supernova neutrinos in dune · 22/08/2019 supernova neutrinos in dune dune the deep underground...
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Supernova Neutrinosin DUNE
Sammy Valder | James Pillow | Kenny Vetter | Sander Breur | Olexiy Dvornikov
And other questions we weren’t asked
SLAC Summer Institute 2019
22/08/2019 Supernova Neutrinos in DUNE
The Question
A star, ten times the mass of the sun, went supernova near the galactic core; a neutron star, two times the mass of the sun, was left behind. Thankfully, DUNE’s Far Detector was up and running and ready to take data.
How many events should DUNE expect to record?
The delay of the neutrino arrivals was determined to be 5 seconds past the gamma-ray time-tag.
What could you learn about neutrinos from this measurement?
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22/08/2019 Supernova Neutrinos in DUNE
DUNE
The Deep Underground Neutrino Experiment will be the largest LArTPC ever built, with 4 individual TPC modules leading to a total fiducial mass of 40kt.
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“And I say: ‘Look! I have hands!’ But the people all around me say: ‘What are hands?’” - Frank Herbert, Dune, 1965
ProtoDUNE-SP: chronicles of an endeavor
The state of the art TPCs will allow for high precision on particle position and energy, allowing for extremely detailed images.
It will incorporate a large physics program, from pinning down the mass hierarchy to being ready to record supernova neutrinos and more.
22/08/2019 Supernova Neutrinos in DUNE
Type II Supernova
● Star burns until Fe core is present. ● As density increases neutrinos get trapped in the core● Once the core mass reaches 1.4M
☉, the core collapses under
gravity at free fall● Collapse halted by nuclear force and a shockwave bounces
back● 𝜈e are produced in huge numbers through electron captures on
free protons behind the shock front● Shock breaks out into neutrino transparent layers, produces
flash of 𝜈e ● Accretion and cooling phases release further neutrinos of all
flavours
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22/08/2019 Supernova Neutrinos in DUNE
Type II Supernova Neutrinos
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~ 1%
Energy losses:
Almost all of the energy is taken by neutrinos! That’s ~ 1053 erg
MC = Mass of the core
RNC = Radius of neutron core
22/08/2019 Supernova Neutrinos in DUNE
Well that was easy(ish)
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22/08/2019 Supernova Neutrinos in DUNE
Well that was easy(ish)
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DUNE Volume DUNE Density
Number of Argon AtomsNeutrino Flux at Earth
Neutrino Cross Section with Argon
Neutrino Interaction Rate
22/08/2019 Supernova Neutrinos in DUNE
Sanity checks: Rate @ DUNE
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“About 3000 events would be expected in a 40 kt fiducial mass liquid argon detector for
a supernova at a distance of 10 kpc.” (DUNE TDR)
1804.01877v1 Source: Kate Scholberg
22/08/2019 Supernova Neutrinos in DUNE
What can we learn about the Neutrinos?
● Neutrino Mass Ordering
● Neutrino Mass bounds
● Oscillation parameter
● Shape of Earth
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22/08/2019 Supernova Neutrinos in DUNE
Neutrino Mass Ordering
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The measurable neutrino flavor spectrum, starting with electron neutrinos produced by the SN, is influenced by three different neutrino oscillation effects:
1. Evolution due to vacuum oscillations2. MSW potential term (matter effect)3. Neutrino self interaction in dense matter
2. 3.
How does NH and IH effect the measurable neutrino flavor spectrum differently ?
22/08/2019 Supernova Neutrinos in DUNE
Neutrino Mass Ordering
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“Oscillations and supernova: a non trivial story.” Kate Scholberg @ SSI 2019
1804.01877v1
22/08/2019 Supernova Neutrinos in DUNE
Neutrino Mass Bound
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22/08/2019 Supernova Neutrinos in DUNE
Neutrino Oscillations
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Our Toy Model: Right-skewed energy distribution with mean neutrino energy of 10 MeV
Note: True energy distribution doesn’t matter so long as it is narrow-band
Probability of oscillation using sin2 (2ϴ12) = 0.846
22/08/2019 Supernova Neutrinos in DUNE
Neutrino Oscillations
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Probability of oscillation becomes fixed for large distances due to “smearing”Since Δm2 and the mixing angles are well-known, deviations from expected values would imply that neutrino profile of current supernova models are incorrect.
