2,434 research outputs found

    Front Form Spinors in Weinberg-Soper Formalism and Melosh Transformations for any Spin

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    Using the Weinberg-Soper formalism we construct the front form (j,0)(0,j)(j,0)\oplus(0,j) spinors. Explicit expressions for the generalised Melosh transformations up to spin two are obtained. The formalism, without explicitly invoking any wave equations, reproduces spin one half front-form results of Melosh, Lepage and Brodsky, and Dziembowski.Comment: 16 Pages, RevTex. We continue to receive reprint requests for this paper. So we now archive it her

    Neutrino oscillations with disentanglement of a neutrino from its partners

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    We bring attention to the fact that in order to understand existing data on neutrino oscillations, and to design future experiments, it is imperative to appreciate the role of quantum entanglement. Once this is accounted for, the resulting energy-momentum conserving phenomenology requires a single new parameter related to disentanglement of a neutrino from its partners. This parameter may not be CP symmetric. We illustrate the new ideas, with potentially measurable effects, in the context of a novel experiment recently proposed by Gavrin, Gorbachev, Veretenkin, and Cleveland. The strongest impact of our ideas is on the resolution of various anomalies in neutrino oscillations and on neutrino propagation in astrophysical environments.Comment: 6 page

    On the spin of gravitational bosons

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    We unearth spacetime structure of massive vector bosons, gravitinos, and gravitons. While the curvatures associated with these particles carry a definite spin, the underlying potentials cannot be, and should not be, interpreted as single spin objects. For instance, we predict that a spin measurement in the rest frame of a massive gravitino will yield the result 3/2 with probability one half, and 1/2 with probability one half. The simplest scenario leaves the Riemannian curvature unaltered; thus avoiding conflicts with classical tests of the theory of general relativity. However, the quantum structure acquires additional contributions to the propagators, and it gives rise to additional phases.Comment: Honorable mention, 2002 Gravity Research Foundation Essay

    Cellular differentiation and nitrogenase activity in the cyanobacterium Anabaena

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    Nitrogenase activity at periods of differentiation of heterocysts and akinetes was assayed by the acetylene reduction technique. There was no nitrogenase activity in ammonium grown, non-heterocystous Anabaena sp.; the activity appeared only after a lag-phase of about 17 - 21 h after the ammonium-grown culture had been transferred to medium free of combined nitrogen. This activity started appearing as the proheterocysts were developing to mature heterocysts. Maximum nitrogenase activity was attained with exponential phase of culture and mature heterocysts. This activity gradually decreased with the differentiation of akinetes. Only insignificant nitrogenase activity was observed in old cultures in which most cells had matured into akinetes

    Special relativity with two invariant scales: Motivation, Fermions, Bosons, Locality, and Critique

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    We present a Master equation for description of fermions and bosons for special relativities with two invariant scales, SR2, (c and lambda_P). We introduce canonically-conjugate variables (chi^0, chi) to (epsilon, pi) of Judes-Visser. Together, they bring in a formal element of linearity and locality in an otherwise non-linear and non-local theory. Special relativities with two invariant scales provide all corrections, say, to the standard model of the high energy physics, in terms of one fundamental constant, lambda_P. It is emphasized that spacetime of special relativities with two invariant scales carries an intrinsic quantum-gravitational character. In an addenda, we also comment on the physical importance of a phase factor that the whole literature on the subject has missed and present a brief critique of SR2. In addition, we remark that the most natural and physically viable SR2 shall require momentum-space and spacetime to be non-commutative with the non-commutativity determined by the spin content and C, P, and T properties of the examined representation space. Therefore, in a physically successful SR2, the notion of spacetime is expected to be deeply intertwined with specific properties of the test particle.Comment: Int. J. Mod. Phys. D (in press). Extended version of a set of two informal lectures given in "La Sapienza" (Rome, May 2001

