Re iew o Di ec Measu emen s o
Neu io Masses
Lo edana Gas aldo
Ki chho Ins i u e o Physics
Heidelbe g Uni e si y
Knowing neu ino mass scale….
Pa icle Physics
Neu ino mass gene a ion
As ophysics
Supe no a neu inos
Cosmology
Ma e dis ibu ion
in he Uni e se
0
m
0
m
1
S a us o he a
𝑚𝑖<0.072eVa 95%C.L.
Cosmology
1=1
3𝑈𝑒𝑖
2𝑚𝑖<ቐ0.079−0.180eV90%C.L.76Ge
0.070−0.240eV90%C.L.130Te
0.036−0.156eV90%C.L.136Xe
𝑖=1
3𝑈𝑒𝑖2𝑚𝑖2<൝0.45eV90%C.L.3H−𝑚(ҧ𝜈𝑒)
15eV90%C.I.163Ho−𝑚(𝜈e)
Neu inoless double be a decay
Kinema ic app oach
2
DESI Coll., JCAP 02 (2025) 021
M. Agos ini e al., Phys. Re . Le . 125, 252502 (2020)
D. Q. Adams e al., a Xi :2404.04453 [nucl-ex] (2024)
S. Abe e al., Phys. Re . Le . 130, 051801 (2023)
KATRIN Coll., Science 338 (2025)
ECHo Coll., a Xi :2509.03423 1 [hep-ex]
S a us o he a
𝑚𝑖<0.072eVa 95%C.L.
Cosmology
Model independen
Neu inoless double be a decay
Kinema ic app oach
𝑖=1
3𝑈𝑒𝑖2𝑚𝑖2<൝0.45eV90%C.L.3H−𝑚(ҧ𝜈𝑒)
15eV90%C.I.163Ho−𝑚(𝜈e)
Neu ino mass de e mina ion ia kinema ic app oach
•will play majo ole in unde s anding he e olu ion
o he Uni e se
•will guide he design o u u e DBD expe imen s
F. Capozzi e al. Phys. Re . D 111 (2025) 0930062
1=1
3𝑈𝑒𝑖
2𝑚𝑖<ቐ0.079−0.180eV90%C.L.76Ge
0.070−0.240eV90%C.L.130Te
0.036−0.156eV90%C.L.136Xe
pn
n
e-
e-
e
e-
pn
p
•1/2 12.3 yea s
•Q= 18 592.01(7) eV
(4*108a oms o 1 Bq)
E.G. Mye s e al., Phys. Re . Le . 114 (2015) 013003
e
e
HeH33
•1/2 4570 yea s
•QEC = (2863.2 0.6) eV
(2*1011 a oms o 1 Bq)
C
163
66
*163
66
e
*163
66
163
67
DyDy
DyHo
E
3H
3He
-163Ho
163Dy
EC
e
*
Be a decay and elec on cap u e
Ch. Schweige e al.,
Na . Phys. 20, 921–927 (2024)
3
pn
n
e-
e-
e
e-
pn
p
e
e
HeH33
C
163
66
*163
66
e
*163
66
163
67
DyDy
DyHo
E
e
*
Be a decay and elec on cap u e
4
3H-based expe imen s –KATRIN
Mos s ingen limi on he
e ec i e neu ino mass:
𝑚𝛽<0.45eV90%C.L.
Achie able limi o KATRIN:
𝑚𝛽<0.3eV90%C.L
KATRIN Collabo a ion, Science 388, 180 (2025) 5
3H-based expe imen s –KATRIN
5
Mos s ingen limi on he
e ec i e neu ino mass:
𝑚𝛽<0.45eV90%C.L.
Achie able limi o KATRIN:
𝑚𝛽<0.3eV90%C.L
KATRIN Collabo a ion, Science 388, 180 (2025)
wha ’s nex ?
