An Update AT PPNS, GENERATOR PROGRESS, NEW PAPERS IN THE - - PowerPoint PPT Presentation

An 𝑜 → ത 𝑜 Update

𝑜 → ഥ 𝑜 AT PPNS, GENERATOR PROGRESS, NEW PAPERS IN THE FIELD, MY UPCOMING PUBLICATIONS, AND FUTURE PLANS BY JOSHUA BARROW, JBARROW3@VOLS.UTK.EDU

Things are starting to happen in 𝑜 → ത 𝑜…

Neutrons and 𝑜 → ത 𝑜 have become a talking point in the past few months!

• See Jeremy Hewes’ thesis for details on ~first order intranuclear modeling and fully

developed convolutional neural network analysis techniques for 𝑜 → ത 𝑜 in 18

40𝐵𝑠

• European Spallation Source NNbar Collaboration meeting (8th) at Institut Laue-Langevin,

Grenoble, France

• Key talks included:

1. Elena Golubeva, giving an overview of our work on 𝑜 → ത 𝑜 on 6

12𝐷

• Will be submitted very soon to PRD (I hope to find some time this week)
• Foundational structure laid for intranuclear 𝑜 → ത

𝑜 in 18

40𝐵𝑠

• Many new isotopic channels (from a 𝑇𝑉 3 symmetry model), not considered in Super-K, see paper
• Full intranuclear cascade

2. Jean-Marc Richard, giving a basic overview of nuclear theory techniques to calculate the annihilation radius probability distribution for 𝑜 → ത 𝑜 in 18

40𝐵𝑠

• Publication is forthcoming (hopefully in a couple of months)
• New distribution is already fully implemented in our generator (still validating!)

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Things are starting to happen in 𝑜 → ത 𝑜…(cont.)

Neutrons and 𝑜 → ത 𝑜 have become a key talking point in the past few months!

• Particle Physics at Neutron Sources (decadal) at Institut Laue-Langevin, Grenoble, France

1. Key people in the field were taken aback by Vincenzo Cirigliano’s talk on the morning of the second day, in which he dedicated the last half to 𝑜 → ത 𝑜 and post-sphaleron baryogenesis

• Said all of the “controversial”, but necessary, things for us without any fanfare (a huge gift!)
• Shows (hopefully!) a growing angst in the field for new results in baryon number violation experiments
• Must explain baryogenesis!

2. Albert Young spoke about prospects for a free neutron beam experiment at ESS and ILL 3. I spoke about intranuclear 𝑜 → ത 𝑜 at DUNE in my talk (see the full talk, with backup slides, here)

• Highlighted Jeremy’s work, DUNE’s reach capability, issues with initial assumptions in current generator, etc.

People seemed very positive and interested!

• Multiple experimental neutron science leaders (Geoff Greene, Mike Snow, Albert Young,

Robert Pattie, Alexey Fomin, etc.) are highly interested in DUNE’s 𝑜 → ത 𝑜 reach capabilities

• Goal is to produce a model with first and second order corrections to better understand signal to background ratios

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Current Generator Work with Elena Golubeva, INR

(in progress)

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Main implementation of JMR’s annihilation distribution is complete

• This effect is essentially independent of the

suppression factor formalism

JMR is finalizing calculations now

• Will be published soon!

Differs from current modeling assumptions in GENIE, where the annihilation is assumed to go as the density distribution of the nucleus

• Effectively (highly?) overestimates the sphericity of

the event topology—CNN? TMVA?

• Chooses higher momentum nucleon annihilation pairs

from a single Bodek-Ritchie momentum distribution

• This is actually quantum mechanically inconsistent

Main focus going forward is…

1. A spectral function implementation for 18 40𝐵𝑠

• Short range correllations are already effectively included by JMR
• Will need to make sure that momentum distributions on our end are used

consistently with his antineutron wave functions

2. Atmospheric neutrino sample to follow 3. I will then endeavor to rework GENIE simulations 4. Move on to GiBUU and NuWRO

Recent articles to check out

Anca Tureanu, Quantum Field Theory of Oscillations: Neutron-Antineutron Conversion Zhang et al, Implications of an Improved Neutron-Antineutron Oscillation Search for Baryogenesis: A Minimal Effective Theory Analysis

• Very useful graphs to compare Super-Kamiodande, DUNE, and ESS limits in a very general

theoretical framework

• Assumes properly understood suppression factor to map on to the same free transformation time
• Contains an immense and absolutely wonderful list of references from the whole of the field
• Jeremy and I are actually cited!

Miller et al, How short ranged-interactions influence long-ranged nuclear properties: Application to nuclear charge radii

• Why short range correllations matter!

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Publications in the pipeline

1. Our 𝑜 → ത 𝑜 on 6

12𝐷 will be submitted to PRD very soon (end of summer?)

2. Currently drafting intranuclear 𝑜 → ത 𝑜 paper for 18

40𝐵𝑠 (fall?)

• Will wait for JMR to publish annihilation distribution article
• Will include suppression factor for 𝐵𝑠?
• Must first implement spectral function consistently
• We do have some events already, but much more work is needed on the modeling and V&V end
• Will hopefully be modeling proton decay soon in this new generator framework!

3. Currently drafting proceedings for Institute for Nuclear Theory Workshop on Neutron Oscillations: Appearance, Disappearance, and Baryogenesis (end of year?)

• Most likely to appear in Nuclear Physics B

4. Currently drafting white paper review article of the field (end of year?)

• Will review basic theory and phenomenology
• Current work and limits in free and bound transformations (ESS, DUNE, Hyper-Kamiokande, maybe ILL)
• Will await most of the above publications, and others that are being discussed now within our own research group and

with several other colleagues

• Talk to me about co-authorship if you’ve done something interesting here; I will be sending out requests at some point

soon

5. Will co-author a joint PPNS free and bound 𝑜 → ത 𝑜 proceedings with Albert Young (no idea???)

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My work over the next 18-24 months…

• 1. Continue modeling work with the new generator for intranuclear 𝑜 → ത

𝑜 in 𝐵𝑠 with Elena Golubeva (~half time)

• 2. Complete short range correlation data analysis for 𝑓 scattering on 𝐷 at JLAB with

Nadia Fomin (~half time for the next ≳ 6 months; may be teaching as well)

• Will hopefully serve as an experimental input to our model in some way (at least for ESS and 𝐷)
• 3. If SCGSR comes through…
• Move to Fermilab for (at least) 1/3-12/23/19
• Work with Minerba Betancourt and Saori Pastore on implementation of a new, data-driven cross section model for

neutrino scattering in GENIE

• Use this to generate Honda-Homestake atmospheric flux samples for the NDK group (and anyone else who wants

them!)

• Work on GENIE remodeling with new annihilation distribution and spectral functions
• Begin modeling of signal and background in GiBUU and NuWRO
• Maybe give a few seminars at Fermilab on 𝐶 − 𝑀 violation and the importance of 𝑜 → ത

𝑜 as a possible explanation of baryogenesis

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