7,973 research outputs found

    New constraints on R-parity violation from proton stability

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    We derive stringent upper bounds on all the (λijkμl)(\lambda''_{ijk} \mu_l)-type combinations from the consideration of proton stability, where λijk\lambda''_{ijk} are baryon-number-violating trilinear couplings and μl\mu_l are lepton-number-violating bilinear mass parameters in a R-parity-violating supersymmetric theory.Comment: 4 pages, Latex, uses axodraw.sty (in the revised version all combinations of the form λ"ijkμl\lambda"_{ijk}\mu_l have been constrained, using one-loop graphs) To appear in Phys. Lett.

    Neutrino mass generation in the SO(4) model

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    Generation of neutrino mass in SO(4) model is proposed here. The algebraic structure of SO(4) is same as to that of SU(2)L×SU(2)RSU(2)_{L}\times SU(2)_{R}. It is shown that the spontaneous symmetry breaking results three massive as well as three massless gauge bosons. The standard model theory according to which there exist three massive gauge bosons and a massless one is emerged from this model. In the framework of SU(2)L×SU(2)RSU(2)_{L}\times SU(2)_{R} a small Dirac neutrino mass is derived. It is also shown that such mass term may vanish with a special choice. The Majorana mass term is not considered here and thus in this model the neutrino mass does not follow seesaw structure.Comment: 7 pages, no figur

    Modified Higgs couplings and unitarity violation

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    Prompted by the recent observation of a Higgs-like particle at the CERN Large Hadron Collider (LHC), we investigate a quantitative correlation between possible departures of the gauge and Yukawa couplings of this particle from their Standard Model expectations and the scale of unitarity violation in the processes WWWWWW \to WW and ttˉWWt\bar t \to WW.Comment: 6 pages, 6 eps figures, Arrayeq.sty attached; v2: minor updates, version published: PRD 87 (2013) 011702(R), Rapid Communicatio

    On certain Toeplitz operators and associated completely positive maps

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    We study Toeplitz operators with respect to a commuting nn-tuple of bounded operators which satisfies some additional conditions coming from complex geometry. Then we consider a particular such tuple on a function space. The algebra of Toeplitz operators with respect to that particular tuple becomes naturally homeomorphic to LL^\infty of a certain compact subset of Cn\mathbb C^n. Dual Toeplitz operators are characterized. En route, we prove an extension type theorem which is not only important for studying Toeplitz operators, but also has an independent interest because dilation theorems do not hold in general for n>2n>2.Comment: 25 pages. arXiv admin note: text overlap with arXiv:1706.0346

    Analysing climate action plans of selected UK cities for their SDG alignment

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    In UK, the Climate change Act of 2008 has placed a binding target of reducing the net carbon emission in 2050 by at least 80% compared to the 1990 baseline. With a high share of urban population, the contribution of cities and urban areas towards climate change mitigation and adaptation becomes crucial. UK being a signatory to the Sustainable Development Goals (SDG) in 2016, there is a new emphasis on the sustainability of cities as well. In this paper, a preliminary analysis of climate action initiatives of three UK cities (Bristol, Leicester and Milton Keynes) and their alignment with the SDG is presented. We used a text mining approach to analyse the climate action plans and then use this to map the alignment with the SDGs. We find that climate action plans have not focused on the sustainable development goals or the SDGs and their focus remains limited mainly to mitigation activities through promotion of renewable energies at homes and in buildings and actions on transport. However, climate action plans could influence a significant number of SDGs and an integrated approach could be beneficial for the cities and their residents

    Clusters of bound particles in the derivative delta-function Bose gas

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    In this paper we discuss a novel procedure for constructing clusters of bound particles in the case of a quantum integrable derivative delta-function Bose gas in one dimension. It is shown that clusters of bound particles can be constructed for this Bose gas for some special values of the coupling constant, by taking the quasi-momenta associated with the corresponding Bethe state to be equidistant points on a single circle in the complex momentum plane. We also establish a connection between these special values of the coupling constant and some fractions belonging to the Farey sequences in number theory. This connection leads to a classification of the clusters of bound particles associated with the derivative delta-function Bose gas and allows us to study various properties of these clusters like their size and their stability under the variation of the coupling constant.Comment: 33 pages, 1 figure, minor typos correcte

    Construction of some special subsequences within a Farey sequence

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    Recently it has been found that some special subsequences within a Farey sequence play a crucial role in determining the ranges of coupling constant for which quantum soliton states can exist for an integrable derivative nonlinear Schrodinger model. In this article, we find a novel mapping which connects two such subsequences belonging to Farey sequences of different orders. By using this mapping, we construct an algorithm to generate all of these special subsequences within a Farey sequence. We also derive the continued fraction expansions for all the elements belonging to a subsequence and observe a close connection amongst the corresponding expansion coefficients.Comment: latex, 8 page

    Parameter estimates for fractional autoregressive spatial processes

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    A binomial-type operator on a stationary Gaussian process is introduced in order to model long memory in the spatial context. Consistent estimators of model parameters are demonstrated. In particular, it is shown that d^Nd=OP((LogN)3N)\hat{d}_N-d=O_P(\frac{(\operatorname {Log}N)^3}{N}), where d=(d1,d2)d=(d_1,d_2) denotes the long memory parameter.Comment: Published at http://dx.doi.org/10.1214/009053605000000589 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org
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