Snowmass Joint Workshop on New Physics Opportunities with Neutrino Experiments: Theoretical & Experimental Perspectives

10 Feb 2022, 08:30 → 12 Feb 2022, 19:00 US/Eastern

Zoom connection:

Plenary and writing/working group sessions (Same room Thursday-Saturday):
https://pitt.zoom.us/j/92800065883

Parallel session 1: Accelerators/Short Baselines (Friday)
https://pitt.zoom.us/s/99215457262

Parallel session 2: Astrophysical Neutrinos (Friday)
https://pitt.zoom.us/s/92915637579

Parallel session 3: Reactors and more (Friday)
https://pitt.zoom.us/s/96924777862

The passcode for all zoom rooms is "snowmass" (no quotes)
 

Workshop Overview

The Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC) at the University of Pittsburgh is excited to host the Snowmass Joint Workshop on New Physics Opportunities with Neutrino Experiments: Theoretical & Experimental Perspectives meeting from Thursday, February 10th, 2022 till Saturday, February 12, 2022. The meeting will be conducted virtually over Zoom.  

This workshop will bring together theorists and experimentalists to discuss and advance opportunities to search for physics beyond the Standard Model with current, near term, and future neutrino experiments in the context of the Snowmass Community Planning studies. The focus will be on the activities of the NF03 topical group (Neutrinos and BSM) and the overlapping physics interests of the following Snowmass topical groups: NF01, NF02, NF03, RF06 and TF11. 

Expected goals from the workshop

• Discuss activities and progress on Snowmass studies on new physics opportunities at neutrino experiments.
• Provide a status update of sub-topical groups activities and remaining studies including timelines, if incomplete.
• Finalize sub-topical group whitepapers.
• Generate first drafts of topical frontier group reports (NF01,NF02,NF03,RF06 and TF11) on new physics opportunities.
• Define clear timelines for completing the sub-topical group whitepapers and topical group reports. 

To participate, please register for the meeting. 

Thursday 10 February

Plenary: Workshop Overview & NF03 Subtopical White Paper Reports - I

Convener: Andre de Gouvea (Northwestern University)

1 Welcome & Logistics

Speaker: Brian Thomas Batell

BSM@Nu-Intro.pdf

2 Workshop Overview

Covers the scope and goals of the workshop

Speaker: Jae Yu (University of Texas at Arlington (US))

yu-nf03-wrkp-overview-021022.pdf

yu-nf03-wrkp-overview-021022.pdf

yu-nf03-wrkp-overview-021022.pptx

3 NF03 Subtopical Group Report 1 - BSM Searches within Neutrino Oscillations

Speaker: Pilar Coloma (Universidad Autónoma de Madrid)

coloma-NF03-workshop.pdf

4 NF03 Subtopical Group Report 2 - Heavy Neutral Leptons

Speakers: Ian Shoemaker (Virginia Tech), Ian Shoemaker

HNL WP Feb 10.pdf

11:15 Break

Plenary: NF03 Subtopical White Paper Reports - II

Convener: Pilar Coloma (Universidad Autónoma de Madrid)

5 NF03 Subtopical Group Report 4 - CEvNS

Speakers: Louis Strigari (Stanford University), Louis Strigari (Texas A&M)

pitt_subtopical_2022.pdf

6 NF03 Subtopical Group Report 5 - Cosmogenic Dark Matter and Exotic Particle Searches

Speakers: Yun-Tse Tsai (SLAC), yun tse tsai (SLAC)

WPReport_20220210.pdf

7 NF03 Subtopical Group Report 6 - Dark Sector Studies with Neutrino Beams

Speaker: Brian Thomas Batell

BSM@Nu-Dark-Sector.pdf

8 NF03 Subtopical Group Report 3 - Baryon Number Violation

Speakers: Bhupal Dev (Washington University in St. Louis), Lisa Koerner (University of Houston (US))

Baryon Number Violation Whitepaper.pdf

13:15 Break

Working Group: Breakout for sub-topical group working sessions

Friday 11 February

Plenary

Convener: Lisa Koerner (University of Houston (US))

9 NF01, NF02, RF06, TH11 and NF03 quick overview

One file consisting of contributions from joint topical groups, managed by Pilar Coloma.

