Search results for "Color"
showing 10 items of 2721 documents
Status after the first LHC run: Looking for new directions in the physics landscape
2015
The LHC data have confirmed the Standard Model as the correct theory at the electroweak scale. It successfully explains the experimental results with high precision and all its ingredients, including the Higgs boson, have been finally verified. At the same time, the negative searches for signals of new phenomena challenge our previous theoretical wisdom on new-physics scenarios.
Natural fourth generation of leptons
2009
We consider implications of a fourth generation of leptons, allowing for the most general mass patterns for the fourth generation neutrino. We determine the constraints due to the precision electroweak measurements and outline the signatures to search for at the LHC experiments. As a concrete framework to apply these results we consider the minimal walking technicolor (MWTC) model where the matter content, regarding the electroweak quantum numbers, corresponds to a fourth generation.
Future tests of Higgs compositeness: direct vs indirect
2015
We estimate the reach of the 14 TeV LHC and future hadronic and leptonic colliders in the parameter space of the minimal composite Higgs model, outlining the complementarity of direct resonance searches and indirect information from the measurements of the Higgs boson couplings. The reach on electroweak charged spin-one resonances, taken here as representative direct signatures, is obtained from the current 8 TeV LHC limits by an extrapolation procedure which we outline and validate. The impact of electroweak precision tests, and their possible improvement at future colliders, is also quantified.
Search for new physics in the dijet mass distribution using 1 fb−1 of pp collision data at s=7 TeV collected by the ATLAS detector
2012
Invariant mass distributions of jet pairs (dijets) produced in LHC proton-proton collisions at a centre-of-mass energy root s = 7 TeV have been studied using a data set corresponding to an integrat ...
Nuclear modification of forward J/ψ production in proton-nucleus collisions at the LHC
2016
We re-evaluate the nuclear suppression of forward J/ψ production at high energy in the Color Glass Condensate framework. We use the collinear approximation for the projectile proton probed at large x and an up to date dipole cross section fitted to HERA data to describe the target in proton-proton collisions. We show that using the Glauber approach to generalize the proton dipole cross section to the case of a nucleus target leads to a nuclear modification factor much closer to LHC data than previous estimates using the same framework.
Single inclusive particle production at high energy from HERA data to proton-nucleus collisions
2013
We study single inclusive hadron production in proton-proton and proton-nucleus collisions in the CGC framework. The parameters in the calculation are determined solely by standard nuclear geometry and by electron-proton deep inelastic scattering data, which is fit using the running coupling BK equation. We show that it is possible to obtain a good fit of the HERA inclusive cross section also without an anomalous dimension in the initial condition. We argue that one must consistently use the proton transverse area as measured by a high virtuality probe in DIS also for the single inclusive cross section in proton-proton and proton-nucleus collisions. We show that this leads to a midrapidity …
Supersymmetric Extension of Technicolor & Fermion Mass Generation
2012
We provide a complete extension of Minimal Walking Technicolor able to account for the standard model fermion masses. The model is supersymmetric at energies greater or equal to the technicolor compositeness scale. We integrate out, at the supersymmetry breaking scale, the elementary Higgses. We use the resulting four-fermion operators to derive the low energy effective theory. We then determine the associated tree-level vacuum and low energy spectrum properties. Furthermore we investigate the phenomenological viability of the model by comparing its predictions with electroweak precision tests and experimental bounds on the mass spectrum. We then turn to the composite Higgs phenomenology at…
Centrality dependence of forward J/ψ suppression in high energy proton–nucleus collisions
2015
The production of forward $J/\psi$ mesons in proton-nucleus collisions can provide important information on gluon saturation. In a previous work we studied this process in the Color Glass Condensate framework, describing the target using a dipole cross section fitted to HERA inclusive data and extrapolated to the case of a nuclear target using the optical Glauber model. In this work we study the centrality dependence of the nuclear suppression in this model and compare our results with recent LHC data for this observable.
Physics at the Large Hadron Collider
2003
Abstract The experiments at the Large Hadron Collider LHC have a large discovery potential for physics beyond the Standard Model and in the investigation of the nature of electroweak symmetry breaking. The large event rates provided by the high luminosity LHC machine will, however, also allow to perform precision measurements of important Standard Model parameters. Both the discovery potential for new physics and the measurements of Standard Model parameters are summarized in the present paper.
Small x physics and RHIC data
2010
This is a review of applications of the Color Glass Condensate to the phenomenology of relativistic heavy ion collisions. The initial stages of the collision can be understood in terms of the nonperturbatively strong nonlinear glasma color fields. We discuss how the CGC framework can and has been used to compute properties of the initial conditions of AA collisions. In particular this has led to recent progress in understanding multiparticle correlations, which can provide a directly observable signal of the properties of the initial stage of the collision process.