Dr. Vladimir Vasiliev
contacts:

University College London,
Department of Physics and Astronomy
Gower Street
WC1E 6BT, London, UK

Office: C14 Physics Building
Tel.: +44 (0) 20 7679 3498
Fax.: +44(0) 20 7679 7145
Email.: vv @ hep.ucl.ac.uk



[research activity] [research interests] [public talks] [lectures]

research activity

data analysis
NEMO 3 is a running experiment looking for neutrino less double beta decay of 7 isotopes. The main goal of the experiment is to explore Dirac or Majorana nature of the neutrino particle, namely if there is a distinction between neutrino and anti-neutrino. The very existence of the Universe implies that the symmetry between particles and anti-particles should be violated at some point and Majorana neutrinos is a very plausible scenario of such violation. Majorana neutrino has other attractive features also. I. e. SeeSaw mechanism, which can explain extreme smallness of neutrino mass compared to other fermions and large mixing between neutrino flavors observed in oscillation experiments.

Im involved in the NEMO3 data analysis from the very beginning of the experiment. I have contributed to the detector response studies, background investigation and most recently finished careful analysis of Mo-100, Se-82 and Te-130 isotopes using 2003-2007 data. The first two in the list have the biggest mass inside NEMO 3, giving more chances to discover neutrino less double beta decay there. But no evidence for the signal has been observed so far. Contrary to that, principle motivation to look at Te-130 isotope is to measure two neutrino mode rather than neutrino less double beta decay. Its half life has been measured before in several experiments using methods of geochemistry. Interesting enough the NEMO 3 measurement differs from them. If one assumes that all the measurements are correct, then the only difference between the two is the time when decay occurred. Then the contradiction can hint a variation of fundamental constants, such as weak interaction constant, which drives the rate of the decay. If confirmed, fundamental constant variation would open a window towards a completely new landscapes in physics.

Recently we have developed in UCL a software package, based on ROOT, which helps users with basic knowledge of C++ to perform analysis of the NEMO 3 data. The package have been successfully used by students here and in Manchester. Currently UK plays an important role in data analysis within the NEMO Collaboration, with me trying to lead the data analysis effort.

simulations
There is a proposal to build a detector of next generation, SuperNEMO, 100 times more sensitive than current NEMO 3. Part of an R&D towards the project is physics simulations. The simulations should provide the targets for detector performance and characteristics in order to reach the desired sensitivity. There is a software group inside SuperNEMO collaboration who's task is to develop the software and make MC simulations of SuperNEMO response. Im acting as a deputy of the group coordinator and heavily involved in both tasks.

hardware
Hardware part of my research is related to R&D of SuperNEMO scintillating plastic calorimeter. The goal was to investigate response and energy resolution of small pieces of PVT scintillator. A method to extract energy resolution from the measurement of BI-207 spectrum has been developed. Coupled with optical simulation performed in the epoch it was predicted that absorption of UV light inside PVT plays important role and reduces expected light output. It was confirmed later when other people analyzed the emitted light with a spectrometer.



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research interests

• Neutrino physics
• Experimental low energy particle physics ( double beta decay, geo and solar neutrinos, dark matter direct search)
• Nuclear physics (natural radioactivity; reactor anti-neutrino monitoring)
• Monte Carlo technique for simulation of complex system behavior
• Data analysis techniques

public talks

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my NEMO3 related projects:

software

UCL software manual

CVS web mirror

NME calculator

internal memos