Speakers: Alexandre Sousa (Harvard University), Alexandre Sousa (University of Cincinnati), Alexandre Sousa (University of Cincinnati), Alexandre Sousa (University of Cincinnati (US)), Andre de Gouvea, Brian Batell, Brian Batell, Brian Thomas Batell (University of Pittsburgh (US)), Brian Thomas Batell, Peter Denton (Brookhaven National Laboratory), Pilar Coloma (Virginia Tech University), Pilar Coloma (Instituto de Fisica Teorica UAM/CSIC), Pilar Coloma (Fermilab), Pilar Coloma (Universidad Autónoma de Madrid)

RF6-overview-Batell.pdf

Snowmass_NF01.pdf

Sousa_NF02_Overview_Snowmass_Joint_Workshop_Feb_11_2022.pdf

TF11_outline_2.pdf

10 Discussion on covered topics and missing ones, prospects and strategy

Discussion mediated by Lisa Koerner

Speaker: Lisa Koerner (University of Houston (US))

11:25 Break

Parallel Session 1: Accelerators/Short Baselines

Convener: Donna Naples

11 MicroBooNE's Low Energy Excess Search: First Results and Future Prospects

The MicroBooNE collaboration recently released a series of measurements aimed at investigating the nature of the excess of low energy electromagnetic interactions observed by the MiniBooNE collaboration. In this talk, we will present the latest results from both a search of single photons in MicroBooNE, as well as a series of three independent analyses leveraging different reconstruction paradigms which look for an anomalous excess of electron neutrino events. This talk will present details of these recent results and cross-checks to demonstrate the robustness of the analyses, and discuss both their interpretation and future studies in the wider context of the various BSM explanations of the MiniBooNE excess.

Speaker: Mark Ross-Lonergan

MRL_NB BSM@NU_MicroBooNE.pdf

12 Searching for Beyond the Standard Model Physics with MicroBooNE

MicroBooNE is an 85-tonne active mass liquid argon time projection chamber (LArTPC) at Fermilab. It has excellent calorimetric, spatial and energy resolution and is exposed to two neutrino beams, which make it a powerful detector not just for neutrino physics, but also for Beyond the Standard Model (BSM) physics. The experiment has competitive sensitivity to heavy neutral leptons possibly present in the leptonic decay modes of kaons, and also to scalar bosons that could be produced in kaon decays in association with pions. In addition, MicroBooNE serves as a platform for prototyping searches for rare events in the future Deep Underground Neutrino Experiment (DUNE). This talk will explore the capabilities of LArTPCs for BSM physics and highlight some recent results from MicroBooNE.

Speaker: Ivan Lepetic

Lepetic_uB_BSMnu.pdf

13 New Proton Beam Dump Experiments at Fermilab: PIP2-BD and SBN-BD

The PIP-II complex at Fermilab is slated for operation later this decade and can support MW-class proton fixed-target programs at both O(1 GeV) and O(10 GeV) in addition to the beam required for DUNE. In this talk we outline new opportunities for BSM searches at O(1 GeV) and O(10 GeV) proton beam dump facilities at Fermilab using existing and proposed neutrino detectors.

Speakers: Jacob Zettlemoyer (Fermilab), Jacob Zettlemoyer (Indiana University Bloomington)

JCZ_Snowmass_BSM_FNAL_BD_2_11_2022.pdf

14 Opportunity to study physics beyond standard neutrino oscillations at the upcoming accelerator based neutrino oscillation experiments

A major goal of the present and future long-baseline neutrino oscillation experiments is to make precision measurements of neutrino flavour oscillations, which are well-explained by mixing between three active flavors within current experimental constraints. However, other mechanisms could be responsible for neutrino flavour change on a sub-leading level. The combination of the high intensity proton beam facilities and high-resolution detectors will make beyond standard model (BSM) physics accessible in the accelerator based neutrino experiments. In this talk, I will discuss about the searches for different BSM physics topics (low mass dark matter, HNL) in the context of ongoing and future neutrino experiments like ICARUS@SBN and at DUNE.

