pinecone/core-2020-05-10-deduplication huggingface dataset:
Reconstruction of changes in the Amundsen Sea and Bellingshausen Sea sector of the West Antarctic Ice Sheet since the Last Glacial Maximum

Marine and terrestrial geological and marine geophysical data that constrain deglaciation since the Last Glacial Maximum (LGM) of the sector of the West Antarctic Ice Sheet (WAIS) draining into the Amundsen Sea and Bellingshausen Sea have been collated and used as the basis for a set of time-slice reconstructions. The drainage basins in these sectors constitute a little more than one-quarter of the area of the WAIS, but account for about one-third of its surface accumulation. Their mass balance is becoming increasingly negative, and therefore they account for an even larger fraction of current WAIS discharge. If all of the ice in these sectors of the WAIS was discharged to the ocean, global sea level would rise by ca. 2 m.\ud
There is compelling evidence that grounding lines of palaeo-ice streams were at, or close to, the continental shelf edge along the Amundsen Sea and Bellingshausen Sea margins during the last glacial period. However, the few cosmogenic surface exposure ages and ice core data available from the interior of West Antarctica indicate that ice surface elevations there have changed little since the LGM. In the few areas from which cosmogenic surface exposure ages have been determined near the margin of the ice sheet, they generally suggest that there has been a gradual decrease in ice surface elevation since pre-Holocene times. Radiocarbon dates from glacimarine and the earliest seasonally open marine sediments in continental shelf cores that have been interpreted as providing approximate ages for post-LGM grounding-line retreat indicate different trajectories of palaeo-ice stream recession in the Amundsen Sea and Bellingshausen Sea embayments. The areas were probably subject to similar oceanic, atmospheric and eustatic forcing, in which case the differences are probably largely a consequence of how topographic and geological factors have affected ice flow, and of topographic influences on snow accumulation and warm water inflow across the continental shelf.\ud
Pauses in ice retreat are recorded where there are “bottle necks” in cross-shelf troughs in both embayments. The highest retreat rates presently constrained by radiocarbon dates from sediment cores are found where the grounding line retreated across deep basins on the inner shelf in the Amundsen Sea, which is consistent with the marine ice-sheet instability hypothesis. Deglacial ages from the Amundsen Sea Embayment (ASE) and Eltanin Bay (southern Bellingshausen Sea) indicate that the ice sheet had already retreated close to its modern limits by early Holocene time, which suggests that the rapid ice thinning, flow acceleration, and grounding line retreat observed in this sector over recent decades are unusual in the context of the past 10,000 years.\u
The Quasar Accretion Disk Size - Black Hole Mass Relation

We use the microlensing variability observed for nine gravitationally lensed
quasars to show that the accretion disk size at 2500 Angstroms is related to
the black hole mass by log(R_2500/cm) = (15.6+-0.2) +
(0.54+-0.28)log(M_BH/10^9M_sun). This scaling is consistent with the
expectation from thin disk theory (R ~ M_BH^(2/3)), but it implies that black
holes radiate with relatively low efficiency, log(eta) = -1.29+-0.44 +
log(L/L_E) where eta=L/(Mdot c^2). These sizes are also larger, by a factor of
~3, than the size needed to produce the observed 0.8 micron quasar flux by
thermal radiation from a thin disk with the same T ~ R^(-3/4) temperature
profile. More sophisticated disk models are clearly required, particularly as
our continuing observations improve the precision of the measurements and yield
estimates of the scaling with wavelength and accretion rate.Comment: 5 pages, 3 figures, submitted to ApJ
A Gauge-Independent Mechanism for Confinement and Mass Gap: Part II --
  G=SU(2) and D=3

We apply to the case of gauge group G = SU(2) in three dimensions a recently
proposed gauge-independent mechanism for confinement that is based on a
particular form of the dual spin foam framework for lattice gauge theory.
Explicit formulae for interaction factors and their asymptotics are introduced
and their behavior in different sectors of the theory are identified and
analyzed. We arrive at several elementary properties of the dual theory that
represent one scenario by which confinement may be realized at weak coupling.
We conclude with an outlook for further development of this approach.Comment: 18 pages, 3 figure
Search for an extended VHE gamma-ray emission from Mrk 421 and Mrk 501
  with the MAGIC Telescope

