15,868 research outputs found
Ordinary atom-mirror atom bound states: A new window on the mirror world
Mirror symmetry is a plausible candidate for a fundamental symmetry of
particle interactions which can be exactly conserved if a set of mirror
particles exist. The properties of the mirror particles seem to provide an
excellent candidate to explain the inferred dark matter of the Universe and
might also be responsible for a variety of other puzzles in particle physics,
astrophysics, meteoritics and planetary science. One such puzzle -- the
orthopositronium lifetime problem -- can be explained if there is a small
kinetic mixing of ordinary and mirror photons. We show that this kinetic mixing
implies the existence of ordinary atom - mirror atom bound states with
interesting terrestrial and astrophysical implications. We suggest that
sensitive mass spectroscopic studies of ordinary samples containing heavy
elements such as lead might reveal the presence of these bound states, as they
would appear as anomalously heavy elements. In addition to the effects of
single mirror atoms, collective effects from embedded fragments of mirror
matter (such as mirror iron microparticles) are also possible. We speculate
that such mirror matter fragments might explain a mysterious UV photon burst
observed coming from a laser irradiated lead target in a recent experiment.Comment: about 8 pages, couple of change
Quantum Information Paradox: Real or Fictitious?
One of the outstanding puzzles of theoretical physics is whether quantum
information indeed gets lost in the case of Black Hole (BH) evaporation or
accretion. Let us recall that Quantum Mechanics (QM) demands an upper limit on
the acceleration of a test particle. On the other hand, it is pointed out here
that, if a Schwarzschild BH would exist, the acceleration of the test particle
would blow up at the event horizon in violation of QM. Thus the concept of an
exact BH is in contradiction of QM and quantum gravity (QG). It is also
reminded that the mass of a BH actually appears as an INTEGRATION CONSTANT of
Einstein equations. And it has been shown that the value of this integration
constant is actually zero. Thus even classically, there cannot be finite mass
BHs though zero mass BH is allowed. It has been further shown that during
continued gravitational collapse, radiation emanating from the contracting
object gets trapped within it by the runaway gravitational field. As a
consequence, the contracting body attains a quasi-static state where outward
trapped radiation pressure gets balanced by inward gravitational pull and the
ideal classical BH state is never formed in a finite proper time. In other
words, continued gravitational collapse results in an "Eternally Collapsing
Object" which is a ball of hot plasma and which is asymptotically approaching
the true BH state with M=0 after radiating away its entire mass energy. And if
we include QM, this contraction must halt at a radius suggested by highest QM
acceleration. In any case no EH is ever formed and in reality, there is no
quantum information paradox.Comment: 8 pages in Pramana Style, 6 in Revtex styl
On arbitrary-level IIR and FIR filters
A recently published method for designing IIR (infinite-impulse-response) digital filters with multilevel magnitude responses is reinterpreted from a different viewpoint. On the basis of this interpretation, techniques for extending these results to the case of finite-impulse-response (FIR) filters are developed. An advantage of the authors' method is that, when the arbitrary-level filter is implemented, its power-complementary filter, which may be required in specific applications, is obtained simultaneously. Also, by means of a tuning factor (a parameter of the scaling matrix), it is possible to generate a whole family of arbitrary-level filters
Lepton Masses in a Minimal Model with Triplet Higgs Bosons and Flavor Symmetry
Viable neutrino and charged lepton masses and mixings are obtained by
imposing a flavor symmetry in a model with a few
additional Higgs. We use two triplet Higgs which are arranged as a
doublet of , and standard model singlet Higgs which are also put as
doublets of . We break the symmetry in this minimal model by giving
vacuum expectation values (VEV) to the additional Higgs fields. Dictated by the
minimum condition for the scalar potential, we obtain certain VEV alignments
which allow us to maintain symmetry in the neutrino sector, while
breaking it maximally for the charged leptons. This helps us to simultaneously
explain the hierarchical charged lepton masses, and the neutrino masses and
mixings. In particular, we obtain maximal and zero .
We allow for a mild breaking of the symmetry for the neutrinos and
study the phenomenology. We give predictions for and the CP
violating Jarlskog invariant , as a function of the symmetry
breaking parameter. We also discuss possible collider signatures and
phenomenology associated with lepton flavor violating processes.Comment: 29 pages, 5 figures. Version to be appeared in PRD. Phenomenology of
Lepton flavor violation and possible collider signatures of this model have
been include
Mirror matter in the solar system: New evidence for mirror matter from Eros
Mirror matter is an entirely new form of matter predicted to exist if mirror symmetry is a fundamental symmetry of nature. Mirror matter has the right broad properties to explain the inferred dark matter of the Universe and might also be responsible for a variety of other puzzles in particle physics, astrophysics, meteoritics and planetary science. It is known that mirror matter can interact with ordinary matter non-gravitationally via photon-mirror photon kinetic mixing. The strength of this possibly fundamental interaction depends on the (theoretically) free parameter . We consider various proposed manifestations of mirror matter in our solar system examining in particular how the physics changes for different possible values of . We find new evidence for mirror matter in the solar system coming from the observed sharp reduction in crater rates (for craters less than about 100 meters in diameter) on the asteroid 433 Eros. We also re-examine various existing ideas including the mirror matter explanation for the anomalous meteorite events, anomalous slow-down of Pioneer spacecraft etc
Modulus stabilization of generalized Randall Sundrum model with bulk scalar field
We study the stabilization of inter-brane spacing modulus of generalized
warped brane models with a nonzero brane cosmological constant. Employing
Goldberger-Wise stabilization prescription of brane world models with a bulk
scalar field, we show that the stabilized value of the modulus generally
depends on the value of the brane cosmological constant. Our result further
reveals that the stabilized modulus value corresponding to a vanishingly small
cosmological constant can only resolve the gauge hierarchy problem
simultaneously. This in turn vindicates the original Randall-Sundrum model
where the 3-brane cosmological constant was chosen to be zero.Comment: 12 Pages, 1 figure, Revtex, Version to appear in Euro. Phys. Let
A Note on Unintentional Adulterations in Ayurvedic Herbs
Medicinal plants constitute an effective source of traditional and modern medicine. Adulterations and substitutions are common in raw material trade of medicinal plants. In general, adulteration is considered as an intentional malpractice. However, in raw material trade unintentional adulteration also exists. This article explains some of the reasons for unintentional adulterations with examples and key characters to distinguish them
- …