Speaker: Dr Animesh Chatterjee

AC_SnowmassFeb11_Talk.pdf

15 BSM searches in LAr using MeV-scale reconstruction

Liquid argon time projection chambers (LArTPCs) can resolve features over a wide range of energies and length scales. Existing reconstruction and analyses focus on higher-energy topologies, like tracks and showers from neutrino interactions. Numerous additional benefits are gained by extending reconstruction capabilities below 100 MeV. The Low-Energy Physics in Neutrino LArTPCs (LEPLAr) Snowmass Working Group aims to explore the benefits and address the many challenges of reconstructing such low-energy features. In this talk, we briefly highlight several interesting BSM models that can be probed by large LArTPCs, searches for which rely either partially or entirely on the ability to resolve energy depositions of ~1 MeV or less.

Speaker: Will Foreman (University of Chicago)

Snowmass_BSMWorkshop_LowEnergyReco.pdf

16 Decays of New-Physics Particles at the DUNE Near Detector(s)

The upcoming Deep Underground Neutrino Experiment (DUNE) and its near detector complex will allow for many searches for new physics. Among these include the possibility that light (MeV - GeV) particles can be produced in/near the DUNE target and decay inside the near detector, producing a striking signature. In this talk, I will demonstrate the many different types of well-motivated new physics that DUNE has the potential of discovering in several years of data collection.

Speaker: Kevin James Kelly (CERN)

KJK_SnowmassBSMNu.pdf

13:15 Break

Parallel Session 2: Astrophysical Neutrinos

Convener: Arnab Dasgupta (PITT-PACC)

17 Tau Neutrino Identification at IceCube for Unitary Violation Tests

The largest tau neutrino dataset to date is IceCube's atmospheric tau neutrino appearance dataset containing $>1,000$ tau neutrino and antineutrino events as determined by a fit to a standard three-flavor oscillation framework. On an event-by-event basis, however, it is impossible to know that any given event is a tau neutrino as they are identical to either an electron neutrino charged-current event or a neutral-current interaction of any active flavor. Nonetheless, we conclusively show that, using only the cascade sample even without knowledge of the oscillation parameters and without assuming that the lepton mixing matrix is unitary, tau neutrino identification is still possible and there is no viable scenario in which all of the tau neutrino candidates are actually electron neutrinos. This is primarily due to the matter effect and the tau lepton production threshold, as well as the fact that tau neutrinos are systematically reconstructed at a lower energy than electron neutrinos due to one or more outgoing neutrinos. This conclusively shows that it is possible for an atmospheric neutrino oscillation experiment to confirm that $U_{\tau1}$, $U_{\tau2}$, and $U_{\tau3}$ are not all zero even with limited particle identification.

Speaker: Dr Peter Denton (Brookhaven National Laboratory)

Denton_Atmospheric_Tau.pdf

18 BSM Oscillation Searches at the IceCube Neutrino Observatory

The IceCube Neutrino Observatory, a gigaton-scale Cherenkov detector located several kilometers beneath the surface of the South Pole, has detected hundreds of thousands of atmospheric neutrinos at energies from a few GeV to 100 TeV. Above 100 GeV, where ordinary oscillation effects become vanishingly small, this data sample offers the opportunity to search for and set constraints on a wide range of beyond-standard-model (BSM) oscillation mechanisms. Such mechanisms include neutral heavy leptons, neutrino decay, neutrino decoherence, and neutrino-nucleus nonstandard interactions (NSI). Here, we present the latest IceCube results and progress of current analyses that search for BSM oscillation signals.

Speaker: Grant Parker (University of Texas at Arlington)

BSM Neutrino Oscillation Analyses in IceCube -- Grant Parker (Snowmass 02.11.21).pdf

BSM Neutrino Oscillation Analyses in IceCube -- Grant Parker (Snowmass 02.11.21).pptx

19 IceCube Sterile Neutrino Searches

The IceCube Neutrino Observatory is a gigaton-scale Cherenkov telescope frozen beneath the ice at the Amundsen-Scott South Pole Station. Spanning approximately a cubic kilometer, it has detected hundreds of thousands of neutrino events at energies ranging from a few GeV to hundreds of TeV. Its high event statistics and sensitivity to a wide range of energies have given it an unprecedented sensitivity to sterile-neutrino oscillation parameters. IceCube may also be poised to make a direct sterile-induced tau-appearance measurement via $\bar{\nu}_{\mu}\to\bar{\nu}_{s}\to\bar{\nu}_{\tau}$ matter-enhanced oscillations and provide further constraint to the $\theta_{24}$ and $\theta_{34}$ mixing angles. Here, ongoing IceCube work and results for both high and low-energy sterile neutrino oscilations analyses are presented, for both cascade and track event topologies.

