Related papers: Towards softer scales in hot QCD
We perform a perturbative QCD analysis of the gluonic gravitational form factors (GFFs) of the proton and pion at large momentum transfer. We derive the explicit factorization formula of the GFFs in terms of the distribution amplitudes of…
A general discussion is presented of the single logarithmic soft factor that appears in two scale QCD observables in processes involving four partons. We treat it as the ``fifth form factor'', accompanying the four collinear singular…
We present an efficient way to calculate the effect of soft QCD radiation at one loop, which is needed for predictions at next-to-next-to-leading logarithmic accuracy. We use rapidity coordinates and isolate the divergences in the…
The emission of energetic gluons in $\tt$ production in $\ee$ annihilation can have important experimental consequences, in particular on top quark mass measurements. We present compact, analytical expressions for the gluon energy…
The response of electromagnetic (EM) fields that are produced in non-central heavy-ion collisions to electromagnetically charged quark gluon plasma can be understood in terms of charge transport and charge diffusion in the hot QCD medium.…
We extend the soft theorems for scattering amplitudes of scalar effective field theories to one-loop order. Our analysis requires carefully accounting for the fact that the soft limit is not guaranteed to commute with evaluating…
We compare a recent lattice determination of the nucleon distribution amplitudes with other approaches and models. We study the nucleon distribution amplitudes up to twist 6 in next-to leading conformal spin and we also investigate…
Starting with QCD, we derive an effective field theory description for forward scattering and factorization violation as part of the soft-collinear effective field theory (SCET) for high energy scattering. These phenomena are mediated by…
In this paper, we investigate the stability properties of soft gluons in SIBYLL 2.1 with reference to its original version 1.7 that corresponds to hadronic hard interactions. In order to investigate the stability structures, we classify the…
This contribution presents the running triple-gluon-vertex coupling constant, g_lambda, in Hamiltonians for the gluons that are characterized by the size 1/lambda. The coupling constant is obtained from renormalization group equations for…
We compute in conventional dimensional regularisation the tree-level splitting amplitudes for a quark parent in the limit where four partons become collinear to each other. This is part of the universal infrared behaviour of the QCD…
The elastic hadronic amplitude is calculated using the nonperturbative light-cone dipole representation for gluon bremsstrahlung. The data for large mass diffraction demand a two-scale structure of light hadrons: the gluon clouds of the…
An impact parameter representation for soft gluon radiation is applied to obtain both the initial decrease of the total cross-section ($\sigma_{tot}$) for proton-proton collisions as well as the later rise of $\sigma_{tot}$ with energy for…
We study the transverse-momentum (q_T) and rapidity (y) distributions of the Higgs boson in perturbative QCD, including the most advanced theoretical information presently available: fixed-order perturbation theory at Next-to-Leading Order…
QCD-based analysis of nonfactorizable parts of weak nonleptonic amplitudes is reported. Nonperturbative effects due to soft gluon exchange play a key role leading to the emergence of a dynamical rule of discarding $1/N_c$ corrections.
In this work we employ the MHV technique to show that scattering amplitudes with any number of consecutive soft particles behave universally in the multi-soft limit in which all particles go soft simultaneously. After identifying the…
Collective excitations of a hot QCD medium are the main focus of the present article. The analysis is performed within semi-classical transport theory with isotropic and anisotropic momentum distribution functions for the gluonic and…
We calculate the thermodynamic functions of a quark-gluon plasma for general N_c and N_f to three-loop order using hard-thermal-loop perturbation theory. At this order, all the ultraviolet divergences can be absorbed into renormalizations…
It is shown that to leading order the collisional energy loss of an energetic parton in the hot quark gluon plasma reads $dE/dx \sim \alpha(m_D^2)T^2$, where the scale of the coupling is determined by the (parametrically soft) Debye…
We calculate within the Hard Thermal Loop expansion the production rate of soft photons and lepton pairs by a hot quark-gluon plasma at thermal equilibrium, up to the 2-loop order. Strong collinear divergences appear to mix the orders of…