Inclusive Four-jet Production at 7 and 13 TeV: Azimuthal Profile in Multi-Regge Kinematics

Recently, new observables in LHC inclusive events with three tagged jets were proposed. Here, we extend that proposal to events with four tagged jets. The events are characterised by one jet in the forward direction, one in the backward direction with a large rapidity distance $Y$ from the first one and two more jets tagged in more central regions of the detector. In our setup, non-tagged associated mini-jet multiplicity is present and needs to be accounted for by the inclusion of BFKL gluon Green functions. The projection of the cross section on azimuthal-angle components opens up the opportunity for defining new ratios of correlation functions of the azimuthal angle differences among the tagged jets that can be used as probes of the BFKL dynamics.Comment: 19 pages, 8 figures; v2: published versio

Probing the BFKL dynamics in inclusive three jet production at the LHC

We propose the study of new observables in LHC inclusive events with three tagged jets, one in the forward direction, one in the backward direction and both well-separated in rapidity from the each other (Mueller-Navelet jets), together with a third jet tagged in central regions of rapidity. Since non-tagged associated mini-jet multiplicity is allowed, we argue that projecting the cross sections on azimuthal-angle components can provide several distinct tests of the BFKL dynamics. Realistic LHC kinematical cuts are introduced.Comment: 8 pages. Talk given by G. Chachamis at the 5th International Conference on New Frontiers in Physics (ICNFP2016), 6-14 July 2016, Kolymbari, Crete, Greec

BFKL Azimuthal Imprints in Inclusive Three-jet Production at 7 and 13 TeV

We propose the study of new observables in LHC inclusive events with three tagged jets, one in the forward direction, one in the backward direction and both well-separated in rapidity from the each other (Mueller-Navelet jets), together with a third jet tagged in central regions of rapidity. Since non-tagged associated mini-jet multiplicity is allowed, we argue that projecting the cross sections on azimuthal-angle components can provide several distinct tests of the BFKL dynamics. Realistic LHC kinematical cuts are introduced.Comment: 17 pages, 7 figure

Multi-Regge kinematics and azimuthal angle observables for inclusive four-jet production

We evaluate differential cross sections for production of four jets in multi-Regge kinematics at a hadron collider. The main focus lies on azimuthal angle dependences. As in previous studies, the ratios of correlation functions of products of cosines of azimuthal angle differences among the tagged jets offer us the cleanest quantities to compare with experimental data. The calculations are based on the jet production from a single BFKL ladder with a convolution of three BFKL Green functions where we always have two forward/backward jets tagged in the final state. We also demand the tagging of two further jets in more central regions of the detectors with a relative separation in rapidity from each other, plus the inclusive production of an arbitrary number of mini-jets. We show that dependences on the transverse momenta and rapidity of the two central jets can be a distinct signal of the onset of BFKL dynamics.Comment: 13 pages, 4 figure

Azimuthal-angle Observables in Inclusive Three-jet Production

We discuss the impact of corrections beyond the leading-logarithmic accuracy on some recently proposed LHC observables that are based on azimuthal-angle ratios in a kinematical setup that is an extension to the usual one for Mueller-Navelet jets, after requiring an extra tagged jet in central regions of rapidity. The corrections tend to be mild which suggests that these observables are an excellent way to probe the onset of BFKL effects at hadronic colliders.Comment: 6 pages, presented by G. Chachamis at the 25th International Workshop on Deep Inelastic Scattering and Related Topics, 3-7 April 2017, Birmingham, U

Collective phenomena in pp and ep scattering

Bjorken scaling violation in deep inelastic electron-proton scattering (DIS) is related to the rise of hadronic cross sections by using the additive quark model. Of special interest is the connection between saturation in the low-x behavior of the DIS structure functions (SF) and possible slow-down of the pp cross section rise due to saturation effects. We also identify saturation effects in the DIS SF with phase transition that can be described by the Van der Waals equation of state

Diffractive production of Λ hyperons in the high-energy limit of strong interactions

We propose the study of the inclusive production of two Λ hyperons or a single Λ-particle in association with a jet, featuring high transverse momenta and large separation in rapidity, as a probe channel of the resummation of energy logarithms in the QCD perturbative series. We give predictions, shaped on kinematic ranges typical of CMS and of the backward CASTOR detector, for cross section and azimuthal-correlation moments between the two emitted objects, showing how considering the tag of Λ baryons eases the comparison between theoretical results and experimental data in the phenomenological context of semihard reactions

Forward Drell-Yan production at the LHC in the BFKL formalism with collinear corrections

Motivated by the recent work of Brzemi\'nski, Motyka, Sadzikowski and Stebel in arXiv:1611.04449, where forward Drell--Yan production is studied in proton-proton collisions at the LHC, we improve their calculation by introducing an unintegrated gluon density obtained in arXiv:1209.1353 and arXiv:1301.5283 from a fit to combined HERA data at small values of Bjorken $x$. This gluon density was calculated within the BFKL formalism at next-to-leading order with collinear corrections. We show that it generates a good description of the forward Drell--Yan cross section dependence on the invariant mass of the lepton pair both for LHCb and ATLAS data.Comment: 11 pages with 5 figure

Probing the BFKL dynamics in inclusive three jet production at the LHC

We propose the study of new observables in LHC inclusive events with three tagged jets, one in the forward direction, one in the backward direction and both wellseparated in rapidity from the each other (Mueller-Navelet jets), together with a third jet tagged in central regions of rapidity. Since non-tagged associated mini-jet multiplicity is allowed, we argue that projecting the cross sections on azimuthal-angle components can provide several distinct tests of the BFKL dynamics. Realistic LHC kinematical cuts are introduced