Speaker: Mr Benjamin Smithers (University of Texas at Arlington)

Smithers - Icecube sterile neutrino searches.pdf

20 Search for Quantum Gravity Using Astrophysical Neutrino Flavour with IceCube

Along with their long propagation from production to detection, neutrino states undergo quantum interference which converts their types, or flavours. High-energy astrophysical neutrinos are known to propagate unperturbed over a billion light-years in vacuum. These neutrinos act as the largest quantum interferometer and are sensitive to the smallest effects in vacuum due to new physics.

Quantum gravity (QG) aims to describe gravity in a quantum mechanical framework, unifying matter, forces and space-time. QG effects are expected to appear at the ultra-high-energy scale known as the Planck energy, E_P~10¹⁹ GeV. Such a high-energy universe would have existed only right after the Big Bang and it is inaccessible by human technologies. On the other hand, it is speculated that the effects of QG may exist in our low-energy vacuum, but are suppressed by the Planck energy as 1/E_P (~10^-19 GeV^-1) or 1/E_P² (~10^-38 GeV^-2) or higher order. The coupling of particles to these effects are too small to measure in kinematic observables, but the phase shift of neutrino waves could cause observable flavour conversions. Here, we report the first result of neutrino interferometry using astrophysical neutrino flavours to search for a new space-time structure. We did not find any evidence of anomalous flavour conversion in IceCube astrophysical neutrino flavour data. We place the most stringent limits of any known technologies, down to ~10^-42 GeV^-2, on the dimension-six operators that parameterize the space-time defects for preferred astrophysical production scenarios. For the first time, we unambiguously reach the signal region of quantum-gravity-motivated physics.

Speaker: Teppei Katori (King's College London)

TK_LV_PITTPACC22.pdf

21 Towards Probing the Diffuse Supernova Neutrino Background in All Flavors

Fully understanding the average core-collapse supernova requires detecting the diffuse supernova neutrino background (DSNB) in all flavors. While the DSNB $\bar{\nu}_e$ flux is near detection, and the DSNB $\nu_e$ flux has a good upper limit and prospects for improvement, the DSNB $\nu_x$ (each of $\nu_\mu, \nu_\tau, \bar{\nu}_\mu, \bar{\nu}_\tau$) flux has a poor limit and heretofore had no clear path for improved sensitivity. We show that a succession of xenon-based dark matter detectors --- XENON1T (completed), XENONnT/LUX-ZEPLIN (running), and DARWIN (proposed) --- can dramatically improve sensitivity to DSNB $\nu_x$ the neutrino-nucleus coherent scattering channel. XENON1T could match the present sensitivity of $\sim 10^3 \; \mathrm{cm}^{-2}~\mathrm{s}^{-1}$ per $\nu_x$ flavor, XENONnT/LUX-ZEPLIN would have linear improvement of sensitivity with exposure, and a long run of DARWIN could reach a flux sensitivity of $\sim 10 \; \mathrm{cm}^{-2}~\mathrm{s}^{-1}$. Together, these would also contribute to greatly improve bounds on non-standard scenarios. Ultimately, to reach the standard flux range of $\sim 1 \; \mathrm{cm}^{-2}~\mathrm{s}^{-1}$, even larger exposures will be needed, which we show may be possible with the series of proposed lead-based RES-NOVA detectors.

Speaker: Anna M. Suliga (UC Berkeley and U. of Wisconsin)

22 Model-Independent Search for sub-MeV Sterile Neutrinos with Superconducting Quantum Sensors

The search for sub-MeV neutrinos via precision nuclear decay measurements is among the most powerful methods for BSM neutrino mass searches since it relies only on the existence of a heavy neutrino admixture to the active neutrinos, and not on the model-dependent details of their interactions. Within this context, the BeEST (Beryllium Electron-capture with Superconducting Tunnel junctions) experiment uses the decay-momentum reconstruction technique to precisely measure the low-energy $^7$Be$\rightarrow^7$Li recoil spectrum via $^7$Be ions implanted into high-rate superconducting quantum sensors. Here we outline the experimental concept of the currently running experiment, sensitivity to additional BSM physics scenarios, and future plans for scaling to 10,000 STJ pixels using new materials for ultra-high energy resolution detectors to probe keV-masses with neutrino couplings of $|U_{ei}|^2\leq10^{-9}$.

