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B. Field

Publications and source records attributed to B. Field.

10 recordsLinked to original sources

LHC Forward Physics

The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.

hep-ph

Limits on TMD Evolution From Semi-Inclusive Deep Inelastic Scattering at Moderate $Q$

In the QCD evolution of transverse momentum dependent parton distribution and fragmentation functions, the Collins-Soper evolution kernel includes both a perturbative short-distance contribution as well as a large-distance non-perturbative, but strongly universal, contribution. In the past, global fits, based mainly on larger $Q$ Drell-Yan-like processes, have found substantial contributions from non-perturbative regions in the Collins-Soper evolution kernel. In this article, we investigate semi-inclusive deep inelastic scattering measurements in the region of relatively small $Q$, of the order of a few GeV, where sensitivity to non-perturbative transverse momentum dependence may become more important or even dominate the evolution. Using recently available deep inelastic scattering data from the COMPASS experiment, we provide estimates of the regions of coordinate space that dominate in TMD processes when the hard scale is of the order of only a few GeV. We find that distance scales that are much larger than those commonly probed in large $Q$ measurements become important, suggesting that the details of non-perturbative effects in TMD evolution are especially significant in the region of intermediate $Q$. We highlight the strongly universal nature of the non-perturbative component of evolution, and its potential to be tightly constrained by fits from a wide variety of observables that include both large and moderate $Q$. On this basis, we recommend detailed treatments of the non-perturbative component of the Collins-Soper evolution kernel for future TMD studies.

hep-ph

Higgs boson production with one bottom quark including higher-order soft-gluon corrections

A Higgs boson produced in association with one or more bottom quarks is of great theoretical and experimental interest to the high-energy community. A precise prediction of its total and differential cross-section can have a great impact on the discovery of a Higgs boson with large bottom-quark Yukawa coupling, like the scalar (h^0 and H^0) and pseudoscalar (A^0) Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) in the region of large \tanβ. In this paper we apply the threshold resummation formalism to determine both differential and total cross-sections for b g \to bΦ(where Φ= h^0, H^0), including up to next-to-next-to-next-to-leading order (NNNLO) soft plus virtual QCD corrections at next-to-leading logarithmic (NLL) accuracy. We present results for both the Fermilab Tevatron and the CERN Large Hadron Collider (LHC).

hep-ph

Tevatron-for-LHC Report of the QCD Working Group

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.

hep-ph

Associated production of A^0 and Z^0 bosons and Rare Pseudoscalar Higgs Decays

We study the production of a pseudoscalar Higgs boson A^0 in association with a Z^0 boson at a future international linear collider (ILC). We consider the contributions to this process at the one loop level in the Minimal Supersymmetric Standard Model (MSSM) from top and bottom quarks as well as stop and sbottom squarks. We also study the squark contributions to the decay widths of the pseudoscalar Higgs boson for the decays A^0 --> γZ^0$ and A^0 --> Z^0 Z^0. The contribution from the supersymmetric loops are found to be directly proportional to the squark mixing and potentially large due to the massive pseudoscalar Higgs coupling to squarks.

hep-ph

Higgs Boson Resummation via Bottom-Quark Fusion

The region of small transverse momentum in q-qbar- and gg-initiated processes must be studied in the framework of resummation to account for the large, logarithmically-enhanced contributions to physical observables. In this letter, we study resummed differential cross-sections for Higgs production via bottom-quark fusion. We find that the differential distribution peaks at approximately 15 GeV, a number of great experimental importance to measuring this production channel.

hep-ph

Next-to-leading Log Resummation of Scalar and Pseudoscalar Higgs Boson Differential Cross-Sections at the LHC and Tevatron

The region of small transverse momentum in q qbar- and gg-initiated processes must be studied in the framework of resummation to account for the large, logarithmically-enhanced contributions to physical observables. In this paper, we will calculate the fixed order next-to-leading order (NLO) perturbative total and differential cross-sections for both a Standard Model (SM) scalar Higgs boson and the Minimal Supersymmetric Standard Model's (MSSM) pseudoscalar Higgs boson in the Heavy Quark Effective Theory (HQET) where the mass of the top quark is taken to be infinite. Resummation coefficients B^2_g, C^2_gg for the total cross-section resummation for the pseudoscalar case are given, as well as C^1_gg for the differential cross-section.

hep-ph

Scalar and Pseudoscalar Higgs Boson Plus One Jet Production at the LHC and Tevatron

The production of the Standard Model (SM) Higgs boson (H) in association with a jet is compared with that of the lightest scalar Higgs boson (h^0) and the pseudoscalar Higgs boson (A^0) of the Minimal Supersymmetric Model (MSSM) at both the CERN Large Hadron Collider (LHC) and the Fermilab Tevatron. We include both top and bottom quark loops to lowest order in QCD and investigate the limits of zero quark mass and infinite quark mass.

hep-ph

NLO corrections to differential cross sections for pseudo-scalar Higgs boson production

We have computed the full next-to-leading (NLO) QCD corrections to the differential distributions $d^2σ/(dp_T~dy)$ for pseudo-scalar Higgs (A) production at large hadron colliders. This calculation has been carried out using the effective Lagrangian approach which is valid as long as the mass of the pseudo-scalar Higgs boson $m_{\rm A}$ and its transverse momentum $p_T$ do not exceed the top-quark mass $m_t$. The shape of the distributions hardly differ from those obtained for scalar Higgs (H) production because, apart from the overall coupling constant and mass, there are only small differences between the partonic differential distributions for scalar and pseudo-scalar production. Therefore there are only differences in the magnitudes of the hadronic differential distributions which can be mainly attributed to the unknown mixing angle $β$ describing the pseudo-scalar Higgs coupling to the top quarks.

hep-ph