3,767 research outputs found
Tsallis’ entropies — Axiomatics, associated f-divergences and Fisher’s information
In a previous paper, de Wet and Österreicher (2016) showed how Arimoto’s extended class of entropies generates a family of f-divergences leading to approximation results and finally to Fisher’s information in a limiting way. In the current paper, the so-called Tsallis class of entropies is used in a similar fashion to generate a new family of f-divergences with analogous properties. The approximation properties are proved in a form which significantly generalizes the corresponding results in the above mentioned paper
Quasiparticle Description of Hot QCD at Finite Quark Chemical Potential
We study the extension of a phenomenologically successful quasiparticle model
that describes lattice results of the equation of state of the deconfined phase
of QCD for Tc <= T < 4 Tc, to finite quark chemical potential mu. The phase
boundary line Tc(mu), the pressure difference (p(T,mu)-p(T,mu=0))/T^4 and the
quark number density nq(T,mu)/T^3 are calculated and compared to recent lattice
results. Good agreement is found up to quark chemical potentials of order mu =
Tc.Comment: 12 pages, 7 figures; added reference
From Rational Bubbles to Crashes
We study and generalize in various ways the model of rational expectation
(RE) bubbles introduced by Blanchard and Watson in the economic literature.
First, bubbles are argued to be the equivalent of Goldstone modes of the
fundamental rational pricing equation, associated with the symmetry-breaking
introduced by non-vanishing dividends. Generalizing bubbles in terms of
multiplicative stochastic maps, we summarize the result of Lux and Sornette
that the no-arbitrage condition imposes that the tail of the return
distribution is hyperbolic with an exponent mu<1. We then extend the RE bubble
model to arbitrary dimensions d and, with the renewal theory for products of
random matrices applied to stochastic recurrence equations, we extend the
theorem of Lux and Sornette to demonstrate that the tails of the unconditional
distributions follow power laws, with the same asymptotic tail exponent mu<1
for all assets. Two extensions (the crash hazard rate model and the
non-stationary growth rate model) of the RE bubble model provide ways of
reconciliation with the stylized facts of financial data. The later model
allows for an understanding of the breakdown of the fundamental valuation
formula as deeply associated with a spontaneous breaking of the price symmetry.
Its implementation for multi-dimensional bubbles explains why the tail index mu
seems to be the same for any group af assets as observed empirically. This work
begs for the introduction of a generalized field theory which would be able to
capture the spontaneous breaking of symmetry, recover the fundamental valuation
formula in the normal economic case and extend it to the still unexplored
regime where the economic growth rate is larger than the discount growth rate.Comment: Latex 27 pages with 3 eps figur
Diboson-Jets and the Search for Resonant Zh Production
New particles at the TeV-scale may have sizeable decay rates into boosted
Higgs bosons or other heavy scalars. Here, we investigate the possibility of
identifying such processes when the Higgs/scalar subsequently decays into a
pair of W bosons, constituting a highly distinctive "diboson-jet." These can
appear as a simple dilepton (plus MET) configuration, as a two-prong jet with
an embedded lepton, or as a four-prong jet. We study jet substructure methods
to discriminate these objects from their dominant backgrounds. We then
demonstrate the use of these techniques in the search for a heavy spin-one Z'
boson, such as may arise from strong dynamics or an extended gauge sector,
utilizing the decay chain Z' -> Zh -> Z(WW^(*)). We find that modes with
multiple boosted hadronic Zs and Ws tend to offer the best prospects for the
highest accessible masses. For 100/fb luminosity at the 14 TeV LHC, Z' decays
into a standard 125 GeV Higgs can be observed with 5-sigma significance for
masses of 1.5-2.5 TeV for a range of models. For a 200 GeV Higgs (requiring
nonstandard couplings, such as fermiophobic), the reach may improve to up to
2.5-3.0 TeV.Comment: 23 pages plus appendices, 9 figure
Identifying Boosted Objects with N-subjettiness
We introduce a new jet shape -- N-subjettiness -- designed to identify
boosted hadronically-decaying objects like electroweak bosons and top quarks.
Combined with a jet invariant mass cut, N-subjettiness is an effective
discriminating variable for tagging boosted objects and rejecting the
background of QCD jets with large invariant mass. In efficiency studies of
boosted W bosons and top quarks, we find tagging efficiencies of 30% are
achievable with fake rates of 1%. We also consider the discovery potential for
new heavy resonances that decay to pairs of boosted objects, and find
significant improvements are possible using N-subjettiness. In this way,
N-subjettiness combines the advantages of jet shapes with the discriminating
power seen in previous jet substructure algorithms.Comment: 26 pages, 26 figures, 2 tables; v2: references added; v3: discussion
of results extende
Jet Substructure Without Trees
We present an alternative approach to identifying and characterizing jet
substructure. An angular correlation function is introduced that can be used to
extract angular and mass scales within a jet without reference to a clustering
algorithm. This procedure gives rise to a number of useful jet observables. As
an application, we construct a top quark tagging algorithm that is competitive
with existing methods.Comment: 22 pages, 16 figures, version accepted by JHE
The QCD equation of state near T_0 within a quasi-particle model
We present a description of the equation of state of strongly interacting
matter within a quasi-particle model. The model is adjusted to lattice QCD data
near the deconfinement temperature . We compare in detail the excess
pressure at non-vanishing chemical potential and its expansion coefficients
with two-flavor lattice QCD calculations and outline prospects of the
extrapolation to large baryon density
Jet Trimming
Initial state radiation, multiple interactions, and event pileup can
contaminate jets and degrade event reconstruction. Here we introduce a
procedure, jet trimming, designed to mitigate these sources of contamination in
jets initiated by light partons. This procedure is complimentary to existing
methods developed for boosted heavy particles. We find that jet trimming can
achieve significant improvements in event reconstruction, especially at high
energy/luminosity hadron colliders like the LHC.Comment: 20 pages, 11 figures, 3 tables - Minor changes to text/figure
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