Speaker: Kyle Leach (Colorado School of Mines)

20220211_BeESTSnowmass.pdf

23 Exploring Fundamental Physics with Atmospheric Collider

Speaker: Volodymyr Takhistov

Snowmass_Neutrino2022_Takhistov.pdf

Parallel Session 3: Reactors and More

Convener: Vittorio Paolone (University of Pittsburgh)

24 Searches for Nonstandard Neutrino Oscillations at Nuclear Reactors

Nuclear reactors have been workhorses for neutrino physics since its inception, and have been critical in establishing neutrino oscillations. While the three-oscillating-neutrino paradigm has been remarkably successful, long-standing anomalies at LSND, MiniBooNE, gallium experiments and reactor experiments may be pointing to the existence of new physics that can affect this phenomenon. In this talk, I will discuss how reactor experiments have contributed to this enterprise, particularly over the past decade. Moreover, I will outline the prospects for near-future endeavors in searching for nonstandard oscillation effects, emphasizing their role in the global neutrino physics program.

Speaker: Jeffrey Berryman (University of California, Berkeley)

Berryman_BSM@nu_slides.pdf

25 BSM Physics Potential of the PROSPECT-II Experiment

The Precision Reactor Oscillation and SPECTrum (PROSPECT) experiment is a short baseline reactor neutrino experiment that produced one of the world-leading limits on eV-scale sterile neutrinos and performed a precision measurement of the reactor antineutrino spectrum from the High Flux Isotope Reactor--a highly enriched uranium reactor--located at Oak Ridge National Laboratory. PROSPECT also demonstrated the capability to perform an on-surface reactor neutrino measurement with a signal-to-background ratio better than 1 for the first time. PROSPECT collaboration is now preparing an upgraded detector for the second phase of the experiment. With evolutionary changes to the PROSPECT detector, PROSPECT-II aims to perform a high precision reactor neutrino spectrum measurement and probe the unexplored parameter space for sterile neutrinos. This talk will describe the unique beyond the standard model physics potential of the PROSPECT-II experiment in addressing the short baseline anomalous results.

Speaker: Pranava Teja Surukuchi

Surukuchi_NF03_Pittsburgh_Workshop.pdf

26 Hidden Sector Searches With Low-Threshold Reactor-Based Neutrino Experiments

The recent observation of coherent neutrino-nucleus elastic scattering, or CEvNS for short, provides a novel window to probe standard and beyond standard physics in the neutrino sector. A key feature of nuclear interactions is when the momentum transferred to the nucleus is relatively small, near or below the MeV scale, so that the neutrino can coherently scatter off the whole nucleus instead of distinguishing its individual nucleons. The coherence of the interaction results in sensitivity to the square of the total weak charge of the nucleus, which could enhance the coherent scattering cross-section by a factor of 10-100 when compared to neutrino-nucleon scattering. In addition, new non-standard interactions of neutrinos with matter can be enhanced at low recoil energies if the new interaction is mediated by a light particle. The light mediator can be a new beyond standard model (BSM) particle, such as a B − L gauge boson or a light scalar, but it can also be the photon if the neutrino possesses a magnetic dipole moment. Both possibilities would signal the presence of new BSM physics. Nuclear reactors provide the largest neutrino flux for a facility on Earth. Reactor neutrino energies are compatible with the coherence enhancement (~2-4 MeV), but at the same time, the scattering kinematics drastically limits the transferred energy, especially to a nucleus. The combination of these three aspects: the cross-section enhancement for nuclear interaction for the reactor neutrino energies, the very low energy threshold of available sensor technologies to observe faint depositions, and the most intense neutrino flux on earth, make the proposed framework a unique tool to search for dark sector candidates and new light physics in new regimes.
In addition, nuclear reactors are also a very intense source of photons that can interact with the reactor structure and produce other dark sector candidates (such as axion-like particles, hidden photons, etc.) that can leave the core and be detected by low threshold sensors. Recent studies have shown competitive sensitivities to search for these models at nuclear facilities.
In this talk, we will discuss different models that can be explored with this technique and we will expose the main advantages of these types of searches over existing alternatives. We will also give some of the technical requirements to achieve the expected sensitivity.

