Experimental Methods in HEP Salasa A. Nawang Iligan Institute of Technology of Mindanao State University Iligan City OUTLINE ● Introduction/Overview ● Principles of detection ● Important aspects in measurement ● Neutrinos: Physics motivation and Measurement ● Our Work 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 2 Introduction/1 Physics [Theory] Expt Detectors Methods Accurate/Precise Getting meaningful Measurement results 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 3 Experimental Design confirmation THEORY EXPERIMENT validation 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 4 Introduction/2 ● Experimental Goal – We want to detect its presence – Look at its tracks/pattern. – Measure its energy deposit, etc... ● Procedure [what forms?] – Depends on the type of particle, mass, charge, etc... ● Motivation – Guided by theory... 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 5 Detection Principle [too primitive] Path of the positron in a CLOUD ELECTROSCOPE Chamber [C. D. Anderson, Phys. Rev. 43 (1933 492)] 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 6 Detection Principle [w/ photons] Scintillator Light Guide PMT 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 7 Detection Principle [e.g. charge particles] They interact via multiple Coulomb scattering via the Stopping power dE/dx. dE/dx is described by the Bethe-Bloch equation About (1/500) of Etotal is transferred per collision with the electron 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 8 dE/dx for electrons/positrons (dE/dx)(dE/dx)TOTAL == (dE/dx)(dE/dx)collision ++ (dE/dx)(dE/dx)radiation Due to the Total Due to Radiation Due to collision Proton's 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 9 Detection Principle [DAQ] 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 10 Detection Principle [e.g. spectrum] 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 11 Range Phenomenon: RANGE STRAGGLING Energy loss is Statistical in nature −1 T O dE S T 0=∫ dE NUMERICAL INTEGRATION 0 [ dx ] 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 12 But, wait a minute... Why spend so much money and put such great effort into studying particles which are so short-lived and which are created only under special circumstances? Why not confine our studies only to Protons, neutrons and electrons... ...a...a detectivedetective agent?agent? 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 13 Via Cosmic-rays Only 14 particles known in 1947: 4 pioneers (γ, p, n, & e), neutrino and anti-neutrino, 3 pions, 2 muons, & Anti-p,n, & positron 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 14 From Cosmic-rays to Accelerators ● 1928-1932: Cockcroft-Walton ● 1930: Robert J. Van de Graaff ● 1930: Ernest O. Lawrence [circular type] ● 1950s: In the US, Cosmotron(~3 GeV @ BNL), Bevatron (~6 GeV @ UC Berkeley), 10-Gev (in Russia) ● 1960: 28-GeV PS @ CERN ● 1961: 33 GeV BNL ● 1967: 76 GeV in Russia ● 1972,1975: 400,500 GeV at Fermi Lab ● 1976: CERN SPS ● 1980s: Tevatron at Fermi-Lab ● Colliders, storage ring, and so on 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 15 So, do we have an accelerator in the Philippines? If Yes, where? 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 16 Mesons of spin zero known in 1960 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 17 ...a Detective work... 3/31 - 4/9,2014, Nawang, S. CERN School Philippines Courtesy: BNL 18 Nucleons and Hyperons known in 1960 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 19 Typical Scenario PUZZLE THEORIST EXPERIMENTALISTS Beta Decay Pauli, Fermi, ... Reines, Cowan,.. Solar Neutrino John Bahcall Raymond Davis [SOLVED?] Atmospheric Neutrino ??? SuperKamiokande Any Particle Physics Puzzle ...it can be anyone here ??? 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 20 Problem in Nuclear Beta Decay CONTINUOS Pauli proposal (1930) New particle exist. Continuous Energy spectrum of Beta electrons!!! 