Experimental Techniques of High Energy, Nuclear, & AstroParticle Physics

Course InfoOffice: PRB 3146Office hours: anytimeEmail: kass.1@osu.eduClass website: http://www.physics.ohio-state.edu/~kass/p880_06.html (will post powerpoint notes)

Grading Policy:40% muon lifetime experiment (discussed on next page)

40% Homework or YOU think up a project (but I need to OK the project…)

20% Final Project (short presentation)

Muon Lifetime ExperimentGoals: Measure the lifetime of the muon () to ~1% precision

Search for unknown particle with lifetime ~2X ’sBreak up into groups of 2 or 3Each group spends ~2 weeks on experiment

experiment is located in SM3018Report written using LATEX

template providedReport should include a section on:

IntroductionApparatusTheory calculation of muon lifetime Discussion of higher order correction Lifetime of free Vs captured Data Analysis Determination of average lifetime Possible separation into + and - lifetimes Upper limit on the amount of a particle with lifetime=4s in data Background estimationSystematic errorsConclusionsReferences

Reports are due before end of the winter quarter

I have a book with many good articles describingsimilar experiments that measure the lifetime

Experimental Techniques of High Energy, Nuclear & AstroParticle Physics

• Introduction to detectorsdiscuss a few typical experiments

• Probability, statistics, and data analysis (Leo, ch 4)prob. distributions, maximum likelihood, least squares fitting,

lying

• Passage of radiation through matter (Leo, ch 2)light and heavy charged particles and photons

• Scintillation devices (Leo, ch 7, 8, 9)counters and calorimeters, energy measurement

• Ionization devices (Leo, ch 6)proportional and drift chambers, momentum measurement

• Semiconductor devices (Leo, ch 10)silicon microstrip detectors, vertexing

Course Outline

References• Particle Data Book (FREE! ORDER ONE TODAY) http://pdg.lbl.gov• Techniques for Nuclear and Particle Physics Experiments, Leo• Particle Detectors, Grupen• The Physics of Particle Detectors, Green• Detectors for Particle Radiation, Kleinknecht• The Particle Detector BriefBook, Bock and Vasilescu

http://www.cern.ch/Physics/ParticleDetector/BriefBook• Introduction to Experimental Particle Physics, Fernow• Statistics for Nuclear and Particle Physicists, Lyons• Probability and Statistics in Particle Physics, Frodesen, Skjeggestad,

Tofe• Statistical Data Analysis, Cowen• Statistics, Barlow• Quarks and Leptons, Halzen and Martin (oldie but still used in P880)• Particle Physics, Martin and Shaw (P780 level)• Introduction to Elementary Particles, Griffiths (P780 level)

Intro to HE/NE/AP ExperimentsWhat are the ingredients of a high energy/nuclear physics/astro-particle experiment?Consider four examples of different types of experiments:

Fixed Target (FOCUS, SELEX, E791)Colliding Beam (BaBar, CDF, STAR)Active Experiment (Super K, SNO)Experiments in Space (GLAST)

Some Common features:energy/momentum measurementparticle identificationtrigger systemdata acquisition and storage systemsoftwarehardworking, smart people…

Some Differences:experiment geometrydata ratesingle purpose vs multi-purposeradiation hardness

A Conceptual Experiment-IImagine an experiment designed to search for Baryons with Strangeness=+1These particles would violate the quark model since Baryons always have negative strangeness in the quark model.

A candidate reaction is: -pk-X+

Since this is a strong reaction we need to conserve:baryon number: X has B=+1strangeness: X has to have +1electric charge: X has to have Q=+1

General requirements of experiment: we need to know that only k- and one other particle produced in final stateTo achieve this we will have to:

get a beam of -’s with well defined momentum (we need an accelerator)get a target with lots of protons (e.g. liquid hydrogen)identify -’s and k-’s

eliminate background reaction: -p -p measure the momentum of the -’s and k-’s

use conservation of E and p to eliminate background reactions: -pk-k+n or k-kop

a way to record the data

A Conceptual Experiment-IIWhat are the important issues for this experiment? -pk-X+

a) How are we going to identify the , kaon and proton? what momentum range do we have to worry about?b) To what precision do we need to measure the momentum of the and k? will need a magnet will need to measure trajectory in magnetic fieldc) Do we need to use a calorimeter to measure energy?d) How will we know that only an X+ is produced?e) How much space do we have for the experiment?f) How much data do we need to collect? what event rate is expected?g) How long will this experiment take? how many people will work on it?h) How much $$$ will the cost?

