Tempo- Jun. 5, 1939

https://neiudc.neiu.edu/tempo/1000/thumbnail.jp

Spectroscopy using the Anisotropic Clover Action

The calculation of the light-hadron spectrum in the quenched approximation to QCD using an anisotropic clover fermion action is presented. The tuning of the parameters of the action is discussed, using the pion and rho dispersion relation. The adoption of an anisotropic lattice provides clear advantages in the determination of the baryonic resonances, and in particular that of the so-called Roper resonance, the lightest radial excitation of the nucleon.Comment: Lattice2002(spectrum), 3 pages, 3 figures, to appear in Proceedings of Lattice 200

How to Put a Heavier Higgs on the Lattice

Lattice work, exploring the Higgs mass triviality bound, seems to indicate that a strongly interacting scalar sector in the minimal standard model cannot exist while low energy QCD phenomenology seems to indicate that it could. We attack this puzzle using the 1/N expansion and discover a simple criterion for selecting a lattice action that is more likely to produce a heavy Higgs particle. Our large $N$ calculation suggests that the Higgs mass bound might be around $850 GeV$, which is about 30% higher than previously obtained

Strong coupling isotropization of non-Abelian plasmas simplified

We study the isotropization of a homogeneous, strongly coupled, non-Abelian plasma by means of its gravity dual. We compare the time evolution of a large number of initially anisotropic states as determined, on the one hand, by the full non-linear Einstein's equations and, on the other, by the Einstein's equations linearized around the final equilibrium state. The linear approximation works remarkably well even for states that exhibit large anisotropies. For example, it predicts with a 20% accuracy the isotropization time, which is of the order of t_iso \lesssim 1/T, with T the final equilibrium temperature. We comment on possible extensions to less symmetric situations.Comment: 4 pages, 4 figures; v2: minor changes, matches PRL versio

Longitudinal Coherence in a Holographic Model of p-Pb Collisions

As a model of the longitudinal structure in heavy ion collisions, we simulate gravitational shock wave collisions in anti-de Sitter space in which each shock is composed of multiple constituents. We find that all constituents act coherently, and their separation leaves no imprint on the resulting plasma, when this separation is $\lesssim 0.26 / T_{hyd}$, with $T_{hyd}$ the temperature of the plasma at the time when hydrodynamics first becomes applicable. In particular, the center-of-mass of the plasma coincides with the center-of-mass of all the constituents participating in the collision, as opposed to the center-of-mass of the individual collisions. We discuss the implications for nucleus-nucleus and proton-nucleus collisions.Comment: 5 pages, 3 figures. v2 matches published versio