Odd events seen– Background?– WIMP?– Needs new detectors

Dark Matter Particle Mass (GeV)

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Normalised rate (events per kg.day)

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Na

UK,Rome,1996

Neutralino predictions

UK unidentified events (5+5+2 kg)

Rome seasonal difference (100kg)

"Dark Matter fits"

gamma & beta background levels

UK,Rome,1998

Xeobjectives of programme 1999-2003

• For Neutron– Standard model: 10-32e.cm– SUSY: 10-25 e.cm

• Measure rotation frequency of cold neutron

– Changes as electric fields applied– Current limits ~5. 10-26 e.cm

• Electric Dipole Moment • If time and parity symmetry broken

– Gives static edm on particles

The Electric Dipole Moment of the Neutron

The ATLAS detector at LHC

• The ATLAS detector is the largest general purpose particle physics detector ever to be built.

• It is designed to provide the maximum physics discovery potential for the new physics expected at the LHC, such as the origin of mass and evidence for supersymmetry.

• To be able to do this physics, the detector must look at 1 000 000 000 000 000 collisions every year and fully measure a selected subset of these.

• The UK is involved in building the innermost tracking detector and the trigger electronics which enables the handful of interesting events to be identified, recorded and (hopefully) provide the evidence for new physics.

Tracking in ATLAS

• A typical physics event is shown in the accompanying figure.

• In order to be able to “measure” these events, extremely precise tracking detectors with a resolution of ~10mm are required to fill a volume of ~10 cubic metres

• A detector based on the use of silicon sensors with 6million individual readout channels has been proposed.

• The RAL group has led the design and engineering of this project and together with the UK university developed the radiation tolerant sensors and electronics required.

• Details shown on the next page :

– Tracker engineering design (size 2m x 7m)

– Silicon module design (size 12cm x 6cm)

– First prototype silicon module

– Custom radiation hard ASIC (6mm x 6mm)

Tracking in ATLAS

Triggering in ATLAS

• The raw data rate from ATLAS is around one million CDs every second, within which the trigger must find rare physics processes with high efficiency. The operation is key to the success of the experiment.

• A three-level trigger scheme is planned. RAL and the UK community are major contributors to levels 1 and 2.

• Level-1 runs at the full LHC rate of 40MHz. It uses signals from calorimeters and muon detectors, requires purpose-built hardware running highly tuned algorithms, and forms initial accept/reject decisions in 2 Seconds. About 1 collision in 1000 is retained.

• Level-2 refines the level-1 output by a further factor of 100, using the full detector at full granularity. It needs carefully selected fast commercial processors connected with highly optimised data links.

• Event selection is completed by a full analysis running on a very large processing farm. Surviving data is recorded.

Electromagnetic Calorimeter for CMS at LHC

Physics Search for the Higgs particle and understanding the origin of Mass Search for new particles and new symmetries such as Supersymmetry

Method High resolution electromagnetic calorimetry (energy of photons, electrons) Signal Higgs decay to two photons. Challenging requirements for detector design. Ensures high sensitivity to other physics channels.Detector Crystals of PbWO4 scintillator: fast (30 ns), dense, radiation hardRAL-PPD CMS Endcap electromagnetic calorimeter Project Co-ordinator Advanced simulation of physics response, to optimise detector design. Develop novel photodetectors (Vacuum Phototriodes) to operate inside 4 Tesla solenoid Appraisal of prototypes in test beams at ISIS and CERN-ID, -ED CMS Endcap e-m calorimeter Project Engineer

Complete engineering design of the detector 3D design, including FEA of advanced, precision carbon fibre alveolar structures. Prototyping.Future Construct all endcap detector modules at RAL

CMS Tracker Readout

• The Problem– 12,000,000 channels of ‘analogue’ readout – (preserving pulse-height information)– 10 encyclopedia per second of information– Elements close to the detector must be

radiation-hard• The Solution

– Purpose-designed very large scale integrated circuits

– using state-of-the-art silicon technology (ASICs)

– + Optical fibre data transmission– + Data-acquisition modules with a high level– of built-in, programmable intelligence

• The CLRC Contribution (PPD and ID)– Design, development and test of the ASICs– Design, development, test, programming – and integration of the readout modules

Prototype readout board

Physics at HERA

• PPD is involved in the two main experiments at HERA: ZEUS and H1

• Electrons (or positrons) collide with protons in a double ring of magnets

• The structure of the proton is probed in very fine detail

• Both neutral currents (γ and Z exchange) and charged currents (W exchange are studied

• The machine performance has steadily improved

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Physics at LEP

• LEP has been running successfully since 1989

• After many years at and around the Z peak, the energy has steadily been increased to 102 GeV per beam

• Precision measurements have been made of the W boson mass

• Despite all our efforts the Higgs boson has not yet been discovered

Results from LEP

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The energy spectrum of direct photons produced in hadronic Z0 decays compared to various QCD-based theoretical predictions. The inner error bars on the points are statistical, the outer error bars are the quadratic sum of statistical and systematic errors. (From Eur. Phys. J. C62 (1998) 39-48)

A magnified view of tracks in the DELPHI silicon vertex detector. Secondary vertices from the decay of b-particles are clearly visible.

Accelerator R&D for Particle Physics

• Objective: develop accelerator R&D in UK for PP facilities• Resources: £300k p.a. from PPARC 1999-2002

• together with £150k p.a. from CLRC• Options and choices:

• Linear colliders (e+ e-)• Muon facilities, including a νfactory (at RAL?)• Generic technologies - e.g. superconducting

magnets and RF• Actions:

• Project plans being finalised• Advisory panels setup

PPD Theory Division

• Particle Physics Phenomenology– theory that is relevant to the UK experimental

programme • Standard Model

• HERWIG - Monte Carlo descriptions of final states : crucial to future detection of Higgs at LHC.

• Higgs - experimental signatures• Proton structure - predictions for Tevatron, LHC

W, Z and Higgs production• Beyond the Standard Model

• SUSY - masses of new particles, experimental signatures, theoretical parameters

• Neutrinos - understanding masses, oscillations, mixing

CLRC’s role in IT for HEP

• Historically, provided central computing facilities for UK HEP

– Large CPU farms

– Disk and tape storage

• BaBar’s Regional Centre sited here:

– One of three world-wide (JREI)

– SUN E4500 processor with 4GB

– 4.5TB disk

– Excellent preparation!

• LHC Computing Challenge JIF bid

– Prototype Tier 1 Regional Centre

• 2200 PCs (450Mhz)

• 54TB disk

• 320TB tape store

• 50Mbps connection to CERN

• Future:

– GRID technology

• Hierarchical GRID of data centres

• http://www.phys.ufl.edu/~avery/mre/white_paper.html

– US HEPN already invested $20M

– CERN active

– UK HEP - and other disciplines (commerce) - must not be left behind!

– CLRC making large contribution towards case for bid against SR2000

• JIF bid integral to this

• BaBar experience vital

– Also possibility for EC funding

• Summary .. Very exciting time for IT!

‘The LHC Computing Challenge’

Tier-1RegionalCentre

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Tier-2RegionalCentre

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ServiceCentre

CERN