Long Baseline Neutrino Oscillation Experiments Alfons Weber University

Long Baseline Neutrino Oscillation Experiments Alfons Weber University of Oxford for the MINOS & OPERA Collaborations HEP 2001, Budapest July 18, 2001 July-2001 A. Weber LBL Experiments:

• Beam travels 735 km to Soudan Minnesota • Sagitta: 10 km • 1 km wide at destination July-2001 A. Weber LBL Experiments: MINOS & OPERA 2

Nu. MI Beam Energy • Fermilab MI – – E = 120 Ge. V 4 x 1013 ppp Cycle 2 sec 10 msec spill • Tuneable neutrino energy, select energy to match mass difference – high: – medium: – low: July-2001 A. Weber LBL Experiments: MINOS & OPERA 7 - 30 10 -3 e. V 2 3 - 10 10 -3 e. V 2 1 - 5 10 -3 e. V 2 3

MINOS Collaboration Around 180 Physicists and Engineers IHEP-Beijing Athens Dubna ITEP-Moscow Lebedev Protvino Cambridge Oxford Rutherford Sussex University College London Argonne Brookhaven Caltech Chicago Elmhurst Fermilab James Madison Harvard Illinois Indiana Livermore Macalester Minnesota Northwestern Pittsburgh South Carolina Stanford Texas-Austin Texas A&M Tufts Western Washington Wisconsin July-2001 A. Weber LBL Experiments: MINOS & OPERA 4

MINOS Far Detector • 2 Super-modules 2. 7 kiloton each • 486 planes of steel and scintillator • 96 scintillator strips/plane • read out at both sides with multi-anode PMTs • Toroidal magnetic field (1. 5 T at 2 m radius) July-2001 A. Weber LBL Experiments: MINOS & OPERA 5

MINOS Scintillator Module July-2001 A. Weber Multiplex Box Optical Connector Connection to electronics Optical Connector Multiplex Box Clear Fiber Ribbon Cable (2 -6 m) WLS Fibers Optical Connector 8 m Optical Connector Connection to electronics Clear Fiber Ribbon Cable (2 -6 m) • Two-ended WLS fiber readout. • Strips assembled into 20 or 28 -wide modules. • WLS fibers routed to optical connectors. • Light routed from modules to PMTs via clear fibers. • 8 Fibers/PMT pixel in far detector. (Fibers separated by ~1 m in a single plane. ) • 1 Fiber/PMT pixel in near detector (avoids overlaps). • Multi-pixel PMTs Hamamatsu M 16 (far), M 64 (near) WLS Fibers Scintillator Module • Extruded scintillator, 4. 1 cm wide PMTs LBL Experiments: MINOS & OPERA 6

MINOS Plane 2 -m wide, 0. 5 -inch thick, steel plates Bottom steel plane layer Scintillator plane Top steel plane layer o Orientations alternate 90 in successive planes July-2001 A. Weber LBL Experiments: MINOS & OPERA 7

MINOS Oscillation Physics • Several channels to analyse neutrino oscillations – – T-Test ne appearance nm disappearance μ hadrons 5 m nt appearance • Combination of all analysis will reveal mixing parameters – m 2 – sin 22 q – flavour July-2001 νμ A. Weber νμ hadrons 1. 5 m LBL Experiments: MINOS & OPERA νμ 8

T-Test • Oscillations or not? • Compare number of short and long events in near and far detector: – long events CC: nm – short events NC: nm, ne, nt ; CC: ne, nt depleted by oscillations discriminates between nm nt and nm ns July-2001 A. Weber LBL Experiments: MINOS & OPERA 9

νμ CC Energy Analysis • Select νμ charge current events and reconstruct neutrino energy range, B field calorimetry • Resolution functions: Δm 2 • Compare energy spectrum in near and far detector • Measure Δm 2 and sin 22θ July-2001 A. Weber LBL Experiments: MINOS & OPERA sin 22θ 10

νμ Disappearance Results July-2001 A. Weber LBL Experiments: MINOS & OPERA 11

CNGS Beam • Baseline: 730 km • <Eν> = 17 Ge. V • optimised for τ appearance • CERN SPS – – July-2001 Ep = 400 Ge. V 4. 8*1013 ppp cycle 6 - 27. 6 sec 7. 6*1019 pot/year A. Weber LBL Experiments: MINOS & OPERA 12

OPERA Collaboration 29 groups~ 130 physicists METU, Ankara, Turkey LAPP and Université de Savoie, Annecy, France INFN and Bari University, Bari, Italy IHEP, Beijing, China PR Humboldt University, Berlin, Germany Bern University, Bern, Switzerland INFN and Bologna University, Bologna, Italy IIHE (ULB-VUB), Brussels, Belgium Joint Institute for Nuclear Research (JINR), Dubna, Russia Laboratori Nazionali di Frascati, INFN Frascati, Italy Toho University, Funabashi, Japan CERN, Geneva, Switzerland Märkische Fachhochschule FB Elektrotechnik, Hagen, Germany Technion, Haifa, Israel Hamburg University, Hamburg, Germany High Energy Physics Group Shandong University, Jinan, Shandong, China PR Aichi Educational University, Kariya, Japan Kobe University, Kobe, Japan IPNL and Université C. Bernard, Lyon, France INR, ITEP and MEPHI, Moscow, Russia Münster University, Münster, Germany Nagoya University, Nagoya, Japan INFN and "Federico II" University, Naples, Italy LAL and Université Paris-Sud, Orsay, France INFN and Padova University, Padova, Italy INFN and "La Sapienza" University, Rome, Italy Rostock University, Rostock, Germany INFN and Salerno University, Salerno, Italy IRES, Strasbourg, France Utsunomiya University, Utsunomiya, Japan Rudjer Boskovic Institute (IRB), Zagreb, Croatia July-2001 A. Weber LBL Experiments: MINOS & OPERA 13