Smearing Effect on Oscillation Probability at Large Distances
22/08/2019 Supernova Neutrinos in DUNE
What can we learn about the Neutrinos?
● Neutrino Mass Ordering
● Neutrino Mass bounds
● Oscillation parameters
● Shape of Earth
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22/08/2019 Supernova Neutrinos in DUNE
What can we learn about the Neutrinos?
● Neutrino Mass Ordering
● Neutrino Mass bounds
● Oscillation parameters
● Shape of the Earth
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22/08/2019 Supernova Neutrinos in DUNE
Is the Earth Flat?
“Modern flat Earth belief originated with the English writer Samuel Rowbotham (1816–1884). ……He later expanded into a book ‘Earth Not a Globe’, proposing the Earth is a flat disc,….Rowbotham further held that the "cosmos" was 3,100 miles (5,000 km) above the Earth. https://en.m.wikipedia.org/wiki/Modern_flat_Earth_societies
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● If Earth is flat, DUNE would expect the same relative number of 𝞶e as all other experiments due to no differences in MSW contribution.
We’ve made a crude assumption on the shape of our Earth
22/08/2019 Supernova Neutrinos in DUNE
Is the Earth Flat?
“Modern flat Earth belief originated with the English writer Samuel Rowbotham (1816–1884). ……He later expanded into a book ‘Earth Not a Globe’, proposing the Earth is a flat disc,….Rowbotham further held that the "cosmos" was 3,100 miles (5,000 km) above the Earth. https://en.m.wikipedia.org/wiki/Modern_flat_Earth_societies
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● If Earth is flat, DUNE would expect the same relative number of 𝞶e as all other experiments due to no differences in MSW contribution.
● Furthermore, DUNE would expect to measure the energy of a 10 gigaton blast deposited by neutrinos from the SN.
We’ve made a crude assumption on the shape of our Earth
Our universe: Flat Earth: Flux increase @ DUNE by 1028
R = 1022 cm R = 108 cm
22/08/2019 Supernova Neutrinos in DUNE
Is the Earth Flat?
“Modern flat Earth belief originated with the English writer Samuel Rowbotham (1816–1884). ……He later expanded into a book ‘Earth Not a Globe’, proposing the Earth is a flat disc,….Rowbotham further held that the "cosmos" was 3,100 miles (5,000 km) above the Earth. https://en.m.wikipedia.org/wiki/Modern_flat_Earth_societies
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● If Earth is flat, DUNE would expect the same relative number of 𝞶e as all other experiments due to no differences in MSW contribution.
● Furthermore, DUNE would expect to measure the energy of a 10 gigaton blast deposited by neutrinos from the SN.
● That is equivalent to 20 times the total energy released by all nuclear testing as of 1996. (i.e pretty bad)
-> Evidence for shape of the Earth
We’ve made a crude assumption on the shape of our Earth
Our universe: Flat Earth: Flux increase @ DUNE by 1028
R = 1022 cm R = 108 cm
22/08/2019 Supernova Neutrinos in DUNE
Summary
● DUNE will see ~4000 neutrinos
● Our order of magnitude calculation agrees with the literature
● From the time spectrum, we can infer the mass hierarchy.
● Difference in arrival time gives us a bound on the mass○
● Unless the Earth is Flat. Then we’ll die.○ Sorry!
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Samy Valder | Jamy Pillow | Keny Vetter | Sandy Breur | Lexy Dvornikov
SLAC Summer Institute 2019
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BACKUPS
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Sanity Checks: Luminosity
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Janka HT. (2017)
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Sterile Neutrinos
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1712.03836
22/08/2019 Supernova Neutrinos in DUNE
Disproving the Flat Earth?
“Modern flat Earth belief originated with the English writer Samuel Rowbotham (1816–1884). Based on conclusions derived from the Bedford Level experiment, Rowbotham published a pamphlet Zetetic Astronomy. He later expanded into a book Earth Not a Globe, proposing the Earth is a flat disc, centred at the North Pole and bounded along its southern edge by a wall of ice, Antarctica. From: https://en.m.wikipedia.org/wiki/Modern_flat_Earth_societies
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We’ve made a crude assumption on the shape of the Earth