Neutrino Oscillation Workshop

Transcription

1 p. 1/3 Physics Capabilities of Future Atmospheric ν-detectors Srubabati Goswami Physical Research Laboratory, Ahmedabad, India Neutrino Oscillation Workshop Conca Specchiulla, Otranto, Italy September 9-16, 212

2 p. 2/3 Atmospheric Neutrinos as Source Cosmic Ray + A air π π + µ + + ν µ µ + e + + ν µ + ν e Provides a broad range of energy as compared to any other natural and artificial sources Provides a wide range of path-length Hence a broad L/E band (1 to 1 5 km/gev). The longer baseline allow matter effects to develop Source of both neutrinos and antineutrinos Source of both ν e and ν µ All these for free!!

3 p. 3/3 Future Detectors for Atm ν Magnetized Iron Detector (INO) 5-1 kt Muon energy measurement, direction reconstruction and charge discrimination capability Can determine the neutrino energy and direction through Hadron shower reconstruction Megaton Water Cerenkov Detector (HK, MEMPHYS) Large volume No charge ID Both electron and muon energy and direction measurement Liquid Argon TPC Excellent electron and muon energy and direction measurement Charge ID? Neutrino Telescope (IceCube, PINGU) Huge Volume (Multi-Mton)

4 p. 4/3 Physics Possibilities with Atmospheric νs Measurement of m 2 31 and sin 2 θ 23 Determine if sin 2 θ 23 is maximal and if not then determination of its octant Determination of Mass Hierarchy or sgn( m 2 31) CPT violation Sterile Neutrinos,Non Standard Interactions, Long Range Forces..., Plan of Talk Determination of Mass Hierarchy and Octant in magnetized Iron Calorimeter and Liquid Argon Detectors

5 Physics Possibilities with Atmospheric ν s An incomplete list of references... Petcov (1998), Chizov, Maris, Petcov (1998), Akhmedov (1999),Akhmedov,Dighe,Lipari,Smirnov (1999),Kim (1998),Peres,Smirnov(1999),Bernabeu, Palomares-Ruiz, Perez, Petcov, (22), GonzalezGarcia, Maltoni (23), Bernabeu, Palomares-Ruiz, Petcov (23), Peres, Smirnov (24), Indumathi, Murthy (24), Gandhi, Ghoshal, Goswami, Mehta, Sankar (24), Gonzalez-Garcia, Maltoni, Smirnov (24), Palomares-Ruiz, Petcov (25), Choubey, Roy (25), Fogli, Lisi, Marrone, Palazzo (25); Huber, Maltoni, Schwetz (25), T. Kajita (25); E. K. Akhmedov, M. Maltoni and A. Y. Smirnov (25), Petcov, Schwetz (26), S. Choubey (26); Indumathi, Murthy, Rajasekaran, Sinha (26), E. K. Akhmedov, M. Maltoni and A. Y. Smirnov (27), R. Gandhi, P. Ghoshal, S. Goswami, P. Mehta, S. U. Sankar and S. Shalgar (27), E. K. Akhmedov, M. Maltoni and A. Y. Smirnov (28), Gandhi, Ghoshal, Goswami, Sankar (28), Mena, Mocioiu, Razzaque (28), Peres, Smirnov (29), Gandhi, Ghoshal, Goswami, Sankar (29), Samanta (26-1), Samanta, Smirnov (21), Conrad, de Gouvea, Shalgar (21), Gonzalez-Garcia, Maltoni, Salvado (211), Barger, Gandhi, Ghoshal, Goswami, Marfatia, Prakash, Raut, Sankar (212), Blennow, Schwetz (212), Akhmedov, Razzaque, Smirnov (212),... S. Choubey, Nu212 p. 5/3

