6,895 research outputs found
Limits on leptonic photon interactions from SN1987a
If massless leptonic photons associated to electron, muon or tau leptonic
number exist they would have been emitted from supernova 1987a via the
annihilation process . By requiring that
this process does not carry away most of the energy that can be radiated by the
supernova we obtain an upper limit on the leptonic photon coupling constants,
. Under certain assumptions about
- trapping conditions we find that the region of might be of interest for an experimental search for leptonic
photons.Comment: 6 pages, AmSTex, LaTex. The limits are revised for neutrino chemical
potential = 0. The new limits do not differ significantly from the
original one. To be published in Phys.Lett.
Quantum Theory of Neutrino Oscillations for Pedestrians - Simple Answers to Confusing Questions
Why are different mass states coherent? What is the correct formula for the
oscillation phase? How can textbook formulas for oscillations in time describe
experiments which never measure time? How can we treat the different velocities
and different transit times of different mass eigenstates and avoid incorrect
factors of two? How can textbook forumulas which describe coherence between
energy states be justified when Stodolsky's theorem states there is no
coherence between different energies? Is covariant relativistic quantum field
theory necessary to describe neutrino oscillations? How important is the
detector, which is at rest in the laboratory and cannot be Lorentz tranformed
to other frames?
These questions are answered by a simple rigorous calculation which includes
the quantum fluctuations in the position of the detector and in the transit
time between source and detector. The commonly used standard formula for
neutrino oscillation phases is confirmed. An "ideal" detector which measures
precisely the energy and momentum of the neutrino destroys all phases in the
initial wave packet and cannot observe oscillations. A realistic detector
preserves the phase differences between neutrinos having the same energy and
different momenta and confirms the standard formula. Whether phase differences
between neutrinos with different energies are observable or destroyed by the
detector is irrelevant.Comment: 10 pages, Introduction expanded to explain sources of confusion in
detai
How strong can the coupling of leptonic photons be?
Consequences of possible existence of leptonic photon are considered for a
range of values of leptonic charge. In the case of a strong Coulomb-like
leptonic repulsion between electrons the existence of ordinary condensed matter
is impossible: antineutrinos cannot neutralize this destructive repulsion. The
upper limit of leptonic charge is inferred from the E\"{o}tv\"os type
experiments. If however there exist light stable scalar bosons with leptonic
charge (e.g. singlet antisneutrinos) they may neutralize the electron
repulsion. Possible experimental manifestations of such leptonic bosons in
gases and condensed matter are briefly discussed.Comment: 13 pages in standard LaTe
Quirks in supersymmetry with gauge coupling unification
I investigate the phenomenology of supersymmetric models with extra
vector-like supermultiplets that couple to the Standard Model gauge fields and
transform as the fundamental representation of a new confining non-Abelian
gauge interaction. If perturbative gauge coupling unification is to be
maintained, the new group can be SU(2), SU(3), or SO(3). The impact on the
sparticle mass spectrum is explored, with particular attention to the gaugino
mass dominated limit in which the supersymmetric flavor problem is naturally
solved. The new confinement length scale is astronomical for SO(3), so the new
particles are essentially free. For the SU(2) and SU(3) cases, the new
vector-like fermions are quirks; pair production at colliders yields
quirk-antiquirk states bound by stable flux tubes that are microscopic but long
compared to the new confinement scale. I study the reach of the Tevatron and
LHC for the optimistic case that in a significant fraction of events the
quirk-antiquirk bound state will lose most of its energy before annihilating as
quirkonium.Comment: 28 page
Physics of vacuum at ITEP and around
Recollections about a few episodes from the history of physics of vacuum,
connected with the names of Pomeranchuk, Landau, Zeldovich, Sakharov and
Kirzhnits. The text of the talk will be published in the Proceedings of the
International Conference ``From the Smallest to the Largest Distances'',
Tribute to Jean Tran-Thanh-Van, May 24-26, 2001 (``Surveys in High Energy
Physics'', Taylor and Francis, 2002, v.16, No.3).Comment: 10 page
Cube or hypercube of natural units
Max Planck introduced four natural units: h, c, G, k. Only the first three of
them retained their status, representing the so called cube of theories, after
the theory of relativity and quantum mechanics were created and became the
pillars of physics. This short note is a little pebble on the tombstone of
Michael Samuilovich Marinov.Comment: 7 pages, to be published in ``Multiple facets of quantization and
supersymmetry'', Michael Marinov Memorial Volume, Eds. M. Olshanetsky and A.
Vainshtein, World Scientific, 200
The Einstein formula: E_0=mc^2 "Isn't the Lord laughing?"
The article traces the way Einstein formulated the relation between energy
and mass in his work from 1905 to 1955. Einstein emphasized quite often that
the mass of a body is equivalent to its rest energy . At the same time
he frequently resorted to the less clear-cut statement of equivalence of energy
and mass. As a result, Einstein's formula still remains much less
known than its popular form, , in which is the total energy equal
to the sum of the rest energy and the kinetic energy of a freely moving body.
One of the consequences of this is the widespread fallacy that the mass of a
body increases when its velocity increases and even that this is an
experimental fact. As wrote the playwright A N Ostrovsky "Something must exist
for people, something so austere, so lofty, so sacrosanct that it would make
profaning it unthinkable."Comment: 20 page
The impact of the Sakata model
The evolution of the Sakata model is described on the basis of personal
recollections, proceedings of international conferences on high energy physics
and some journal articles.Comment: 17 pages. To be published in the Proceedings of the International
Symposium PNLambda50 `The Jubilee of the Sakata Models'. November 25-26,
2006, Nagoya University, Japa
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