Experimental Techniques of High Energy, Nuclear, & AstroParticle Physics

1. Experimental Techniques of High Energy, Nuclear, & AstroParticle Physics Course Info Office: PRB 3146 Office hours: anytime Email: kass.1@osu.edu Class 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)

2. Muon Lifetime Experiment Goals: Measure the lifetime of the muon (m) to ~1% precision Search for unknown particle with lifetime ~2X m’s Break up into groups of 2 or 3 Each group spends ~2 weeks on experiment experiment is located in SM3018 Report written using LATEX template provided Report should include a section on: Introduction Apparatus Theory calculation of muon lifetime Discussion of higher order correction Lifetime of free m Vs captured m Data Analysis Determination of average m lifetime Possible separation into m+ and m- lifetimes Upper limit on the amount of a particle with lifetime=4ms in data Background estimation Systematic errors Conclusions References Reports are due before end of the winter quarter I have a book with many good articles describing similar experiments that measure the m lifetime

3. Experimental Techniques of High Energy, Nuclear & AstroParticle Physics Course Outline • Introduction to detectors discuss 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

4. 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)

5. Intro to HE/NE/AP Experiments What 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 measurement particle identification trigger system data acquisition and storage system software hardworking, smart people… Some Differences: experiment geometry data rate single purpose vs multi-purpose radiation hardness

6. A Conceptual Experiment-I Imagine an experiment designed to search for Baryons with Strangeness=+1 These particles would violate the quark model since Baryons always have negative strangeness in the quark model. A candidate reaction is: p-p®k-X+ Since this is a strong reaction we need to conserve: baryon number: X has B=+1 strangeness: X has to have +1 electric 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 state To achieve this we will have to: get a beam of p-’s with well defined momentum (we need an accelerator) get a target with lots of protons (e.g. liquid hydrogen) identify p-’s and k-’s eliminate background reaction: p-p®p-p measure the momentum of the p-’s and k-’s use conservation of E and p to eliminate background reactions: p-p®k-k+n or k-kop a way to record the data

7. A Conceptual Experiment-II What are the important issues for this experiment? p-p®k-X+ a) How are we going to identify the p, 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 p and k? will need a magnet will need to measure trajectory in magnetic field c) 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?

8. Simple Quark Model1960’s Quarks are point-like spin ½ objects. Quarks “feel” the strong force, in addition to EM, Weak, and Gravitational forces. Mesons: pair of quark and anti-quark Baryons: triplets of quarks

9. Pentaquarks ! Evidence for a Narrow S=+1 Baryon Resonance in Photoproduction from the Neutron PRL 91, July 2003. T.Nakano et al. Experiment studies: gn®nK+K- but, does not measure the neutron K+n=Q5=dudus s nK- is not exotic nK+ is exotic

10. Example of fixed target experiment: FOCUS Momentum: silicon+drift chambers+PWC’s+magnet Energy: EM+hadronic calorimeters Particle ID: Cerenkov Counters, muon filter calorimeter Real life view

11. BaBar Experiment@ SLAC e+e-®B+B- • B+®YK*+ • Y ®m+m- • K*+ ®Ks0p+ • Ks0 ®p+ p- • B-®D*0 p- • D*0 ® D0 g • D0 ® K- p+ General 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 detector Must measure: momentum of charged particles energy of g’s and po’s Must identify particles: charged: e, m, p, k, p neutral: g, p0, k0, L 1.5 T Solenoid Electromagnetic Calorimeter (EMC) Detector of Internally Recflected Cherenkov Light (DIRC) e+ (3.1 GeV) SVT, DCH: charged particle tracking Þ vertex &mom. resolution EMC: electromagnetic calorimetry Þg/p0/h DIRC, IFR, DCH: charged particle ID Þp/K/p e- (9 GeV) Drift Chamber (DCH) Instrumented Flux Return (IFR) Silicon Vertex Tracker (SVT)

12. BaBar

13. Example of active experiment: SuperKamiokande Original purpose of experiment was to search for proton decay: p®e+p0 Baryon and lepton numberviolation 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." Inside SuperK General Requirements for experiment Need lots of protons (decay rate of 1032 years®7x103 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 p0’s Reject unwanted backgrounds (cosmic rays, natural radiation) 103m underground at the Mozumi mine of the Kamioka Mining&Smelting Co Kamioka-cho, Japan

14. Super Kamiokande Closer look at experimental requirements: Identifying p’0s tricky since p0®gg thus must identify g’s Need to measure energy or momentum of e and p0 impractical to use magnetic field Þ 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 po to see if they come from common point cerenkov light is directional Need to measure timing of e and po to see if they were produced at common time cerenkov light is “quick”, can to timing to few nanoseconds BUT DON’T FORGET CIVIL ENGINEERING! Nov 12 2001: accident destroys 1/3 of phototubes Nov. 13: Bottom of the SK detector covered with shattered PMT glass pieces and dynodes.

15.  e– e+ Gamma Ray Large Area Space Telescope(GLAST) A high energy physics experiment in space Study g-rays from 20 MeV-300 GeV Measure energy and direction Dark matter annihilation Gamma ray bursters Active Galactic Nuclei ACD Segmented scintillator tiles 0.9997 efficiency Si Tracker pitch = 228 µm 8.8 105 channels 12 layers × 3% X0 + 4 layers × 18% X0 + 2 layers CsI Calorimeter Hodoscopic array 8.4 X0 8 × 12 bars 2.0 × 2.7 × 33.6 cm • cosmic-ray rejection • shower leakage correction size: 1.8x1.8x1m

16. Particle Detection In order to detect a particle it must interact with matter The most important “detection” processes are electromagnetic: Energy loss due to ionization electrons particles heavier than electrons (e.g. m, p, k, p) Energy loss due to photon emission bremsstrahlung (mainly electrons) Interaction of photons with matter photoelectric effect Compton effect pair production (g®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 (p,k,p) interact with matter via the strong interaction and create particles through inelastic collisions. These particles lose their energy via EM processes: p0®gg or p+®m+n, m+®e+nn