3H-based expe imen s –KATRIN ++
Di e en ial spec um
++
be e use o acqui ed e en s
•Time o Fligh (elec on agging)
•Mic ocalo ime e s as ocal plane de ec o s
Ko ac e al. 2025, a Xi :2502.05975
A omic 3H sou ce
A oid b oadening (~ 1 eV)
A oid limi ing sys ema ics o T2
6
Phase III:
Neu ino mass sensi i i y 𝑚𝛽≥ 100 meV
• A omic sou ce de elopmen
T2molecules need o be b oken
Sys em wi h a pa icula magne ic ield con igu a ion o
anspo and o a oid molecula ecombina ion
• La ge- olume CRES
Ca i y-Based CRES Expe imen
Ca i y a 26 GHz: using TE01 mode in 1 T MRI magne
Low equency appa a us: easibili y o CRES
in la ge olume and low ields ( equencies)
3H-based expe imen s –P ojec 8
A omic sou ce
11 m
9
Phase III:
Neu ino mass sensi i i y 𝑚𝛽≥ 100 meV
• A omic sou ce de elopmen
T2molecules need o be b oken
Sys em wi h a pa icula magne ic ield con igu a ion o
anspo and o a oid molecula ecombina ion
• La ge- olume CRES
Ca i y-Based CRES Expe imen
Ca i y a 26 GHz: using TE01 mode in 1 T MRI magne
Same equency as Phase II: same RF se up,
wa eguide L = 14 cm, R = 0.7 cm, V ∼20 cm3
Low equency appa a us: easibili y o CRES
in la ge olumes and low ields ( equencies)
B ≈ 0.035 T, c≈ 1 GHz, V ~ 0.3m3
Phase IV:
Neu ino mass measu emen i 𝑚𝛽≥ 40 meV
3H-based expe imen s –P ojec 8
10
3H-based expe imen s –QTMN
•Quan um noise limi ed mic owa e senso s a ~18GHz
(co esponding o 0.7T ield)
•3D B- ield mapping wi h ≲1 𝜇T p ecision, using H-a oms as
quan um senso s (Rydbe g Magne ome y)
•P oduc ion and con inemen o H-a oms, ≥ 1012 cm-3
Technology Demons a ion (2021-2025):
CRESDA-0 = CRES Demons a ion Appa a us
Funded as pa o he Quan um Technologies o Fundamen al Physics p og amme
Neu ino mass measu emen om a omic 3H β-decay ia
Cyclo on Radia ion Emission Spec oscopy using la es
ad ances in quan um echnologies.
A.A.S. Amad e al., New Jou nal o Physics, DOI 10.1088/1367-2630/adc624 11
3H-based expe imen s –QTMN
Funded as pa o he Quan um Technologies o Fundamen al Physics p og amme
•C yogenic (30K) pulsed supe sonic sou ce
•H2/D2/T2dissocia ion using DC discha ge seeded
•A omic beam cha ac e isa ion using Resonance
Enhanced Mul i Pho on Ionisa ion (REMPI)
H/D/T-a oms con inemen wi h s o age ing
12
3H-based expe imen s –QTMN
•NbN, Nb, Al, Ti pa amps ab ica ed and es ed a 18 GHz
•Robus and epea able ab ica ion, quan um-noise
limi ed pe o mance
•Can be ope a ed a 4K –po en ial o wo-s age
ampli ica ion
Supe cond. Sci. Technol. 36 105010 (2023), a Xi :2406.02455 2 (2024)
Funded as pa o he Quan um Technologies o Fundamen al Physics p og amme
Kine ic induc ance pa ame ic ampli ie s
13
3H-based expe imen s –QTMN
Funded as pa o he Quan um Technologies o Fundamen al Physics p og amme
Quan um Technologies o Neu ino Mass (QTNM) 14
1081091010 1011 1012 1013 1014
T a om numbe densi y [cm−3]
10−2
10−1
100
90% CL sensi i i y on mβ[eV/c2]
10−3m3
⇥
1yea ,σB/B=10−6
10 m3
⇥
10 yea s, σB/B=10−6
10 m3
⇥
10 yea s, σB/B=10−7
0.05m3
⇥
1yea ,σB/B=10−6
mmin
β(IO)
KATRIN (cu en )
KATRIN (final sensi i i y)
Figu e 3: Dependence o he sensi i i y o a CRES expe imen o mβ,on he T a om
numbe densi y in hemeasu emen olume. These o di↵e en olumesconside ed a e
indica ed. In each case, hecolou ed bands ep esen he angeo sensi i i iesexpec ed
om a equency measu emen p ecision se by he C am´e -Rao bound (equa ion 10,
con inuouscu e) o ha se by −1
obs (dashed-do ed cu e). In all cases he magne ic
field s eng h was chosen obe1 T (see ex o de ails). Ho izon al lines deno ing he
cu en , and ul ima ep ojec ed limi o heKATRIN expe imen wi h T2molecules[15],
and heminimally allowed alueo mβ o IO neu inos, i.e., mmin
β(IO), a ealso shown.
