Search for cosmic neutrino point sources & extended sources with 6-21 lines of KM3NeT/ARCA

Sea ch o cosmic neu ino
poin sou ces & ex ended sou ces
wi h 6-21 lines o KM3NeT/ARCA
NeuTel wo kshop
Padua, I aly
Sep embe 30 h, 2025
KM3Neu ino Telescope / As opa icle Resea ch wi h Cosmics in he Abyss is a neu ino obse a o y, cu en ly
being build a he bo om o he Medi e anean Sea. I can do mul i- la ou as onomy (𝜈𝜈𝑒𝑒, 𝜈𝜈𝜇𝜇, 𝜈𝜈𝜏𝜏), has sub-
deg ee angula esolu ion, is sensi i e in a la ge ene gy ange[MeV -PeV], and can p obe many di e en ype o
𝜈𝜈-sou ces. I s loca ion in he No he n hemisphe e p o ides a good iew o he Galac ic Region
The KM3eT/ARCA de ec o
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 2
KM3-230213A
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 3
The ul a-high-ene gy cosmic neu ino(KM3-230213A) de ec ion by KM3NeT, no only demons a es he
de ec o ’s capabili y o de ec neu inos a he highes ene gies, bu also ein o ces he scien i ic po en ial o
KM3NeT/ARCA in p obing ex eme as ophysical en i onmen s.
* KM3NeT Collabo a ion: Obse a ion o an ul a-high-ene gy cosmic neu ino wi h KM3NeT. Na u e, 2025, 638.8050: 376-382.
Neu ino as onomy
As ophysical neu ino sou ces a e cosmic ay
accele a o s. The wo main machanisms o high-
ene gy neu ino p oduc ion a e:
(1) When cosmic ays in e ac wi h ma e (had o-
nuclea in e ac ions):
𝑝𝑝+𝑝𝑝 →𝑝𝑝+𝑛𝑛+𝜋𝜋+
𝑝𝑝+𝑝𝑝 →𝑝𝑝+𝑝𝑝+𝜋𝜋0
𝑝𝑝+𝑛𝑛 →𝑝𝑝+𝑛𝑛+𝜋𝜋0
𝑝𝑝+𝑛𝑛→𝑝𝑝+𝑝𝑝+𝜋𝜋−
(2) When cosmic ays in e ac wi h pho ons (pho o-
had onicin e ac ions):
𝑝𝑝+𝛾𝛾 →Δ+→𝑛𝑛+𝜋𝜋+
𝑝𝑝+𝛾𝛾 →Δ+→𝑝𝑝+𝜋𝜋0
While he neu al pions decay in o 𝛾𝛾- ays: 𝜋𝜋0→𝛾𝛾+𝛾𝛾,
neu inos a e p oduced in he decay o he cha ged
pions:
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 4
𝜋𝜋+→𝜇𝜇++𝝂𝝂𝝁𝝁
𝜋𝜋+→𝜇𝜇+→𝑒𝑒++𝝂𝝂𝒆𝒆+�
𝝂𝝂𝝁𝝁𝜋𝜋−→𝜇𝜇−+�
𝝂𝝂𝝁𝝁
𝜋𝜋+→𝜇𝜇−→𝑒𝑒−+�
𝝂𝝂𝒆𝒆+𝝂𝝂𝝁𝝁
Neu ino As onomy
*IceCube Collabo a ion: Obse a ion o high-ene gy neu inos om he Galac ic plane. Science, 2023, 380(6652), 1338-1343
In hei espec i e ene gy anges he
sou ces NGC 1068 and TXS 0506+056
con ibu e no mo e han 1% o he o e all
di use lux o as ophysical neu inos.*
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 5

Candida e sou ces
106 sou ces a e selec ed based on: GeV –EeVin o ma ion om o he neu ino expe imen s, cosmic ay
expe imen s as well as op ical measu emen s in he ange -90°< 𝜹𝜹< 40° o which KM3NeT has > 35% isibili y
(a e cu o upgoing + ho izon al). The 19 ex ended sou ces a e es ed assuming a Gaussian wi h sp ead (σ)
equal o hei ex ension [0.1°−2.2°], and assumed o be ci cula ly-symme ic.
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 6
E en selec ion
Signal de ini ion: A cosmic neu ino wi h an ou going muon econs uc ed be e han 1°.
Basic e en selec ion c i e ia (“p e-cu s”):
1. Selec ho izon al/up-going acks (𝑐𝑐𝑐𝑐𝑐𝑐 𝜃𝜃 k >−0.1),
2. Selec e en s wi h high numbe o hi s used in he econs uc ion (𝑁𝑁ℎ𝑖𝑖𝑖𝑖𝑐𝑐 >20),
3. Selec e en s wi h good i quali y (based on likelihood o econs uc ion) (lik >50).
Addi ional selec ion c i e ia o he ARCA6-8 sample:
1. Selec ho izon al/up-going e en s passing he showe econs uc ion (cos 𝜃𝜃shw >−0.1).
Addi ional selec ion c i e ia o he ARCA19-21 sample:
1. Selec e ens wi h a long ack leng h (len >100m),
2. Selec e en s wi h an ene gy abo e 100 GeV (𝐸𝐸>100 GeV),
3. Selec e en s wi h good i quali y (based on likelihood o econs uc ion) (lik >101.8),
4. Selec e en s es ima ed o ha e a small e o in i s econs uc ed di ec ion (𝛽𝛽0>10−2.25),
5. Boos ed decision ee (BDT > 0.9996).
Backg ound es ima ion: made wi h sc ambled da a.
Ve y High Ene gy e en KM3-230213A* emo ed om da a sample.
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* KM3NeT Collabo a ion: Obse a ion o an ul a-high-ene gy cosmic neu ino wi h KM3NeT. Na u e, 2025, 638.8050: 376-382.
E en selec ion in numbe s
P ecu s Final cu le el
ARCA6-8 ARCA19-21 ARCA6-8 ARCA19-21
Da a 119313 293965* 15742 1544*
Muons 125314 334902 13278 150
A m nu 921 3798 750 863
Cos nu 12 32 912
Cos signal (wi h muon,
Wi hin 1 deg ee) 312 210
MC o 126246 338731 14038 1025
Muon_con amina ion 99% 99% 95% 15%
Signal e iciency 83% 78%
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 8
Da a a e aken wi h 6 -21 lines, be ween May 2021 and Sep . 2023. A e e en selec ion, he ARCA19-21 da a
sample has a muon con amina ion o 15%. A cosmic neu ino lux o 𝝓𝝓𝒄𝒄𝒄𝒄𝒄𝒄
𝝂𝝂+�
𝝂𝝂=𝟏𝟏.𝟐𝟐⋅𝟏𝟏𝟏𝟏−𝟒𝟒 𝑬𝑬𝝂𝝂
𝐆𝐆𝐆𝐆𝐆𝐆
−𝟐𝟐 GeV-1 m-2 s-1
s -1 pe la ou yields 21.4 cosmic neu ino e en s in he ull ARCA6-21 sample, o which 12.1 con ain a muon
and a e econs uc ed wi h <1°accu acy.
Da asample a e e en selec ion
30-9-2025 Sea ch o cosmic neu ino sou ces wi h KM3NeT/ARCA 9
* KM3-230213A emo ed
KM3NeT
da ase
Numbe o
e en s
ARCA 6 4205
ARCA 8 11537
ARCA 19 182
ARCA 21 1361*
ARCA6-21
o al 17285