The Dynamical Dipole Mode in Fusion Reactions with Exotic Nuclear Beams

We report the properties of the prompt dipole radiation, produced via a collective bremsstrahlung mechanism, in fusion reactions with exotic beams. We show that the gamma yield is sensitive to the density dependence of the symmetry energy below/around saturation. Moreover we find that the angular distribution of the emitted photons from such fast collective mode can represent a sensitive probe of its excitation mechanism and of fusion dynamics in the entrance channel.Comment: 5 pages, 3 figures, to appear in Phys.Rev.

Transport properties in correlated systems: An analytical model

Several studies have so far investigated transport properties of strongly correlated systems. Interesting features of these materials are the lack of resistivity saturation well beyond the Mott-Ioffe-Regel limit and the scaling of the resistivity with the hole density in underdoped cuprates. Due to the strongly correlated nature of these materials, mainly numerical techniques have been employed. A key role in this regards is thought to be played by the continuous transfer of spectral weight from coherent to incoherent states. In this paper we employ a simple analytical expression for the electronic Green's function to evaluate both quasi-particle and transport properties in correlated systems. Our analytical approach permits to enlighten the specific role of the spectral transfer due to the correlation on different features. In particular we investigate the dependence of both quasi-particle and transport scattering rate on the correlation degree and the criterion for resistivity saturation. systems.Comment: 11 pages, 8 figures. New version correcting a mistake of the previous version and added figure

LHC Z‘Z^` discovery potential for models with continuously distributed mass

We study the Large Hadron Collider (LHC) discovery potential for $Z^`$ models with continuously distributed mass for $\sqrt{s} = 7, 10$ and 14 TeV centre-of-mass energies. One of possible LHC signatures for such models is the existence of broad resonance in Drell-Yan reaction $pp \to Z^` + ... \to l^+l^- + ...$.Comment: 14 pages, some references and formula adde

Change Blindness, Attention, and Driving Performance

Concern over older driver high traffic fatality rates has resulted in an effort to identify risk factors and to develop methods of assessment. This study examines two attention-related tasks, Useful Field of View (UFOV) and Change Blindness (CB), in relation to vision and cognitive test batteries and driving performance measures collected using a simulator and an instrumented vehicle. Eight older adults with Alzheimer’s disease and nine comparison subjects between 64 and 81 participated. Factor analysis results indicate that UFOV and CB relate to different factors. While UFOV relates to memory, decision-making, attention, and visual spatial ability, CB relates to vision and attention. The type of images used on a CB task influence how the task relates to driving performance measures. Researchers should be thoughtful when selecting images to include in CB tasks to maximize insight into real-world drivin

Quantum Gravity Effects in Black Holes at the LHC

We study possible back-reaction and quantum gravity effects in the evaporation of black holes which could be produced at the LHC through a modification of the Hawking emission. The corrections are phenomenologically taken into account by employing a modified relation between the black hole mass and temperature. The usual assumption that black holes explode around $1$TeV is also released, and the evaporation process is extended to (possibly much) smaller final masses. We show that these effects could be observable for black holes produced with a relatively large mass and should therefore be taken into account when simulating micro-black hole events for the experiments planned at the LHC.Comment: 14 pages, 8 figures, extended version of hep-ph/0601243 with new analysis of final products, final version accepted for publication in J. Phys.

A review of Quantum Gravity at the Large Hadron Collider

The aim of this article is to review the recent developments in the phenomenology of quantum gravity at the Large Hadron Collider. We shall pay special attention to four-dimensional models which are able to lower the reduced Planck mass to the TeV region and compare them to models with a large extra-dimensional volume. We then turn our attention to reviewing the emission of gravitons (massless or massive) at the LHC and to the production of small quantum black holes.Comment: 32 pages, invited revie

Differences in Simulated Car Following Behavior of Younger and Older Drivers

Older drivers are at risk for vehicle crashes due to impairments of visual processing and attention, placing these drivers at greater risk in driving tasks that require continuous attention to neighboring traffic, especially lead vehicles (LVs). We investigated car following behavior in 42 younger drivers (ages 18 to 44 years) and 58 older drivers (ages 65 to 86 years) in a driving simulator. The drivers were instructed to maintain two car lengths from a virtual LV. The LV varied its velocity according to a sum of three sine waves, making the velocity changes unpredictable to the drivers. A Fourier analysis was performed using the vehicle trajectory data to derive measures of coherence, gain, and delay as indices of car following behavior. These measures as well as headway distance were compared between the two groups. Older drivers were less able to match changes in the LV velocity indicated by lower coherence (0.76 v. 0.84, p=0.019) and larger gain (2.24 v. 1.74, p=0.031). However, these drivers followed further behind the LV than younger drivers, a potential compensatory strategy that may reduce collision risk for older drivers

Lorentz Violation in Warped Extra Dimensions

Higher dimensional theories which address some of the problematic issues of the Standard Model(SM) naturally involve some form of $D=4+n$-dimensional Lorentz invariance violation (LIV). In such models the fundamental physics which leads to, e.g., field localization, orbifolding, the existence of brane terms and the compactification process all can introduce LIV in the higher dimensional theory while still preserving 4-d Lorentz invariance. In this paper, attempting to capture some of this physics, we extend our previous analysis of LIV in 5-d UED-type models to those with 5-d warped extra dimensions. To be specific, we employ the 5-d analog of the SM Extension of Kostelecky et. al. ~which incorporates a complete set of operators arising from spontaneous LIV. We show that while the response of the bulk scalar, fermion and gauge fields to the addition of LIV operators in warped models is qualitatively similar to what happens in the flat 5-d UED case, the gravity sector of these models reacts very differently than in flat space. Specifically, we show that LIV in this warped case leads to a non-zero bulk mass for the 5-d graviton and so the would-be zero mode, which we identify as the usual 4-d graviton, must necessarily become massive. The origin of this mass term is the simultaneous existence of the constant non-zero $AdS_5$ curvature and the loss of general co-ordinate invariance via LIV in the 5-d theory. Thus warped 5-d models with LIV in the gravity sector are not phenomenologically viable.Comment: 14 pages, 4 figs; discussion added, algebra repaire

Discriminating graviton exchange effects from other new physics scenarios in e^+e^- collisions

We study the possibility of uniquely identifying the effects of graviton exchange from other new physics in high energy e^+e^- annihilation into fermion-pairs. For this purpose, we use as basic observable a specific asymmetry among integrated differential distributions, that seems particularly suitable to directly test for such gravitational effects in the data analysis.Comment: 18 pages, including figures; v2: additional references and acknowledgements. To appear in PR