J. R. Forshaw

The University of Manchester, Manchester, England, United Kingdom

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Publications (127)336.16 Total impact

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    René Ángeles-Martínez · Jeffrey R. Forshaw · Michael H. Seymour
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    ABSTRACT: We study in detail the exchange of a Coulomb (Glauber) gluon in the first few orders of QCD perturbation theory in order to shed light on their accounting to all orders. We find an elegant cancellation of graphs that imposes a precise ordering on the transverse momentum of the exchanged Coulomb gluon.
    Preview · Article · Oct 2015 · Journal of High Energy Physics
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    J. R. Forshaw · Ruben Sandapen
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    ABSTRACT: We report on the results of our recent research published in [1] that shows that AdS/QCD generates predictions for the rate of diffractive \rho-meson electroproduction that are in agreement with data collected at the HERA electron-proton collider [2,3]. Preliminary results of this research were presented in [4].
    Full-text · Article · Nov 2012
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    Jeffrey R. Forshaw · Michael H. Seymour · Andrzej Siodmok
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    ABSTRACT: We investigate the breakdown of collinear factorization for non-inclusive observables in hadron-hadron collisions. For pure QCD processes, factorization is violated at the three-loop level and it has a structure identical to that encountered previously in the case of super-leading logarithms. In particular, it is driven by the non-commutation of Coulomb/Glauber gluon exchanges with other soft exchanges. Beyond QCD, factorization may be violated at the two-loop level provided that the hard subprocess contains matrix element contributions with phase differences between different colour topologies.
    Full-text · Article · Jun 2012 · Journal of High Energy Physics
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    J. R. Forshaw · R. Sandapen
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    ABSTRACT: We show that AdS/QCD generates predictions for the rate of diffractive rho meson electroproduction that are in agreement with data collected at the HERA electron-proton collider.
    Full-text · Article · Mar 2012 · Physical Review Letters
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    J. R. Forshaw · R. Sandapen
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    ABSTRACT: We report on a successful extraction of the twist-2 and twist-3 Distribution Amplitudes (DAs) of the rho meson using the HERA data on diffractive rho photoproduction. We extract these DAs using several Colour Glass Condensate (CGC) inspired and a Regge inspired dipole models. All our extracted DAs are consistent with Sum Rules and lattice predictions.
    Full-text · Article · Dec 2011
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    S. Ask · J. H. Collins · J. R. Forshaw · K. Joshi · A. D. Pilkington
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    ABSTRACT: We explore how the colour of any new TeV-scale resonances that decay into top quark pairs can be identified by studying the dependence of the observed cross-section on a central jet veto. To facilitate this study, colour octet resonance production was implemented in Pythia8 and colour singlet resonance production is simulated after minor modifications. We find that the colour of a 2 TeV resonance can be identified with 10/fb of data at a centre-of-mass energy of 14 TeV for a wide range of couplings, but only if the uncertainty in the theoretical prediction is dramatically reduced from its current level.
    Preview · Article · Aug 2011 · Journal of High Energy Physics
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    ABSTRACT: This report is based on a ten-week program on "Gluons and the quark sea at high-energies", which took place at the Institute for Nuclear Theory in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics. This report is organized around four major themes: i) the spin and flavor structure of the proton, ii) three-dimensional structure of nucleons and nuclei in momentum and configuration space, iii) QCD matter in nuclei, and iv) Electroweak physics and the search for physics beyond the Standard Model. Beginning with an executive summary, the report contains tables of key measurements, chapter overviews for each of the major scientific themes, and detailed individual contributions on various aspects of the scientific opportunities presented by an EIC.
    Full-text · Article · Aug 2011
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    [Show abstract] [Hide abstract]