6 p. 6/3 India Based Neutrino Observatory Proposal Goal : To build an underground laboratory for science with neutrino physics as major activity The Detector: Magnetized Iron CALorimeter detector (ICAL) for detection of atmospheric neutrinos in its first phase. Detector choice based on Technological capabilities available in the country Complementarity to Existing/Planned neutrino detectors in the world Modularity and the possibility of phasing Compactness and ease of construction Other Possibilities Neutrinoless double beta decay, Dark Matter Experiment (DINO).. Second phase end detector for a beam experiment International participation is welcome

7 p. 7/3 INO: Approval Status Approvals from Indian Funding Agencies for Construction of an underground Laboratory and surface facilities at Pottipuram village in South India Construction of 5 kton magnetized Iron Calorimeter detector to study neutrino properties Construction of INO center (The National Center for High Energy Physics) at Madurai in South India Human Resource Development Detector R & D Completion of project in 6 years N. Mondal, LP211

8 p. 8/3 INO: Location South India, Bodi West Hills, Pottipuram, Theni district, Tamil Nadu 9 58 N and E 11 km from Madurai city of Madurai (has airport) Flat terrain with good access to major roads Low rainfall, low humidity Portal outside the RF boundary, surface facilities not on Forest Land, no clearing of forests required Environmental and Forest Clearances obtained 26 Hectre Land provided free of cost by state Govt.

9 p. 9/3 INO: Site at a Glance Cavern set in Charkonite Rock under the 1589 m peak; Vertical cover 1289 m; Accessible through a 2 km tunnel Cavern 1 will host 5 kt ICAL ( space for 1 kt); Other caverns for multiple experiments (νββ, DM)

10 p. 1/3 The detector: Active Detector Element : Resistive Plate Chambers made of glass Iron plates Separatd by RPCs S. Agarwalla, NNN211

11 p. 11/3 Salient Feautures of the Detector Sensitive to muons Good Energy determination from Track length Track curvature in a magnetic field Directionality from tracking and ns timing resolution Charge identification from track curvature in magnetic field Hadron Shower reconstruction enables to determine the neutrino energy

12 p. 12/3 Detector R&D Status Development of RPC Full size RPC s (2m X 2m ) being fabricated in INO Labs Large scale production developed with the help of Industry Electronics Designing and Prototyping of electronics, trigger and data acquisition systems in progress Magnet Prototype magnet running at VECC Calcutta 8m 8m 2 layers 8 ton engineering module is being planned

13 p. 13/3 INO: Simulation Framework at a Glance Neutrino Event Generation a + X -> A + B +... Generates particles that result from a random interaction of a neutrino with matter using theoretical models. Event Simulation A + B +... through RPCs + Mag.Field Simulate propagation of particles through the detector (RPCs + Magnetic Field) Event Digitisation (x,y,z,t) of A + B noise + detector efficiency Add detector efficiency and noise to the hits Output: i) Reaction Channel ii) Vertex Information Iii) Energy & Momentum of all Particles Output: i) x,y,z,t of the particles at their interaction point in detector ii) Energy deposited iii) Momentum information Output: i) Digitised output of the previous stage (simulation) Event Reconstruction (E,p) of + X = (E,p) of A + B +... Fit the tracks of A + B +... to get their energy and momentum. Output: i) Energy & Momentum of the initial neutrino N. Mondal, LP211

14 p. 14/3 INO: Simulation Status σ Pµ /P µ Momentum Resolution Cos θ=.35 Cos θ=.55 Cos θ=.85 σ θ cos(θ) Resolution Cos θ=.35 Cos θ=.55 Cos θ=.85 Inhomogeneous magnetic field implemented Muon energy and direction resolution from tracks achieved improvements possible REC Eff P µ (GeV) Reconstruction Efficiency Cos θ=.35 Cos θ=.55 Cos θ=.85 INO Collab, 212 CID Eff P µ (GeV) CID Efficiency Cos θ=.35 Cos θ=.55 Cos θ=.85 Hadron energy resolution available Neutrino energy and direction resolution using muon and hadron information possible Optimization of iron plate thicknes in progress P µ (GeV) P µ (GeV)