Context: Part of the very high energy $\gamma$-ray radiation coming from
extragalactic sources is absorbed through the pair production process on the
extragalactic background light photons. Extragalactic magnetic fields alter the
trajectories of these cascade pairs and, in turn, convert cosmic background
photons to gamma-ray energies by inverse Compton scattering. These secondary
photons can form an extended halo around bright VHE sources.
  Aims: We searched for an extended emission around the bright blazars Mrk 421
and Mrk 501 using the MAGIC telescope data.
  Methods: If extended emission is present, the angular distribution of
reconstructed gamma-ray arrival directions around the source is broader than
for a point-like source. In the analysis of a few tens of hours of
observational data taken from Mrk 421 and Mrk 501 we used a newly developed
method that provides better angular resolution. This method is based on the
usage of multidimensional decision trees. Comparing the measured shapes of
angular distributions with those expected from a point-like source one can
detect or constrain possible extended emission around the source. We also
studied the influence of different types of systematic errors on the shape of
the distribution of reconstructed gamma-ray arrival directions for a point
source.
  Results: We present upper limits for an extended emission calculated for both
sources for various source extensions and emission profiles. We discuss
possible constraints on the extragalactic magnetic fields strength. We obtain
upper limits on the extended emission around the Mrk~421 (Mrk~501) on the level
of < 5% (< 4%) of the Crab Nebula flux above the energy threshold of 300 GeV.
Using these results we discuss possible constraints on the extragalactic
magnetic fields strength around a few times $10^{-15}$~G.Comment: 8 pages, 9 figures, accepted for publication in A&
Eccentricity and elliptic flow in proton-proton collisions from parton
  evolution

It has been argued that high-multiplicity proton-proton collisions at the LHC
may exhibit collective phenomena usually studied in the context of heavy-ion
collisions, such as elliptic flow. We study this issue using DIPSY - a Monte
Carlo event generator based on the QCD dipole model. We calculate the
eccentricity of the transverse area defined by the spatial distribution of
produced gluons. The resulting elliptic flow is estimated to be about 6%,
comparable to the value in nucleus-nucleus collisions at RHIC and the LHC.
Experimentally, elliptic flow is inferred from the azimuthal correlation
between hadrons, which receives contributions from collective flow, and from
various other effects referred to as "nonflow". We discuss how to identify in
experiments the signal of flow in the presence of large nonflow effects.Comment: v2: Four-particle correlation added, improved discussions on the
  signatures of flow. v3: Improved treatment of fluctuations in the flow
  analysis. v4: Minor changes for journal submissio
Large-N reduction of SU(N) Yang-Mills theory with massive adjoint
  overlap fermions

We study four dimensional large-N SU(N) Yang-Mills theory coupled to adjoint
overlap fermions on a single site lattice. Lattice simulations along with
perturbation theory show that the bare quark mass has to be taken to zero as
one takes the continuum limit in order to be in the physically relevant
center-symmetric phase. But, it seems that it is possible to take the continuum
limit with any renormalized quark mass and still be in the center-symmetric
physics. We have also conducted a study of the correlations between Polyakov
loop operators in different directions and obtained the range for the Wilson
mass parameter that enters the overlap Dirac operator.Comment: 8 pages, 5 figure
Towards a q-analogue of the Kibble--Slepian formula in 3 dimensions

We study a generalization of the Kibble-Slepian (KS) expansion formula in 3
dimensions. The generalization is obtained by replacing the Hermite polynomials
by the q-Hermite ones. If such a replacement would lead to non-negativity for
all allowed values of parameters and for all values of variables ranging over
certain Cartesian product of compact intervals then we would deal with a
generalization of the 3 dimensional Normal distribution. We show that this is
not the case. We indicate some values of the parameters and some compact set in
R^{3} of positive measure, such that the values of the extension of KS formula
are on this set negative. Nevertheless we indicate other applications of so
generalized KS formula. Namely we use it to sum certain kernels built of the
Al-Salam-Chihara polynomials for the cases that were not considered by other
authors. One of such kernels sums up to the Askey-Wilson density disclosing its
new, interesting properties. In particular we are able to obtain a
generalization of the 2 dimensional Poisson-Mehler formula. As a corollary we
indicate some new interesting properties of the Askey-Wilson polynomials with
complex parameters. We also pose several open questions
High-precision e-expansions of three-loop master integrals contributing
  to the electron g-2 in QED

