539 research outputs found

    Massive Scattering Amplitudes in Six Dimensions

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    We show that a natural spinor-helicity formalism that can describe massive scattering amplitudes exists in D=6D=6 dimensions. This is arranged by having helicity spinors carry an index in the Dirac spinor {\bf 4} of the massive little group, SO(5)Sp(4)SO(5) \sim Sp(4). In the high energy limit, two separate kinds of massless helicity spinors emerge as required for consistency with arXiv:0902.0981, with indices in the two SU(2)SU(2)'s of the massless little group SO(4)SO(4). The tensors of 4{\bf 4} lead to particles with arbitrary spin, and using these and demanding consistent factorization, we can fix 33- and 44-point tree amplitudes of arbitrary masses and spins: we provide examples. We discuss the high energy limit of scattering amplitudes and the Higgs mechanism in this language, and make some preliminary observations about massive BCFW recursion.Comment: 37 pages; v2: minor improvements, JHEP versio

    Contrasting SYK-like Models

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    We contrast some aspects of various SYK-like models with large-NN melonic behavior. First, we note that ungauged tensor models can exhibit symmetry breaking, even though these are 0+1 dimensional theories. Related to this, we show that when gauged, some of them admit no singlets, and are anomalous. The uncolored Majorana tensor model with even NN is a simple case where gauge singlets can exist in the spectrum. We outline a strategy for solving for the singlet spectrum, taking advantage of the results in arXiv:1706.05364, and reproduce the singlet states expected in N=2N=2. In the second part of the paper, we contrast the random matrix aspects of some ungauged tensor models, the original SYK model, and a model due to Gross and Rosenhaus. The latter, even though disorder averaged, shows parallels with the Gurau-Witten model. In particular, the two models fall into identical Andreev ensembles as a function of NN. In an appendix, we contrast the (expected) spectra of AdS2_2 quantum gravity, SYK and SYK-like tensor models, and the zeros of the Riemann Zeta function.Comment: 45 pages, 17 figures; v2: minor improvements and rearrangements, refs adde

    Towards a Finite-NN Hologram

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    We suggest that holographic tensor models related to SYK are viable candidates for exactly (ie., non-perturbatively in NN) solvable holographic theories. The reason is that in these theories, the Hilbert space is a spinor representation, and the Hamiltonian (at least in some classes) can be arranged to commute with the Clifford level. This makes the theory solvable level by level. We demonstrate this for the specific case of the uncolored O(n)3O(n)^3 tensor model with arbitrary even nn, and reduce the question of determining the spectrum and eigenstates to an algebraic equation relating Young tableaux. Solving this reduced problem is conceptually trivial and amounts to matching the representations on either side, as we demonstrate explicitly at low levels. At high levels, representations become bigger, but should still be tractable. None of our arguments require any supersymmetry.Comment: 16 page

    (Anti-)Symmetrizing Wave Functions

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    The construction of fully (anti-)symmetric states with many particles, when the single particle state carries multiple quantum numbers, is a problem that seems to have not been systematically addressed in the literature. A quintessential example is the construction of ground state baryon wave functions where the color singlet condition reduces the problem to just two (flavor and spin) quantum numbers. In this paper, we address the general problem by noting that it can be re-interpreted as an eigenvalue equation, and provide a formalism that applies to generic number of particles and generic number of quantum numbers. As an immediate result, we find a complete solution to the two quantum number case, from which the baryon wave function problem with arbitrary number of flavors follows. As a more elaborate illustration that reveals complications not visible in the two quantum number case, we present the complete class of states possible for a system of five fermionic particles with three quantum numbers each. Our formalism makes systematic use of properties of the symmetric group and Young tableaux. Even though our motivations to consider this question have their roots in SYK-like tensor models and holography, the problem and its solution should have broader applications.Comment: v3: journal version, contains slightly expanded discussions and example

    An assessment of fruiting and polyembryony in Langsat (Lansium domesticum Corr.) from Nilgiris, India

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    In this paper we report the fruit characteristics and seed polyembryony in langsat, Lansium parasiticum (syn. Lansium domesticum Corr.). This fruit tree belongs to the family Meliaceae in order Sapindales and is considered to be native of western South East Asia and is common in both wild and cultivated forms throughout Malaysia and Philippines where the fruits are very popular and the tree is being utilized in reforestation efforts. It is also grown in southern Thailand and Vietnam and flourishes in the Nilgiris and other humid areas of South India. In the present investigation we report the morphological and biochemical parameters of the plants and fruits obtained from State Horticultural Farm, Buliar (latitude 11.34; longitude 76.79) in Tamil Nadu, at elevation of 360 m MSL and receiving average annual rainfall of 125.14 cm. The plantation was established in the year 1900 and consists of various tropical trees like mangosteen, langsat, arecanut, coffee, silveroak, pepper, cinnamon in tier system of planting

    Enhancement of Shelf-Life of Tomatoes Using Herbal Extracts

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    A study was taken up to enhance the shelf life of tomatoes by using Garlic (Allium sativam Linn) and Ginger (Zingiber officinale Rose) extracts at different concentrations viz, 1%, 5% and 10%. Tomatoes keeping quality was improved by spraying 10% garlic and ginger extracts, which reduced the spoilage, physiological loss and microbial load on the surface of the fruits. Among these, 10% garlic extract was more efficient in controlling spoilage microorganisms, enhancing shelf life and redicing physiological weight loss.   This study revealed the possibility of utilization of Garlic (Allium sativam Linn) and Ginger (Zingiber officinale Rose) extracts to enhance the keeping quality of tomatoes
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