decay e en s. Fo a om numbe densi iesabo e1011 cm−3, he a ea which a adia ing
elec on sca e s om he backg ound gaso neu al Ta oms plays an inc easingly
significan ole, due o he limi s ha his sca e ing p ocess imposes on he maximal
alueo obs.
In his egime, he p ecision wi h which he cyclo on equency can be eco e ed
acco ding o he C am´e -Rao bound o↵e s a highe sensi i i y o mβ, o any gi en
a om numbe densi y, han he p ecision se by −1
obs.A densi ies abo e
⇠
1013 cm−3,
hesca e ing a e igh ly es ic s, and ul ima ely leads oa educ ion in, heachie able
sensi i i y.
*** The eseems o beli ledis inc ion be ween sensi i i y, p ecision and accu acy.
We need o check o consis ency***
The uppe h ee cu es (g een, iole ando ange) in figu e 3 a e he esul s o
calcula ions in which he ac ional unce ain y in he s eng ho he magne ic field
expe ienced by he adia ing elec on isσB/B=10−6:σB=1µTin hepa icula case
conside ed. Unde hese condi ions, a compac CRESappa a us wi h an ins umen ed
olume o 10−3m3is expec ed o p o ide a sensi i i y below 1 eV/c2 o T a om
numbe densi ies be ween 1012 and 1013 cm−3.Bea ing in mind he cha ac e is ics
and specifica ions o cu en ly a ailable H a om sou ces ha could be ope a ed o
P e e ed Loca ion:
Culham Cen e o
Fusion Ene gy
CRESDA-0 → CRESDA+T i ium → 100 meV → 50 meV → 10 meV
(2020 - 2025) (2026 - 2030) (2030 – 2040….)
14
3H-based expe imen s –PTOLEMY
PonTeco o Obse a o y o Ligh Ea ly-uni e se Massi e-neu ino Yield
Designed o he de ec ion o elic neu inos
𝜈𝑒+3𝐻→𝑒−+3𝐻𝑒
Monoch oma ic peak a Q+m
Neu ino mass as by-p oduc
AG.Cocco, G.Mangano, M.Messina JCAP 06(2007)015
15
3H-based expe imen s –PTOLEMY
PTOLEMY Coll., JCAP 07 (2019) 047
AG.Cocco, G.Mangano, M.Messina JCAP 06(2007)015
15
PonTeco o Obse a o y o Ligh Ea ly-uni e se Massi e-neu ino Yield
Designed o he de ec ion o elic neu inos
𝜈𝑒+3𝐻→𝑒−+3𝐻𝑒