In this paper we calculate at high-precision the Laurent expansions in
e=(4-D)/2 of the 17 master integrals which appeared in the analytical
calculation of 3-loop QED contribution to the electron g-2, using difference
and differential equations. The coefficients of the expansions so obtained are
in perfect agreement with all the analytical expressions already known. The
values of coefficients not previously known will be used in the high-precision
calculation of the 4-loop QED contribution to the electron g-2.Comment: 7 pages, 1 figure, LaTex, to be published in Physics Letters
Flavour-Changing Neutral Currents and Leptophobic Z' Gauge Bosons

Leptophobic Z' gauge bosons can appear in models with an E_6 gauge symmetry.
We show that flavour-changing neutral currents can be generated in some of
these models due to the mixing of the ordinary d_R, s_R and b_R quark fields
with the exotic h_R. Because the Z' does not couple to charged leptons, the
constraints on the flavour-changing couplings U^{Z'}_{db} and U^{Z'}_{sb} are
relatively weak. Indeed, B_q--Bbar_q mixing (q=d,s) can be dominated by Z'
exchange, which will affect CP-violating rate asymmetries in B decays. Rare
hadronic B decays can also be affected, while decays involving charged leptons
will be unchanged.Comment: 11 pages, LaTeX, no figure
INTEGRAL/SPI data segmentation to retrieve source intensity variations

The INTEGRAL/SPI, X-gamma-ray spectrometer (20 keV - 8 MeV) is an instrument
for which recovering source intensity variations is not straightforward and can
constitute a difficulty for data analysis. In most cases, determining the
source intensity changes between exposures is largely based on a priori
information. We propose techniques that help to overcome the difficulty related
to source intensity variations, which make this step more rational. In
addition, the constructed "synthetic" light curves should permit us to obtain a
sky model that describes the data better and optimizes the source
signal-to-noise ratios. For this purpose, the time intensity variation of each
source was modeled as a combination of piecewise segments of time during which
a given source exhibits a constant intensity. To optimize the signal-to-noise
ratios, the number of segments was minimized. We present a first method that
takes advantage of previous time series that can be obtained from another
instrument on-board the INTEGRAL observatory. A data segmentation algorithm was
then used to synthesize the time series into segments. The second method no
longer needs external light curves, but solely SPI raw data. For this, we
developed a specific algorithm that involves the SPI transfer function. The
time segmentation algorithms that were developed solve a difficulty inherent to
the SPI instrument, which is the intensity variations of sources between
exposures, and it allows us to obtain more information about the sources'
behavior.Comment: 23 pages, 15 figures. Accepted for publication in A&
Hydrogen lines in LAMOST low resolution spectra of RR Lyrae stars

The LAMOST spectroscopic survey for Galactic structure and evolution has been
in operation since October 2012, following a one-year pilot survey. The pilot
survey produced a data release containing over 600,000 stellar spectra. By
cross-checking with a large time series photometric database of RR Lyrae stars
in high Galactic latitude regions, we found a total number of 157 stars that
have been observed with LAMOST. In this sample, we successfully captured three
RR Lyrae stars in the fast expansion phase, all of them showing significant
hypersonic shock wave features in the spectra. By fitting the H{\alpha} line
shape, we determine that the emission features seen within the broader
H{\alpha} absorption line suggest hypersonic relative motions in the
atmospheres of these three objects. With a further LAMOST survey of millions of
stars, we will capture a large sample of RR Lyrae stars in their hypersonic
expansion phase, and therefore provide a large database for the study of the
internal structure and pulsation mechanism of RR Lyrae stars.Comment: 17 pages, 3 figures, Accepted by New Astronom
The $k$-in-a-tree problem for graphs of girth at least~$k$

For all integers $k\geq 3$, we give an $O(n^4)$ time algorithm for the
problem whose instance is a graph $G$ of girth at least $k$ together with $k$
vertices and whose question is "Does $G$ contains an induced subgraph
containing the $k$ vertices and isomorphic to a tree?". This directly follows
for $k=3$ from the three-in-a-tree algorithm of Chudnovsky and Seymour and for
$k=4$ from a result of Derhy, Picouleau and Trotignon. Here we solve the
problem for $k\geq 5$. Our algorithm relies on a structural description of
graphs of girth at least $k$ that do not contain an induced tree covering $k$
given vertices ($k\geq 5$)
Basis invariant measure of CP-violation and renormalization

