443 research outputs found
A Generalization of the Stillinger-Lovett Sum Rules for the Two-Dimensional Jellium
In the equilibrium statistical mechanics of classical Coulomb fluids, the
long-range tail of the Coulomb potential gives rise to the Stillinger-Lovett
sum rules for the charge correlation functions. For the jellium model of mobile
particles of charge immersed in a neutralizing background, the fixing of
one of the -charges induces a screening cloud of the charge density whose
zeroth and second moments are determined just by the Stillinger-Lovett sum
rules. In this paper, we generalize these sum rules to the screening cloud
induced around a pointlike guest charge immersed in the bulk interior of
the 2D jellium with the coupling constant ( is the
inverse temperature), in the whole region of the thermodynamic stability of the
guest charge . The derivation is based on a mapping technique of
the 2D jellium at the coupling = (even positive integer) onto a
discrete 1D anticommuting-field theory; we assume that the final results remain
valid for all real values of corresponding to the fluid regime. The
generalized sum rules reproduce for arbitrary coupling the standard
Z=1 and the trivial Z=0 results. They are also checked in the Debye-H\"uckel
limit and at the free-fermion point . The generalized
second-moment sum rule provides some exact information about possible sign
oscillations of the induced charge density in space.Comment: 16 page
Evolution of circular, non-equatorial orbits of Kerr black holes due to gravitational-wave emission: II. Inspiral trajectories and gravitational waveforms
The inspiral of a ``small'' () compact body into a
``large'' () black hole is a key source of
gravitational radiation for the space-based gravitational-wave observatory
LISA. The waves from such inspirals will probe the extreme strong-field nature
of the Kerr metric. In this paper, I investigate the properties of a restricted
family of such inspirals (the inspiral of circular, inclined orbits) with an
eye toward understanding observable properties of the gravitational waves that
they generate. Using results previously presented to calculate the effects of
radiation reaction, I assemble the inspiral trajectories (assuming that
radiation reacts adiabatically, so that over short timescales the trajectory is
approximately geodesic) and calculate the wave generated as the compact body
spirals in. I do this analysis for several black hole spins, sampling a range
that should be indicative of what spins we will encounter in nature. The spin
has a very strong impact on the waveform. In particular, when the hole rotates
very rapidly, tidal coupling between the inspiraling body and the event horizon
has a very strong influence on the inspiral time scale, which in turn has a big
impact on the gravitational wave phasing. The gravitational waves themselves
are very usefully described as ``multi-voice chirps'': the wave is a sum of
``voices'', each corresponding to a different harmonic of the fundamental
orbital frequencies. Each voice has a rather simple phase evolution. Searching
for extreme mass ratio inspirals voice-by-voice may be more effective than
searching for the summed waveform all at once.Comment: 15 pages, 11 figures, accepted for publication in PRD. This version
incorporates referee's comments, and is much less verbos
Diffractive light quark jet production at hadron colliders in the two-gluon exchange model
Massless quark and antiquark jet production at large transverse momentum in
the coherent diffractive processes at hadron colliders is calculated in the
two-gluon exchange parametrization of the Pomeron model. We use the helicity
amplitude method to calculate the cross section formula. We find that for the
light quark jet production the diffractive process is related to the
differential off-diagonal gluon distribution function in the proton. We
estimate the production rate for this process at the Fermilab Tevatron by
approximating the off-diagonal gluon distribution function by the usual
diagonal gluon distribution in the proton. And we find that the cross sections
for the diffractive light quark jet production and the charm quark jet
production are in the same order of magnitude. We also use the helicity
amplitude method to calculate the diffractive charm jet production at hadron
colliders, by which we reproduce the leading logarithmic approximation result
of this process we previously calculated.Comment: 15 pages, 4 PS figures, Revte
Anomalous Effects of "Guest" Charges Immersed in Electrolyte: Exact 2D Results
We study physical situations when one or two "guest" arbitrarily-charged
particles are immersed in the bulk of a classical electrolyte modelled by a
Coulomb gas of positive/negative unit point-like charges, the whole system
being in thermal equilibrium. The models are treated as two-dimensional with
logarithmic pairwise interactions among charged constituents; the
(dimensionless) inverse temperature is considered to be smaller than 2
in order to ensure the stability of the electrolyte against the collapse of
positive-negative pairs of charges. Based on recent progress in the integrable
(1+1)-dimensional sine-Gordon theory, exact formulas are derived for the
chemical potential of one guest charge and for the asymptotic large-distance
behavior of the effective interaction between two guest charges. The exact
results imply, under certain circumstances, anomalous effects such as an
effective attraction (repulsion) between like-charged (oppositely-charged)
guest particles and the charge inversion in the electrolyte vicinity of a
highly-charged guest particle. The adequacy of the concept of renormalized
charge is confirmed in the whole stability region of inverse temperatures and
the related saturation phenomenon is revised.Comment: 21 pages, 1 figur
Black hole thermodynamical entropy
As early as 1902, Gibbs pointed out that systems whose partition function
diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs
(BG) theory. Consistently, since the pioneering Bekenstein-Hawking results,
physically meaningful evidence (e.g., the holographic principle) has
accumulated that the BG entropy of a black hole is
proportional to its area ( being a characteristic linear length), and
not to its volume . Similarly it exists the \emph{area law}, so named
because, for a wide class of strongly quantum-entangled -dimensional
systems, is proportional to if , and to if
, instead of being proportional to (). These results
violate the extensivity of the thermodynamical entropy of a -dimensional
system. This thermodynamical inconsistency disappears if we realize that the
thermodynamical entropy of such nonstandard systems is \emph{not} to be
identified with the BG {\it additive} entropy but with appropriately
generalized {\it nonadditive} entropies. Indeed, the celebrated usefulness of
the BG entropy is founded on hypothesis such as relatively weak probabilistic
correlations (and their connections to ergodicity, which by no means can be
assumed as a general rule of nature). Here we introduce a generalized entropy
which, for the Schwarzschild black hole and the area law, can solve the
thermodynamic puzzle.Comment: 7 pages, 2 figures. Accepted for publication in EPJ
PYTHIA 6.4 Physics and Manual
The PYTHIA program can be used to generate high-energy-physics `events', i.e.
sets of outgoing particles produced in the interactions between two incoming
particles. The objective is to provide as accurate as possible a representation
of event properties in a wide range of reactions, within and beyond the
Standard Model, with emphasis on those where strong interactions play a role,
directly or indirectly, and therefore multihadronic final states are produced.
The physics is then not understood well enough to give an exact description;
instead the program has to be based on a combination of analytical results and
various QCD-based models. This physics input is summarized here, for areas such
as hard subprocesses, initial- and final-state parton showers, underlying
events and beam remnants, fragmentation and decays, and much more. Furthermore,
extensive information is provided on all program elements: subroutines and
functions, switches and parameters, and particle and process data. This should
allow the user to tailor the generation task to the topics of interest.Comment: 576 pages, no figures, uses JHEP3.cls. The code and further
information may be found on the PYTHIA web page:
http://www.thep.lu.se/~torbjorn/Pythia.html Changes in version 2: Mistakenly
deleted section heading for "Physics Processes" reinserted, affecting section
numbering. Minor updates to take into account referee comments and new colour
reconnection option
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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Track A Basic Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd
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