j. stefan institute, ljubljana institute: multidisciplinary institute, largest research institution...
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J. Stefan Institute, Ljubljanahttp://www-f9.ijs.si
Institute:Multidisciplinary institute, largest research institution in Slovenia•Physics (solid state, particle physics, nuclear physics, theory, surface science, reactor physics)•Chemistry•Biochemistry•Electronics, electrotechnics
Staff: about 1000
Main facilities: •TRIGA MarkIII reactor •Tandem 2 MeV
Peter Križan, UL+JSI
JSI: interdisciplinary research is
easy – next door lab might have a
solution for your troubles
Example: High power pulsed laser
in the solid state department (80fs
pulse width, 10J/pulse)
excellent for Single Event Upset
(EPS) tests of read-out electronics
for Belle SVD
Experiments: ATLAS, Belle, AUGER Past: HERA-B, CPLEAR, DELPHI
Staff: Researchers: ~20 (including part time professors of the
Universities of Ljubljana and Maribor) PhD students: ~10
Particle physics department (F9)
Physics Panel, 17/06/20084
Research Programme – Snapshot
R&D projects
• Cryogenic detectors (CERN RD-39)
• Diamond detectors (RD-42)
• Radiation hard detectors (RD-50)
ATLAS experiment at LHC in CERN~2000 researchers, 167 institutions
Belle experiment at KEK-B in KEK~380 researchers, 55 institutions
EU projects Grid computing (EGEE-I, II, III)
Medical imaging detectors (MADEIRA)
MC training on particle detectors
(MCPAD)
RADFET dosimetry (RADOS)
Physics Panel, 17/06/2008
Experimental Paricle Physics 5
Decays to CP eigenstates
difference of effective lifetimes measured in
decays to CP (D0 → K+K-, +-) and non-CP states (D0 → K-+)
precise measurement first evidence of mixing
(30 years after D0 discovery)
+
)%25.032.031.1( CPy
yKK
Ky
CPVnoCP
1)(
)(
Belle, Phys. Rev. Lett. 98, 211803 (2007)
ratio
(K+K-++-) vs. K-+
y: one of parameters determining the rate of mixing
Highlights - D0 Meson Mixing
Expertise(in experimental methodology)
• RICH detectors: DELPHI, HERA-B, Belle upgrade• Si strip detectors: DELPHI, RD20, ATLAS, Belle• Diamond sensors: ATLAS BCM, Belle radiation monitoring• readout/ trigger electronics: HERA-B (RICH, tracker), Belle
(SVD, PID upgrade) • Grid computing: CrossGrid (EU project), BalticGrid
(EU project), WLCG• Monte Carlo simulations (detector modelling, physics
simulations)• Lecturing at the University of Ljubljana (undergraduate and
postgraduate courses): particle physics, detector techniques, analysis methods; supervising diploma, MSc and PhD theses.
7
JSI@ATLASATLAS
– Members since 1996– SemiConductor Tracker
• Radiation hardness studies and QA (at the reactor center)
• Low-mass tapes and thermal enclosure heaters
– Beam Conditions Monitor– Radiation monitors– Physics analysis and MC software– Grid computing – TIER-2 centre
8
Into the Future – R&D for sLHC
• sLHC = LHC x 10 in luminosity– Severe radiation damage to tracker– Current tracker needs to be replaced– All-Si tracker envisaged– Si (short) strips at outer radii– Pixels inside
• Active in two ATLAS R&D projects– Diamond pixels– n+p strips– Recent striking result
Collected charge from n+p strips independent of fluence if sufficiently high bias applied
HERA-B RICH
100 m3 of C4F10 ~1 ton of gas
HERA-B RICH Little noise, ~30 photons per ring
Typical event
Worked very well!
Kaon efficiency and pion, proton fake probability
KK
pKK
Belle PID upgrade R+D
Two new particle ID devices, both RICHes:
Barrel: TOP – a special kind of DIRC
Endcap: proximity focusing RICH
stack two tiles with different refractive indices: “focusing” configuration
How to increase the number of photons without degrading the resolution?
normal
Radiator with multiple refractive indices
n1< n2
focusing radiator
n1= n2
4cm aerogel single index
2+2cm aerogel
Focusing configuration – data
NIM A548 (2005) 383
JSI is looking forward to the collaboration
within the MC-PAD project
Physics Panel, 17/06/2008
Experimental Paricle Physics 15
Highlights - Direct CP Violation
Belle, Nature 452, 332 (2008)
Difference between B and B decays CP violation known; magnitude too small
to describe matter domination in universe
within SM AK+- ≈ AK+0 008.0018.0094.0 KA
01.003.007.00 KA
)()(
)()(0 fBNfBN
fBNfBNf
A
~ one out of 105 B mesons
decays to this final states
037.0164.0 A
difficult to explain within SM
(especially in combination with other meas.);
hint for yet unknown sources of CP violation?