Monoch oma ic peak a Q+m
Neu ino mass as by-p oduc
3H-based expe imen s –PTOLEMY
P o o ype se -up in cons uc ion a LNGS
M.G. Be i e al., Nano Le . 22, 7 (2022) 2971
C. Pepe e al., Phys.Re .Applied 22 (2024) 4, L041007
A. Apponi e al., JINST 17 (2022) 05, P05021
PTOLEMY Coll., a Xi :2503.10025
PTOLEMY Coll., JCAP 07 (2019) 047 16
3H-based expe imen s –PTOLEMY
Fi s goal:
demons a e easibili y wi h mode a e 3H sou ce
on g aphi e subs a e
ull loading: 𝜌=0.2mg/m2
1 µg 716 MBq
•Weakly dependen upon ene gy esolu ion
( o e< 400 meV –0.94 eV FWHM)
•1 μg: compe i i e wi h he o hcoming gene a ion
•100 μg (0.5 m2) close o p obe he IO scena io
17
ECHo-1k HOLMES
200 million e en s om 100 eV o 5000 eV 60 million e en s abo e 300 eV
EFWHM = (6.59 0.16) eV EFWHM = (6 1) eV
numbe o e en s in [2900 –5000] eV = 80
b= (9.1 1.3) × 10−6 /eV/pixel/day b= (1.7 ± 0.1) × 10−4/eV/pixel/day
163Ho-based expe imen s –P oo o Concep Expe imen s
24
ECHo-1k HOLMES
𝑑𝑁
𝑑𝐸=𝐶× 𝐴(𝐸)×𝐹𝑃𝑆(𝑄,𝐸) ⊗𝑔𝐸,𝜎 +𝑏(𝐸)
•No analy ical unc ion is a ailable o desc ibe A(E), he p obabili y o c ea e exci ed s a es wi h
a gi en ene gy in he 163Dy a om
•In M. B aß e al., New J. Phys. 22 (2020) 093018 i is s a ed ha A(E) is e y smoo h
•Tes o di e en unc ions has been pe o med
𝐹𝑃𝑆= 𝑄−𝐸 𝑄−𝐸2−𝑚𝛽
2
25
163Ho-based expe imen s –P oo o Concep Expe imen s
ECHo-1k HOLMES
Q= 2862(4) eV Q = 2848−6
+7eV
𝑚𝜈<15eV/c2(90% C.I.) 𝑚𝜈<27eV/c2(90% C.L)
BK. Alpe e al. (HOLMES Coll.), a Xi :2503.19920 2 [hep-ex]
accep ed in PRL 26
F. Adam e al. (ECHo Coll.), a Xi :2509.03423 1 [hep-ex]
submi ed o PRL
163Ho-based expe imen s –P oo o Concep Expe imen s
ECHo-1k HOLMES
Q= 2862(4) eV Q = 2848−6
+7eV
𝑚𝜈<15eV/c2(90% C.I.) 𝑚𝜈<27eV/c2(90% C.L)
BK. Alpe e al. (HOLMES Coll.), a Xi :2503.19920 2 [hep-ex]
accep ed in PRL 26
F. Adam e al. (ECHo Coll.), a Xi :2509.03423 1 [hep-ex]
submi ed o PRL
wha ’s nex ?
