William B. Kilgore

Brookhaven National Laboratory, New York City, New York, United States

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Publications (66)162 Total impact

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    ABSTRACT: We compute the contribution to the total cross section for the inclusive production of a Standard Model Higgs boson induced by two quarks with different flavour in the initial state. Our calculation is exact in the Higgs boson mass and the partonic center-of-mass energy. We describe the reduction to master integrals, the construction of a canonical basis, and the solution of the corresponding differential equations. Our analytic result contains both Harmonic Polylogarithms and iterated integrals with additional letters in the alphabet.
    Preview · Article · Jul 2015 · Journal of High Energy Physics
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    ABSTRACT: We compute the contribution to the total cross section for the inclusive production of a Standard Model Higgs boson induced by two quarks with different flavour in the initial state. Our calculation is exact in the Higgs boson mass and the partonic center-of-mass energy. We describe the reduction to master integrals, the construction of a canonical basis, and the solution of the corresponding differential equations. Our analytic result contains both Harmonic Polylogarithms and iterated integrals with additional letters in the alphabet.
    Full-text · Article · Jun 2015
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    William B. Kilgore
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    ABSTRACT: I discuss the contributions of the one-loop single-real-emission amplitudes, $gg\to H g$, $qg\to H q$, etc. to inclusive Higgs boson production through next-to-next-to-next-to-leading order in the strong coupling.
    Preview · Article · Jul 2014
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    William B. Kilgore
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    ABSTRACT: I compute the contributions of the one-loop single-real-emission amplitudes, $gg\to H g$, $qg\to H q$, etc., to inclusive Higgs boson production through next-to-next-to-next-to-leading order (N^3LO) in the strong coupling $\alpha_s$. The next-to-leading (NLO) and next-to-next-to-leading order (NNLO) terms are computed in closed form, in terms of $\Gamma$-functions and the hypergeometric functions ${}_{2}F_{1}$ and ${}_{3}F_{2}$. I compute the \nnnlo\ terms as Laurent expansions in the dimensional regularization parameter through order $(\epsilon^{1})$. To obtain the \nnnlo\ terms, I perform an extended threshold expansion of the phase space integrals and map the resulting coefficients onto a basis of harmonic polylogarithms.
    Preview · Article · Dec 2013 · Physical Review D
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    William B. Kilgore
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    ABSTRACT: The infrared structure of (multi-loop) scattering amplitudes is determined entirely by the identities of the external particles participating in the scattering. The two-loop infrared structure of pure \qcd\ amplitudes has been known for some time. By computing the two-loop amplitudes for $\bar{f}\,f\longrightarrow X$ and $\bar{f}\,f\longrightarrow V_1\,V_2$ scattering in an $SU(N)\times SU(M)\times U(1)$ gauge theory, I determine the anomalous dimensions which govern the infrared structure for any massless two-loop amplitude.
    Preview · Article · Aug 2013 · European Physical Journal C
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    William B. Kilgore
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    ABSTRACT: I describe a procedure by which one can transform scattering amplitudes computed in the four dimensional helicity scheme into properly renormalized amplitudes in the 't Hooft-Veltman scheme. I describe a new renormalization program, based upon that of the dimensional reduction scheme and explain how to remove both finite and infrared-singular contributions of the evanescent degrees of freedom to the scattering amplitude.
    Preview · Article · May 2012 · Physical review D: Particles and fields
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    ABSTRACT: This is a summary of the activities of the Physics at the LHC working group in the XIth Workshop on High Energy Physics Phenomenology (WHEPP-XI) held at the Physical Research Laboratory, Ahmedabad, India in January 2010. We discuss the activities of each sub-working group on physics issues at colliders such as Tevatron and Large Hadron Collider (LHC). The main issues discussed involve (1) results on W mass measurement and associated QCD uncertainties, (2) an attempt to understand the asymmetry measured at Tevatron in the top quark production, and (3) phenomenology of warped space dimension model. Keywords.Large Hadron Collider; top quark; W-mass; QCD and EW radiative corrections; extra dimensions.
    No preview · Conference Paper · Apr 2012
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    William B. Kilgore · Christian Sturm