15 p. 15/3 Mass Hierarchy Sensitivity Crux of the matter : Matter Effect tan2θ 13 m = m 2 31 sin2θ 13 m 2 31 cos 2θ 13±2 2G F n e E For m 2 atm > matter resonance in neutrinos For m 2 atm < matter resonance in anti neutrinos Experiments sensitive to matter effects can probe the mass hierarchy Matter effects for m 2 atm channel depend crucially on θ 13 Thus both parameters get related Large measured θ 13 = good news Detectors with charge id that can discriminate between neutrinos and antineutrinos can be crucial

16 p. 16/3 Matter effect at large baselines.8.6 P µe P µµ P ee km NH IH E (GeV).8.6 P µe P µµ P ee km NH IH E (GeV) Large matter effects at long baselines in both µ and e events = Hierarchy Sensitvity ν µ survival probability can rise or fall in matter Energy and angular smearing important

17 p. 17/3 Atmospheric Neutrinos at INO Sensitive only to Muons Differential Number of Muons d 2 N µ = 1 dω m de m 2π 1 1 de t Energy and Angular Smearing Functions dω t R(E t, E m )R(Ω t, Ω m )[Φ d µp µµ + Φ d ep eµ ]σǫ R(Ω t, Ω m ) = N exp [ (θ t θ m ) 2 + sin 2 θ t (φ t φ m ) 2 ] 2( θ) 2. R(E m, E t ) = 1 exp [ (E m E t ) 2 ] 2πσ 2σ 2. Simplest Approach Use fixed widths for energy and angular smearing

18 p. 18/3 Effect of Smearing on muon χ INO, 1 Mt yr INO, 1 Mt yr 15% energy resolution 1 o angular resolution 5 4 χ 2 µ + χ2 µ angular resolution (degree) energy resolution (%) With increased energy or angular smearing the χ 2 for muon like events decrease. Effect of energy smearing is more R. Gandhi, P. Ghoshal, S.G., P. Mehta, S. Shalgar, S. Umashankar, PRD, 27 Also, T. Schwetz and S.T. Petcov, Nucl. Phys. B, 26

19 p. 19/3 Hierarchy Sensitivity at INO Events generated from NUANCE (5 kt, 1 yr exposure) Two sets of energy/angular resolutions: high (1%, 1 o ) and low (15%, 15 o ) Energy threshold 2 GeV, charge ID 1%, constant reconstruction efficiency 85% True normal hierarchy, (θ 23 ) tr = 45 o, δ CP =, (sin 2 2θ 13 ) tr =.1, m 2 31 = ev 2, m 2 21 = ev 2, sin 2 θ 12 =.31 Res set χ 2 marg,no pri χ 2 marg,pri χ 2 fp Low High Using Projected priors: m 2 31 = 2%, sin 2 θ 23 =.6 and fixed θ 13 > 2σ to 3σ sensitivity to mass Hierarchy in 1 years See also Blenow and Schwetz, 21

20 p. 2/3 Hierarchy Sensitivity from INO simulation Using 5 Kton detector and events generated from NUANCE Using ICAL resolutions in Muon energy and Zenith Angle Using efficiency and Charge-ID from ICAL simulations sin 2 2 sin =.1 sin =.8 Normal Hierarchy Marginalized over Δm 2 atm & θ23 with priors with projected errors INO Preliminary Years sin =.12 sin =.1 sin =.8 Inverted Hierarchy Marginalized over Δm 2 atm & θ23 with priors with projected errors INO Preliminary Years 2 3 INO Collab, 212 True Values: m 2 31 = ev 2 sin 2 θ 23 =.5 m 2 21 = ev 2 sin 2 θ 12 =.31 δ CP = For sin 2 2θ 13 =.1 χ 2 proj pri = σ sensitivity in 1 years (Using Projected priors: m 2 31 = 2%, sin 2 θ 23 =.6 and fixed θ 13 )