    Interactions of a j=1j=1 boson in the 2(2j+1)2(2j+1) component theory

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    The amplitudes for boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the used model is the Weinberg's 2(2j+1)2(2j+1) component formalism for describing a particle of spin jj, recently developed substantially. The boson-boson amplitude is then compared with the two-fermion amplitude obtained long ago by Skachkov on the ground of the hamiltonian formulation of quantum field theory on the mass hyperboloid, p02p2=M2p_0^2 -{\bf p}^2=M^2, proposed by Kadyshevsky. The parametrization of the amplitudes by means of the momentum transfer in the Lobachevsky space leads to same spin structures in the expressions of TT matrices for the fermion and the boson cases. However, certain differences are found. Possible physical applications are discussed.Comment: REVTeX 3.0 file. 12pp. Substantially revised version of IFUNAM preprints FT-93-24, FT-93-3

    Metabolomics characterization of Senna tora (L.) Roxb. using different approaches

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    The present study aimed to investigate the variety of elements, chemical compounds and their corresponding functional groups in the whole plant, leaves, and seeds of Senna tora. A preliminary phytochemical analysis has revealed the presence of secondary metabolites including alkaloids, flavonoids, tannins, terpenoids, cardiac active glycosides, phenolics, etc. Gas Chromatography and Mass Spectrophotometry (GC-MS) analysis of leaves and seeds of S. tora has depicted 31 and 27 compounds, respectively. Fourier Transform Infrared (FT-IR) Spectroscopy has further unveiled the presence of different functional groups such as amines, aromatic compounds, carboxyl groups, ketones etc. associated with different metabolites. Wavelength Dispersive X-ray Fluorescence (WD-XRF) has revealed the presence of more than 20 elements (macro and micro) including Ca, Mg, Fe, K, etc. This study has highlighted the detailed account of the chemical compounds and elements present in the plant species under investigation and substantiated its medicinal importance in the traditional health care system

    Interplay of gravitation and linear superposition of different mass eigenstates

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    The interplay of gravitation and the quantum-mechanical principle of linear superposition induces a new set of neutrino oscillation phases. These ensure that the flavor-oscillation clocks, inherent in the phenomenon of neutrino oscillations, redshift precisely as required by Einstein's theory of gravitation. The physical observability of these phases in the context of the solar neutrino anomaly, type-II supernovae, and certain atomic systems is briefly discussed

    Spin half fermions with mass dimension one: theory, phenomenology, and dark matter

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    We provide the first details on the unexpected theoretical discovery of a spin-one-half matter field with mass dimension one. It is based upon a complete set of dual-helicity eigenspinors of the charge conjugation operator. Due to its unusual properties with respect to charge conjugation and parity, it belongs to a non-standard Wigner class. Consequently, the theory exhibits non-locality with (CPT)^2 = - I. We briefly discuss its relevance to the cosmological `horizon problem'. Because the introduced fermionic field is endowed with mass dimension one, it can carry a quartic self-interaction. Its dominant interaction with known forms of matter is via Higgs, and with gravity. This aspect leads us to contemplate the new fermion as a prime dark matter candidate. Taking this suggestion seriously we study a supernova-like explosion of a galactic-mass dark matter cloud to set limits on the mass of the new particle and present a calculation on relic abundance to constrain the relevant cross-section. The analysis favours light mass (roughly 20 MeV) and relevant cross-section of about 2 pb. Similarities and differences with the WIMP and mirror matter proposals for dark matter are enumerated. In a critique of the theory we bare a hint on non-commutative aspects of spacetime, and energy-momentum space.Comment: 78 pages [Changes: referee-suggested improvements, additional important references, and better readability

    Chromatic adaptation and photoreversal in blue-green alga Calothrix clavata West

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    Complementary chromatic adaptation, a well-established phenomenon in some blue-green algae, has been observed inCalothrix clavata, a heterocystous blue-green alga of the family Rivulariaceae. The chromatic adaptation has been observed for fluorescent and incandescent light by measuring the absorption spectra. The material grown in fluorescent light forms more of phycoerythrin whereas more of phycocyanin tends to be formed in incandescent light. Besides this, photoreversal was observed by transferring the incandescent light grown alga to fluorescent light conditions and vice-versa. Effect of photoreversal and chromatic adaptation has also been discussed for this alga under different monochromatic light conditions. The influence of different light conditions on morphological changes, heterocysts and hormogonia formation has also been investigated. Both chromatic adaptation and photomorphogentic phenolmena in this alga show the involvement of some photoreversible (red:green) pigment
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