    ABSTRACT: This report is based on a ten-week program on "Gluons and the quark sea at high-energies", which took place at the Institute for Nuclear Theory in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics. This report is organized around four major themes: i) the spin and flavor structure of the proton, ii) three-dimensional structure of nucleons and nuclei in momentum and configuration space, iii) QCD matter in nuclei, and iv) Electroweak physics and the search for physics beyond the Standard Model. Beginning with an executive summary, the report contains tables of key measurements, chapter overviews for each of the major scientific themes, and detailed individual contributions on various aspects of the scientific opportunities presented by an EIC.
    Full-text · Article · Jul 2011
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    ABSTRACT: We study dijet production in proton-proton collisions with a veto on the emission of a third jet in the rapidity region in between the two leading ones. We resum the leading logarithms in the ratio of the transverse momentum of the leading jets and the veto scale and we match this result to leading-order QCD matrix elements. We find that, in order to obtain sensible results, we have to modify the resummation and take into account energy-momentum conservation effects. We compare our theoretical predictions for the gap fraction to experimental data measured by the ATLAS collaboration and find good agreement, although our results are affected by large theoretical uncertainties. We then discuss differences and similarities of our calculation to other theoretical approaches.
    Full-text · Article · Jul 2011 · Journal of High Energy Physics
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    J. R. Forshaw · R. Sandapen
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    ABSTRACT: We extract the leading twist-2 and subleading twist-3 Distribution Amplitudes (DAs) of the rho meson using the HERA data on diffractive rho photoproduction. We do so using several Colour Glass Condensate (CGC) inspired and a Regge inspired dipole models. We find that our extracted twist-2 DA is not much model dependent and is consistent with QCD Sum Rules and lattice predictions. The extracted twist-3 DA is more model dependent but is still consistent with the Sum Rules prediction.
    Full-text · Article · Apr 2011 · Journal of High Energy Physics
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    J. R. Forshaw · R. Sandapen
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    ABSTRACT: Diffractive rho meson production has been identified as one of the important processes where saturation can be probed at a future Electron-Ion Collider (EIC). A source of uncertainty in making predictions for this process lies within the assumed form of the meson light-cone wavefunction. We report here the results of reference [1] where a Regge-inspired dipole model was used to extract this wavefunction as well as the corresponding leading twist-2 Distribution Amplitude from the current accurate HERA data. In addition, we shall check the robustness of the conclusions in reference [1] by using alternative Colour Glass Condensate dipole models. Comment: 9 pages, 5 figures. Proceedings Contribution for the workshop "Gluons and the quark sea at high energies: distributions, polarization, tomography", Institute for Nuclear Theory, Seattle, U.S. September 13 to November 19, 2010
    Full-text · Article · Dec 2010
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    J. R. Forshaw · R. Sandapen
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    ABSTRACT: We extract the light-cone wavefunctions of the ρ meson using the HERA data on diffractive ρ photoproduction. We find good agreement with predictions for the distribution amplitude based on QCD sum rules and from the lattice. We also find that the data prefer a transverse wavefunction with enhanced end-point contributions.
    Full-text · Article · Nov 2010 · Journal of High Energy Physics
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    Tim Coughlin · Jeffrey Forshaw
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    ABSTRACT: We investigate the theoretical description of the central exclusive production process, $h_1 + h_2 \to h_1+X+h_2$. Taking Higgs production as an example, we compute the subset of next-to-leading order corrections sensitive to the Sudakov factor appearing in the process. Our results agree with those originally presented by Khoze, Martin and Ryskin except that the scale appearing in the Sudakov factor, $\mu=0.62 \sqrt{\hat{s}}$, should be replaced with $\mu=\sqrt{\hat{s}}$, where $\sqrt{\hat{s}}$ is the invariant mass of the centrally produced system. We show that the replacement leads to approximately a factor 2 suppression in the cross-section for central system masses in the range 100--500GeV. Comment: 5 pages, 2 figures; to appear in the proceedings of DIS2010
    Preview · Article · Jun 2010
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    M. G. Albrow · T. D. Coughlin · J. R. Forshaw