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    ABSTRACT: The Drell-Yan mechanism for the production of lepton pairs is one of the most basic processes for physics studies at hadron colliders. It is therefore important to have accurate theoretical predictions. In this work we compute the two-loop virtual mixed QCD x QED corrections to Drell-Yan production. We evaluate the Feynman diagrams by decomposing the amplitudes into a set of known master integrals and their coefficients, which allows us to derive an analytical result. We also perform a detailed study of the ultraviolet and infrared structure of the two-loop amplitude and the corresponding poles in epsilon.
    Preview · Article · Jul 2011 · Physical review D: Particles and fields
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    ABSTRACT: This is a summary of the activities of the Physics at the LHC working group in the XIth Workshop on High Energy Physics Phenomenology (WHEPP-XI) held at the Physical Research Laboratory, Ahmedabad, India in January 2010. We discuss the activities of each sub-working group on physics issues at colliders such as Tevatron and Large Hadron Collider (LHC). The main issues discussed involve (1) results on W mass measurement and associated QCD uncertainties, (2) an attempt to understand the asymmetry measured at Tevatron in the top quark production, and (3) phenomenology of warped space dimension model. Keywords.Large Hadron Collider; top quark; W-mass; QCD and EW radiative corrections; extra dimensions.
    No preview · Article · May 2011 · Pramana
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    William B. Kilgore
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    ABSTRACT: A basic introduction to the application of QCD at hadron colliders is presented. I briefly review the phenomenological and theoretical origins of QCD, and then discuss factorization and infrared safety, parton distributions, the computation of hard scattering amplitudes and applications of perturbative QCD.
    Preview · Article · Apr 2011 · Pramana
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    William B. Kilgore
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    ABSTRACT: I apply commonly used regularization schemes to a multi-loop calculation to examine the properties of the schemes at higher orders. I find complete consistency between the conventional dimensional regularization scheme and dimensional reduction, but I find that the four dimensional helicity scheme produces incorrect results at next-to-next-to-leading order and singular results at next-to-next-to-next-to-leading order. It is not, therefore, a unitary regularization scheme.
    Preview · Article · Feb 2011 · Physical review D: Particles and fields
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    William B. Kilgore
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    ABSTRACT: I describe a method for determining the coefficients of scalar integrals for one-loop amplitudes in quantum field theory. The method is based upon generalized unitarity and the behavior of amplitudes when the free parameters of the cut momenta approach infinity. The method works for arbitrary masses of both external and internal legs of the amplitudes. It therefore applies not only to QCD but also to the Electroweak theory and to quantum field theory in general.
    Preview · Article · Dec 2007
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    ABSTRACT: The experiments at Run 2 of the Tevatron have each accumulated over 1 inverse femtobarn of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focussed on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.
    Full-text · Article · Nov 2006
  • William B. Kilgore
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    ABSTRACT: I describe a parton-level Monte Carlo calculation of Drell-Yan production at next-to-next-to-leading order. The calculation is performed with a subtraction scheme in which the subtraction term is the squared matrix element itself.. The method builds upon the Dipole Formalism and, with proper modifications, could be applied to deep inelastic scattering and e(+)e(-) annihilation to hadrons.
    No preview · Article · Oct 2006 · Nuclear Physics B - Proceedings Supplements
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    ABSTRACT: This Report summarises the activities of the "SM and Higgs" working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. On the one hand, we performed a variety of experimental and theoretical studies on standard candles (such as W, Z, and ttbar production), treating them either as proper signals of known physics, or as backgrounds to unknown physics; we also addressed issues relevant to those non-perturbative or semi-perturbative ingredients, such as Parton Density Functions and Underlying Events, whose understanding will be crucial for a proper simulation of the actual events taking place in the detectors. On the other hand, several channels for the production of the Higgs, or involving the Higgs, have been considered in some detail. The report is structured into four main parts. The first one deals with Standard Model physics, except the Higgs. A variety of arguments are treated here, from full simulation of processes constituting a background to Higgs production, to studies of uncertainties due to PDFs and to extrapolations of models for underlying events, from small-$x$ issues to electroweak corrections which may play a role in vector boson physics. The second part of the report treats Higgs physics from the point of view of the signal. In the third part, reviews are presented on the current status of multi-leg, next-to-leading order and of next-to-next-to-leading order QCD computations. Finally, the fourth part deals with the use of Monte Carlos for simulation of LHC physics. Comment: 234 pages, 173 figures. Web page of the workshop (with links to the talks): http://lappweb.in2p3.fr/conferences/LesHouches/Houches2005/
