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B. F. L. Ward

Publications and source records attributed to B. F. L. Ward.

At least 109 records · Page 6Linked to original sources
arXiv2008

New Developments in Precision LHC Theory: QEDXQCD Exponentiation, Shower/ME Matching, IR-Improved DGLAP-CS Theory and Implications for UV Finite Quantum Gravity

We present the recent developments in exact amplitude-based resummation methods for non-Abelian gauge theories as they relate to precision LHC physics. We discuss QEDXQCD exponentiation, shower/ME matching, IR-improved DGLAP-CS theory and implications, as developed by one of us (BFLW), for a UV finite theory of quantum general relativity.

hep-ph↗
arXiv2007

On the all-order epsilon-expansion of generalized hypergeometric functions with integer values of parameters

We continue our study of the construction of analytical coefficients of the epsilon-expansion of hypergeometric functions and their connection with Feynman diagrams. In this paper, we apply the approach of obtaining iteratated solutions to the differential equations associated with hypergeometric functions to prove the following result (Theorem 1): The epsilon-expansion of a generalized hypergeometric function with integer values of parameters is expressible in terms of generalized polylogarithms with coefficients that are ratios of polynomials. The method used in this proof provides an efficient algorithm for calculatiing of the higher-order coefficients of Laurent expansion.

hep-th↗
arXiv2007

IR-Improved DGLAP Theory: Kernels, Parton Distributions, Reduced Cross Sections

It is shown that exact, amplitude-based resummation allows IR-improvement of the usual DGLAP theory. This results in a new set of kernels, parton distributions and attendant reduced cross sections, so that the QCD perturbative result for the respective hadron-hadron or lepton-hadron cross section is unchanged order-by-order in $α_s$ at large squared-momentum transfers. We compare these new objects with their usual counter-parts and illustrate the effects of the IR-improvement in some phenomenological cases of interest with an eye toward precision applications in LHC physics scenarios.

hep-ph↗
arXiv2007

Multiple (inverse) binomial sums of arbitrary weight and depth and the all-order epsilon-expansion of generalized hypergeometric functions with one half-integer value of parameter

We continue the study of the construction of analytical coefficients of the epsilon-expansion of hypergeometric functions and their connection with Feynman diagrams. In this paper, we show the following results: Theorem A: The multiple (inverse) binomial sums of arbitrary weight and depth (see Eq. (1.1)) are expressible in terms of Remiddi-Vermaseren functions. Theorem B: The epsilon expansion of a hypergeometric function with one half-integer value of parameter (see Eq. (1.2)) is expressible in terms of the harmonic polylogarithms of Remiddi and Vermaseren with coefficients that are ratios of polynomials. Some extra materials are available via the www at this http://theor.jinr.ru/~kalmykov/hypergeom/hyper.html

hep-th↗
arXiv2007

IR-Improved DGLAP Theory

We show that it is possible to improve the infrared aspects of the standard treatment of the DGLAP evolution theory to take into account a large class of higher order corrections that significantly improve the precision of the theory for any given level of fixed-order calculation of its respective kernels. We illustrate the size of the effects we resum using the moments of the parton distributions.

hep-ph↗
arXiv2007

Exact Quantum Loop Results in the Theory of General Relativity

We present a new approach to quantum general relativity based on the idea of Feynman to treat the graviton in Einstein's theory as a point particle field subject to quantum fluctuations just as any such field is in the well-known Standard Model of the electroweak and strong interactions. We show that by using resummation techniques based on the extension of the methods of Yennie, Frautschi and Suura to Feynman's formulation of Einstein's theory, we get calculable loop corrections that are even free of UV divergences. One further by-product of our analysis is that we can apply it to a large class of interacting field theories, both renormalizable and non-renormalizable, to render their UV divergences finite as well. We illustrate our results with applications of some phenomenological interest.

hep-ph↗
arXiv2007

All order epsilon-expansion of Gauss hypergeometric functions with integer and half/integer values of parameters

