Search results for "GLASS"
showing 10 items of 1153 documents
Particle production from the Color Glass Condensate: proton-nucleus collisions in light of the HERA data
2014
We compute single inclusive hadron production in proton-proton and proton-nucleus collisions consistently within the CGC framework. The parameters in the calculations are obtained from electron-proton DIS and standard nuclear geometry. We obtain a good description of the DIS data without an anomalous dimension in the initial condition of the BK evolution and get a good agreement with the available single inclusive proton-proton and proton-nucleus data.
Forward particle correlations in the color glass condensate
2012
Multiparticle correlations, such as forward dihadron correlations in pA collisions, are an important probe of the strong color fields that dominate the initial stages of a heavy ion collision. We describe recent progress in understanding two-particle correlations in the dilute-dense system, e.g. at forward rapidity in deuteron-gold collisions. This requires evaluating higher point Wilson line correlators from the JIMWLK equation, which we find well described by a Gaussian approximation. We then calculate the dihadron correlation, including both the "elastic" and "inelastic" contributions, and show that our result includes the double parton scattering contribution.
Are the Angular Correlations in pA Collisions due to a Glasmion or Bose Condensation ?
2014
Experiments at the LHC have recently reported results on the angular asymmetry coefficients $v_n[m]$, for various angular moments $n$ and orders of cumulants $m$, in high multiplicity p+Pb collisions. These coefficients are large, and have both even and odd moments. We discuss here some of the implications of these results for our understanding of the initial state of the collision (Color Glass Condensate) and for the evolution in the final state (Glasma and thermalized Quark Gluon Plasma). We show the Color Glass Condensate predicts large even moments, $v_n$ with $n$ an even integer. Odd moments are generated by final state interactions or fragmentation. For a multi-particle determination …
Discrimination of LINAC photon and sunlight contributions in watch glass analyzed by means of thermoluminescence
2012
Abstract The research described in this paper shows how to extract from the glow curves of watch glasses exposed to LINAC photons and sunlight a contribution sensitive to LINAC photons dose. As first step, the dependence of the TL signal due to sunlight on the exposure duration was studied and a signal saturation was observed after about 20 weeks. The comparison of TL signals due to solar light and to LINAC photons highlights a partial overlap of the two signals. Here, two different analysis procedures of glow curves (general order kinetics deconvolution and principal components analysis) are reported to point out components which depend differently on LINAC photon radiation dose. For both …
Structure of chromomagnetic fields in the glasma
2014
The initial stage of a heavy ion collision is dominated by nonperturbatively strong chromoelectric and -magnetic fields. The spatial Wilson loop provides a gauge invariant observable to probe the dynamics of the longitudinal chromomagnetic field. We discuss recent results from a real time lattice calculation of the area-dependence of the expectation value of the spatial Wilson loop. We show that at relatively early times after the collision, a universal scaling as a function of the area emerges at large distances for very different initial conditions, with a nontrivial critical exponent. A similar behavior has earlier been seen in calculations of the gluon transverse momentum spectrum, whic…
Single inclusive hadron production in pA collisions at NLO
2016
We study single inclusive forward hadron production in high energy proton-nucleus collisions at next-to-leading order in the Color Glass Condensate framework. Recent studies have shown that the next-to-leading order corrections to this process are large and negative at large transverse momentum, leading to negative cross sections. We propose to overcome this difficulty by introducing an explicit rapidity factorization scale when subtracting the rapidity divergence into the evolution of the target.
Theory of orientational glasses models, concepts, simulations
1992
Abstract This review describes the various attempts to develop a theoretical understanding for ordering and dynamics of randomly diluted molecular crystals, where quadrupole moments freeze in random orientations upon lowering the temperature, as a result of randomness and competing interactions. While some theories attempt to model this freezing into a phase with randomly oriented quadrupole moments in terms of a bond-disorder concept analogous to the Edwards-Anderson model of spin glasses, other theories attribute the freezing to random field-like terms in the Hamiltonian. While models of the latter type have been studied primarily by microscopic molecular field-type treatments, the former…
The four dimensional Ising spin glass: A Monte Carlo study (invited)
1991
We describe results of Monte Carlo simulation studies on the Ising spin glass in four dimensions on a hypercubic lattice with nearest neighbor bonds. Studies of the equilibrium static properties show that the system undergoes a genuine phase transition to an ordered spin glass phase. Critical dynamical behavior is analyzed to obtain the dynamic exponent. Finally, we describe results on the spin glass phase, in particular the finite size scaling of the order parameter distribution function, and compare it with existing models of the spin glass phase, namely the droplet model and the Parisi solution for the low temperature phase of the infinite range spin glass.
MC Study of the p-state Mean-Field Potts Glass
1999
The p-state mean-field Potts glass with ±J-couplings is studied by Monte Carlo (MC) simulations, both for p = 3 and p = 6 states. At the exactly known glass transition temperature Tc, the moments q( k ) of the spin glass order parameter satisfy for p = 3 a simple scaling behavior, q( k ) \({q^{\left( k \right)}}\alpha {N^{ - k/3}}{\tilde f_k}\left\{ {{N^{1/3}}\left( {1 - T/{T_c}} \right)} \right\},k = 1,2,3,...\). The specific-heat maxima exhibit a similar behavior, c V max α const — N -l/3, while the approach of the maxima positions T max to T c as N → ∞ is non-monotonic. For p = 6 the results are compatible with the expected result of a quite peculiar first-order phase transition. The spe…
Two-dimensional isotropic orientational glasses: a computer-simulation study
1989
The analogue of the Edwards-Anderson model for isotropic vector spin glasses, but taking three-component quadrupoles instead of spins at each lattice site, is studied on the square lattice with extensive Monte Carlo calculations, using a nearest-neighbor symmetric gaussian interaction. It is shown that at low temperaturesT the model develops a short range order both with respect to glass like correlations and with respect to “ferromagnetic” correlations among the quadrupoles. The associated correlation lengths and susceptibilities diverge asT→0, and the critical exponents for this zero-temperature phase transition are estimated. Dynamic correlation functions are analyzed as well and it is s…