The OPERA Experiment super m m spectrometer odule Magnetised Iron Dipoles Drift tubes and RPCs brick (56 Pb/Em. “cells”) n 10 ~ m module 8 cm (10 X 0) n target and t decay detector Each “super-module” is a sequence of 24 “modules” consisting of - a “wall” of Pb/emulsion “bricks” - planes of orthogonal scintillator strips July-2001 A. Weber brick wall scintillator strips LBL Experiments: MINOS & OPERA 14

Muon Identification High precision drift tube trackers • Reject charm background • Tag and analyse τ μ • measure Eν spectrum with 0. 5 m 1 m 0. 5 m – target – spectrometer (calorimeter) – identify muons – shower energy measurement 6. 7 m • Fe walls: 7. 1 λint instrumented • Spectrometer – 3 external high resolution drift tubes Target super module Magnetised Fe plates + RPC July-2001 A. Weber LBL Experiments: MINOS & OPERA 15

Target section Selected brick Sampling by Target Tracker planes ( X, Y ) Brick wall 10 cm Event as seen by the target tracker Emulsion-Scintillator strip Hybrid Target p. h. 0 max Selected bricks extracted daily using dedicated robot July-2001 A. Weber • Tracker task select bricks efficiently • High scanning power + low background allow coarse tracking LBL Experiments: MINOS & OPERA 16

Scintillator Strip Target Trackers WLS fibres PMT 64 strips planes unit 6. 7 m • Scintillator strips (2. 6 cm wide, 1 cm thick) • Light read out at both WLS fibre ends • Multi anode 64 ch. PMT (baseline) • Minimum: 6 p. e. • Probability for 0 p. e. = 0. 2% July-2001 A. Weber LBL Experiments: MINOS & OPERA 17

Emulsion Brick Origami packed ECC brick for OPERA Vacuum packing • Protection against light and humidity variations. • Keep the position between films and lead plates. • Vacuum preserved over 10 years n 10 X 0 ( 56 emulsion films ) 12. 5 cm July-2001 A. Weber 235 k bricks for 3 super modules LBL Experiments: MINOS & OPERA 18

nt Candidate Classes “ Long decays reconstruct kink topology “ Short decays detect large impact parameter track Loose cut to reject low momentum tracks July-2001 A. Weber LBL Experiments: MINOS & OPERA 19

Selection Efficiencies (in % and including BR) • Electron/Hadron ID • Muon ID – track in brick – MIP in scintillator tracker – momentum measurement in dipolar magnet – track in brick – shower in brick: E • multiple scattering • number of tracks – distinguish by fit to shower profile * weighted sum of DIS and QE events July-2001 A. Weber LBL Experiments: MINOS & OPERA 20

Sensitivity (average 90 % CL upper limit for a large number of experiment in the absence of a signal) 5 years 3 years 5 years data taking m 2 = 1. 2 x 10 -3 e. V 2 at full mixing sin 2 (2 ) = 6. 0 x 10 -3 at large m 2 July-2001 A. Weber LBL Experiments: MINOS & OPERA 21

Determination of m 2 ( 10 -3 e. V 2 ) 90 % CL limits * (mixing constrained by Super. K) 1. 5 3. 2 5. 0 Upper limit 2. 1 3. 8 5. 6 OPERA Lower limit 0. 8 2. 6 4. 3 90 % CL in 5 years (U - L) / (2*True) 41 % 19 % 12 % * assuming the observation of a number of events corresponding to those expected for the given m 2 Probability to observe Super. K signal July-2001 A. Weber LBL Experiments: MINOS & OPERA 22

Schedule • MINOS – – – approved FD installation cosmics ND installation neutrino beam physics results • OPERA (1999) (now) (2001) (2003) (2004/5) +2 years – – – approved installation cosmics Filling emulsion neutrino beam physics results (2001) (2002) (2004/5) (2004) (2005) +3 -5 years Exciting time! The 2 complementary experiments will reveal the exact nature of the atmospheric neutrino anomaly and measure the oscillation parameters. July-2001 A. Weber LBL Experiments: MINOS & OPERA 23

Particle ID c 2 e Hadron (1) Different energy loss by multiple scattering E(x)=E 0 e (-x/X 0) for electrons c 2 e E(x)=E 0(1 -(d. E/dx)x) for hadrons c 2 h (2) Detection of electromagnetic shower Requires low background track density controlled fading Sensitive to electrons close to the Pb critical energy 5 X 0 5 cm Shower detected Electron c 2 h 1 mm July-2001 A. Weber LBL Experiments: MINOS & OPERA 24

Short decays Long decays Expected background (5 years data taking) July-2001 A. Weber LBL Experiments: MINOS & OPERA 25