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3-12-2004 NIKHEF Fokke de Boer 1
anomalous internal pair conversion
as a sign for elusive
light neutral particles
e+
e–
3-12-2004 NIKHEF Fokke de Boer 2
anomalous internal pair conversion
as a sign for elusive
light neutral particles
e+
e–
3-12-2004 NIKHEF 3
3-12-2004 NIKHEF 4
co-authorsJohan van Klinken 1
Helmut Bokemeyer 2
Klaus Bethge 3
Oliver Fröhlich 3
Alkis Müller 3
Kurt Stiebing 3
Margo Csatlós 4
Zoltan Gácsi 4
Janos Gulyás 4
Mathias Hunyadi 4
Attila Krasznahorkay 4
Zoltan Máté 4
René van Dantzig 5
Tjeerd Ketel 5
1 Groningen2 Darmstadt3 Frankfurt
4 Debrecen5 Amsterdam
3-12-2004 NIKHEF 5
light neutral particles
• upper limits
• in emulsions
• in nuclear transitions
• spectroscopy
• and dark matter
branching ratios
511 keV radiation
pair production
anomalous IPC
fantasy
3-12-2004 NIKHEF 6
candidate bosons
o light Higgs (0+) to explain muonic X-rays anomalies
Watson and Sundaresan (1971)o axion, a light pseudoscalar boson (0-) invented to
prevent large CP-violations,
Peccei and Quinn (1978)o U-boson a supersymmetric gauge boson (1+, 1-) ,
Fayet (1981)
3-12-2004 NIKHEF 7
particle data book
3-12-2004 NIKHEF 8
allowed window (not for T=1 axions)
3-12-2004 NIKHEF 9
emulsion events
3-12-2004 NIKHEF 10
3-12-2004 NIKHEF 11
3-12-2004 NIKHEF 12
spin-parity conservation.
3-12-2004 NIKHEF 13
width
3-12-2004 NIKHEF 14
EEEy
yEmX
/)(
)2
(sin)1( 2222
correlation angle ω (degrees)
number ofIPC pairs(a.u.)
3-12-2004 NIKHEF 15
detector array
3-12-2004 NIKHEF 16
3-12-2004 NIKHEF 17
studied reactions
3-12-2004 NIKHEF 18
alpha nuclei
3-12-2004 NIKHEF 19
agreement with E1-IPC in 12C
3-12-2004 NIKHEF 20
agreement with IPC in 12C and a deviation in 8Be
Phys.Lett. B388 (1996) 235
7Li(p,)8Be 1+, T=1, 17.6 MeV11B(p,)12C 1-, T=1, 17.2 MeV
3-12-2004 NIKHEF 21
isoscalar decay from 18.15 MeV in 8Be
3-12-2004 NIKHEF 22
results from IKF, KVI and SUNY branching ratios and widths
an isoscalar boson scenario with mass of 9 MeV/c2, with spin 0- or 1+,and coupling strength αX
proportional to the isoscalar width in the magnetic transition.
3-12-2004 NIKHEF 23
KVI annual report 2002
3-12-2004 NIKHEF 24
16O (0-,T=0) 10.96 MeV decay
3-12-2004 NIKHEF 25
To be published in Phys. Rev. Lett.
16O (0-,T=0) 10.95 MeV decay (M0 transition !!)
3-12-2004 NIKHEF 26
boson search program
3-12-2004 NIKHEF 27
8Be (1+,T=1) 17.64 MeV decay
3-12-2004 NIKHEF 28
8Be (1+,T=0) 18.15 MeV decay
3-12-2004 NIKHEF 29
16O (0-,T=0) 10.96 MeV decay
3-12-2004 NIKHEF 30
12C (1+,T=0) 12.71 MeV decay
3-12-2004 NIKHEF 31
12C (1+,T=1) 17.23 MeV decay
3-12-2004 NIKHEF 32
16O (0+,T=0) 6.05 MeV decay
3-12-2004 NIKHEF 33
16O 6.05, 8.87, and 10.96 MeV decay
3-12-2004 NIKHEF 34
3-12-2004 NIKHEF 35
3-12-2004 NIKHEF 36
SPI data are consistent with positrons that originate from centre of the Galaxy and either: • low-mass X-ray binaries, • novae, • type Ia supernovae, • or possibly light dark matter.
INTEGRAL satellite
3-12-2004 NIKHEF 37
3-12-2004 NIKHEF 38
summary• anomalous internal pair conversion is observed
in isoscalar nuclear transitions
• magnetic monopole transition in 16O is found
• several candidates for isoscalar neutral bosons in the 2-15 MeV mass region are reported
• one of the vector boson candidates may be the U-boson and be intermediate in the annihilation of light dark matter