BCS Strategy Member Groups Autumn Convention 2014 Maggie Kneller, Council-elected Trustee.
Neel Kabadi and Kelsey Reppert Mentor: Dr. James Kneller...
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Turbulent and Collective Effects on Supernova Neutrinos Neel Kabadi and Kelsey Reppert Mentor: Dr. James Kneller Advisors: Dr. Gail McLaughlin, Dr. Tina Lund, and Dr. Annelise Malkus North Carolina State University Undergraduate Research in Computational Astrophysics Program Introduction • There have been many studies which analyze different effects on neutrino oscillations in supernovae • Some of the factors which influence neutrino oscillations include: • The MSW Effect – The refraction of neutrinos as they propagate through matter • Collective Effects – Neutrinos' effects on each other • SASI Turbulence – Turbulence caused by a stalled shock wave in a supernova ● Each of these effects have mainly been studied separately ● In particular, it is not certain how much effect turbulence has on oscillations in the collective regime ● Our aim is to determine whether turbulence in the collective regime affects neutrino oscillations Methods • We used a new code for the neutrino evolution and hydro- simulations to calculate the neutrino evolution propagating through supernovae • This new code incorporated turbulence, high neutrino density collective interactions, and MSW effects • Turbulence was simulated near the progenitor star, where collective effects dominate i.e. less than the line in the graph below • We ran simulations, varying different parameters such as the final distance, hierarchy, and the amount of turbulence • This allowed us to compare simulations with and without turbulence • We ran simulations of 8.8, 10.8, and 18.8 solar mass progenitors each at two different times • While varying these inputs we looked for outputs that presented interesting features • We ran the interesting simulations again but with many more outputs • We looked through our numerous graphs to find situations where collective interactions were affected by turbulence • Around 1000 km we expect to see mostly effects from collective interactions, possibly some from early MSW effects Summary • In most cases, we found that turbulence does not have an effect on the collective interactions in neutrino oscillations • The only profile that was affected by turbulence in the collective regime was profile 585 of the 10.8 solar mass progenetor • This indicates that lower mass stars will be more affected by turbulence • We found effects on the collective interactions only at levels of 50% turbulence • Until we receive data which quantifies the level of turbulence generated by the standing accretion shock instability in a proto-neutron star, we can not know for sure if 30%-50% is a reasonable range for the amount of turbulence that would affect the neutrino oscillations Background ● Supernova explosions emit on the order of 10 58 neutrinos ● This neutrino flux is responsible for transferring momentum to the stalled shock wave at a size of ~200km in radius ● The neutrinos emitted by the supernova will eventually reach the Earth ● We can observe these neutrinos with large detectors which are called neutrino telescopes ● As they propagate towards the Earth, they change lepton flavor ● This phenomenon is known as transformation, or oscillation ● To better analyze the signals we receive on earth we need to fully understand these oscillation patterns Each graph plots the probability of a given change in mass state of an antineutrino versus energy in MeV in the simulation run with a 10.8 solar mass star with varying levels of turbulence. Top left is 0% turbulence, top right is 10%, bottom left is 30%, and bottom right is 50%. Acknowledgments ● Funding from the NSF ● Research assistance and guidance from Dr. Kneller, Dr. McLaughlin, Dr. Lund, Dr. Malkus, Dr. Blondin and all the faculty involved in the URCA References ● Volpe, Christina, and Kneller, James. "Turbulence effects on supernova neutrinos.", Physical Review D, vol. 82, Issue 12, id. 123004, N.p., n.d. Web. 6 June 2012. ● V. N. Tsytovich, R. Bingham, J.M. Dawson, H.A. Bethe, "Collective neutrino- plasma interactions", Astroparticle Physics, Volume 8, Issue 4, April 1998, Pages 297-307, ISSN 0927-6505, 10.1016/S0927-6505(97)00044-3 . We aim to determine if the addition of turbulence affects neutrino oscillations in the collective regime. Results • We found increasing turbulence mostly showed effects in the neutrino oscillations in 10.8 solar mass star model, but had no effect on the neutrino oscillations in the 18.8 solar mass model • Because of this, we ran simulations which allowed us to analyze the probability of neutrino oscillation at regularly selected distances for the 10.8 solar mass progenitor • Added variability due to many MSW resonances shows up quite often • Collective interactions were only affected by turbulence in one case (seen in the graph in the upper right) where the overall shape of the curve is changed by adding turbulence • The spikes seen in the bottom graphs for low energies can be attributed to early MSW effects Credit: Nick Ballon / Super-Kamiokande Observatory A group of scientists on a boat inside the Super-Kamiokande Neutrino Observatory, a neutrino telescope that resides 1 km underneath the Japanese city of Hida. This observatory is filled with 50 kilotons of super pure water and photo multiplier tube sensors. (Mev) (Mev) (Mev) (Mev) This table shows shows matter-state transitions that occur due to MSW resonances * indicates anti matter-state We found that for low mass iron core progenitors turbulence can have an effect on the collective interactions of antineutrinos. This graph shows the density profile of the 10.8 solar mass progenitor with profile 585 used for our simulations. The graphs in the upper right show output probabilities at 1000 km or 10 8 cm. This is close to forward shock seen in this graph. Labeled is the region where collective effects occur. Collective region
Transcript of Neel Kabadi and Kelsey Reppert Mentor: Dr. James Kneller...
