Related papers: Does shape matter? v_2 vs eccentricity in small x …
We compute multi-gluon production in the Color Glass Condensate approach in dilute-dense collisions, p$A$, extending previous calculations up to four gluons. We include the contributions that are leading in the overlap area of the collision…
Elliptic flow ($v_2$) fluctuations in central heavy-ion collisions are direct probes of the fluctuating geometry of the quark-gluon plasma, and, as such, are strongly sensitive to any deviation from spherical symmetry in the shape of the…
Measurements of double-helicity asymmetries for inclusive hadron production in polarized p+p collisions are sensitive to helicity--dependent parton distribution functions, in particular to the gluon helicity distribution, Delta(g). This…
Gluon distributions of colliding hadrons saturate as a result of the non-linear evolution equations of QCD. As a consequence there exists the so called saturation momentum, which is related to the gluon density per unit rapidity per…
Non-trivial geometrical effects in relativistic central collisions of deformed nuclei are studied using a simple version of optical Glauber model. For very small impact parameters large centrality and eccentricity fluctuations are observed.…
It is shown that odd harmonic azimuthal correlations, including the directed flow $v_1$, in forward two-particle production in peripheral proton-nucleus ($pA$) collisions can arise simply from the radial nuclear profile of a large nucleus.…
We discuss the total collision singularities of the gravitational N-body problem on shape space. Shape space is the relational configuration space of the system obtained by quotienting ordinary configuration space with respect to the…
This short overview includes recent results from the ALICE Collaboration on anisotropic flow of charged and identified particles in sqrt(sNN) = 2.76 TeV Pb-Pb collisions. We also discuss charge dependent and event plane dependent azimuthal…
The particle momentum anisotropy ($v_n$) produced in relativistic nuclear collisions is considered to be a response of the initial geometry or the spatial anisotropy $\epsilon_n$ of the system formed in these collisions. The linear…
We study the influence of two--loop radiative corrections of enhanced electroweak strength on Higgs production at the LHC. We consider Higgs production by the gluon fusion mechanism, with the subsequent decay of the Higgs boson into a pair…
We study the production asymmetry of charm versus anticharm mesons in photon-proton interactions. We consider photon gluon fusion plus higher order corrections in which light quarks through vector meson-proton interactions contribute to the…
Using event-by-event hydrodynamic calculations, we find that the fluctuations of the elliptic flow ($v_2$) in the reaction plane have a negative skew. We compare the skewness of $v_2$ fluctuations to that of initial eccentricity…
Accurate gluon densities at small $x$ are essential for reducing theoretical uncertainties in collider predictions, yet remain one of the least constrained ingredients in global analyses. We report recent advances in the resummation of…
We investigate the correlation between various aspects of the initial geometry of heavy ion collisions at the Relativistic Heavy Ion Collider energies and the final anisotropic flow, using v-USPhydro, a 2+1 event-by-event viscous…
We study the gravitational collapse of an overdensity of nonrelativistic matter under the action of gravity and a chameleon scalar field. We show that the spherical collapse model is modified by the presence of a chameleon field. In…
The strong fluctuations in the initial energy density of heavy-ion collisions allow an efficient selection of events corresponding to a specific initial geometry. For such "shape engineered events", the elliptic flow coefficient, $v_2$, of…
The study of gluon radiation in QCD, in the limit of small ("soft") momentum, remains an active research area, with a variety of phenomenological and theoretical applications. Soft gluon emission leads to large logarithms in perturbation…
Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam…
I discuss novel QCD phenomena recently observed in p+p, p+A and A+A collisions, that result from the non-linear dynamics of small-x gluons. I focus on di-hadron correlation measurements, as opposed to single-hadron observables often too…
The CDF and D0 collaborations have observed a forward-backward asymmetry in t-tbar production at large invariant mass in excess of the standard model prediction. One explanation involves a heavy color octet particle with axial vector…