ICARUS
Detector
ArgoNeuTDetector

SBNDDetector

NuMI BeamShort-Baseline LAr-TPC detectors @ Fermilab

Signatures for New Physics inShort-Baseline Liquid Argon Neutrino Experiments
Twentieth Lomonosov Conference on Elementary Particle Physics
August 25th 2021
Ornella PalamaraFermilab!

Outline๏ Why BSM in Short-Baseline* (SBL) Liquid Argon Time Projection
Chamber (LAr TPC) Neutrino Experiments?

๏ Four LAr TPC experiments sitting on two neutrino beams (NuMI andBNB) at Fermilab๏ Short-Baseline Neutrino Program: sterile neutrinos & other BSMexplorations

๏ ArgoNeuT: improved limits on millicharged particles and heavy NeutralLeptons*Short-Baseline: L~100-1000 m, L/E~1eV , to be compared with2Long-Baseline: L~100-1000 Km, L/E~10-3eV22"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Why BSM in SBL LAr TPC Neutrino Experiments?

๏ The combination of:

100-1000 m

๏ High-intensity proton beams (high intensity neutrino beams) for neutrino precisionmeasurements coupled with
๏ (Large mass) LAr TPC detectors close to the beam target, with
๏ Extraordinary event imaging
๏ Fine granularity calorimetry and excellent particle identification
๏ Excellent timing resolution and๏ Low energy thresholdopens unprecedented opportunities to probe signatures for New Physics scenarios/BSM
phenomena in the neutrino sector and beyond
3\"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

New Physics Opportunities
New Physics observables can be placed into two categories:
Modifications to the neutrino oscillation paradigm(effects of BSM physics on neutrino oscillation)
Novel experimental signatures(dark matter, heavy neutrinos, millicharged particles…)
produced in the beam target

Sterile neutrinos
Neutrino tridents
Light Dark Matter
Heavy Neutral Leptons
Millicharged particles…
4"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Fermilab – Neutrino beams
BNB#

Fermilab’s$low'energy$neutrino$beam:$$$<Eν>$≈$700$MeV$
Booster#'#8#GeV#protons#

NuMI#

Fermilab’s$high'energy$neutrino$beam:$<Eν>$≈$4I7$GeV$(tunable)$Main#Injector#'#120#GeV#protons#
IPA$2015,$Madison$5

Anne$Schukra8,$Fermilab$"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./83$;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Short-Baseline LAr TPC detectors at Fermilab: ArgoNeuTICARUS
Detector

SBND
Detector

NuMI BeaArgoNeuT
DetectormShort-Baseline LAr-TPC detectors @ Fermilab
First LAr TPC detector at FNAL
5 months data taking in 2009-2010

0.24 tons active volume LAr TPC

6On-axis on NuMI <E𝜈>≃4 GeV

100 m underground, in front of the MINOS ND,~ 1km from target"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Short-Baseline LAr TPC detectors at Fermilab: MicroBooNE

ICARUS
Detector

SBND
Detector

NuMI BeaArgoNeuT
Detectorm

Short-Baseline LAr-TPC detectors @ Fermilab

Currently the world’s longest running LAr TPC(2015-present)
On-axis on BNB and off-axis on NuMI
[see presentation by J.H. Jo on Aug. 19th]7"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Short-Baseline LAr TPC detectors at Fermilab: SBN detectors

ICARUS
Detector

SBND
Detector

NuMI Bea

ArgoNeuTDetectormShort-Baseline LAr-TPC detectors @ Fermilab

Two other detectors to form the Short-Baseline(SBN) program
On-axis on BNB (SBND, MicroBooNE, ICARUS)
and off-axis on NuMI (MicroBooNE, ICARUS)

8"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Short Baseline Neutrino program
arXiv:1503.01520, January 2014
P.Machado, O.P., D. Schmitz, Annu. Rev. Nucl. Part. Sci. 2019 DOI 10.1146

Designed for Sterile Neutrino searches
Same neutrino beam, nuclear target, detector technology:
reducing systematic uncertainties to the % level9"#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

SBN Far detector: ICARUS
ICARUS has been commissioning since Summer 2020and collecting neutrino data from the BNB and NuMI
beams since March 2021
Improvements in progress during Summer 2021
shutdown
Physics data collection will begin in October 2021!

10 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

SBN Near detector: SBND
TPC components all at Fermilab
TPC assembly in progress at Fermilab
Warm outer vessel installed in the building
Cryogenics/cryostat installation in progress
Ready for cold commissioning by end of 2022

TPC

Anode plane assembly

CE front-end motherboard
Warm cryostat
CPA plane installed
X-ARAPUCA production
PDS module

11 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Why Liquid Argon Time Projection Chamber?