21 p. 21/3 Effect of δ CP on hierarchy sensitivity INO Collab, 212 sin =.1 all parameters are fixed χ 2 of wrong mass ordering 1 5 INO high resolution INO low resolution NOvA INO Preliminary cp{ } δ [π] Data simulated for NH and δ CP = and fitted for IH with varying δ CP MH sensitivity with atmospheric neutrinos almost independent of δ CP Complementarity with LBL experiments

22 p. 22/3 Octant sensitivity in P µµ P D 1/2 sin 2 θ 23 D gives the deviation of sin 2 θ 23 sgn(d) gives the octant o sin 2 θ E (GeV) NH, ν-resonance E (GeV) IH, anti-ν-resonance P m µµ sin 4 θ 23 sin 2 2θ m 13 sin 2 (1.27 m 31L/E) Octant sensitvity from the sin 4 θ 23 term S.Choubey. and P. Roy hep-ph/59197 Indumathi,Murthy, Rajasekaran,Sinha hep-ph/63264

23 p. 23/3 Octant Sensitivity at INO Events generated from NUANCE (5 kt, 1 yr exposure) Results for high (1%, 1 o ) resolutions Energy threshold 2 GeV, charge ID 1%, reconstruction efficiency 85% χ 2 tot σ Without prior With prior true θ 23 True Parameters Normal Hierarchy (θ 23 ) tr = 45 o, δ CP =, (sin 2 2θ 13 ) tr =.1, m 2 21 = ev 2 sin 2 θ 12 =.31 < 2σ sensitvity for θ 23 π/4 > 5 Analysis using INO simulation code in progress

24 p. 24/3 Magentized Liquid-Ar TPC 5-1 Kton Magnetized LiqAr detector Energy threshold 1 GeV Sensitive to both muons and electrons 1% CID for muons and 2% for electrons in the energy range 1-5 GeV σ Ee = σ Eµ =.1; σ Ehad = (.15) 2 /E had + (.3) 2 σ Eν = (σ El ) 2 + (.15) 2 /(ye ν ) + (.3) 2 ; y average rapidity =.45 σ θe = 1.72 ; σ θµ = σ θhad = 2.29 ; σ θνe = 2.8 ; σ θνµ = 3.2 Barger,Gandhi,Ghosal,Goswami,Marfatia,Prakash,Raut,Umashankar, Phys. Rev.Lett., 212

25 p. 25/3 Hierarchy and Octant with electron events excess of electron-like events: N e N e 1 (r s )P 2ν( m 2 31,θ 13) θ 13 -effects + (r c )P 2ν( m 2 21,θ 12) m 2 21-effects r = F µ F e the flux ratio 2s 13 s 23 c 23 r Re(A ee A µe) interference: δ CP for multi-gev events N e / N e < cosθ ν nadir < 1 sin 2 θ 23 =.64 normal 1.1 sin 2 θ 23 =.36 inverted sin 2 2θ 13 normal inverted Bernabeu, Palomares-Ruiz, Petcov, hep-ph/35152 Resonant matter effect in P 2ν ( m 2 31, θ 13 ) for multi-gev neutrinos. NH neutrinos IH - antineutrinos All three terms important for sub-gev neutrinos Sensitivity to both Hierarchy and Octant

26 p. 26/3 Hierarchy Sensitivity using LiqAr TPC 4 Liquid argon (25 kt yr), marginalized hierarchy sensitivity m 2 31 tr =.24 ev2, true NH, test IH 4 Liquid argon (25 kt yr), marginalized hierarchy sensitivity m 2 31 tr =.24 ev2, true IH, test NH prior 3 sin 2 θ 23 =.4 sin 2 θ 23 =.5 sin 2 θ 23 =.6 prior 3 sin 2 θ 23 =.4 sin 2 θ 23 =.5 sin 2 θ 23 =.6 χ 2 tot 2 χ 2 tot 2 1 3σ sensitivity 1 3σ sensitivity sin 2 θ 23 =.5, no charge-id DB RENO.1.12 true sin 2 2θ 13 sin 2 θ 23 =.5, no charge-id DB RENO.1.12 true sin 2 2θ 13 χ 2 = χ 2 µ + χ 2 µ + (χ 2 e + χ 2 ē) 1 5GeV + (χ 2 e+ē) 5 1GeV + χ 2 prior True values of undisplayed Parameters: ( m 2 31 ) = ev 2, (δ CP ) =, m 2 21 = ev 2, θ 12 = 34 Marginalized over all parameters > 5σ sensitivity for sin 2 2θ 13 =.1 and sin 2 θ 23 =.5 Drastic drop in sensitivity if no CID is assumed.

