10,920 research outputs found

    Precision determination of the top-quark mass

    Full text link
    Precision determinations of the top-quark mass require theory predictions with a well-defined mass parameter in a given renormalization scheme. The top-quark's running mass in the MSbar scheme can be extracted with good precision from the total cross section at next-to-next-to-leading order in QCD. The Monte Carlo top-quark mass parameter measured from comparison to events with top-quark decay products is not identical with the pole mass. Its translation to the pole mass scheme introduces an additional uncertainty of the order of 1 GeV.Comment: Presented at Loops and Legs in Quantum Field Theory 2014, Weimar, Germany and Large Hadron Collider Physics 2014, New York, US

    Higher-Order Corrections in Threshold Resummation

    Full text link
    We extend the threshold resummation exponents G^N in Mellin-N space to the fourth logarithmic (N^3LL) order collecting the terms alpha_s^2 (alpha_s ln N)^n to all orders in the strong coupling constant as. Comparing the results to our previous three-loop calculations for deep-inelastic scattering (DIS), we derive the universal coefficients B_q and B_g governing the final-state jet functions to order alpha_s^3, extending the previous quark and gluon results by one and two orders. A curious relation is found at second order between these quantities, the splitting functions and the large-angle soft emissions in Drell-Yan type processes. We study the numerical effect of the N^3LL corrections using both the fully exponentiated form and the expansion of the coefficient function in towers of logarithms.Comment: 20 pages, LaTeX, 6 eps-figures. Misprints in equations and fig. 5 correcte

    NNLO splitting and coefficient functions with time-like kinematics

    Get PDF
    We discuss recent results on the three-loop (next-to-next-to-leading order, NNLO) time-like splitting functions of QCD and the two-loop (NNLO) coefficient functions in one-particle inclusive e+e- annihilation. These results form the basis for extracting fragmentation functions for light and heavy flavors with NNLO accuracy that will be needed at the LHC and ILC. The two-loop calculations have been performed in Mellin space based on a new method, the main features of which we also describe briefly.Comment: Presented by A.M. at Loops and Legs in Quantum Field Theory, 23-28 April 2006, Eisenach, German

    Towards three-loop QCD corrections to the time-like splitting functions

    Full text link
    We report on the status of a direct computation of the time-like splitting functions at next-to-next-to-leading order in QCD. Time-like splitting functions govern the collinear kinematics of inclusive hadron production and the evolution of the parton fragmentation distributions. Current knowledge about them at three loops has been inferred by means of crossing symmetry from their related space-like counterparts, which has left certain parts of the off-diagonal quark-gluon splitting function undetermined. This motivates an independent calculation from first principles. We review the tools and methods which are applied to attack the problem.Comment: 11 pages, 5 figures; presented at the Epiphany Conference 2015 (Cracow, Poland); additional files: MassFactorization.n

    On "dynamical mass" generation in Euclidean de Sitter space

    Full text link
    We consider the perturbative treatment of the minimally coupled, massless, self-interacting scalar field in Euclidean de Sitter space. Generalizing work of Rajaraman, we obtain the dynamical mass m^2 \propto sqrt{lambda} H^2 of the scalar for non-vanishing Lagrangian masses and the first perturbative quantum correction in the massless case. We develop the rules of a systematic perturbative expansion, which treats the zero-mode non-perturbatively, and goes in powers of sqrt{lambda}. The infrared divergences are self-regulated by the zero-mode dynamics. Thus, in Euclidean de Sitter space the interacting, massless scalar field is just as well-defined as the massive field. We then show that the dynamical mass can be recovered from the diagrammatic expansion of the self-energy and a consistent solution of the Schwinger-Dyson equation, but requires the summation of a divergent series of loop diagrams of arbitrarily high order. Finally, we note that the value of the long-wavelength mode two-point function in Euclidean de Sitter space agrees at leading order with the stochastic treatment in Lorentzian de Sitter space, in any number of dimensions.Comment: LaTeX, 15 page