ArgoNeuTeveprotonν interactiontnMuon
Chargedπ

LAr TPC: Bubble chamber quality of data withadded calorimetry

12 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

The LAr TPC Technology
LAr TPC technology offers the ability to measure neutrino interactions
in real time with (sub)-millimeter position resolution, andhas excellent sensitivity for energy depositions from sub-MeV to few GeV,
far beyond that offered by any other neutrino detector

LArTPC at work: imagining and energy• Multiple 2D and the 3D

reconstruction of charged
particles ⇒ Imaging• Total charge proportional tothe deposited energy ⇒Calorimetry• dE/dx along the track ⇒Particle Identification
13 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

From “easy” to progressively more complicated topologies…

𝜋

14 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8e;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

The Low Energy Frontier

LAr TPC’s have demonstrated to be able to detect and reconstruct(sub-)MeV energy depositions!

R. Acciarri et al., Phys. Rev. D 99, 012002 (2019)

300 KeV threshold!
๏Topologically separated low-energy depositions are identified as electrons produced byCompton scattering of๏ de-excitation photons from the target nucleus and๏ photon produced by neutron inelastic interactions

๏The capability to resolve the individual collisions down to < MeV threshold is crucial for๏ detection and reconstruction of supernova neutrino interactions in large LArTPCs (ex. DUNE)๏ studies of new physics scenarios that could benefit invaluably from such low-energy reconstruction
15 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Experimental Hints For Beyond Three Neutrino Mixing
Short-Baseline Neutrino Anomalies
Accelerator “anomalies” (LNSD and MiniBooNE experiments) +Reactor and gallium “anomalies”[see presentations by A. Minotti and S.H. See on Aug. 20th]

could be pointing at BSM physics in the neutrino sector:
additional “sterile” neutrino state(s) withlarge mass-squared differences,driving neutrino oscillation at small distances

SBL, Δm2≳1 eV2Atmospheric, Δm2≃2.5 10-3 eV2Solar, Δm2≃7.4 10-5 eV2

16 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Electrons or photons?
MiniBooNE
Phys. Rev. D 103, 052002 (2021)

data

MiniBooNE Low Energy excess…
Photons? Electrons?

LAr TPC !
17 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Electron-𝛾 discrimination in LAr TPC
e𝛾ArgoNeuT
Phys.Rev. D95 (2017) 072005

𝛾Analyzing topology(gap from thevertex) and dE/dx

e-𝛾 discrimination capability of LAr is
crucial to understand thesignal/background nature of the 𝜈e-likeexcess observed by MiniBooNE
18 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

MicroBooNE experiment๏ Designed to investigate the low energy excess events

observed by the MiniBooNE experiment

๏ Physics run completed, R&D program now underway
๏ A series of first results on the “low energy excess” arearound the corner (different final states)

19 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

The Light Sterile Neutrino Experimental Landscapeallowedby DIS

The test of the sterile hypothesis

What is going on?
allowedbyAPP

M. Dentler et al., JHEP 08:010 (2018)

4.7 𝜎 tension arises when combining
𝜈e appearance and 𝜈𝜇 disappearance data sets
20 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

SBN Sterile Neutrino Sensitivity
𝜈𝜇→𝜈e Appearance sensitivity~3 years~3 yearsνµ → νe appearance

10𝜈𝜇→𝜈x Disappearance sensitivity
νµ disappearance(1)

10

LSND 90%

Global 3+1, 3σ allowed(2)

LSND 99%

ν µ / ν µ Dis, 3σ excluded(1)

SBN 3σ(2)ν e / ν e App, 3σ allowed

Δm241 (eV2)Δm241 (eV2)

Global 3+1, 3σ allowed

SBN 3σ1

SBN 5σ10−1

SBN 5σ110−1(1) S. Gariazzo et al., arXiv:1703.00860 [hep-ph](1) S. Gariazzo et al., arXiv:1703.00860 [hep-ph](2) M. Dentler et al., arXiv:1803.10661 [hep-ph](2) M. Dentler et al., arXiv:1803.10661 [hep-ph]10−310−2

sin22θµe10−1

110−210−1

P. Machado, O.P., D. Schmitz: Annual Rev. Nucl. Part. Sci. 2019.69:363-387

SBN can cover the parameters
allowed by past anomalies at
5𝜎 significance

21 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./81

sin22θµµ

SBN also has sensitivity to 𝜈𝜇disappearance
The observation of 𝜈𝜇 disappearance

would be essential to theinterpretation of any electron neutrinoexcess as being due to the existence ofsterile neutrinos;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Evolving Landscape…
Several alternative BSM models to explain SBL anomalies (ex. 𝜈e appearance butnot 𝜈𝜇 disappearance) have been proposed๏ Many of these models predict complex final states and differing levels of

hadronic activity

Several cases:“trident” lepton+leptonfinal state

Note: not an exhaustive list!
22 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8Courtesy of P. Machado;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Evolving Landscape…

๏Some of these signatures are “clearer”, like theμ+μ– trident๏

Others are more challenging, especially due tobackgrounds๏

In several detectors
๏ photons, electrons and e+e- areindistinguishable

Courtesy of P. Machado

23 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Evolving Landscape…
SBND(TH version)

๏Courtesy of P. Machado

SBN(D) experiment(s) exploring the landscapeand testing not only the sterile neutrino
hypothesis, but also other new physics models
๏Leveraging on the unique capabilities of theLAr TPC technology which open up more
information than available in a Cerenkov
detector such as MiniBooNE

๏Characterize in term of particle content andkinematics

๏

Recognize the presence hadronic activity is
critical to distinguish these possibilities!