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 21 Neutrino particle Observed… Reines and Cowan (1956) Detector at the Savanna River υ + → + + Nuclear Reactor e p n e Frederick Reines received nobel prize in 1995 …We are happy to announce to you [Pauli] that we have definitely Detected neutrinos … 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 22 Solar Neutrino Problem Sudbury Neutrino Observatory RESULT RATIO 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 23 Raymond Davis Jr.’s Perseverance: 30 years pioneering solar neutrino detection (1969-1999) Homestake mine tank: 20 feet in diameter, 48 feet long, held 100,000 gallons of perchloroethylene . It was located 4,900 feet below ground surface 4/5/14 24 Atmospheric Neutrinos Expect an isotropic flux of neutrinos at High energies For E > a few GeV, and a given neutrino flavor, (Up-going/Down-going) ~ 1.0 Expected uncertainty less than 1% 4/5/14 25 Did the muon neutrinos change to another kind? 4/5/14 26 Atmospheric Neutrinos 4/5/14 27 Atmospheric Neutrinos Eν>1.3 GeV PUZZLE: Evidence for oscillation of atmospheric neutrinos, Where did the other Phys. Rev. Lett. 81 (1998) 1562-1567 muon neutrinos go? 4/5/14 28 Motivation to perform an experiment/measurement ● It depends if you are a: ● Student ● Newly working Researcher ● Administrator ● Government ● etc... 4/5/14 29 ...OR ● Science propagation of knowledge ● Confirmation ● Search for truth... 4/5/14 30 K2K (KEK to KAMIOKA) Search for NEUTRINO OSCILLATIONS using accelerator-produced neutrinos (April 1999-November 2004) Far Detector(Super-Kamiokande) Near Detector(KEK) ● Detect neutrino signal after possible ● Measure neutrino flux oscillation ● Study Neutrino interactions ● 250km from KEK, Tsukuba ● Located, 200m downstream Neutrino Beam ● 99% νμ beam ● Average energy ~ 1.3 GeV ● Produced by 12 GeV PS accelerator at KEK 4/5/14 31 4/5/14 32 Bruno Pontecorvo’s Vision (Neutrino Oscillation, 1957) Other neutrino flavors were not yet know at that time J. Exptl. Theoret. Phys. 33, 1957, 549 Pontecorvo’s idea: ν⇒ ν In analogy to K O ⇒ K O oscillation Neutrino Flavor Mechanism 3/31 - 4/9,2014, Nawang, S. CERN School Philippines 33 Different Neutrino species exists (1962) νe ,μ , τ +N →{e ,μ ,ν }+ X Leon M. Lederman, Melvin Schwartz , Jack Steinberger The Nobel Prize in Physics 1988 For the neutrino beam method and the demonstration of the doublet structure of the leptons through the discovery of the muon neutrino 4/5/14 34 Neutrino Mixing Neutrino Flavors Mass eigenstates MIXING Flavor states NOT EQUAL TO Mass Eigenstates ν = ν = µ τ i ∑ Uiα α i e, , α 4/5/14 35 Unitary matrix U Mixing angle Maki-Nakagawa-Sakata Matrix: sij = sin θ ij cij = cos θij Mixing pattern borrowed from Cabibbo-Kobayashi-Maskawa Matrix in quark sector U U U e1 e2 e3 = = θ = θ U U µ 1 U µ 2 U µ 3 sij sin ij cij cos ij U τ 1 U τ 2 U τ 3 c s 0 1 0 0 1 0 0 c 0 s 12 12 13 13 = − U s12 c12 0 0 c23 s23 0 1 0 0 1 0 − − iδ − 0 0 1 0 s23 c23 0 0 e s13 0 c13 4/5/14 36 Two Flavor state In the two-flavor neutrino oscillation framework, the probability that a neutrino of energy E with a flavor state νμ will later be observed In the νμ eigenstate after traveling a distance L in vacuum is given by 2 2 L(km) 2 P(ν µ → ν τ ) = sin 2θ sin 1.27 ∆ m 23 E(GeV) 23 sin 2 2θ = 1, ∆ m2 = 3.0x10− 3 eV2 ,L = 250 km (Values taken from Solar neutrino data) 4/5/14 37 Physics/Neutrino Interaction CCQE ● ~100% efficiency for NSK ● reconstruct Eν from(θμ,Pμ) CC nQE ● ~100% efficiency for NSK ● Bkg for Eν measurement NC ● Less 50% efficiency for NSK ● Bkg for CCQE tracks 4/5/14 38 Typical νμ production From Accelerator machine detector 4/5/14 39 Principle of Measurement ● Measurement of neutrino flux with CCQE interactions between two identical (except the size) detectors [water Cerenkov Detector] ● Measurement of Disappearance at SK ● Same Target and technique, but different spectra 4/5/14 40 Overview of Detectors MUMON ND 4/5/14 41 Phys Rev D 74 (2006) pp072003 Nature of Measurement ● PRESENCE or ABSENCE ● Confirmation thru its signature or decay mode, or interactions, if there are any. ● If present, ● How many?...its like counting how many fish in the net. ● If absent, ● (Keep it secret first) …...repeat again, and again... 4/5/14 42 Cherenkov Radiation Cherenkov Light ring 4/5/14 43 Detection Principle Charged particles travelling In water at speed greater than c/n emit Cherenkov light υ + → + − e n p e υ + → + + e p n e − υ µ + n → p + µ + υ µ + p → n + µ The cone aperture determines Cherenkov light is detected by an Velocity. If we can identify the array of light sensitive PMTs. The image Particle then we know the is in the form of a ring (red tubes) energy 4/5/14 44 Long Track 4/5/14 45 Stopping Track Cherenkov LIGHT 4/5/14 46 Particle Identification Cherenkov Light 4/5/14 48 Tracking Detector TOP View Side View 4/5/14 49 CCQE Candidate ν+n⇒ p+μ 4/5/14 50 CCQE Candidate ν+n⇒ p+μ 4/5/14 51 CC-pπ Candidate ν+n⇒ p+μ+π 4/5/14 52 o π Candidate O 4/5/14 π ⇒ γ+γ 53 νe CCQE Candidate −❑ 4/5/14 νe +n⇒ e + p 54 Event Selection ● Criteria (decide to accept/reject an event) ● Cuts ● Time cut ● Energy Cut ● etc..