It is proved that the Laurent expansion of the following Gauss hypergeometric functions, 2F1(I1+a*epsilon, I2+b*ep; I3+c*epsilon;z), 2F1(I1+a*epsilon, I2+b*epsilon;I3+1/2+c*epsilon;z), 2F1(I1+1/2+a*epsilon, I2+b*epsilon; I3+c*epsilon;z), 2F1(I1+1/2+a*epsilon, I2+b*epsilon; I3+1/2+c*epsilon;z), 2F1(I1+1/2+a*epsilon,I2+1/2+b*epsilon; I3+1/2+c*epsilon;z), where I1,I2,I3 are an arbitrary integer nonnegative numbers, a,b,c are an arbitrary numbers and epsilon is an arbitrary small parameters, are expressible in terms of the harmonic polylogarithms of Remiddi and Vermaseren with polynomial coefficients. An efficient algorithm for the calculation of the higher-order coefficients of Laurent expansion is constructed. Some particular cases of Gauss hypergeometric functions are also discussed.

hep-th↗
arXiv2006

Resummed Quantum Gravity

We present the current status of the a new approach to quantum general relativity based on the exact resummation of its perturbative series as that series was formulated by Feynman. We show that the resummed theory is UV finite and we present some phenomenological applications as well.

hep-ph↗
arXiv2006

Planck Scale Remnants in Resummed Quantum Gravity

We show that, in a new approach to quantum gravity in which its UV behavior is tamed by resummation of large IR effects, the final state of the Hawking radiation for an originally very massive black hole is a Planck scale remnant which is completely accessible to our universe. This remnant would be expected to decay into n-body final states, leading to Planck scale cosmic rays.

hep-ph↗
arXiv2006

Comparisons of Exact Results for the Virtual Photon Contribution to Single Hard Bremsstrahlung in Radiative Return for Electron-Positron Annihilation

We compare fully differential exact results for the virtual photon correction to single hard photon bremsstrahlung obtained using independent calculations, both for electron-positron annihilation at high-energy colliders and for radiative return applications. The results are compared using Monte Carlo evaluations of the matrix elements as well as by direct analytical evaluation of certain critical limits. Special attention is given to the issues of numerical stability and the treatment of finite-mass corrections. It is found that agreement on the order of 10^{-5} or better is obtained over most of the range of hard photon energies, at CMS energies relevant to both high energy collisions and radiative return experiments.

hep-ph↗
arXiv2006

New Applications of Resummation in Non-Abelian Gauge Theories: QED X QCD Exponentiation for LHC Physics, IR-Improved DGLAP Theory and Resummed Quantum Gravity

We present the elements of three applications of resummation methods in non-Abelian gauge theories: (1), QED X QCD exponentiation and shower/ME matching for LHC physics; (2), IR improvement of DGLAP theory; (3), resummed quantum gravity and the final state of Hawking radiation. In all cases, the extension of the YFS approach, originally introduced for Abelian gauge theory, to non-Abelian gauge theories, QCD and quantum general relativity, leads to new results and solutions which we briefly summarize.

hep-ph↗
arXiv2006

Virtual Corrections to Bremsstrahlung in High-Energy Collider Physics: LHC and e+ e- Colliders

We describe radiative corrections to bremsstrahlung and their application to high energy collider physics, focusing on the applications to luminosity measurement, fermion pair production and radiative return. We review the status of one loop radiative corrections in BHLUMI and the KKMC, including cross checks with newer results developed independently for radiative return. We outline a YFS-exponentiated approach to the Drell-Yan process for LHC physics, including a discussion of the relevant radiative corrections.

hep-ph↗
arXiv2005

Virtual Corrections to Bremsstrahlung with Applications to Luminosity Processes and Radiative Return

We will describe radiative corrections to bremsstrahlung, focusing on applications to luminosity, fermion pair production, and radiative return at high-energy e+ e- colliders. A precise calculation of the Bhabha luminosity process was essential at SLC and LEP, and will be equally important in ILC physics. We will review the exact results for two-photon radiative corrections to Bhabha scattering which led to the precision estimates for the BHLUMI MC. We will also compare the implementation of the virtual photon correction to bremsstrahlung for fermion pair production in the KK MC to similar exact expressions developed for other purposes, and discuss applications to radiative return in high energy e+ e- colliders.

hep-ph↗
arXiv2005

Final State of Hawking Radiation in Quantum General Relativity

We use a new approach to the UV behavior of quantum general relativity, together with some recent results from the phenomenological asymptotic safety analysis of the theory, to discuss the final state of the Hawking radiation for an originally very massive black hole solution of Einstein's theory. We find that, after the black hole evaporates to the Planck mass size, its horizon is obviated by quantum loop effects, rendering the entire mass of the originally massive black hole accessible to our universe.

hep-ph↗