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C. Royon

Publications and source records attributed to C. Royon.

At least 73 records · Page 4Linked to original sources
arXiv2009

Gaps between jets at hadron colliders in the next-to-leading BFKL framework

We investigate diffractive events in hadron-hadron collisions, in which two jets are produced and separated by a large rapidity gap. In perturbative QCD, the hard color-singlet object exchanged in the t-channel, and responsible for the rapidity gap, is the Balitsky-Fadin-Kuraev-Lipatov (BFKL) Pomeron. We perform a phenomenological study including the corrections due to next-to-leading logarithms (NLL). Using a renormalisation-group improved NLL kernel, we show that the BFKL predictions are in good agreement with the Tevatron data, and present predictions which could be tested at the LHC.

hep-ph↗
arXiv2009

Understanding the structure of the proton: From HERA and Tevatron to LHC

In this review, we first discuss the perspectives concerning a better determination of the proton structure in terms of quarks and gluons at LHC after describing the results coming from HERA and Tevatron. In a second part of the review, we describe the diffractive phenomena at HERA and Tevatron and the consequences for LHC.

hep-ph↗
arXiv2009

Parton Distributions

We provide an assessment of the state of the art in various issues related to experimental measurements, phenomenological methods and theoretical results relevant for the determination of parton distribution functions (PDFs) and their uncertainties, with the specific aim of providing benchmarks of different existing approaches and results in view of their application to physics at the LHC. We discuss higher order corrections, we review and compare different approaches to small x resummation, and we assess the possible relevance of parton saturation in the determination of PDFS at HERA and its possible study in LHC processes. We provide various benchmarks of PDF fits, with the specific aim of studying issues of error propagation, non-gaussian uncertainties, choice of functional forms of PDFs, and combination of data from different experiments and different processes. We study the impact of combined HERA (ZEUS-H1) structure function data, their impact on PDF uncertainties, and their implications for the computation of standard candle processes, and we review the recent F_L determination at HERA. Finally, we compare and assess methods for luminosity measurements at the LHC and the impact of PDFs on them.

hep-ph↗
arXiv2008

Azimuthal decorrelation of Mueller-Navelet jets at the Tevatron and the LHC

We study the production of Mueller-Navelet jets at hadron colliders in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) framework. We show that a measurement of the relative azimuthal angle ΔΦbetween the jets can provide a good testing ground for corrections due to next-leading logarithms (NLL). Besides the well-known azimuthal decorrelation with increasing rapidity interval Δηbetween the jets, we propose to also measure this effect as a function of R=k_2/k_1, the ratio between the jets transverse momenta. Using renormalisation-group improved NLL kernel, we obtain predictions for dσ/dΔηdR dΔΦ. We analyse NLL-scheme and renormalisation-scale uncertainties, and energy-momentum conservation effects, in order to motivate a measurement at the Tevatron and the LHC.

hep-ph↗
arXiv2008

Geometric Scaling of $F_2$ and $F_2^c$ in data and QCD Parametrisations

The scaling properties at low $x$ of the proton DIS cross section and its charm component are analyzed with the help of the quality factor method. Scaling properties are tested both in the deep inelastic scattering data and in the structure functions reconstructed from CTEQ, MRST and GRV parametrisations of parton density functions. The results for DIS cross sections are fully compatible between data and parametrisations. Even with larger error bars, the charm component data favors the same geometric scaling properties as the ones of inclusive DIS. This is not the case for all parametrisations of the charm component.

hep-ph↗
arXiv2008

Hybrid Pomeron Model of exclusive central diffractive production

Central diffractive production of heavy states (massive dijets, Higgs boson) is studied in the exclusive mode using a new Hybrid Pomeron Model (HPM). Built from Hybrid Pomerons defined by the combination of one hard and one soft color exchanges, the model describes well the centrally produced diffractive dijet data at the Tevatron. Predictions for the Higgs boson and dijet exclusive production at the LHC are presented.

hep-ph↗
arXiv2008

Anomalous WW $γ$ coupling in photon-induced processes using forward detectors at the LHC

We present a new method to test the Standard Model expectations at the LHC using photon-induced $WW$ production. Both $W$ decay in the main ATLAS or CMS detectors while scattered protons are measured in forward detectors. The sensitivity to anomalous $WWγ$ triple gauge coupling can be improved by more than a factor 5 or 30 compared to the present LEP or Tevatron sensitivity respectively.

hep-ph↗
arXiv2008

Diffraction at the Tevatron and the LHC

In these lectures, we present and discuss the most recent results on inclusive diffraction at the Tevatron collider and give the prospects at the LHC. We also describe the search for exclusive events at the Tevatron. Of special interest is the exclusive production of Higgs boson and heavy objects ($W$, top, stop pairs) at the LHC which will require precise measurements and analyses of inclusive and exclusive diffraction to constrain further the gluon density in the pomeron. At the end of these lectures, we describe the projects to install forward detectors at the LHC to fulfil these measurements.

hep-ph↗
arXiv2008

Next-to-leading BFKL phenomenology of forward-jet cross sections at HERA

We show that the forward-jet measurements performed at HERA allow for a detailed study of corrections due to next-to-leading logarithms (NLL) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach. While the description of the dσ/dx data shows small sensitivity to NLL-BFKL corrections, these can be tested by the triple differential cross section dσ/dxdk_T^2dQ^2 recently measured. These data can be successfully described using a renormalization-group improved NLL kernel while the standard next-to-leading-order QCD or leading-logarithm BFKL approaches fail to describe the same data in the whole kinematic range. We present a detailed analysis of the NLL scheme and renormalization-scale dependences and also discuss the photon impact factors.

hep-ph↗
arXiv2007

Next-leading BFKL effects in forward-jet production at HERA

We show that next-leading logarithmic (NLL) Balitsky-Fadin-Kuraev-Lipatov (BFKL) effects can be tested by the forward-jet cross sections recently measured at HERA. For dσ/dx, the NLL corrections are small which confirms the stability of the BFKL description. The triple differential cross section dσ/dxdk_T^2dQ^2 is sensitive to NLL effects and opens the way for an experimental test of the full BFKL theoretical framework at NLL accuracy.

hep-ph↗
arXiv2007

Search for exclusive events using the dijet mass fraction at the Tevatron

In this paper, we discuss the observation of exclusive events using the dijet mass fraction as measured by the CDF collaboration at the Tevatron. We compare the data to pomeron exchange inspired models as well as Soft color interaction ones. We also provide the prediction on dijet mass fraction at the LHC using both exclusive and inclusive diffractive events.

hep-ph↗