245 research outputs found
Measuring beta_s with Bs -> K0(*) K0bar(*) -- a Reappraisal
The Bs-Bsbar mixing phase, beta_s, can be extracted from Bs -> K0(*)
K0bar(*), but there is a theoretical error if the second amplitude, Vub* Vus
P'uc, is non-negligible. Ciuchini, Pierini and Silvestrini (CPS) have suggested
measuring Puc in Bd -> K0(*) K0bar(*), and relating it to P'uc using SU(3). For
their choice of the direct and indirect CP asymmetries in Bd -> K0(*) K0bar(*),
they find that the error on beta_s is very small, even allowing for 100% SU(3)
breaking. In this paper, we re-examine the CPS method, allowing for a large
range of the Bd -> K0(*) K0bar(*) observables. We find that the theoretical
error in the extraction of beta_s can be quite large, up to 18 degrees. This
problem can be ameliorated if the value of SU(3) breaking were known, and we
discuss different ways, both experimental and theoretical, of determining this
quantity.Comment: 16 pages, 5 figures, LaTeX. References added, text slightly modified,
analysis and conclusions unchange
The B-->pi K Puzzle and Supersymmetry
At present, there are discrepancies between the measurements of several
observables in B-->pi K decays and the predictions of the standard model (the
``B-->pi K puzzle''). Although the effect is not yet statistically significant
-- it is at the level of \gsim 3\sigma -- it does hint at the presence of new
physics. In this paper, we explore whether supersymmetry (SUSY) can explain the
B-->pi K puzzle. In particular, we consider the SUSY model of Grossman, Neubert
and Kagan (GNK). We find that it is extremely unlikely that GNK explains the
B-->pi K data. We also find a similar conclusion in many other models of SUSY.
And there are serious criticisms of the two SUSY models that do reproduce the
B-->pi K data. If the B-->pi K puzzle remains, it could pose a problem for SUSY
models.Comment: 14 pages, 2 figures; added reference
Messages in Paint: An archaeometric analysis of pigment use in Aboriginal Australia focusing on the production of rock art
Anthropogenically modified pigments are held to be some of the earliest, most unambiguous and persistent evidence for behavioural modernity, frequently (and often tenuously) invoked as material expression of symbolic thought and action. Recent finds, increases in the sophistication of analytic techniques and theoretical frameworks have renewed interest in ochre, reflected by a spike in actualistic studies, investigations of pigment morphology and geochemistry. Archaeological studies continue a bias towards Pleistocene pigments, while archaeometric research continues to focus on ochre from known source locations, and in Australia, ethnographically documented mines. Here I take a different tack, targeting Holocene ochres, focusing on pigments with at least one known, indisputably symbolic function- the production of rock art. As part of the physical and metaphorical (cultural) landscape, rock art offers a unique pigment archive as it remains in the location in which it was created. A decade since the first published application of portable X-ray Fluorescence (pXRF) to rock art there has been an absence of critical scrutiny and methodological development. Aiming to redress this, I use conventional and Synchrotron X-ray Diffraction, Micro Computed Tomography and Scanning Electron Microscopy to explain and evaluate pXRF. I develop novel methods of using geochemical data to identify paint mineralogy (including differentiating between paints of the same colour), recognise the chemical signatures of taphonomy and compare ochres from excavated contexts with rock art. Interpreting the resultant elemental profiles relies on understanding the complex taphonomy of pigments and the chemical expression of non-cultural phenomena, something not adequately addressed previously. This work therefore offers a non-invasive means by which large scale studies of archaeological pigments can be undertaken
B -> phi K*, B -> phi Ks and New Physics
We consider the new-physics (NP) solution to the polarization puzzle in B ->
phi K* decays. We note that any such solution must reproduce the data in B ->
phi Ks, where there are disagreements with the standard model in CP-asymmetry
measurements. We examine 10 NP operators, of S/P, V/A and T variety. We find
that, as long as B -> phi Ks exhibits large CP-violating effects, no single
operator can explain the observations in both B -> phi K* and B -> phi Ks. For
2-NP-operator solutions, there are four possibilities, all of S/P type, which