Simple Quark Model1960’s

d u s c b t

Electric charge

-1/3 2/3 -1/3 2/3 -1/3 2/3

Isospin Iz -1/2 +1/2 0 0 0 0

strangeness

0 0 -1 0 0 0

charm 0 0 0 +1 0 0

bottom 0 0 0 0 -1 0

topness 0 0 0 0 0 +1

Mesons: pair of quark and anti-quarkBaryons: triplets of quarks

Quarks are point-like spin ½ objects.Quarks “feel” the strong force, in addition to EM, Weak, and Gravitational forces.

Pentaquarks !

s

Experiment studies:nnK+K-

but, does not measure the neutron

nK+ is exotic

Evidence for a Narrow S=+1 Baryon Resonance in Photoproduction from the NeutronPRL 91, July 2003. T.Nakano et al.

K+n5=dudusnK- is not exotic

Example of fixed target experiment: FOCUS

Real life view

Momentum: silicon+drift chambers+PWC’s+magnet

Energy: EM+hadronic calorimeters

Particle ID: Cerenkov Counters, muon filter calorimeter

BaBar Experiment@ SLACGeneral purpose detector to study lots of different final states produced by

e+e- annihilations at 10 GeV cm energy

Must have cylindrical geometry since beams pass through the detectorMust measure: momentum of charged particles energy of ’s and o’sMust identify particles: charged: e, , , k, p neutral: , 0, k0,

e+e-B+B-

B+

s

s

B-D

DDDK

1.5 T Solenoid Electromagnetic Calorimeter

(EMC)Detector of Internally

Recflected Cherenkov

Light (DIRC)

Instrumented Flux Return

(IFR)

Silicon Vertex Tracker (SVT)

Drift Chamber (DCH)e- (9 GeV)

e+ (3.1 GeV)

SVT, DCH: charged particle tracking vertex &mom. resolution

EMC: electromagnetic calorimetry

/0/

DIRC, IFR, DCH: charged particle ID /K/p

BaBar

Example of active experiment: SuperKamiokande

Inside SuperK

Original purpose of experiment was to search for proton decay: pe+0 Baryon and lepton number violation predicted by many grand unified models (e.g. SU(5))BUT it discovered neutrino oscillations instead: Prof. M. Koshiba (U. Tokyo) is awarded 2002 Nobel Prize "for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos."

General Requirements for experimentNeed lots of protons (decay rate of 1032 years7x103 tons of H2O) Size: Cylinder of 41.4m (Height) x 39.3m (Diameter) Weight: 50,000 tons of pure water

Need to identify e-’s and 0’s Reject unwanted backgrounds (cosmic rays, natural radiation) 103m underground at the Mozumi mine of the Kamioka Mining&Smelting Co Kamioka-cho, Japan

Super KamiokandeCloser look at experimental requirements: Identifying ’0s tricky since 0 thus must identify ’s Need to measure energy or momentum of e and 0

impractical to use magnetic field measure energy using amount of Cerenkov light detect cerenkov light using photomultiplier tubes 11,200 photomultiplier tubes, each 50cm in diameter , the biggest size in the world Energy Resolution: 2.5% @ 1 GeV and 16% (at 10 MeV) Energy Threshold: 5 MeV Need to measure direction of e and o to see if they come from common point cerenkov light is directional Need to measure timing of e and o to see if they were produced at common time cerenkov light is “quick”, can to timing to few nanoseconds

Nov. 13: Bottom of the SK detector covered with shattered PMT glass pieces and dynodes.

BUT DON’T FORGETCIVIL ENGINEERING!Nov 12 2001: accident destroys 1/3 of phototubes

e+ e–

Si Trackerpitch = 228 µm8.8 105 channels12 layers × 3% X0

+ 4 layers × 18% X0

+ 2 layers

CsI CalorimeterHodoscopic array8.4 X0 8 × 12 bars

2.0 × 2.7 × 33.6 cm cosmic-ray rejection shower leakage correction

ACDSegmented scintillator tiles0.9997 efficiency

A high energy physics experiment in spaceStudy -rays from 20 MeV-300 GeV

Measure energy and direction Dark matter annihilation

Gamma ray bursters

Active Galactic Nuclei

Gamma Ray Large Area Space Telescope(GLAST)

size: 1.8x1.8x1m

Particle DetectionIn order to detect a particle it must interact with matterThe most important “detection” processes are electromagnetic: Energy loss due to ionization electrons particles heavier than electrons (e.g. , , k, p) Energy loss due to photon emission bremsstrahlung (mainly electrons) Interaction of photons with matter photoelectric effect Compton effect pair production ( e+e-) Coulomb scattering (multiple scattering) Other/combination of electromagnetic processes

cerenkov light scintillation light electromagnetic shower transition radiation

Calculation of above processes involve classical EM and QED

Hadrons (,k,p) interact with mattervia the strong interaction and create particles through inelastic collisions.These particles lose their energy via EM processes:0or ++e