Speaker: Jingke Xu (Lawrence Livermore National Laboratory)

27 Searching for Neutrinoless Double Beta Decay with Xenon-doped Liquid Argon TPCs

The physics programs of LArTPCs primarily focus on signals in the GeV energy range. In recent years, the potential for LArTPCs as a low-energy experiment has been fruitfully explored, specifically regarding its sensitivity to signals as low as 5-10 MeV such as those associated with supernova burst and solar neutrinos in DUNE. In this presentation, we will discuss the requirements and modifications that could extend a DUNE-like detector to energies to the MeV-scale and could enable us to further expand DUNE's physics program to searches for neutrino-less double-beta decay in xenon-doped liquid argon TPC at the multi-kiloton scale. I will present the modifications we propose with corresponding sensitivity estimates for the effective Majorana mass measurements beyond the inverted hierarchy region, and describe the rich and diverse R&D program that this research avenue would open.

Speakers: Andrew Mastbaum (Rutgers University), Joseph Zennamo, Fernanda Psihas (Fermi National Accelerator Laboratory)

20220211_DopedLArTPCs.pdf

28 Study of invisible neutrino decay at ESSnuSB

In this presentation I will discuss the phenomena of invisible neutrino decay in which a heavy active neutrino state decays into a light sterile neutrino state and present a comparative analysis of two baseline options, 540 km and 360 km, for the ESSnuSB experimental setup. In particular, I will discuss the capability of this experiment to: (i) put a bound on the decay parameter, (ii) discover decay, and (iii) measure the decay parameter precisely. I will also discuss the effect of decay in $\delta_{\rm CP}$ measurement.

Speaker: Dr Monojit Ghosh (University of Hyderabad, Hyderabad, India)

talk_snow_mg.pdf

29 Improving CP Sensitivity with Muon Decay at Rest

At long-baseline experiments, the genuine CP effect from the PMNS mixing matrix can be faked by the ubiquitous matter effect. The reduction of the experimental sensitivity to $\delta_D$ drops by 20% due to matter density uncertainties. In this work we present an experimental configuration that combines the DUNE experiment with a muon decay-at-rest ($\mu$DAR) source. The $\mu$DAR source provides a complementary $\overline \nu_\mu \rightarrow \overline \nu_e$ channel at a low energy, O(30) MeV. The synergy between DUNE and $\mu$DAR improves the sensitivity of $\delta_D$ by up to 50%, even in the presence of matter density uncertainties.

Speaker: Pedro Pasquini

Improving_CP_Sensitivity_with_Muon_Decay_at_Rest_Snowmass2022.pdf

13:15 Break

13:30 Break

Working Group: Breakout for sub-topical group working sessions

Saturday 12 February

Plenary: Summary of the workshop, closing discussions

Conveners: Alexandre Sousa (University of Cincinnati (US)), Alexandre Sousa (Harvard University), Alexandre Sousa (University of Cincinnati), Alexandre Sousa (University of Cincinnati)

30 Summary on nu-N Interactions Workshop in BSM@nu Context

Speakers: Noemi Rocco, Noemi Rocco (Argonne National Laboratory), Noemi Rocco, Vedran Brdar (MPIK Heidelberg), Vedran Brdar, Vedran Brdar (University of Zagreb (HR))

talk_Rocco.pdf

Vedran.pdf

31 Summary of the workshop

Speaker: Prof. Jae Yu (University of Texas at Arlington (US))

yu-nf03-wrkp-summary-021222.pdf

yu-nf03-wrkp-summary-021222.pptx

32 Closing discussions and further feedback from the community

Discussion mediated by Lisa Koerner.

Speakers: Lisa Koerner (University of Houston (US)), Lisa Whitehead Koerner (University of Houston)

11:30 Break

Working Group: Free form Breakout Sessions for subtopical white paper groups