are presently allowed. We discuss ways of distinguishing among these solutions
in the future. Models which contain only V/A operators, such as those with
supersymmetry or extra Z' bosons, cannot explain both B -> phi Ks and B -> phi
K* data. On the other hand, the two-Higgs-doublet model, which has only S/P
operators, is favored.}Comment: 16 pages, late
Patterns of New Physics in B Decays
We show that any new physics (NP) which affects B decays with penguin
contributions can be absorbed by redefinitions of the standard-model (SM)
diagrammatic amplitudes. Hence, there are no clean signals of NP in such decays
unless there is an accurate theoretical estimate of parameters or a justifiable
approximation can be made. In all decays with penguin contributions, NP
simultaneously affects pairs of diagrams. The evidence for a large C' from fits
to B-> pi K data is naturally explained if NP contributes to P_EW, since NP
affects the P_EW and C' diagrams as a pair. The weak phase gamma measured in
B-> pi K decays will always agree with its SM value even in the presence of NP,
if the NP contributes in such a way that the amplitudes retain the SM form
after suitable redefinitions.Comment: 4 pages, revtex, no figures; Several changes made to highlight
results obtaine
A Holocene sequence from Walufeni Cave, Southern Highlands Province, and its implications for the settlement of the Great Papuan Plateau, Papua New Guinea
This paper presents preliminary results from the 2019 excavations at Walufeni Cave, at the eastern end of the Great Papuan Plateau (GPP) in western Papua New Guinea. Preliminary dating and analysis of the unfinished excavations at Walufeni Cave span the Holocene and probably continue into the Late Pleistocene, confirming the presence of people on the Plateau from at least the Early Holocene and potentially much earlier. The data presented here offer a site-specific model of early intensive site use from at least 10,000 years ago, then ephemeral use, followed by a sustained Late Holocene occupation. Although there are significant changes in the quantity of material discard over time, there is little evidence for significant change in the subsistence base or technology, reflecting a degree of relative homogeneity until the Late Holocene, when we see the introduction of pig, a change of focus in the plant economy and the presence of marine shell from the southern coast
Alien Hand, Restless Brain: Salience Network and Interhemispheric Connectivity Disruption Parallel Emergence and Extinction of Diagonistic Dyspraxia
International audienceDiagonistic dyspraxia (DD) is by far the most spectacular manifestation reported by sufferers of acute corpus callosum (CC) injury (so-called "split-brain"). In this form of alien hand syndrome, one hand acts at cross purposes with the other "against the patient's will". Although recent models view DD as a disorder of motor control, there is still little information regarding its neural underpinnings, due to widespread connectivity changes produced by CC insult, and the obstacle that non-volitional movements represent for task-based functional neuroimaging studies. Here, we studied patient AM, the first report of DD in patient with complete developmental CC agenesis. This unique case also offers the opportunity to study the resting-state connectomics of DD in the absence of diffuse changes subsequent to CC injury or surgery. AM developed DD following status epilepticus (SE) which resolved over a 2-year period. Whole brain functional connectivity (FC) was compared (Crawford-Howell [CH]) to 16 controls during the period of acute DD symptoms (Time 1) and after remission (Time 2). Whole brain graph theoretical models were also constructed and topological efficiency examined. At Time 1, disrupted FC was observed in inter-hemispheric and intra-hemispheric right edges, involving frontal superior and midline structures. Graph analysis indicated disruption of the efficiency of salience and right frontoparietal (FP) networks. At Time 2, after remission of diagnostic dyspraxia symptoms, FC and salience network changes had resolved. In sum, longitudinal analysis of connectivity in AM indicates that DD behaviors could result from disruption of systems that support the experience and control of volitional movements and the ability to generate appropriate behavioral responses to salient stimuli. This also raises the possibility that changes to large-scale functional architecture revealed by resting-state functional magnetic resonance imaging (fMRI) (rs-fMRI) may provide relevant information on the evolution of behavioral syndromes in addition to that provided by structural and task-based functional imaging