P. Machado, O.P., D. Schmitz: Annu. Rev. Nucl. Part. Sci. 2019.69:363-387

24 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

SBND-PRISM: Sampling Multiple Off-Axis Fluxes
with the Same Detector
Unique feature: a Slightly Off-Axis Detector

Muon neutrino

Electron neutrino

Exploring physics potential of SBND-PRISM•Interaction Model Constraint•

SBN Sterile Neutrino Oscillations•

SBND-Only Sterile Neutrino Oscillations•

Dark Matter Searches•….

νe to νμ ratio changes
moving off-axis

25 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Searches for new physics in LAr TPC: signatures in SBND
Dark Matter - electron-positron pairMonte Carlo simulations

Heavy Sterile Neutrino Dark Neutrino - electron-positron pairelectron-positron pair

J.R.Jordan et al., arXiv:1806.05185

P. Ballet et al., JHEP 04 (2017) 102

Machado et al.,Phys. Rev. Lett. 121, 241801 (2018)

Dark Matter - forward electron
γ (p3)mA!∗

V. De Romeri et al.,χ (p1) arXiv:1903.10505 [hep-ph]…several other SBND studies are ongoingχ̄ (p2)
SBND-PRISM: Signal isunfocused while background(𝜈-e elastic events) decrease
with the off-axis angle

26 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Searches for new physics in LAr TPC: signatures in SBND
Dark Matter - electron-positron pairMonte Carlo simulations

Heavy Sterile Neutrino Dark Neutrino - electron-positron pairelectron-positron pair

J.R.Jordan et al., arXiv:1806.05185

P. Ballet et al., JHEP 04 (2017) 102

Machado et al.,Phys. Rev. Lett. 121, 241801 (2018)

Dark Matter - forward electronγ (p3)mA!∗

๏

V. De Romeri et al.,χ (p1) arXiv:1903.10505 [hep-ph]χ̄ (p2)

MicroBooNE searched for๏ Heavy Neutral leptons (N→𝜇±𝜋∓ decay
channel in a delayed time window)
P. Abratenko et al., Phys. Rev. D 101, 052001

SBND-PRISM: Signal isunfocused while background(𝜈-e elastic events) decrease
with the off-axis angle

๏Higgs scalar portal (e+e- final state fromNuMi off-axis events)
P. Abratenko et al., arxiv:2106.00568

๏DUNE(-ND) will also probe several BSM
scenarios
B. Abi et al, Eur. Phys. J. C (2021) 81

27 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Searches for new physics in LAr TPC: ArgoNeuTFirst search for Heavy Neutral Leptons N 𝜈𝜇+𝜇- in LAr TPC
Assuming HNL production predominately from 𝜏± decay:D/Ds decay to 𝜏, that subsequently decay to HNLs
𝜏± →N X± (X± is a SM particle e.g. π±)
HNL decay (MC)N 𝜈𝜇+𝜇-0 events observed in the data
R. Acciarri et al., accepted by Phys. Rev. Lett.

ArgoNeuT𝜇𝜇+

Minos-ND

28 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8

Significant increase in the parameter
space exclusion region!
;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Searches for new physics in LAr TPC: ArgoNeuTFirst search for Millicharged Particles in LAr TPC
mCP have an electric charge Q=ϵ⋅e (ϵ≪1)

Sketch byR. Acciarri et al., Phys. Rev. Lett., 124, 131801 (2020)

Low energy
threshold (300 KeV)
is the key!

Leading constraints in unexploredparameter regions!
[see presentation by Z. Liu on Aug. 20th]
29 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

Summary
LAr TPC neutrino detectors at Short-Baseline are fantastic tools to look for
new physics in the neutrino sector and beyond!
ArgoNeuT, a small LAr-TPC exposed to the NuMI beam at Fermilab provided
leading constraints on millicharged particles and heavy neutral leptons
in unexplored parameter space regions!

The three SBN detectors sitting
on the BNB at Fermilab will
perform a world-leading searchfor eV-scale sterile neutrinos

Beyond the flagship oscillation searches, the SBN program has abroad science goal, which addresses alternative explanations of theSBL anomalies and includes other BSM explorations
30 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

OVERFLOW

31 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

LArTPC at work
LightDetection
System(LDS)

Charged particles in LAr
produce freeionization electrons andscintillation lightm.i.p. at 500 V/cm: ~ 60,000 e/cm
~ 50,000 photons/cm

Ionization charge drifts
in a uniform electricfield towards thereadout wire-planes

Digitized signals from the wires
are collected [time of the wire
pulses gives the drift coordinateof the track and amplitude gives
the deposited charge]

Electron drift time ~ ms

VUV photons propagate
and areshifted into VIS photons
32 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8

Scintillation light fast
signals from LDSs give
event timing;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!

33 "#$%&'&(&)&$*$+,-.&/0)1$23)$415$%678,98$,.$+:;$410/),.3$<=>1),(1./8;3(3.383?$@3.21)1.91A$B0-#$CD/6$CEC!