PoojaGuptaOnbehalfofLBNECollaborationUniversityofCalifornia,Davis

Time

There exist only 3 « active » neutrinos, with their antineutrinos

ν+N⇒l‐+hadrons

anti‐ν+N⇒l++hadrons

They only feel weak interactions:

couplings to W± (CC) and Z0 (NC)

In the MSM, SU(2)xU(1)

leptons appear as left-handed doublets + right-handed singlets

( l- , ν )L ( l- )R

No right-handed ν (or left-handed anti- ν) ⇒ ν are massless

The current understanding of neutrino physics confirms neutrinos have mass hence indicating physics beyond Standard Model.

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Current limits on Neutrino parameters

TwoNeutrinoscase:

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Todetectneutrinos:Seeνβ≠αinaναbeam(Appearance)Seesomeofknownναfluxdisappear(Disappearance)

ProbabilitydependsonΔm2andhencecouldjusttellusmassdifferencebetweentw0massstates

Solarν+KamLAND

Atmosphericν&longbaselineνµDisappearance

ReactorExperiment

LongBaselineνeAppearance

c

c

sin22θ13 < 0.19 (90% CL)

Remaining Parameters:   θ13   Mass Hierarchy   CP Violating Phase δ

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1)   Rich Structure depending on the ν mass hierarchy and δCP : we need information from both 1st & 2nd oscillation maxima to resolve these ambiguities.

Increasing L: - 1st and 2nd oscillation maxima at higher energy (more favorable region, larger stats, away from larger nuclear effects) - larger matter effects (increasing the potential for the determination of ν mass hierarchy)

2)   Search for CP violation with the channels νµ→νe/ νµ→νe by looking for a difference between νe/ νe appearance probability.

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Parke

  Neutrino Mass Hierarchy   Neutrino CP Violation   Proton Decay   Diffuse Supernova Neutrinos   Supernova Neutrino Burst   Precision Oscillation Parameters   Atmospheric Neutrinos   High Energy Neutrinos   Solar Neutrinos

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•  Cosmic muon background rate ~0.1 Hz at 4850 feet underground •  Helps immensely in Proton Decay, relic neutrinos

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  High energy protons hit a target and produce charged pion and kaon particles   The particles are “focused” by a magnetic field to go in the desired direction   The pions and kaons decay into muons and muon neutrinos   The direction of the magnetic field determines whether neutrinos or anti-neutrinos are generated

  Broad band beam covering 0.5 to few GeV.   Minimum flux above 5 GeV to lower backgrounds from feed

down.   Minimize electron neutrino background by design.   Target, shielding, and materials need to handle 700 kW.

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M. Bishai

Entrance Drift at 4850L

Excavation Drift at Lower Level, 5060L

Large Cavity

Utility Room

Water Level

Secondary Egress During Excavation

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  Well understood and proven technology by SuperK (50kT);   Aim is to go to 300Kton   Good tracking especially at 1 GeV or less   Good PID capability at low energy   Energy resolution for e and µ ~3% (SK)   Signal energy resolution ~ 10%;   Cosmic ray rate at 4850ft is ~0.1 Hz.   Excellent sensitivity to p π0e+

  Low νe signal efficiency (~15-20%);   Low efficiency to pK+ ν bar

Challenges:

  Huge amount of photo sensors needed (~110,000 for 40% coverage as SK). Reduction by a factor of 2 works well for high energy applications (beam and proton decay). To what extent is additional reduction possible?   Very large under ground cavities needed

Water Cherenkov

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  Electronic "bubble chamber", detailed event topology   Brilliant energy reconstruction and track resolution of every particle, capable up to higher energies   PID with dE/dx and separation of tracks possible   Basically background-free for many applications   Better sensitivity to p K+ ν bar

Challenges:   “Complicated" detector technology   Huge number of channels (depending on position resolution)

  Not proven at 50Kt size;  Safety issues, technical risks and uncertain cost

Liquid Argon TPC

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  Tests a fundamental, but unexplained conservation law: Baryon number.   There are two favored and benchmark decay modes: e+π0 (gauge mediated) and νK+ (SUSY D=5) Good for water Good for LAr

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  Current limits in most channels dominated by Super-Kamiokande.   Observation would be de-facto discovery of Grand Unification

  When a star's core collapses, ~99% of the gravitational binding energy of the proto-neutron star goes into ν's of all flavors with ~MeV energies (Energy can escape via ν's)

  Mostly ν - ν pairs from Proto-neutron star cooling

  Timescale: prompt after core collapse, overall Δt~10's of seconds

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K. Scholberg

  Huge signal for a galactic supernova   Very precise knowledge of the cross- section (~0.2%) for νe + p e+ + n   Double Coincidence: Zero background (need Gd)   Positron spectrum mirrors neutrino spectrum

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Diffuse SN flux: Added depth at DUSEL and large detector mass would makes detection possible.

DUSEL cosmic muon rate an order of magnitude smaller than Kamioka, so we expect 15.5 MeV threshold instead of 19.3 MeV. This enhances signal by 40% in addition to just detector mass scaling. Gadolinium doping might also add as much as a factor of two or more in sensitivity

Gadolinium loading plus extra depth would increase sensitivity by approximately by factor of two.

DUSEL 300KTon Gd loaded at 4850’ depth

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L. Whitehead

700 kW ν 5yr + ν 5yr 2x107 s/yr 120 GeV 200 KTon WC δCP=0 δ CP=+90 δ CP=-90 Background: All beam

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700 kW ν 5yr + ν 5yr 2x107 s/yr 120 GeV 34 Kton LAr δCP=0 δ CP=+90 δ CP=-90 Background: All beam

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THANK YOU

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Neutrinos–enhancedAnti‐neutrinos–suppressed

Anti‐neutrinos–enhancedNeutrinos‐suppressed

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NH IH

G. Rameika In term

(- )sign is for neutrino channel with normal hierarchy or antineutrino channel with inverted hierarchy (+)antineutrino channel with normal hierarchy or neutrino channel with inverted hierarchy