1,904 research outputs found

    Can Polarised Drell-Yan Shed More Light On The Proton Spin?

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    We analyse polarised Drell-Yan process using the factorisation method and derive operator definitions for polarised parton distribution functions. We demonstrate that a factorisation analogous to that in the unpolarised Drell-Yan case holds in this process. We study the leading order gluonic contribution to the first moment of polarised Drell-Yan function and show that it is consistent with results obtained from polarised deep inelastic scattering.Comment: 12 page

    NNLO Corrections to the Polarized Drell-Yan Coefficient Function

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    We present the full next-to-next-to-leading order (NNLO) corrections to the coefficient function for the polarized cross section dΔσ/dQd \Delta\sigma/d Q of the Drell-Yan process. We study the effect of these corrections on the process p+p→l+l−+‘X′p+p\to l^+l^-+`X' at an C.M. energy S=200GeV\sqrt{S}=200 GeV. All QCD partonic subprocesses have been included provided the lepton pair is created by a virtual photon, which is a valid approximation for a lepton pair invariant mass Q<50GeVQ<50 GeV. For this reaction the dominant subprocess is given by q+qˉ→γ∗+‘X′q+\bar q\to \gamma^*+`X' and its higher order corrections so that it provides us with an excellent tool to measure the polarized sea-quark densities.Comment: 5 pages, 5 figures, 7th DESY Workshop on Elementary Particle Theory, Loops and Legs in Quantum Field Theory, Zinnowitz, Germany, April 25-30, 200

    Production of a KK-graviton and a Vector Boson in ADD Model via Gluon fusion

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    In the models with large extra-dimensions, we examine the production of a vector boson (\gamma / Z) in association with the Kaluza-Klein (KK) modes of the graviton via gluon fusion. At the leading order, the process takes place through quark-loop box and triangle diagrams and it is ultraviolate finite. We report the results for the LHC. We also discuss the issues of anomaly and decoupling of heavy quarks in the amplitude.Comment: 12 pages, 8 figures, some references and a note in the appendix adde

    Conservation and management of marine fishery resources of Kerala State, India

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    The highly productive fisheries of Kerala, India, are suffering from overexploitation. Use of unsuitable fishing gears that result in a high level of wasteful bycatch and destruction of egg bearing and juvenile fish should be controlled. This paper makes some suggestions for monitoring and conservation of the fisheries in Kerala

    Higgs boson production through bbˉb \bar b annihilation at threshold in N3^3LO QCD

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    We present threshold enhanced N3^3LO QCD corrections to inclusive Higgs production through bottom anti-bottom annihilation at hadron colliders using threshold resummed cross section. The resummed cross section is obtained using factorization properties and Sudakov resummation of the inclusive cross section. We use the recent results on threshold N3^3LO corrections in QCD for Drell-Yan production and three loop QCD corrections to Higgs form factor with bottom anti-bottom quark to achieve this task. This is the first step towards the evaluation of complete N3^3LO result. We have numerically demonstrated the importance of such corrections at the LHC.Comment: 15 pages, 1 figur

    Two-loop corrections to Higgs boson production

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    In this paper we present the complete two-loop vertex corrections to scalar and pseudo-scalar Higgs boson production for general colour factors for the gauge group SU(N){\rm SU(N)} in the limit where the top quark mass gets infinite. We derive a general formula for the vertex correction which holds for conserved and non conserved operators. For the conserved operator we take the electromagnetic vertex correction as an example whereas for the non conserved operators we take the two vertex corrections above. Our observations for the structure of the pole terms 1/ϵ41/\epsilon^4, 1/ϵ31/\epsilon^3 and 1/ϵ21/\epsilon^2 in two loop order are the same as made earlier in the literature for electromagnetism. However we also elucidate the origin of the second order single pole term which is equal to the second order singular part of the anomalous dimension plus a universal function which is the same for the quark and the gluon. [3mm]Comment: 27 pages LaTeX.We correct some misprints. Moreover we have discovered that the second order single pole term is equal to the singular part of the second order anomalous dimension plus a universal function which is the same for the quark and the gluon. This holds for vertex corrections as well as for scattering amplitude
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