DRAFT Supernova Burst Physics At DUNE Alex Friedland University - PowerPoint PPT Presentation

DRAFT Supernova Burst Physics At DUNE Alex Friedland University of Tokyo, Feb 12, 2017 Wednesday, February 8, 17 1

Outline DUNE Experiment and Collaboration Core collapse supernova: overview Things to observe: Stages of the explosion in neutrinos Oscillations effects Particle and Nuclear physics effects Detection issues Wednesday, February 8, 17 2

About DUNE Deep Underground Neutrino Experiment Neutrino beam from Fermilab to a large liquid argon detector 1,300 km away in South Dakota Wednesday, February 8, 17 3

DUNE Collaboration As of today: 60 % non-US 945 collaborators from 161 institutions in 30 nations Armenia, Brazil, Bulgaria, Canada, CERN, Chile, China, Colombia, Czech Republic, Finland, France, Greece, India, Iran, Italy, Japan, Madagascar, Mexico, Netherlands, Peru, Poland, Romania, Russia, South Korea, Spain, Sweden, Switzerland, Turkey, UK , Ukraine, USA Wednesday, February 8, 17 4

DUNE Timeline Looking ahead: Strategic Goals • DUNE is committed to delivering: - Two large-scale engineering prototype detectors ( protoDUNE-SP and protoDUNE-DP ) operational at CERN in 2018 - DUNE TDR for the CD-2/3B and LBNC Reviews in 2019 - 20-kt (fiducial mass) Far Detector ready for beam in 2026 • Two 10-kt detector modules (not necessarily the same design) - Near detector system(s) operational in time for first beam Ultimate plan is for 40 kton of LAr far detector four modules of 10 kton each Wednesday, February 8, 17 5

Why SNB neutrinos at DUNE? Unique characteristics make is a very important, complementary machine to SuperK/HyperK Sensitivity primarily to electron neutrinos Energy resolution Time snapshots of all stages of the explosion Different side of the Earth: Earth matter effect! Wednesday, February 8, 17 6

What happens when all fuel is exhausted? The star can be supported by the electron degeneracy pressure only when electrons are non-relativistic M ❊ ~ (M Pl /M N ) 2 M Pl ~ 1.4 M ⊙ !! Chandrasekhar mass. (We live in an amazing universe!) When the Iron core reaches this mass, gravity at last wins The Fe core collapses in free fall, at v ~c/4 , until reaching (supra)nuclear densities, 10 10 g/cm 3 → 10 14 g/cm 3 Wednesday, February 8, 17 7

Gravity-powered neutrino bomb The gravitational binding energy G N M 2 /R ~ 3*10 53 ergs ( ~10% of rest mass!) is initially stored mostly in the Fermi seas of electrons & electron neutrinos Photons are hopelessly stuck. Neutrinos diffuse out easier. The weak interactions mean free path: λ ~( G F2 E 2 n) -1 ~ a few cm t ~ R 2 /c λ ~ 10 12 cm 2 /(3 cm 3*10 10 cm/s) ~ 10 s For comparison, solar luminosity is 3.8*10 33 ergs/s. A core- collapse supernova shines in neutrinos as bright as 10 20 Suns. Instantaneously outshines the visible universe. Wednesday, February 8, 17 8

60-year-old problem. Why should we care? Origin of stuff: Supernovae synthesize and disperse heavy elements. (“Theory of everything”) BBN created hydrogen and helium. Chemical elements around us were once inside a star Supernova “feedback” is crucial to understanding the universe around us (galaxy). Conditions not reproducible on Earth make them unique laboratories for particle and nuclear physics. E.g.: Flavor oscillations in dense neutrino gas The final state is one big nucleus Sterile neutrinos, axions, Majorons, dark photons, etc, etc Wednesday, February 8, 17 9

Evolution of the explosion is reflected in neutrinos Neutronization burst, accretion and cooling phases can all be seen in neutrinos. All stages are extremely important!! Signal depends on the progenitor star 8.8 solar mass 10.8 solar mass 0.5 0.5 ν e ν e 0.4 0.4 anti − ν e anti − ν e L ν [10 53 erg/s] L ν [10 53 erg/s] 0.3 0.3 0.2 0.2 0.1 0.1 0 0 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 Time After Bounce [s] Time After Bounce [s] Fig from Fischer, Whitehouse, Mezzacappa, Thielemann, Liebendörfer, arXiv: 0908.1871 Wednesday, February 8, 17 10

Accretion ≈“Shock2 Revival” Cooling (no2oscillations) CC NC We may see something like this (illustration from Messer) Wednesday, February 8, 17 11