A diverse Pleistocene marsupial trackway assemblage from the Victorian Volcanic Plains, Australia
A diverse assemblage of late Pleistocene marsupial trackways on a lake bed in south-western Victoria provides the first information relating to the gaits and morphology of several megafaunal species, and represents the most speciose and best preserved megafaunal footprint site in Australia. The 60-110 ka volcaniclastic lacustrine sedimentary rocks preserve trackways of the diprotodontid Diprotodon optatum, a macropodid (probably Protemnodon sp.) and a large vombatid (perhaps Ramsayia magna or '. Phascolomys' medius) and possible prints of the marsupial lion, Thylacoleo carnifex. The footprints were imprinted within a short time period, demonstrating the association of the taxa present, rather than the time-averaged accumulations usually observed in skeletal fossil deposits. Individual manus and pes prints are distinguishable in some trackways, and in many cases some digital pad morphology is also present. Several parameters traditionally used to differentiate ichnotaxa, including trackway gauge and the degree of print in-turning relative to the midline, are shown to be subject to significant intraspecific variation in marsupials. Sexual dimorphism in the trackway proportions of Diprotodon, and its potential for occurrence in all large bodied, quadrupedal marsupials, is identified here for the first time
A reassessment of the early archaeological record at Leang Burung 2, a Late Pleistocene rock-shelter site on the Indonesian island of Sulawesi
This paper presents a reassessment of the archaeological record at Leang Burung 2, a key early human occupation site in the Late Pleistocene of Southeast Asia. Excavated originally by Ian Glover in 1975, this limestone rock-shelter in the Maros karsts of Sulawesi, Indonesia, has long held significance in our understanding of early human dispersals into ‘Wallacea’, the vast zone of oceanic islands between continental Asia and Australia. We present new stratigraphic information and dating evidence from Leang Burung 2 collected during the course of our excavations at this site in 2007 and 2011–13. Our findings suggest that the classic Late Pleistocene modern human occupation sequence identified previously at Leang Burung 2, and proposed to span around 31,000 to 19,000 conventional 14C years BP (~35–24 ka cal BP), may actually represent an amalgam of reworked archaeological materials. Sources for cultural materials of mixed ages comprise breccias from the rear wall of the rock-shelter–remnants of older, eroded deposits dated to 35–23 ka cal BP–and cultural remains of early Holocene antiquity. Below the upper levels affected by the mass loss of Late Pleistocene deposits, our deep-trench excavations uncovered evidence for an earlier hominin presence at the site. These findings include fossils of now-extinct proboscideans and other ‘megafauna’ in stratified context, as well as a cobble-based stone artifact technology comparable to that produced by late Middle Pleistocene hominins elsewhere on Sulawesi
Bioavailable soil and rock strontium isotope data from Israel
Strontium isotope ratios (87Sr / 86Sr) of biogenic material such as bones and teeth reflect the local sources of strontium ingested as food and drink during their formation. This has led to the use of strontium isotope ratios as a geochemical tracer in a wide range of fields including archaeology, ecology, food studies and forensic sciences. In order to utilise strontium as a geochemical tracer, baseline data of bioavailable 87Sr / 86Sr in the region of interest are required, and a growing number of studies have developed reference maps for this purpose in various geographic regions, and over varying scales. This study presents a new data set of bioavailable strontium isotope ratios from rock and soil samples across Israel, as well as from sediment layers from seven key archaeological sites. This data set may be viewed and accessed both in an Open Science Framework repository (https://doi.org/10.17605/OSF.IO/XKJ5Y, Moffat et al., 2020) or via the IRHUM (Isotopic Reconstruction of Human Migration) database.This research has been supported by the Australian Research Council (grant nos. DP0664144, DP110101417,
and DE160100703) and the Flinders University (Research Investment Fund Grant)
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