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B. F. L. Ward

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

At least 127 records · Page 7Linked to original sources

Radiative Corrections to Bremsstrahlung in Radiative Return

Radiating a photon from the initial state provides a useful tool for studying a range of low energy physics using a high-energy e+ e- accelerator. Accurate results require careful calculation of the first order virtual photon corrections. We compare exact results for initial state radiative corrections, finding agreement to an order of 10^{-5} or better as a fraction of the Born cross-section for most of the range of photon energies, at CMS energies relevant in both high-energy collision and radiative return experiments.

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Black Holes and Massive Elementary Particles in Resummed Quantum Gravity

Einstein's general theory of relativity poses many problems to the quantum theory of point particle fields. Among them is the fate of a massive point particle. Since its rest mass exists entirely within its Schwarzschild radius, in the classical solutions of Einstein's theory, the respective system should be a black hole. We address this issue using exact results in a new approach to quantum gravity based upon well-tested resummation methods in point particle quantum field theory. We show that the classical conclusion is obviated by quantum loop effects. We show that our new approach already passes two theoretical checks with the published literature; for, it reproduces known results on the one-loop correction to the graviton self-energy in scaler matter coupled to Einstein's gravity as analyzed by 't Hooft and Veltman and it is consistent with the asymptotic safety results of Bonnanno and Reuter on the behavior of Newton's constant in the deep Euclidean regime. Indeed, our approach is consistent with the black hole phenomenology of the latter authors, including their results on the final state of the Hawking radiation for an originally massive black hole. Further black hole related phenomenological implications are also discussed.

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New Results on Precision Studies of Heavy Vector Boson Physics

We present new results for two important heavy vector boson physics processes: (1), virtual corrections to hard bremsstrahlung which are relevant to precision predictions for the radiative return process in Z boson production at and beyond LEP2 energies ; and, (2), electric charge screening effects in single W production with finite p_T, multiple photon radiation in high energy collider physics processes. In both cases we show that we improve the respective precision tag significantly. Phenomenological implications are discussed.

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Quantum Corrections to Newton's Law in Resummed Quantum Gravity

We present the elements of resummed quantum gravity, a new approach to quantum gravity based on the work of Feynman using the simplest example of a scalar field as the representative matter. We show that we get a UV finite quantum correction to Newton's law.

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Threshold Corrections in Precision LHC Physics: QED otimes QCD

With an eye toward LHC processes in which theoretical precisions of 1 percent are desired, we introduce the theory of the simultaneous YFS resummation of QED and QCD to compute the size of the expected resummed soft radiative threshold effects in precision studies of heavy particle production at the LHC. Our results show that both QED and QCD soft threshold effects must be controlled to be on the conservative side to achieve such precision goals.

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Threshold Corrections in QED otimes QCD at the LHC

In some processes at the LHC, theoretical precisions of 1 percent are desired. With an eye toward such precisions, we introduce the theory of the simultaneous YFS resummation of QED and QCD to compute the size of the expected resummed soft radiative threshold effects in precision studies of heavy particle production at the LHC. Our results, that the soft QED threshold effects are at the level of 0.3 percent whereas the soft QCD threshold effects enter at the level of 20 percent, show that both must be controlled to be on the conservative side to achieve such precision goals.

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The Virtual Correction to Bremsstrahlung in High-Energy e+ e- Annihilation: Comparison of Exact Results

We have compared the virtual corrections to single hard bremsstrahlung as calculated by S. Jadach, M. Melles, B.F.L. Ward and S.A. Yost to several other expressions. The most recent of these comparisons is to the leptonic tensor calculated by J.H. Kuhn and G. Rodrigo for radiative return. Agreement is found to within a part in 10^5 or better, as a fraction of the Born cross section, for most of the range of photon energies. The massless limits have been shown to agree analytically to NLL order.

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Comparison of Exact Results for the Virtual Corrections to Bremsstrahlung in Electron-Positron Annihilation at High Energies

We have compared the virtual corrections to electron-positron annihilation to fermion pairs with single hard bremsstrahlung as calculated by S. Jadach, M. Melles, B.F.L. Ward and S.A. Yost to several other expressions. The most recent of these comparisons is to the leptonic tensor calculated by J.H. Kuhn and G. Rodrigo for radiative return. Agreement is found to within $10^{-5}$ or better, as a fraction of the Born cross section.

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QED \otimes QCD Threshold Corrections at the LHC

We use the theory of YFS resummation to compute the size of the expected resummed soft radiative threshold effects in precision studies of heavy particle production at the LHC, where accuracies of 1 percent are desired in some processes. We find that the soft QED threshold effects are at the level of 0.3 percent whereas the soft QCD threshold effects enter at the level of 20 percent and hence both must be controlled to be on the conservative side to achieve such goals.

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Comparisons of Fully Differential Exact Results for O(alpha) Virtual Corrections to Single Hard Bremsstrahlung in e+e- Annihilation at High Energies

We present comparisons of the fully differential exact virtual correction to the important single hard bremsstrahlung process in e+e- annihilation at high energies, which is essential for precision studies of the Standard Model from 1 GeV to 1 TeV, as calculated by two completely independent methods and groups. We show that the two sets of results are in excellent agreement. Phenomenological implications are discussed.

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Massive Elementary Particles and Black Holes

An outstanding problem posed by Einstein's general theory of relativity to the quantum theory of point particle fields is the fate of a massive point particle; for, in the classical solutions of Einstein's theory, such a system should be a black hole. We use exact results in a new approach to quantum gravity to show that this conclusion is obviated by quantum loop effects. Phenomenological implications are discussed

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Precision Electro-Weak and Hadronic Luminosity Calculations

We have used YFS Monte Carlo techniques to obtain per-mil level accuracy for the Bhabha scattering cross section used in the luminosity monitor in electro-weak scattering experiments. We will describe techniques for extending these methods for use in the W production luminosity cross section for hadron colliders.

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Are Massive Elementary Particles Black Holes?

We use exact results in a new approach to quantum gravity to study the effect of quantum loop corrections on the behavior of the metric of space-time near the Schwarzschild radius of a massive point particle in the Standard Model. We show that the classical conclusion that such a system is a black hole is obviated. Phenomenological implications are discussed.

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Precision calculation for e+ e- -> 2f: the KK MC project

We present the current status of the coherent exclusive (CEEX) realization of the YFS theory for the processes in e+ e- -> 2f via the KK MC. We give a brief summary of the CEEX theory in comparison to the older (EEX) exclusive exponentiation theory and illustrate recent theoretical results relevant to the LEP2 and LC physics programs.

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QCD soft gluon exponentiation: YFS MC Approach

We develop and prove the theory of the QCD extension of the YFS Monte Carlo approach to higher order QED radiative corrections. As a corollary, a new approach to quantum gravity by one of us (B.F.L.W.) is illustrated. Semi-analytical results and preliminary explicit Monte Carlo data are presented for the processes p-bar p -> t-bar t + X at FNAL energies. We comment briefly on the implications of our results on the CDF/D0 observations and on RHIC/LHC physics.

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Quantum Corrections to Newton's Law

We present a new approach to quantum gravity starting from Feynman's formulation for the simplest example, that of a scalar field as the representative matter. We show that we extend his treatment to a calculable framework using resummation techniques already well-tested in other problems. Phenomenological consequences for Newton's law are described.

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