We analyze, in the context of a simple toy model, for which renormalization
schemes the CP-properties of bare Lagrangian and its finite part coincide. We
show that this is the case for the minimal subtraction and on-shell schemes.
The CP-properties of the theory can then be characterized by CP-odd basis
invariants expressed in terms of renormalized masses and couplings. For the
minimal subtraction scheme we furthermore show that in CP-conserving theories
the CP-odd basis invariants are zero at any scale but are not renormalization
group invariant in CP-violating ones.Comment: 5 page
Possible Evidence for Radial Flow of Heavy Mesons in d+Au Collisions

Recent measurements of particle correlations and the spectra of hadrons at
both RHIC and the LHC are suggestive of hydrodynamic behavior in very small
collision systems (p+Pb, d+Au and p+p collisions). The measurements are both
qualitatively and quantitatively similar to what is seen in central heavy ion
collisions where low viscosity hot nuclear matter is formed. While light quarks
and gluons are thought to make up the bulk matter, one of the most surprising
results in heavy ion collisions is that charm quarks also have a large $v_2$,
suggesting that they too participate in the matter. Measurements of the
transverse momentum spectra of electrons from the decay of $D$ and $B$ mesons
in d+Au show an enhancement in central collisions relative to p+p. We employ
the blast-wave model to determine if the flow of heavy quarks in d+Au and p+Pb
data is able to explain the enhancement observed in the data. We find a
reasonable description of the data with blast-wave parameters extracted from
fits to the light hadron spectra, suggesting hydrodynamics as a possible
explanation.Comment: final published versio
Cosmic Ray acceleration and Balmer emission from RCW 86 (G315.4-2.3)

Context. Observation of Balmer lines from the region around the forward shock
of supernova remnants (SNR) may provide valuable information on the shock
dynamics and the efficiency of particle acceleration at the shock.
  Aims. We calculated the Balmer line emission and the shape of the broad
Balmer line for parameter values suitable for SNR RCW 86 (G315.4-2.3) as a
function of the cosmic-ray (CR) acceleration efficiency and of the level of
thermal equilibration between electrons and protons behind the shock. This
calculation aims at using the width of the broad Balmer-line emission to infer
the CR acceleration efficiency in this remnant.
  Methods. We used the recently developed nonlinear theory of diffusive
shock-acceleration in the presence of neutrals. The semianalytical approach we
developed includes a description of magnetic field amplification as due to
resonant streaming instability, the dynamical reaction of accelerated particles
and the turbulent magnetic field on the shock, and all channels of interaction
between neutral hydrogen atoms and background ions that are relevant for the
shock dynamics.
  Results. We derive the CR acceleration efficiency in the SNR RCW 86 from the
Balmer emission. Since our calculation used recent measurements of the shock
proper motion, the results depend on the assumed distance to Earth. For a
distance of 2 kpc the measured width of the broad Balmer line is compatible
with the absence of CR acceleration. For a distance of 2.5 kpc, which is a
widely used value in current literature, a CR acceleration efficiency of 5-30%
is obtained, depending upon the electron-ion equilibration and the ionization
fraction upstream of the shock. By combining information on Balmer emission
with the measured value of the downstream electron temperature, we constrain
the CR acceleration efficiency to be ~20%.Comment: 7 pages, 6 figures. Accepted for publication in A&A (minor changes to
  match the published version
The protoplanetary disk of FT Tauri: multi-wavelength data analysis and
  modeling