27 p. 27/3 Octant Sensitivity using LiqAr TPC 2 Liquid argon (5 kt yr), marginalized octant sensitivity with priors 2 Liquid argon (5 kt yr), marginalized octant sensitivity with priors 15 m 2 31 tr =.24 ev2, NH sin 2 2θ 13 (true) =.7 sin 2 2θ 13 (true) =.1 15 m 2 31 tr =.24 ev2, IH sin 2 2θ 13 (true) =.7 sin 2 2θ 13 (true) =.1 5 Ktyr exposure χ 2 tot prior 1 3σ sensitivity χ 2 tot prior 1 3σ sensitivity 5 2σ sensitivity 5 2σ sensitivity true θ 23 true θ 23 NH : 2σ discrimination for θ 23 π/4 > 3.5 (sin 2 2θ 23 <.985). 3σ Discrimination for θ 23 π/4 > 5 IH : 2σ Discrimination for θ 23 π/4 > 4 (sin 2 2θ 23 <.985). NH IH θ 23 χ 2 cid χ 2 Not having CID no cid θ 23 χ 2 cid χ 2 no cid does not affect the results so drastically

28 p. 28/3 Conclusion In view of large θ 13 determination of of mass hierarchy and octant using matter effect in atmospheric neutrinos look very promising INO a strong contender because of the possibility of magnetization and charge identification 3σ sensitvity to mass hierarchy in 1 years for 5 kton detector Hierarchy sensitivity from atmospheric neutrinos independent of δ CP Complimentary information to Long Baseline Experiments.. INO R&D going on full swing Liquid Argon detectors with charge-id provides excellent hierarchy sensitivity > 5σ for 25 ktyrs Non-Magnetized LArTPC would necessarily need larger volume/exposure Other possibilities..cpt violation, Sterile Neutrinos,NSI,...

29 p. 29/3 Acknowledgements INO collaboration Ahmadabad: Physical Research Lab. Aligarh: Aligarh Muslim University A llahabad: HRI Calicut : University of Calicut Chandigarh: Panjab University Chennai : IIT, Madras IMSc Delhi : University of Delhi G uwahati : IIT, Guwahati Hawaii (USA) : University of Hawaii Indore: IIT, Indore Jammu : University of Jammu Kalpakkam : IGCAR Kolkata : Ramakrishna Mission Vivekananda University, SINP, VECC, University of Calcutta Lucknow : Lucknow University Madurai : American College Mumbai : BARC Mumbai : IIT, Bombay TIFR Mysore : University of Mysore Sambalpur : Sambalpur University; Srinagar : University of Kashmir Varanasi : Banaras Hindu University Special Thanks : Animesh Chatterjee, Sandhya Choubey,Anushree Ghosh, Pomita Ghoshal, Sushant Raut, Nita Sinha, Tarak Thakore

30 p. 3/3 INO: Timeline N. Mondal, LP211

31 p. 31/3 Background A preliminary study using a GEANT based simulation of cosmic ray muon background in INO shows that these are unlikely to mimic the signal Indumathi and Murthy, hep-ph/47336 NC background: the 6 cm thickness of the iron plates is sufficient to absorb any pions and kaons in the 1 1 GeV range before they can decay. Oscillated ν τ induced muons softer in energy and can be eliminated by suitable energy cuts Agarwalla, Raychaudhuri, Samanta, hep-ph/5515