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    ABSTRACT: We review the subject of central exclusive particle production at high energy hadron colliders. In particular we consider reactions of the type A + B -> A + X + B, where X is a fully specified system of particles that is well separated in rapidity from the outgoing beam particles. We focus on the case where the colliding particles are strongly interacting and mainly they will be protons (or antiprotons) as at the ISR, SppS, Tevatron and LHC. The data are surveyed and placed within the context of theoretical developments. Comment: 64 pages
    Preview · Article · Jun 2010 · Progress in Particle and Nuclear Physics
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    ABSTRACT: Proceedings of the 13th International Conference on Elastic and Diffractive Scattering (Blois Workshop) - Moving Forward into the LHC Era
    Full-text · Article · Feb 2010
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    ABSTRACT: Proceedings from a 3-day discussion on Standard Model discoveries with the first LHC data Comment: 9 contributions to the proceedings of the LHC Standard Model workshop
    Full-text · Article · Jan 2010
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    T. D. Coughlin · J. R. Forshaw
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    ABSTRACT: We investigate the theoretical description of the central exclusive production process, h1+h2 -> h1+X+h2. Taking Higgs production as an example, we sum logarithmically enhanced corrections appearing in the perturbation series to all orders in the strong coupling. Our results agree with those originally presented by Khoze, Martin and Ryskin except that the scale appearing in the Sudakov factor, mu=0.62 \sqrt{\hat{s}}, should be replaced with mu=\sqrt{\hat{s}}, where \sqrt{\hat{s}} is the invariant mass of the centrally produced system. We confirm this result using a fixed-order calculation and show that the replacement leads to approximately a factor 2 suppression in the cross-section for central system masses in the range 100-500 GeV. Comment: 41 pages, 19 figures; minor typos fixed; version published in JHEP
    Preview · Article · Dec 2009 · Journal of High Energy Physics
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    Simone Marzani · Jeffrey Forshaw · James Keates
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    ABSTRACT: We study the effect of soft gluon resummation on the gaps-between-jets cross-section at the LHC. We review the theoretical framework that enables one to sum logarithms of the hard scale over the veto scale to all orders in perturbation theory. We then present a study of the phenomenological impact of Coulomb gluon contributions and super-leading logarithms on the gaps between jets cross-section at the LHC. Comment: Talk given at ''London workshop on Standard Model Discoveries with early LHC data'', UCL, London, 31 March-1 April 2009. Also given at ''DIS 2009'', Madrid, Spain, 26-30 Apr 2009
    Full-text · Article · Jun 2009
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    Jeffrey Forshaw · James Keates · Simone Marzani
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    ABSTRACT: We study the effect of a veto on additional jets in the rapidity region between a pair of high transverse momentum jets at the LHC. We aim to sum the most important logarithms in the ratio of the jet transverse momentum to the veto scale and to that end we attempt to assess the significance of the super-leading logarithms that appear at high orders in the perturbative expansion. We also compare our results to those of HERWIG++, in an attempt to ascertain the accuracy of the angular ordered parton shower. We find that there are large corrections that arise for large enough jet transverse momenta as a consequence of Coulomb gluon exchanges. Comment: 25 pages
    Preview · Article · May 2009 · Journal of High Energy Physics
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    B E Cox · J. R. Forshaw · R. Sandapen
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    ABSTRACT: We compute the rate for diffractive Υ meson production at the Tevatron and the LHC. The Υ is produced diffractively via the subprocess γ+p → Υ+p where the initial photon is radiated off an incoming proton (or antiproton). We consider the possibility to use low angle proton detectors to make a measurement of the γp cross-section and conclude that a measurement of the cross-section at a centre of mass energy in excess of 1 TeV is possible at the LHC. This is in the region where saturation effects are likely to reveal themselves.
    Full-text · Article · May 2009 · Journal of High Energy Physics

Publication Stats

3k Citations
336.16 Total Impact Points

Institutions

  • 1991-2015
    • The University of Manchester
      • • School of Physics and Astronomy
      • • Theoretical Physics Division
      Manchester, England, United Kingdom
  • 1999-2000
    • CERN
      • Physics Department (PH)
      Genève, Geneva, Switzerland
  • 1998
    • North Carolina State University
      Raleigh, North Carolina, United States
  • 1996
    • Lund University
      • Department of Theoretical Physics
      Lund, Skåne, Sweden
  • 1993
    • Pennsylvania State University
      University Park, Maryland, United States