    REPRESENTATION OF JAVANESE MESSIANIC MANIFESTO IN THE DOMAIN OF IMPERIAL LITERATURES

    Get PDF
    Artikel ini bertujuan untuk melacak dan mendeskripsikan 'representasi manifesto messianisme Java pada ranah karya-karya sastrakeraton.' Sejak semula, masyarakat Jawa memiliki ideologi tentang manifesto messianisme sebagai identitas kultural. Pada ranah politik kerajaan Jawa, sebenarnya ideologi ini dianggap sebagai wahana orientasi kosmik. Sejak era kerajaan Kediri, masa kebudayaan Jawa-Kuna (Jawa Hindu-Buddha), hingga era kerajaan Mataram, masa kebudayaan Jawa-Islam; para 'rakawi' dan 'pujangga' telah mengadopsi, mengembangkan, mengkristalkan, mereformulasikan, bahkan telah merekayasa ulang tentang episteme messianik Jawa melalui proses pengimitasian konsep messianisme Kitab-kitab Suci dari peradaban Semit (Arab) dan Arya (India). Sebagai bentuk messianisme hibrida yang berpangkal pada 'imitatio Indica- Islamica', secara literal memang disadap dari kultur Brahmani dan Ibrahimi yang kemudian mengalami proses reinkamasi dalamepisteme Jawa berkat ekstasinalar penulis-penulis Jawayangmenjadikan keraton sebagai skriptoria. Temuan yang berkaitan dengan pengaruh kultur keagamaan manea tentang manifesto messianisme asing dalam teks-teks tertulis berbahasa Jawa, mungkin dapat dianalisis melalui karya-karya sastra keraton yang menyuarakan kronologi profetisme Jawa, seperti Kakawin Bharatayudha, Kakawin Sutasoma, dan Kitab Primbon QuraisyAdammakna. Dalam sejarah sastra Jawa, karya-karya sastra yang bersifat messianik, yang digubah oleh para penulis keraton, kenyataannya telah menciptakan konsep yang tidak berbeda, meskipun mereka menggunakan istilah-istilah religiositas dari agama Hindu, Buddha, maupun Islam. Istilah-istilah keagamaan yang melintas batas itu difungsikan untuk memproklamirkanjati diri dan superioritasMesias Jawa yang tentu saja berbeda dengan messianismemanca. Dalamkonteks ini, ideologimessianistik Jawa dapat diidentiflkasi dan direpresentasimelalui dua hal; (1) orientasimessiansime etnik yang merujuk pada paradigma identitas kultural Jawa, (2) orientasi eskatologi messianisme Jawa Islam. Studi ini bertujuan untuk merangkai jaring intelektual keraton sejakmasa kebudayaan Jawa Kuna hingga Jawa Islam seputar messianisme Jawa: (i) episteme tentang inkamasi, (ii) konsepMesias Jawa yang bersifat hibrida

    NNLO Time-like Splitting Functions in QCD

    Full text link
    We review the status of the calculation of the time-like splitting functions for the evolution of fragmentation functions to the next-to-next-to-leading order in perturbative QCD. By employing relations between space-like and time-like deep-inelastic processes, all quark-quark and the gluon-gluon time-like splitting functions have been obtained to three loops. The corresponding quantities for the quark-gluon and gluon-quark splitting at this order are presently still unknown except for their second Mellin moments.Comment: 4 pages LaTeX, proceedings of the DIS 2008 Workshop, 7-11 April 2008, Londo

    BˉXsγ\bar B\to X_s \gamma with a warped bulk Higgs

    Get PDF
    We study the decay BˉXsγ\bar B\to X_s\gamma in Randall-Sundrum models with an IR-localised bulk Higgs. The two models under consideration are a minimal model as well as a model with a custodial protection mechanism. We include the effects of tree- and one-loop diagrams involving 5D gluon and Higgs exchanges as well as QCD corrections arising from the evolution from the Kaluza-Klein scale to the typical scale of the decay. We find the RS corrections to the branching fraction can be sizeable for large Yukawas and moderate KK scales TT; for small Yukawas the RS contribution is small enough to be invisible in current experimental data.Comment: 20 pages, 5 figures(V2: references added, matches version published in Nuclear Physics B
    corecore