Turbulent and Collective Effects on Supernova NeutrinosNeel Kabadi and Kelsey Reppert Mentor: Dr. James Kneller
Advisors: Dr. Gail McLaughlin, Dr. Tina Lund, and Dr. Annelise MalkusNorth Carolina State University Undergraduate Research in Computational Astrophysics Program
Introduction
• There have been many studies which analyze different effects on neutrino oscillations in supernovae • Some of the factors which influence neutrino oscillations include:
• The MSW Effect – The refraction of neutrinos as they propagate through matter
• Collective Effects – Neutrinos' effects on each other• SASI Turbulence – Turbulence caused by a stalled shock
wave in a supernova● Each of these effects have mainly been studied separately ● In particular, it is not certain how much effect turbulence has on oscillations in the collective regime● Our aim is to determine whether turbulence in the collective regime affects neutrino oscillations
Methods
• We used a new code for the neutrino evolution and hydrosimulations to calculate the neutrino evolution propagating through supernovae• This new code incorporated turbulence, high neutrino density collective interactions, and MSW effects• Turbulence was simulated near the progenitor star, where collective effects dominate i.e. less than the line in the graph below• We ran simulations, varying different parameters such as the final distance, hierarchy, and the amount of turbulence• This allowed us to compare simulations with and without turbulence• We ran simulations of 8.8, 10.8, and 18.8 solar mass progenitors each at two different times• While varying these inputs we looked for outputs that presented interesting features• We ran the interesting simulations again but with many more outputs• We looked through our numerous graphs to find situations where collective interactions were affected by turbulence• Around 1000 km we expect to see mostly effects from collective interactions, possibly some from early MSW effects
Summary
• In most cases, we found that turbulence does not have an effect on the collective interactions in neutrino oscillations • The only profile that was affected by turbulence in the collective regime was profile 585 of the 10.8 solar mass progenetor• This indicates that lower mass stars will be more affected by turbulence • We found effects on the collective interactions only at levels of 50% turbulence• Until we receive data which quantifies the level of turbulence generated by the standing accretion shock instability in a protoneutron star, we can not know for sure if 30%50% is a reasonable range for the amount of turbulence that would affect the neutrino oscillations
Background
● Supernova explosions emit on the order of 1058 neutrinos● This neutrino flux is responsible for transferring momentum to the stalled shock wave at a size of ~200km in radius ● The neutrinos emitted by the supernova will eventually reach the Earth● We can observe these neutrinos with large detectors which are called neutrino telescopes● As they propagate towards the Earth, they change lepton flavor● This phenomenon is known as transformation, or oscillation● To better analyze the signals we receive on earth we need to fully understand these oscillation patterns
Each graph plots the probability of a given change in mass state of an antineutrino versus energy in MeV in the simulation run with a 10.8 solar mass star with varying levels of turbulence. Top left is 0% turbulence, top
right is 10%, bottom left is 30%, and bottom right is 50%.
Acknowledgments
● Funding from the NSF● Research assistance and guidance from Dr. Kneller, Dr. McLaughlin, Dr. Lund, Dr. Malkus, Dr. Blondin and all the faculty involved in the URCA
References
● Volpe, Christina, and Kneller, James. "Turbulence effects on supernova neutrinos.", Physical Review D, vol. 82, Issue 12, id. 123004, N.p., n.d. Web. 6 June 2012.● V. N. Tsytovich, R. Bingham, J.M. Dawson, H.A. Bethe, "Collective neutrinoplasma interactions", Astroparticle Physics, Volume 8, Issue 4, April 1998, Pages 297307, ISSN 09276505, 10.1016/S09276505(97)000443.
We aim to determine if the addition of turbulenceaffects neutrino oscillations in the collective regime.
Results
• We found increasing turbulence mostly showed effects in the neutrino oscillations in 10.8 solar mass star model, but had no effect on the neutrino oscillations in the 18.8 solar mass model• Because of this, we ran simulations which allowed us to analyze the probability of neutrino oscillation at regularly selected distances for the 10.8 solar mass progenitor• Added variability due to many MSW resonances shows up quite often • Collective interactions were only affected by turbulence in one case (seen in the graph in the upper right) where the overall shape of the curve is changed by adding turbulence • The spikes seen in the bottom graphs for low energies can be attributed to early MSW effects
Credit: Nick Ballon / SuperKamiokande Observatory
A group of scientists on a boat inside the SuperKamiokande Neutrino Observatory, a neutrino telescope that resides 1 km underneath the Japanese city of Hida. This observatory is filled with 50 kilotons of super pure water and photo multiplier tube sensors.
(Mev)(Mev)
(Mev) (Mev)
This table shows shows matterstate transitions that occur due to MSW resonances
* indicates anti matterstate
We found that for low mass iron core progenitors turbulencecan have an effect on the collective interactions of antineutrinos.
This graph shows the density profile of the 10.8 solar mass progenitor with profile 585 used for our simulations. The graphs in the upper right show output probabilities at 1000 km or 108 cm. This is close to forward shock seen in this graph. Labeled is the region where collective effects occur.
Collective region
