Related papers: Extra dimensions and invisible decay of orthoposit…
In models of Randall-Sundrum type orthopositronium (o-Ps) can disappear due to tunnelling into additional dimension(s). The experimental signature of this effect is the invisible decay of orthopositronium. We point out that this process may…
We propose an experiment to search for invisible decays of orthopositronium (o-Ps) with a 90% confidence sensitivity in the branching ratio as low as $10^{-8}$. Evidence for this decay mode would unambigously signal new physics: either the…
In a class of extra dimensional models with a warped metric and a single brane the photon can be localized on the brane by gravity only. An intriguing feature of these models is the possibility of the photon escaping into the extra…
A class of extra dimensional models with a warped metric predict tunneling of a massive particle localized on our brane and escaping into additional dimensions. The experimental signature of this effect is the disappearance of the particle…
Mirror matter is a possible dark matter candidate. It is predicted to exist if parity is an unbroken symmetry of the vacuum. The existence of the mirror matter, which in addition to gravity is coupled to our world through photon-mirror…
We report on a direct search for a three-body decay of the orthopositronium into a photon and two penetrating particles, o-Ps -> gamma + X1 + X2. The existence of this decay could explain the discrepancy between the measured and the…
Currently, the experimental uncertainty for the determination of the ortho-positronium (o-Ps) decay rate is at 150 ppm precision; this is two orders of magnitude lower than the theoretical one, at 1 ppm level. Here we propose a new proof of…
Whether in the Standard Model or beyond it, neutrinos contribute to the invisible decay mode of orthopositronium but practically not at all to that of parapositronium. Although this remark does not resolve the orthopositronium decay puzzle,…
Following recent theoretical results, it is suggested that positronium (Ps) might undergo spontaneous oscillations between two 4D spacetime sheets whenever subjected to constant irrotational magnetic vector potentials. We show that these…
Time evolution of the probability of quasilocalized massive modes decay trough the tunneling into an extra dimension is analyzed in the Randall-Sundrum braneworld model.
The discrepancy between the experimental decay rate of orthopositronium (o-Ps) and the QED theoretical prediction can be solved by invoking decays of o-Ps into exotic particles with branching ratios of the order of 10^{-3}. We show that…
The phenomenological possibilities of the Randall-Sundrum non-compact extra dimension scenario with the AdS horizon increased to approximately a millimeter length, corresponding to an effective brane tension of TeV^4, are investigated. The…
A possible solution to the hierarchy problem is the presence of extra spatial dimensions beyond the three ones which are known from our everyday experience. The phenomenological ADD model of large extra-dimensions predicts a missing…
Searches for extra spatial dimensions remain among the most popular new directions in our quest for physics beyond the Standard Model. High-energy collider experiments of the current decade should be able to find an ultimate answer to the…
We approach to the ortho-positronium (o-Ps) as a relativistic two-body problem in $2+1$ dimensions in which o-Ps is composed of two-oppositely charged particles interacting via an attractive Coulomb force. In addition to separation of…
The large difference between the Planck scale and the electroweak scale, known as the hierarchy problem, has been addressed in some models through the existence of extra spatial dimensions. A search for evidence of extra spatial dimensions…
The results of a new search for positronium decays into invisible final states are reported. Convincing detection of this decay mode would be a strong evid ence for new physics beyond the Standard Model (SM): for example the existence of…
The Arkani-Hamed-Dimopoulos-Dvali and the Randall-Sundrum models with extra spacelike dimensions, recently proposed as a solution to the hierarchy problem, are reviewed. We discuss their basic properties and phenomenological effects of…
The large difference between the Planck scale and the electroweak scale, known as the hierarchy problem, is addressed in certain models through the postulate of extra spatial dimensions. A search for evidence of extra spatial dimensions in…
In light of current atmospheric neutrino oscillation data, we revisit the invisible decay of the standard model Higgs boson and other pseudoscalar mesons which can be enhanced because of large number of KK modes in models with right handed…