Investigating the evolution of protoplanetary disks is crucial for our
understanding of star and planet formation. Several theoretical and
observational studies have been performed in the last decades to advance this
knowledge. FT Tauri is a young star in the Taurus star forming region that was
included in a number of spectroscopic and photometric surveys. We investigate
the properties of the star, the circumstellar disk, and the accretion and
ejection processes and propose a consistent gas and dust model also as a
reference for future observational studies. We performed a multi-wavelength
data analysis to derive the basic stellar and disk properties, as well as mass
accretion/outflow rate from TNG-Dolores, WHT-Liris, NOT-Notcam, Keck-Nirspec,
and Herschel-Pacs spectra. From the literature, we compiled a complete Spectral
Energy Distribution. We then performed detailed disk modeling using the MCFOST
and ProDiMo codes. Multi-wavelengths spectroscopic and photometric measurements
were compared with the reddened predictions of the codes in order to constrain
the disk properties. This object can serve as a benchmark for primordial disks
with significant mass accretion rate, high gas content and typical size.Comment: 16 pages, 9 figures, accepted for publication in A&
Study of hadronic event-shape variables in multijet final states in pp
  collisions at sqrt(s) = 7 TeV

Event-shape variables, which are sensitive to perturbative and
nonperturbative aspects of quantum chromodynamic (QCD) interactions, are
studied in multijet events recorded in proton-proton collisions at sqrt(s) = 7
TeV. Events are selected with at least one jet with transverse momentum pt >
110 GeV and pseudorapidity abs(eta) < 2.4, in a data sample corresponding to
integrated luminosities of up to 5 inverse femtobarns. The distributions of
five event-shape variables in various leading jet pt ranges are compared to
predictions from different QCD Monte Carlo event generators.Comment: Replaced with published version. Added journal reference and DO
Entanglement Entropy of Disjoint Regions in Excited States : An Operator
  Method

We develop the computational method of entanglement entropy based on the idea
that $Tr\rho_{\Omega}^n$ is written as the expectation value of the local
operator, where $\rho_{\Omega}$ is a density matrix of the subsystem $\Omega$.
We apply it to consider the mutual Renyi information
$I^{(n)}(A,B)=S^{(n)}_A+S^{(n)}_B-S^{(n)}_{A\cup B}$ of disjoint compact
spatial regions $A$ and $B$ in the locally excited states defined by acting the
local operators at $A$ and $B$ on the vacuum of a $(d+1)$-dimensional field
theory, in the limit when the separation $r$ between $A$ and $B$ is much
greater than their sizes $R_{A,B}$. For the general QFT which has a mass gap,
we compute $I^{(n)}(A,B)$ explicitly and find that this result is interpreted
in terms of an entangled state in quantum mechanics. For a free massless scalar
field, we show that for some classes of excited states,
$I^{(n)}(A,B)-I^{(n)}(A,B)|_{r \rightarrow \infty} =C^{(n)}_{AB}/r^{\alpha
(d-1)}$ where $\alpha=1$ or 2 which is determined by the property of the local
operators under the transformation $\phi \rightarrow -\phi$ and $\alpha=2$ for
the vacuum state. We give a method to compute $C^{(2)}_{AB}$ systematically.Comment: 22 pages; v3, typos corrected, published versio
Long-term monitoring of PKS 2155$-$304 with ATOM and H.E.S.S.:
  investigation of optical/$\gamma$-ray correlations in different spectral
  states

In this paper we report on the analysis of all the available optical and very
high-energy $\gamma$-ray ($>$200 GeV) data for the BL Lac object PKS
2155$-$304, collected simultaneously with the ATOM and H.E.S.S. telescopes from
2007 until 2009. This study also includes X-ray (RXTE, Swift) and high-energy
$\gamma$-ray (Fermi-LAT) data. During the period analysed, the source was
transitioning from its flaring to quiescent optical states,and was
characterized by only moderate flux changes at different wavelengths on the
timescales of days and months. A flattening of the optical continuum with an
increasing optical flux can be noted in the collected dataset, but only
occasionally and only at higher flux levels. We did not find any universal
relation between the very high-energy $\gamma$-ray and optical flux changes on
the timescales from days and weeks up to several years. On the other hand, we
noted that at higher flux levels the source can follow two distinct tracks in
the optical flux-colour diagrams, which seem to be related to distinct
$\gamma$-ray states of the blazar. The obtained results therefore indicate a
complex scaling between the optical and $\gamma$-ray emission of PKS
2155$-$304, with different correlation patterns holding at different epochs,
and a $\gamma$-ray flux depending on the combination of an optical flux and
colour rather than a flux alone.Comment: 10 pages, 5 figures, Accepted for publication in Astronomy &
  Astrophysic