163Ho-based expe imen s –P oo o Concep Expe imen s
Aim: each sub-eV sensi i i y in nex upg ade
Minimal design:
20000 pixel Mul iplexed eadou
~10 Bq/pixel
EFWHM < 5 eV
pu< 10-6
b < 10-6 /eV/de ec o /day
Be e model o 163Ho spec um
numbe o e en s = 1013
27
163Ho-based expe imen s–Fu u e Pe spec i es
Aim: each sub-eV sensi i i y in nex upg ade
Minimal design:
20000 pixel Mul iplexed eadou
~10 Bq/pixel
EFWHM < 5 eV
pu< 10-6
b < 10-6 /eV/de ec o /day
Be e model o 163Ho spec um
•Fab ica ion a ays wi h EFWHM < 5 eV OK
•P oduc ion & pu i ica ion o he 163Ho sou ce OK
•Implan a ion ~10 Bq/pixel possible bu no i ial
•s ill necessa y wo k on backg ound educ ion
•Mul iplexing big challenge:
high ene gy esolu ion + la ge bandwid h
27
A. Faessle e al., J. Phys. G 42 (2015) 015108
R. G. H. Robe son, Phys. Re . C 91, 035504 (2015)
A. Faessle e al., Phys. Re . C 91, 064302 (2015)
A. Faessle and F. Simko ic, Phys. Re . C 91, 045505 (2015)
A. De Rujula and M. Lusignoli, JHEP 05 (2016) 015,
A. Faessle e al., Phys. Re . C 95, (2017) 045502
M. B aß e al., Phys. Re . C 97 (2018) 054620
M. B aß and M. W. Ha e ko , New J. Phys. 22 (2020) 093018
163Ho-based expe imen s–Fu u e Pe spec i es
Aim: each sub-eV sensi i i y in nex upg ade
Minimal design:
20000 pixel Mul iplexed eadou
~10 Bq/pixel
EFWHM < 5 eV
pu< 10-6
b < 10-6 /eV/de ec o /day
Be e model o 163Ho spec um
•Fab ica ion a ays wi h EFWHM < 5 eV OK
•P oduc ion & pu i ica ion o he 163Ho sou ce OK
•Implan a ion ~10 Bq/pixel possible bu no i ial
•s ill necessa y wo k on backg ound educ ion
•Mul iplexing big challenge:
high ene gy esolu ion + la ge bandwid h
•Fu u e high s a is ics spec a will help o cons ain model
27
A. Faessle e al., J. Phys. G 42 (2015) 015108
R. G. H. Robe son, Phys. Re . C 91, 035504 (2015)
A. Faessle e al., Phys. Re . C 91, 064302 (2015)
A. Faessle and F. Simko ic, Phys. Re . C 91, 045505 (2015)
A. De Rujula and M. Lusignoli, JHEP 05 (2016) 015,
A. Faessle e al., Phys. Re . C 95, (2017) 045502
M. B aß e al., Phys. Re . C 97 (2018) 054620
M. B aß and M. W. Ha e ko , New J. Phys. 22 (2020) 093018
F. Ah ens e al., a Xi :2507.09240 [nucl-ex]
F. Ah ens e al., a Xi :2507.09240 [nucl-ex]
163Ho-based expe imen s–Fu u e Pe spec i es
ECHo-LE (2026 - 2030)
De ec o ab ica ion on going
10 wa e wi h pixel op imiza ion om
ECHo-100k phase
Focus on mic owa e-SQUID mul iplexing
400 channels pe mul iplexing line
Imp o e ene gy esolu ion om p oo o concep
esul s
HOLMES+
Imp o ing he mul iplexing
less cos x channel, highe mul iplexing ac o
Reducing he c i ical empe a u e o he TES
o educe he e ec o Ho speci ic hea
Kine ic Induc ance Cu en Senso s (KICs)
M. Neidig e al., a Xi :2509.07671 1
163Ho-based expe imen s –Nex S eps
28
Conclusions
J. Fo maggio, alk @Eu opean S a egy o Pa icle Physics,
23.–27. Juni 2025 29
The de e mina ion o he neu ino mass scale will guide
beyond S anda d Model heo ies and suppo ou unde s anding o
he Uni e se
The s udy o low ene gy elec on cap u e and be a spec a p o ides
a less model dependen app oach o neu ino mass de e mina ion
3H is an ideal candida e o de e mining he neu ino mass scale.
Di e en expe imen al concep ha e been de eloped and
con inuously imp o ed
163Ho is gaining impo ance hanks o he success ul R&D in ECHo
and HOLMES
Challenging bu ealis ic plans o he de e mina ion o
he neu ino mass scale a e going o be implemen ed
Thanks o:
Angelo Nuccio i and Ma eo Bo ghesi o he HOLMES Collabo a ion
Joe Fo maggio and Juliana S achu ska o P ojec 8
Ruben Saakyan o QTNM
Ma cello Messina o PTOLEMY
KATRIN Collabo a ion and ECHo Collabo a ion