    Full-text · Article · Apr 2006
  • William B. Kilgore
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    ABSTRACT: There has been great progress in Higgs physics recently. Inclusive production channels have now been computed to next‐to‐next‐to‐leading order, and many associated production channels and their backgrounds have been computed to next‐to‐leading order. We are well positioned to discover the Higgs boson at the LHC and to make crucial first measurements of the Higgs boson couplings. © 2005 American Institute of Physics
    No preview · Article · Mar 2005
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    ABSTRACT: Sixty-two patients with coccidioidal meningitis underwent neuroimaging. Magnetic resonance imaging detected neuroimaging abnormalities in 76% of patients, and computed tomography scanning detected neuroimaging abnormalities in 41.6%. The most common abnormal neuroimaging findings were hydrocephalus (51.6%), basilar meningitis (46.8%), and cerebral infarction (38.7%). Significantly elevated mortality rates were associated with hydrocephalus and hydrocephalus coexisting with infarction. Basilar meningitis did not influence outcome. Patients without neuroimaging abnormalities had a mortality rate of 7.7%.
    Preview · Article · Mar 2005 · Clinical Infectious Diseases
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    William B. Kilgore
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    ABSTRACT: I describe a subtraction scheme for the next-to-next-to-leading order calculation of single inclusive production at hadron colliders. Such processes include Drell-Yan, W^{+/-}, Z and Higgs Boson production. The key to such a calculation is a treatment of initial state radiation which preserves the production characteristics, such as the rapidity distribution, of the process involved. The method builds upon the Dipole Formalism and, with proper modifications, could be applied to deep inelastic scattering and e^+ e^- annihilation to hadrons. Comment: 4 pages
    Preview · Article · Mar 2004 · Physical Review D
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    ABSTRACT: Granulomatous disorders may be associated with hypercalcemia. In sarcoidosis, the pathogenesis of hypercalcemia has been clarified, whereas in other granulomatous disorders, such as coccidioidomycosis, the mechanism is unclear. We present 13 patients with coccidioidomycosis and hypercalcemia to illustrate the clinical course and the mechanism of hypercalcemia. We retrospectively reviewed all patients admitted to Kern Medical Center, a 270-bed public hospital, from 1990 through 1997 with coccidioidomycosis and a serum calcium level of greater than 10.5 mg/dL on at least 3 occasions. In addition, no other causes for hypercalcemia were identified. The mean highest serum calcium level was 12.7 +/- 1.8 mg/dL. All patients had disseminated disease. Six patients were nonambulatory and 4 had bone involvement. Of the 9 patients in whom parathyroid hormone was measured, it was normal in 6 and suppressed in 3. Of the 9 patients in whom 25-hydroxyvitamin D was measured, it was normal in 6, suppressed in 2, and elevated in 1. Of the 7 patients in whom 1,25-dihydroxyvitamin D was measured, it was normal in 3 and suppressed in 4. Urinary calcium was elevated in 2 patients, both of whom were ambulatory. Nonambulatory patients had significantly higher serum calcium levels (14.3 +/- 1.0 mg/dL) than ambulatory patients (11.3 +/- 0.46 mg/dL) (P<0.001). The mechanism of hypercalcemia in coccidioidomycosis is unrelated to increased production of 1,25-dihydroxyvitamin D. Nonambulatory status is associated with higher mean serum calcium.
    No preview · Article · Jan 2004 · The American Journal of the Medical Sciences
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    Robert Harlander · William Kilgore
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    ABSTRACT: New techniques developed in connection with the NNLO corrections to the Higgs production rate at hadron colliders and some recent applications are reviewed.
    Preview · Article · Jun 2003

Publication Stats

2k Citations
162.00 Total Impact Points

Institutions

  • 1999-2013
    • Brookhaven National Laboratory
      • Physics Department
      New York City, New York, United States
  • 2005
    • California State University, Bakersfield
      Bakersfield, California, United States
  • 1998-2004
    • Kern Medical Center
      Bakersfield, California, United States
  • 1995-1997
    • Fermi National Accelerator Laboratory (Fermilab)
      • Theoretical Physics Department
      Batavia, Illinois, United States
  • 1992-1994
    • University of California, Berkeley
      • Department of Physics
      Berkeley, California, United States