Basics of detection 31 Low-energy neutrino signal in LAr • Elastic scattering (ES) on electrons SN ν cross sections on Ar ν + e - → ν + e - • Charged-current (CC) interactions on Ar ν e + 40 Ar → 40 K* + e - E ν e > 1.5 MeV hep-ph/0307222 _ JCAP 10 (2003) 009 _ ν e + 40 Ar → 40 Cl* + e + JCAP 08 (2004) 001 E ν e > 7.48 MeV I.G-B & A.Rubbia • Neutral current (NC) interactions on Ar ν + 40 Ar → ν + 40 Ar* E ν > 1.46 MeV Wednesday, February 8, 17 12

Predicted signal, for a reference SN model DUNE: 40 kton LAr (SN @10 kpc) Expected event spectrum Time-dependent signal integrated over time Wednesday, February 8, 17 13

ls$ ances$adiabaLc,$small$enough$to$ignore$mixing$$ Or maybe the signal suddenly stops, a black hole forms (O’Connor) Wednesday, February 8, 17 14

Neutronization burst Thompson, Burrows, Pinto, astro-ph/0211194 Wednesday, February 8, 17 15

Update from Oak Ridge 2D - ν e t otal counts vs. time Messer, Devotie, et al. In prep. 2000 40 Ar ➝ e - + 40 K * ν e + rapid shock 1500 expansion - Si-Si/O events accretion-powered 1000 evolution 500 shock lift-off 0 0 100 200 300 400 500 time [ms] C15-2D, angle-averaged, SNOwGLoBES Ar17kt, 10 kpc Wednesday, February 8, 17 16

Oscillations! In the normal hierarchy, almost the entire neutronization burst would oscillate away! Why? Wednesday, February 8, 17 17

Sun: 2-state oscillations sin 2 θ sin 2 θ � + cos 2 θ cos 2 θ � P 2 ( ν e → ν e ) = sin 2 θ � sin 2 θ vac cos 2 θ � cos 2 θ vac Core Vacuum In the Sun, the density scale height is R sun /10, while l osc is comparable to the width of Japan (KamLAND) -> The evolution is adiabatic (no level jumping) Wednesday, February 8, 17 18

SN ν oscillations: 2 MSW densities ν -sphere ν e ν μ ν τ “regular MSW” _ _ _ ν e ν μ ν τ Wednesday, February 8, 17 19

SN MSW transformations, schematics F ( ν e ) Given the scale height in the ➡ sin 2 θ 13 progenitor, the MSW F ( ν µ, τ ) evolution is very adiabatic sin 2 θ � the adiabaticity of the ➡ atmospheric resonance is F ( ν µ, τ ) controlled by theta13 cos 2 θ � Prediction for the nue signal ➡ sin 2 θ 13 during the neutronization F ( ν µ, τ ) burst is critically dependent sin 2 θ � on the sign of mass hierarchy F ( ν µ, τ ) cos 2 θ � One of 3-4 different ways of ➡ determining hierarchy from -- the SN signal (redundancy!) F ( ν e ) Wednesday, February 8, 17 20

SN ν : very rich physics ν -sphere Collective ν e ν μ ν τ turbulence _ _ _ front shock ν e ν μ ν τ “regular MSW” Wednesday, February 8, 17 21

WC LAr * See LBNE science document, 1307 .7335 Wednesday, February 8, 17 22

Another smoking-gun feature. Tracking the shock in real time LBNE science document arXiv:1307 .7335v3 multiangle collective oscillations + moving shock Figure 7–5: Observed spectra in 34 kton of LAr for a 10 kpc core collapse, representing The neutrino spectrum is modulated, but not antineutrinos (simultaneously observed by SK/HK) Wednesday, February 8, 17 23

Observations Wednesday, February 8, 17 24

32 ν e CC final states: de-excitation γ s • Lack of precision models of low energy neutrino argon reactions • No measurements are available • Some efforts to study this problem with indirect beam sources and small-scale experiments 40 K • Fermi transition to 4.38 MeV IAS • σ precisely known < 1% • Raghavan, PRD 34 (1986) 2088 40 K : • GT transitions of various Experimental data of β -decay of the mirror 40 Ti nucleus • Ormand et al., Rhys. Lett. B 345 (1995) 343-350 • Trinder et al., Phys. Lett. B 415 (1997) 211-216 • Bhattacharya et al., Phys. Rev. C 58 3677 (1998) Wednesday, February 8, 17 25

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