118770480
The temperature in Hawking radiation as tunneling
Abstract The quasi-classical method of deriving Hawking radiation under the consideration of canonical invariance is investigated. We find that the horizon should be regarded as a two-way barrier and the ingoing amplitude should be calculated according to the negative energy particles tunneling into the black hole because of the whole space–time interchange and thus the standard Hawking temperature is recovered. We also discuss the advantage of the Painleve coordinates in Hawking radiation as tunneling.
123328820
Entropy Conservation in the Transition of Schwarzschild-de Sitter Space to de Sitter Space through Tunneling
We revisit Parikh-Wilczek tunneling through the de Sitter horizon and obtain the tunneling rate in Schwarzschild-de Sitter space, which is non-thermal and closely related to the change of entropy. We discuss the thermodynamics of Schwarzschild-de Sitter space and show existence of correlation which can ensure conservation of the total entropy in the transition process of Schwarzschild-de Sitter space to de Sitter space. The correlation and the conserved entropy provide a way to explain the entropy in empty de Sitter space.
119185446
Hidden messenger revealed in Hawking radiation: A resolution to the paradox of black hole information loss
Using standard statistical method, we discover the existence of correlations among Hawking radiations (of tunneled particles) from a black hole. The information carried by such correlations is quantified by mutual information between sequential emissions. Through a careful counting of the entropy taken out by the emitted particles, we show that the black hole radiation as tunneling is an entropy conservation process. While information is leaked out through the radiation, the total entropy is conserved. Thus, we conclude the black hole evaporation process is unitary. (C) 2009 Elsevier B.V. All rights reserved.
118352477
Noncommutative information is revealed from Hawking radiation as tunneling
We revisit the tunneling process from a Schwarzschild black hole in the noncommutative spacetime and obtain the nonthermal tunneling probability. In such nonthermal spectrum, the correlations are discovered, which can carry the information about the noncommutativity. Thus this enlightens a way to find the noncommutative information in the Hawking radiation. The entropy is also shown to be conserved in the whole radiation process, which implies that the unitarity is held even for the Hawking radiation from noncommutative black holes.
118358667
Hawking radiation as tunneling derived from black hole thermodynamics through the quantum horizon
We show that the first law of the black hole thermodynamics can lead to the tunneling probability through the quantum horizon by calculating the change of entropy with the quantum gravity correction and the change of surface gravity is presented clearly in the calculation. The method is also applicable to the general situation which is independent on the form of black hole entropy and this verifies the connection of black hole tunneling with thermodynamics further. In the end we discuss the crucial role of the relation between the radiation temperature and surface gravity in this derivation. (C) 2008 Elsevier B.V. All rights reserved.
118653526
On the Hamiltonian form of 3D massive gravity
We present a Chern-Simons-like action for the general massive gravity model propagating two spin-2 modes with independent masses in three spacetime dimensions (3D), and we use it to find a simple Hamiltonian form of this model. The number of local degrees of freedom, determined by the dimension of the physical phase space, agrees with a linearized analysis except in some limits, in particular that yielding topologically new massive gravity, which therefore suffers from a linearization instability.
33585399
Thermal charm production in a quark-gluon plasma in Pb-Pb collisions at s**(1/2)(NN) = 5.5-TeV
Charm production from the quark-gluon plasma created in the midrapidity of central heavy ion collisions at the Large Hadron Collider (LHC) is studied in the next-to-leading order in QCD. Using a schematic longitudinally boost-invariant and transversally expanding fire-cylinder model, we find that charm production could be appreciably enhanced at LHC as a result of the high temperature that is expected to be reached in the produced quark-gluon plasma. Sensitivities of our results to the number of charm quark pairs produced from initial hard scattering, the initial thermalization time and temperature of the quark-gluon plasma, and the charm quark mass are also studied.
117428082
The Physics of $Z^0/\gamma^*$-tagged jets at the LHC
Electroweak bosons produced in conjunction with jets in high-energy collider experiments is one of the principle final-state channels that can be used to test the accuracy of perturbative Quantum Chromodynamics calculations and to assess the potential to uncover new physics through comparison between data and theory. In this paper we present results for the $Z^0/\gamma^*$+jet production cross sections at the LHC at leading and next-to-leading orders. In proton-proton reactions we elucidate up to ${\cal O}(G_F\alpha_s^2)$ the constraints that jet tagging via the $Z^0/\gamma^*$ decay dileptons provides on the momentum distribution of jets. In nucleus-nucleus reactions we demonstrate that tagged jets can probe important aspects of the dynamics of quark and gluon propagation in hot and dense nuclear matter and characterize the properties of the medium-induced parton showers in ways not possible with more inclusive measurements. Finally, we present specific predictions for the anticipated suppression of the $Z^0/\gamma^*$+jet production cross section in the quark-gluon plasma that is expected to be created in central lead-lead collisions at the LHC relative to the naive superposition of independent nucleon-nucleon scatterings.
119399463
Parton energy loss at twist-six in deeply inelastic e–A scattering
Abstract Within the framework of the generalized factorization in pQCD, we investigate the multiple parton scattering and induced parton energy loss at twist-6 in deeply inelastic e – A scattering with the helicity amplitude approximation. It is shown that twist-6 processes will give rise to additional nuclear size dependence of the parton energy loss due to LPM interference effect while its contribution is power suppressed.
15237897
JET QUENCHING OF MASSIVE QUARKS IN A NUCLEAR MEDIUM
Utilizing the generalized factorization of twist-4 processes, we derive the modified heavy quark fragmentation function after considering the gluon radiation induced by multiple scattering in DIS. It is found that the mass eects of heavy quark may reduce the gluon formation time and change the medium size dependence of heavy quark energy loss. The radiative energy loss is also significantly suppressed relative to a light quark due to the dead-cone eect. In relativistic heavy-ion collisions, when a fast parton propagating in a dense medium, it may experience multiple scattering with other partons in nucleus and lose a large amount of energy loss via induced gluon radiation 1 . Such kind of jet quenching phe
14036517
Multiple parton scattering in nuclei: Quark–quark scattering
Abstract Modifications to quark and antiquark fragmentation functions due to quark–quark (antiquark) double scattering in nuclear medium are studied systematically up to order O ( α s 2 ) in deeply inelastic scattering (DIS) off nuclear targets. At the order O ( α s 2 ) , twist-four contributions from quark–quark (antiquark) rescattering also exhibit the Landau–Pomeranchuk–Migdal (LPM) interference feature similar to gluon bremsstrahlung induced by multiple parton scattering. Compared to quark–gluon scattering, the modification, which is dominated by t-channel quark–quark (antiquark) scattering, is only smaller by a factor of C F / C A = 4 / 9 times the ratio of quark and gluon distributions in the medium. Such a modification is not negligible for realistic kinematics and finite medium size. The modifications to quark (antiquark) fragmentation functions from quark–antiquark annihilation processes are shown to be determined by the antiquark (quark) distribution density in the medium. The asymmetry in quark and antiquark distributions in nuclei will lead to different modifications of quark and antiquark fragmentation functions inside a nucleus, which qualitatively explains the experimentally observed flavor dependence of the leading hadron suppression in semi-inclusive DIS off nuclear targets. The quark–antiquark annihilation processes also mix quark and gluon fragmentation functions in the large fractional momentum region, leading to a flavor dependence of jet quenching in heavy-ion collisions.